1502 PROPOSED RULE MAKING

eral Regulations. With respect to carbon principally reactive hydrocarbons, and ENVIRONMENTAL PROTECTION monoxide, hydrocarbons, photochemical nitrogen oxides are exposed to sunlight, oxidants, and nitrogen oxides, adverse Photochemical oxidants cause irritation AGENCY welfare effects have not been -observed of the mucous membranes, damage to to occur at levels below the levels of the vegetation, and deterioration of mate- [42 CFR Part 410 ] proposed primary standards. For each of rials. They affect the clearance mecha- NATIONAL PRIMARY AND SECOND- those pollutants, therefore, the proposed nism of the lungs and alter resistance secondary standard has been specified at to respiratory bacterial infection. Photo- ARY AMBIENT AIR QUALITY the level of the proposed primary stand- chemical oxidants have been implicated STANDARDS ard. as accelerators in the aging process. Notice of Proposed Standards for Sul- The characteristics of the six air pol- Detailed information on photochemi- fur Oxides, Particulate Matter, lutants named above are, briefly, as cal oxidants Is presented in the docu- Car- follows:. ment "Air Quality Criteria for Photo- bon Monoxide, Photochemical Oxi- Sulfur oxides. Sulfur oxides, which chemical Oxidants" (NAPCA Publication dants, Hydrocarbons, and Nitrogen arise primarily from the combustion of No. AP-63) which provided a basis for Oxides sulfur-containing fossil fuels, are preva- the development of the standards set lent in polluted Section 109 of the Clean Air air. Their presence in the forth below. Act, as ambient air has been associated with Hydrocarbons. Hydrocarbons are pri- amended December 31, 1970 (Public Law a. variety of respiratory diseases and In- 91-640), directs the Administrator of the marily associated, with the procesing, creased mortality rates. They represent marketing, and use of petroleum prod- Environmental Protection Agency to a significant economic burden and have publish, no later than January 30, 1971, ucts and are widely prevalent in the am- proposed national primary and second- a nuisance impact. Sulfur dioxide Is an bient air. They constitute the principal indicator of the presence of sulfur oxides portion of these volatile reactive organic ary ambient air quality standards for in each pollutant for which air quality cri- polluted air and is an important index substances in the atmosphere which are teria were issued prior to enactment of of the effects which have been associated the precursors of other compounds the amendments. The section also pro- with these contaminants. formed in the atmospheric photochemi- vides that after December 31, 1970, the Detailed information on sulfur oxides cal system and which result in the mani- Administrator shall, simultaneously with is presented in thd document "Air Quality festations of photochemical smog. Meth- his Criteria for Sulfur Oxides" (NAPCA Pub- ane, which occurs naturally in the at- issuance of air quality criteria and mosphere information on control techniques for a lication No. AP-50), which provided a at relatively high levels, is not pollutant, publish proposed national basis for the development of the stand- considered to be involved in the photo- primary and secondary ards set forth below. chemical reactions. The only direct effect ambient air qual- attributable to ambient ity standards for that pollutant. Pri- Particulatematter. Particulate matter levels of hydro- mary refers to any matter dispersed in the carbons is the vegetation damage from ambient air quality standards de- ethylene. fine levels of air quality which the Ad- air, whether solid or liquid, in which the ministrator judges individual particles are larger than small Detailed information on hydrocarbons necessary, based on is presented in the document "Air the air quality criteria and allowing an molecules but smaller than 500 microns. Qual- adequate margin of safety, to protect Particles smaller than 1 micron in ity Criteria for Hydrocarbons" (NAPCA the Publication No. AP-64) public health. Secondary ambient air diameter originate in the atmosphere which provided a principally through condensation and basis for the development of the stand- quality standards define levels of air ards set forth below. quality which the Administrator judges combustion, while larger particles arise necessary, principally from erosion and abrasion. Nitrogen oxides. Nitrogen oxides result based on the air quality cri- from the teria to protect the public welfare from Particulate matter of technological fixation of nitrogen and oxygen any origin is pervasive in its distribution and at high temperatures and are typically known or anticipated adverse effects associated with of an air pollutant. is associated with a variety of adverse combustion processes. effects on public health and welfare. Par- They are also related to certain chemical Prior to December 31, 1970, air quality processes. The principal nitrogen oxide criteria had been issued for these five ticulate matter in the respiratory tract may produce injury by itself, or it may formed- in the combustion process is pollutants: Sulfur oxides and particu- nitric oxide. This compound has not been late matter (34 P.R. 1988); carbon mon- act in conjunction with gases, altering their sites or their mode of action. Parti- shown to have health or welfare effects oxide, photochemical oxidants, and hy- at present or anticipated ambient con- drocarbons (35 F.R. 4768). The Admin- cles cleared from the respiratory tract by transfer to the lymph, blood, or gastro- centrations. However, there are several istrator has determined that nitrogen atmospheric reactions which lead to the oxides, which are present in the ambient intestinal tract may produce effects elsewhere in the body. oxidation of nitric oxide to nitrogen di- air as a result of emissions from numer- oxide, and the presence of nitrogen di- ous and diverse mobile and stationary Detailed information on particulate matter is presented in the document oxide in ambient air has been associated sources and for which air quality criteria with a variety of respiratory diseases. were not issued prior to December 31, "Air Quality Criteria for Particulate Matter" (NAPCA Publication No. AP- Nitrogen dioxide is essential to the pro- 1970, are air pollutants which adversely duction of photochemical smog. At affect public health and welfare. In ac- 49), which provided a basis for the devel- opment of the standards set forth below. higher concentrations, Its presence has cordance with section 108 of the Act, been implicated in the corrosion of elec- the following are published in a notice Carbon monoxide. Carbon monoxide is trical components as well as vegetation in this issue of the FEDERAL REGISTER: the product of incomplete combustion of damage. 1. A list of air pollutants, required to carbonaceous fuels and Is widely preva- Detailed lent in ambient air. It is absorbed information on nitrogen ox- be published no later-than January 30, ides Is presented In the document "Air 1971, which identifies nitrogen oxides as through the lungs and reacts primarily with the hemoglobin in red blood cells. Quality Criteria for Nitrogen OxIdes" air pollutants for which air quality cri- (EPA Publication No. AP-84) which pro- terla will be issued and for which na- It decreases the oxygen carrying capac- ity of the blood vided a basis for the development of the tional primary and secondary ambient and reduces the avail- standards set forth below. air quality standards will be promulgated, ability of oxygen transported to vital tis- sues by the blood. The air quality criteria documents re- and ferred to Detailed information on carbon men-, above are available from the 2. An announcement of the issuance of Superintendent of Documents, Govern- air quality criteria for nitrogen oxides. oxide is presented in the document "'Air Quality Criteria for ment Printing Office, Washington, D.C. Pursuant to section 109 of the Clean Carbon Monoxide" 20402. Prices are as follows: (NAPCA Publication No. AP-62), which Air Act, notice is hereby given of pro- Sulfur oxides (AP-5O) ------01.29 posed national primary provided a basis for the development of and secondary the standards set forth below. Particulate matter (AP-49) ------. 1,75 ambient air quality Carbon monoxido (AP-62) ------1. 0 standards as set forth Photochemical oxidants. Photochemi- in Part 410 below, which would be added Hydrocarbons (AP-4) ------1. 5 cal oxidants are produced in the atmos- Photochemical oxidants (AP-03) ..- 1. '5 to Chapter IV of Title 42, Code of Fed- phere when reactive organic substances, Nitrogen oxides (AP-84) ------. 1,0 FEDERAL REGISTER, VOL 36, NO. 21-SATURDAY, JANUARY 30, 1971 PROPOSED RULE MAKING 1503

Orders for any of the above documents Appendix F-Method for Determination or (a) 60 micrograms per cubic meter- Nitrogen Dioxide in the Atmosphere annual arithmetic mean. should be accompanied by a check or (24-Hour Sampling Method). money order payable to the Superin- (b) 260 micrograms per cubic meter- tendent of Documents. § 410.1 Definitions. maximum 24-hour concentration not to Copies .of the summary-and-conclu- (a) As used in this part, all terms not be exceeded more than once per year. sions chapter of each air quality criteria defined herein shall have the meaning § 410.6 National primary ambient air document are available free of charge given them by the Act. quality standards for particulate from the Air Pollution Control Office, (b) "Act" means the Clean Air Act, mnatter. Environmental Protection Agency;,600 as amended (Public Law 91-604). At- The national primary ambient air Fishers Lane, -Rockville, MD 20852, (c) "Agency" means the Environmen- quality standards for particulate mat- tention: Publications Section. tal Protection Agency. ter, measured by the high-volume sam- Interested persons may submit written (d) "Administrator" means the Ad- Office pling method, as described n Appendix comments in triplicate to the Qf ministrator of the Environmental Pro- B to this part, are: the Acting Commissioner, Air Pollution tection Agency. Control Office, Environmental Protection (a) 75 micrograms per cubic meter- Agency, Parklawn Building, Room 17-59, § 410.2 Scope. annual geometric mean. 5600 Fishers Lane, Rockville, MD 20852. (a) National primary and secondary Wb)260 micrograms per cubic meter- All relevant comments received not later ambient air quality standards under sec- maximum 24-hour concentration not to than 45 days after the publication of tion 109 of the Act are set forth in this be exceeded more than once per year. this proposal will be considered. The part. § 410.7 National secondary ambient air standards, modified as the Administrator (b) National primary ambient air quality standards for particulate deems appropriate after consideration of quality standards define levels of air mantter. be promulgated no later comments, will quality which the Administrator Judges The national secondary ambient air than 90 days from the date of publica- are necessary, with an adequate margin this notice, as required by the quality standards for particulate matter, tion of of safety, to protect the public health. measured by the high-volume sampling Act. National secondary ambient air quality is method, as described in Appendix B to This notice of proposed rulemaking standards define levels of air quality this part, are: Issued under the authority of section 4, which the Administrator judges neces- Public Law 91-601, 84 Stat. 1679. from (a) 60 micrograms per cubic meter- sary to protect the public welfare annual geometric mean. Dated: January 25, 1971. any known or anticipated adverse effects of a pollutant. Such standards are sub- Wb)150 micrograms per cubic meter- WrILrAx D. RucsKmsiaus, ject to revision, and additional primary maximum 24-hour concentration not to Administrator. and secondary standards may be promul- be exceeded more than once per year. A new Part 410 would be added to gated as the Administrator deems neces- § 410.8 National primary and secondary Chapter IV, Title 42, Code of Federal sary to protect the public health and ambient air quality standards for Regulations, as follows: welfare. carbon monoxide. (c) The promulgation of national pri- The national primary and secondary PART 410-NATIONAL PRIMARY "mary and secondary ambient air quality ambient air quality standards for carbon AND SECONDARY AMBIENT AIR standards shall not be considered in any monoxide, measured by the nondispersive QUALITY STANDARDS manner to allow significant deterioration infrared method, as described in Ap- Sec. of existing air quality in any portion of pendix C to this part or equivalent 410.1 Definitions. any State. method, are: 410.2 Scope. (d) The proposal, promulgation, or re- (a) 10 milligrams per cubic meter- 41063 Measurement corrections. vision of national primary and secondary maximum 8-hour concentration not to 410.4 National primary ambient air qual- standards shall not ity standards for sulfur oxides ambient air quality be exceeded more than once per year. (sulfur dioxide). prohibit any State from establishing am- (b) 15 milligrams per cubic meter- 410.5 National secondary ambient air qual- bient air quality standards for that State maximum 1-hour concentration not to be ity standards for sulfur oxides or any portion thereof which are more exceeded more than once per year. (sulfur dipxlde). stringent than the national standards. 410.6 National primary ambient air quality § 410.9 National primary and secondary standards for particulate matter. § 410.3 Measurement corrections. ambient air quality standards for 110.7 National secondary ambient air qual- All measurements of air quality are photochemical oxidants. ity standards for particulate mat- corrected to a reference temperature of The national primary and secondary ter. C. and to a reference pressure of 760 410.8 National primary and secondary am- 200 ambient air quality standards for photo- bient air quality standards for car- millimeters of mercury. chemical oxidants, measured by a method bon monoxide. § 410.4- National primary ambient air referenced to the neutral-buffered I per- 410.9 National primary and secondary am- quality standards for sulfur oxides cent potassium iodide colorimeteric tech- bient air quality standards for (sulfur dioxide). nique and corrected for interferences due photochemlcal oxidants. to nitrogen oxides and sulfur dioxide, as 410.10 National primary and secondary am.- The national primary ambient air in Appendix D to this part, are: blent air quality standards for quality standards for sulfur oxides, described hydrocarbons. 125 micrograms per cubic meter-maxi- measured as sulfur dioxide by a method concentration not to be ex- 410.11 National primary and secondary am- method, mum 1-hour blent air quality standards for ni- referenced to the pararosaniline ceeded more than once per year. trogen dioxide. as described in Appendix A to this part, Appendix A-Method for Determination are: § 410.10 National primary and second- of Sulfur Dioxide (Pararosanhine (a) 80 micrograms per cubic meter- ary ambient air quality standards for Method). annual arithmetic mean. hydrocarbons. Appendix B-Procedure for Determination of (b) 365 micrograms per cubic meter- The national primary and secondary Suspended Particulates (High Vol- for hydro- ume Method). maximum 24-hour concentration not to ambient air quality standards Appendix C-Method for Continuous Meas- be exceeded more than once per year. carbons, measured by the flame ioniza- urement of Carbon Monoxide (Ion- tion detection method, as described in dispersive Infrared Spectrometry). § 410.5 National secondary ambient air Appendix E to this part (Part 1), and Appendix D-Method for Determination of quality standards for sulfur oxides corrected for methane in the sampled Oxidants (Neutral Buffered Potas- (sulfur dioxide). air by the procedures described In Ap- sium Iodide Method). pendix E to this part, or by an equiva- 1: Method for Continuous The national secondary ambient air Appendix B-Part quality standards for sulfur oxides, meas- lent procedure, are: 125 micrograms per Measurement of Hydrocarbons 3-hour concen- (Flame Ionl2ation Method). ured as sulfur dioxide by a method ref- cubic meter-maximum Part 2: Method for Measurement of erenced to the pararosaniline method, as tratlon (6 to 9 am.) not to be exceeded Methane. described In Appendix A to this part, are: more than once per year.

FEDERAL REGISTER, VOL 36, NO. 21-SATURDAY, JANUARY 30, 1971 PROPOSED RULE MAKING

Air Flowmeter or Volume Meter- 6.2.2 Formaldehyde (0.2 percent)-Dilute 5.1.3 5 ml. formaldehyde solution (3G-38 percent) § 410.11 National primary and second- Capable of measuring air flow within ±h2 with distilled water. Prepare ary ambient air quality standards for wet or dry gas meter, with ma- to 1,000 mil. percent. A daily. nitrogen dioide. a specially calibrated rotameter, nometer, or 6.2.3 Stock lodino Solution (0.1 N).-)lpco A 22-gauge hypodermic The national primary and secondary is satisfactory. g. iodine In a 250-ml. beaker; add 40 g. needle 1-in. long may be used as a critical 12.7 standards for nitro- potassium Iodide and 25 MIl. water. Stir until ambient air quality orifice to give a flow of about 1 liter/min. if a method all is dissolved, then dilute to 1,000 nil, with gen dioxide, measured by been calibrated In the system. Use it has first distilled water. referenced to the 24-hour sampling a membrane filter to protect the needle. as described in Appendix F to 6.2.4 Iodine Solution (0.01 N)-Preparo method, 5.2 Analysis. 0.01 N iodine solution by di- 5.2.1 Spectrophotometer-Suitable for approximately this part, are: 50 ml. of stock solution to 600 ml. measurement of absorbance at 548 nm. with luting (a) 100 micrograms per cubic meter- water. effective spectral band of less than 15 nm. with distilled annual arithmetic mean. an Starch Indicator Solutlon-TrItu- blank problems may occur with 6.2.5 micrograms per cubic meter- Reagent and 0.002 g. merouri (b) 250 having greater spectral rate 0.4 g. soluble starch not to be ex- spectrophotometers (preservative) with a little water, and 24-hour concentration The wavelength calibration of iodide band width. to 200 ml. boiling vm ter. ceeded more than once per year. 'the instrument should be verified. If trans- add the paste slowly the solution is clear; mittance is measured, this can be converted Continue boiling until ApPrNDix A to a glazs-stoppered bottle. to absorbance: cool, and transfer PAnr 1-aerHOV FeR DrEa=ATIo5 OF 6..6 Stock Sodium Thiosulfate Solution SULFUR DIoxm. (P1ARAOA ILINE SIETUOD) A = logo (IT) (0.1 N)-Prepare a stock solution by dissolv- .S3U1O) 6. Reagents. 6.1 Sampling. Ing 25 g. sodium thlosulfato (NaZO 1. Principle and applicability of method. ml. freshly boiled, cooled, distilled 6.1.1 Distilled water-Must be free from in 1,000 1.1 Sulfur dioxide is absorbed from air in a g. sodium carbonate to oxidants. water and add 0.1 solution of potassium tetrachloromercurate Allow the solution to stand 1 6.1.2 Absorbing Reagent (0.04 Id Potas- the solution. (TCM). A diohlorosulfitomercurato complex, day before standardizing. To standardize, in the sium Tetrachloromercurate (TCM))-DIs- which resists oxidation by the oxygen accurately weigh, to the neareat 0.1 mg. 1,5 s complex solve 10.86 g. mercuric chloride, 0.066 g. air, is formed.I Once formed, this g. primary standard potassium lodate dried ozone, EDTA (Ethylenediarninetetraacetc acid dl- ° is stable to strong oxidants (eg., and dilute to volume In a 600-ml. sodium salt), and 6.0 g. potassium chloride at 180 C. oxides of nitrogen). a 500 ml. Iodine flask, in water and bring to mark in a 1,000-ml. volumetric flask. To 1.2 The complex is reacted with pararos- pipet 50 mL. of Iodate solution. Add 2 g. flask. (Caution: highly poisonous. aniline and formaldehyde to form in- volumetric Iodide and 10 nil. of 1 N hydro- If spilled on skin, flush off with water im- potassium tensely colored pararosanline methyl suil- the flask. After 5 min- is The pH of this reagent should chloric acid. Stopper fonic acid. The absorbance of the solution mediately.) with stock thlozulfate solution be approximately 4.0, but it has been shown utes, titrate measured spectrophotometrcally. a pale yellow. Add 5 Ml. starch Indicator Concentra- that there is no appreciable difference in col- to 2. Range and sensitivity. 2.1 and complete the titration. Calou- of 25 to lection efficiency over the range of pH 5 to solution tions of sulfur dioxide in the range late the normality of the stock solution. 1,000 ag./m.3 (0.01 to 0.40 p.pm.) can be pH 3.7 The absorbing reagent is normally sta- dis- measured under the conditions given. One ble for 6 months. If a precipitate forms, N= ,IX2.80 to concentrations below 25 card the reagent. can extrapolate of stock thiozulfato rolu- volumes of air, 6.2 Analysis. N=Normallty g./m.3 by sampling larger tion. but only if the absorption efficiency of the 6.2.1 Sulfamlc Acid (0.6 percent)-Dis- acid In 100 Ml. distilled M= Volume of thlosulfate required, ml. particular system is first determined. Higher solve 0.6 g. sulfamie daily. W= Weight of potassium lodate, grams. concentrations can be analyzed by using water. Prepare fresh 'smaller gas samples, a larger collection vol- a suitable aliquot of the collected ume, or 10 (conversion of g. to mag.) X 0.1 (fraction lodato used) sample. 35.67 equivalent weight of potassium lodato 2.2 The lower limit of detection of sulfur dioxide In 10 ml. TC-M is 0.75 pg. (based on twice the standard deviation) representing a concentration of 25 pg./m.' SOs (0.01 p.pam.) 6.2.7 Sodium Thiosulfate Titrant (0.01 32,000 =Mlllequivalent wt., pg. stock thiosulfate A=Volume thloeulfate for blank, ml. in an air sample of 30 liters. N)-Dilute 100 mL. of the dis- B=Volumo thlosulfate for sample, ml 2.3 Beer's Law is followed through the solution to 1,000 ml. with freshly boiled tilled water. N=Normality of thosulfate titrant. working range from 0.0 to 1.0 absorbance standard sulfite solution, Ml, ion in 25 MI. = Normality of Stock Solution 25 =Volume units (0 to 27 pg. of sulfite Normality 0.02 =Dilutlon factor. final solution computed as S%0). X0.100. effects of the stable for 30 days If kept at 3. Interferences. 3.1 The Sulflte Solution for This solution Is 5 have been 6.2.8 Standardized 5* C. (refrigerator). If not kept at 0., principle known Interferences of Working Sulfite-TCO Solu- Interferences by Preparation prepare daily. minimized or eliminated. tion-Dissolve 0.30 g. sodium metabisulfite oxides of nitrogen are eliminated by sulfamc 6.2.10.1 Dye Specifications-Tho pararo- 6 (NaA O, or 0.40 g. sodium sulfite (NaeO.) the following per- acid, a ozone by time-delay, and heavy met- cooled, distilled saniline dye must meat in 500 ml. of recently boiled, formance specifications: (1) The dye must als by EDTA (ethylenediaminetetraacetic (Sulfite solution is unstable; it is phosphoric acid.'4 water. wavelength of maximum absorbanco acid disodium salt) and therefore important to use water of the have a 10 pg. Mln(Il), and when assayed in a buffered solu- At least 60 pg. Fe(III), highest purity to minimize this instability.) at 540 nm. absorbing reageni acetate-acetio acid; (2) 10 pg. Cr(III) in 10 ml. This solution contains the equivalent of 320 tion of 0.1 M sodium In the procedure. No signif- the absorbanco of the reagent blank, which can be tolerated to 400 pg./ml. of SO, The actual concentra- icant interference was found with 10 pg is temperature-sensitive (0.015 absorbanco tion of the solution is determined by adding 0.170 absorb- Cu(I1) and 22 pg.V(V). iodine and back-titrating with stand- unit/* C.), should not exceed and stability. 4.1 excess at 22' 0. with a 1-cm, optical 4. Precision, accuracy, sodium thiosulfate solution. To back- ance unit at the 95 per- ard path length, when the blank Is prepared ac- Relative standard deviation titrate, pipet 50 ml. of the 0.01 N iodine into 4.6 percent for th analytical proce- cent confidence level is each of two 500-ml. iodine flasks (A and B). cording to the prescribed analytical procedure using standard samples. water,. dure and to the specified concentration of the To flask A (blank) add 25 ml. distilled (Scotlon 4.2 After sample collection the solution B (sample) pipet 25 mL sulflte dye; (3) the calibration curve and to flask 8.2.1) should have a slope of 0.030±0.002 are relatively stable. At 250 C. losses of sulftu solution. Stopper the flasks and allow to occur at the rate of 1.5 percent pei absorbance units/ g. SO, at this path length dioxide react for 5 min. Prepare the working sulfite- solution day. When samples are stored at 5* C. for 3( (6.2.9) at the same time iodine when the dye Is pure and the sulilto TCM Solution is properly standardized. days, no detectable losses of sulfur dioxidi solution is added to the flasks. By means of a The presence of EDTA enhances thi 6.2.10.2 Preparation of Stock Solution- occur. buret containing standardized 0.01 N Thlo- (909-100 percent pure) stability of SO, in solution, and the rate o: sulfate, titrate each flask in turn to a pale A specially purified decay is independent of the concentration : solution of pararosaniline, which meets the : yellow. Then add 5 nl. starch solution and SO' above specifications, Is commercially avail- continue the titration until the blue color able in the required 0.20 percent concentra- 5. Apparatus.5.1 Sampling. disappears. If this cannot be obtained, normally usei tion (Heleco*). 5.1.1 Absorber-Absorbers 6.2.9 Working Sulfite-TOM Solution- the stock solution may be prepared by di(- in air pollution sampling are acceptable fo 100 Pipet accurately 2 ml. of the standard solu- solving 0.200 g. of the purified dye in concentrations above 25 pg./m.' (0.01 p.p=m.) acid in a 100 Ml. tion into a 100-ml. volumetric flask and bring ml. of 1 N hydrochloric An all-glass midget impinger, as shown lj glass stoppered graduated cylinder. (Sco to mark with 0.04 M TOM. Calculate the con- Figure 1, Is recommended for 30-minut Scaringelli, et al.' for the purlilcation and dioxide in the working samples. centration of sulfur assay procedures.) 5.1.2 Pump-Capable of maintaining v; solution: 60th and Woodland pg.SO/ml= (A--B) (N) (32,000) XO.02 *Hartmen-Leddon, air pressure differential greater than 0.7 at 25 Avenue, Philadelphia, PA 19143. mosphere at the desired flow rate. FEDERAL REGISTER, VOL 36, NO. 21-SATURDAY, JANUARY 30, 1971 PROPOSED RULE MAKING 1505

6.2.11 Pararozanlfine Rege-t-To a 250- Do not allow the colored colution to stand 0.2 ulfur Dloxfl Concentrtfo--Cm- lvolumetri flasks, add 20 ml. stock para- in the absorbance cells. bcu a film of dye puto the cnconration of sulfur dioxide ia formula: rosaniline solution. Add an additional 0.2 may be deposited. Clean celis with alcohol the Lonlplo by the followinZ, ml. stock solution for each percent the after use. If the temperature of the deter- (A-A.)(1031) (D) stock assays below 100 percent. Then add minations does not differ by more then 2" C. SOS,/ ~(m.== 25 mL 3 A phosphoric acid and dilute to vol- from the calibration temperature (8&2). the V. iume with distilled water. This reagent Is reagent blank should be within 0.03 absorb- A =Sample aborne. stable for at least 9 months. ance unit of the y-interczpt of the calibra. A.=lcareat blank araac. 7. Procedure. 7.1 SZamplIng-Procedures tion curve (82). If the reagent blank differs 163=Converrlon of liters to cubic mete. are described for short term (30 Tain.) and by more than 0.03 abzorbanco unit, from that V-=The camplo volume correctedto 235 C. for long term (24 hours) sampling. One can found in the calibration curve, prepare a and 76 mam. Ha., liter. select different combinations of sampling new curve. 1 rate and time to meet special needs. Fixing 7.22 Abzorbanca Rau -If the abzorb- B= Slope cfllbration- rlibration fac- tor. sample volume at 30 liters maintains linear- once of the sample solution ran[es botnea r-13-f.a.b- ity between absorbance and concentration 1.0 and 2.0. the sample can be diluted 1:1 with Eorbance unit over this dynamic range. a portion of the rcagent blanT: and read curve, aborb- 7.1.1 30-lInute Sampling-Insert a within a few minute. Solutions with higher ance unlts! z. system, absorbance can be diluted up to aixfold with = midget impinger into the sampling 0.2.1 Conversion of j./m. to p.pm-f to the im- the reagent blank In order to obtain on-scalo Figure 1. Add 10 ml. TCM solution dcsired. the concentration of sulfur dioxide for readings within 10 percent of the true ab- pinger. Collect sample at 1 liter/mn. may be calculated a3 p.pm. SO at standard from sorbanco value. 30 -in- Shield the absorbing reagent conditions as follows: direct sunlight during and after sampling by 8. Calibration and efflcfencles. 8.1 Flow- covering' the impinger with aluminum foil, meters and Hypodermic Neefdlc--Callbrato p.p.n. SO%=F. MS0 'X.322 X I0- the actual flowmeters and hypodermlo needle against to prevent deterioration. Record Wezt,P. T. and Gaesee flow rate by a calibrated wet test meter. 10. Bibliography/. 1. " volume of air by multiplying the G. C.. 'Thatlon of Sulfur Dioxide as Sulfito- the time In minutes. Remove and stopper the 89. Calibration Curves. Solution- mercurato llIand Subsequent Colorimetris impinger. If the sample must be stored for 82.1 Procedure with Sulfto 28, keep it at Accurately pipet graduated amounts of the Determtnation". Anal Chem. 1816 (1956). more than a day before analysis, Chemistry." 5* C. in a refrigerator (see 4.2). vwoking sulfite-TCM soDlution (cuch as 0. 2. Epbraims. R- "Inorganic p. 562. Edited by P.C. L. Theme and Robert:% 7.1.2 24 Hour Sampling-Place 15-20 ml. 0.5. 1, 2. 3. and 4 ml.) Into a cerles of 25-ml. flass. Add sufflclent TCM colu- 5th Edition. Inteisclence. (1948). TCM solution in a midget impinger or 50 volumetric 3. R., B.. ml. in a larger Impinger and collect the sam- tion to each flaIr to bring the volume to Lylcz. G. Dowllng. P. and Blan- ple at 0.2 liter/min. for 24 hours. Make approximately 10 ml. Then add the remain- chard. V. 3. "Quantitative Determination of sure no entrainment of solution results with ing reagents as described in 7.2.2. For maxi- Formaldehyde in Parts Per Hundred Million. Level". T. Air. Poll. Cont. the impnger. During collection and storage mum precision use a constant-temperaturo Concentration As protect from direct sunlight. Record the total bath. The temperature of calibration must sco. 15,10o (1905). volume of sample by multiplying the flow be maintained within 41* 0. and in the 4. Scar~nsgelil. F. P.; Sal-n- B. M.. and rate by the time in minutes. If storage is range of 20 to 30" 0. The temperature of Frey, S. A.. "Spectrophotometrlc Determina- necessary, refrigerate at 5' C. (see 4.2). calibration and the temperature of analysL tion of Atmopherlc Sulfur Dloxide, Anal 7.2 Analysis. must be within 2 degree3. Plot the ab.sorbanco Chem. 39. 1703 (19G7). J. B.: E.; 72.1 Sample Preparation-After collec- against the total concentration In pg. SO for 6. Pate. Ammons, B. Swanson, tion, If a precipitate is observed in the sam- the corresponding solution. 'Ih total pg. SO, G. A.; Lodge, J.P., Jr., "Nitrite Interference ple, remove It by contrifugation. in solution equals the concentration of the in Spectrophotometric Determination of At- 7.2.1.1 30-Minute Sample--Transfer the standard (Section 0.2.) in rg. SO,/ml. times mo pheri Sulfur Dioxide". Anal. Chem. ST. sample quantitatively to a 25-ml. volumetric the ml. sulflt* solution added (pg. S0 1 =pg./ 042 (1005). flask; use about 5 ml. distilled -ater for ml. SO:XmL added). A linear relationship 0. Zurlo. IT.and Grlfflnl. A. Lt. 'Mleasure- rinsing. Delay analyses for 20 -ain, to allow should be obtained, and the y-intercept ment of the EO, Content of Air In the Pres- any ozone to decompose. should be within D.02 absorbance unit of the ence of Oxides of Nitrogen and Heavy Mletal s. 7.2.1. 24-Hour Sample-Dilute the entire zero standard azborbance. For maximum pre- Lied. Lavoro. 53, 330 (1962). sample to 25 ml. for the midget Impinger of cislon determine the line of beat fit using 7. Scaringnll. F. P, Elfers, L,, Norris. D. 50 ml. for the larger impinger, with absorbing regression analysis by the method of lenst nd Hochbelcer S., "Enhanced Stability cC solution. Pipet one-tenth of the sample Into squares. Under these conditions the plot need Sulfur Dioxide in Solution". Anal. Cham. 42. a 25 ml. volumetric flask for chemical analy- be determined only once to determine the 1818 (1970). ses. Delay analyses for 20 min. to allow any calibration factor (reciprocal of the slope of 8. Urone. P.; Evans. 3. B.. and Noyes. C. LL ozone to decompose. - the line). (See Section 02.10.1 for speciflca- 1 1!acer Techniquw in Sulfur Dioxide C.:loz1- 7.2.2 Determination-For each set of de- tions on the slope of the calibration curve.) metric and Conductlomatric WethodJ". AnaL terminations prepare a reagent blank by add- This calibration factor can be uced for cal- Chem 37. U04 (11)G,5). Ing 10 ml. unexposed T=ia solution to a 25 culating results provided ther are no rndi- 0. Brstrmoi. C. E, '"he Absorption of Sul- ml. volumetric flask. Prepare a control solu- cal changes In temperature or pH. At leat fur Dioxide at Low Concentrations (p.p=m) tion by adding 2 mL of working sulflte-'TC one control sample containing a known con- Studied by an sotoplc Tracer Method". In- solution. and 8ml. TOM solution to a 25-ml. centration of SO for each series of deter- tern. J.Air Vater Poll. 9.33 (1965). volumetric flask. To each flask containing minations, is recommended to Insure the 10. OlZaage, A. 11 end Ortman, G. C. "Pri- either sample, control solution or reagent reliability of this factor. mary Standards for Trace Gas Analysis". blank, add 1 ml, 0.6 percent sulfamic acid 8.2. Procedure with S02 Ga o-Se Part 2. Ana. Chem- 38,7C3 (10M). and-allow to react 10 ain, to destroy Z.3 Sampling Efliclency--Collection effi- 1L Scarinzelll. P. P.: Prey. S.A.. and Saltz- clency is above 98 percent; efficiency may fall man. B. E, "Evaluation of Teflon Permeation the nitrite from oxides of nitrogen. Ac- Tubes for Use with Sulfur Dioxide". Amer. curately pipet in 2 ml. 0.2 percent formal- off, however, at concentrations below 25 Ind.Hygiene AS=ac. 23,270 (1"o'I). dehyde solution, then 5 ml. pararosaniline pag./mA'8 12. Thomas. LL D. and Amtowar R. E., solution. Start a laboratory timer that has 9. Calculations.9.1 Conversion of Volume-- "Gaz Dilution Apparatus for Preparing Re- been set for 30 minutes. Bring all flasks to Convert the volume of air sampled to the producible Dynamic Gas Mixtures In any D.- volume with freshly boiled and cooled dis- volume at standard conditions of 25 0. sired Concentrtion and Complexity". J.Air 10, 818 tilled water and mix thoroughly. After S0 160 mm. Hg.: Poll. Cont. Asacc. (1965). 13. Lodge, J. P. Jr. Pate, J. B.. Ammos. min. and before 60 min., determine the ob- P 298 B. , and Swnon. 0. A.. Ilse of Hypoder- sorbances of the sample, reagent blank and V,=VX-X- rate Needle3 as Critical Orilaces In Air Sam- the control solution at 548 nra. using 1-cm. 760 (t+273) plLng." 3. Air Poll. Cont. Amsoc. 16, 19T (196). V.=Volume of air at 25' 0. end '10 mm. optical path length cells. Use distilled water, Hg. not the .reagent blank, as the reference. V=Volume of air sampled, liters. A. Gwsou calibration. Certified permea- (NoTE: This is Important because of the color P=Barometrio preruro, mm. Hg. tion tubes containing liquified sulfur dliox- sensitivity of the reagent blank to tempera- t=Temperaturo of air sample. 0. ide ara available from the National Bureau ture changes which can be Induced in the Ordinarily, the correction for presuro is of Standards and may be used for gaseous cell compartment of a spectrophotometer.)' slight and may be neglected. callbratton.

FEDERAl REGISTER, VOL 36, WO. 21-SATURDAY, JANUARY 30, 1971 1506 PROPOSED RULE MAKING

(1) Commercially available permeation B. Procedure for preparing calibration tion efficiency of the sampling oystem, tubes* may be calibrated as follows: Obtain curves. One can prepare a multitude of Actually, the standard concentrations of 25 an FEP TefionR permeation tube that emits curves by selecting different combinations Ag./mr. and below of sulfur dioxide are sulfur dioxide at a rate of 0.2 to 0.4 pg./ of sampling rate and sampling time. (Cal- slightly below the dynamic range of the min. (0.08 to 0.15 pl./min. at standard con- ibration should be made under the same method. If this Is the range of interest, the ditions of 250 C. and 1 atmosphere.) A per- conditions used in sampling and analyses). diluent air stream must be adjust to deliver meation tube with an effective length of 2 to Twenty-four hour samples must be cali- these lower concentrations, and the total 4 cm., and outer diameter of 0.63 cm. will brated for 24 hours. The above description volume of air collected must be increased to rate if held represents a typical procedure for simulating obtain sufficient color within the dynamic yield the desired permeation ° at a constant temperature of 20 C. Using ambient air sampling of short duration. The range of the procedure. The calibration factor the system shown in Figure 2, calibrate the system is designed to provide an accurate must be reestablished, if collection effieienoy tube gravimetrically at the intended operat- measurement of sulfur dioxide in the range diff er significantly from that obtained abo'Vo ing temperature to a precision within ±2 of 0.01 to 0.5 p.p.m. It can be modified 25 1g./m.3 The remainder of the analytical percent. The temperature of the tube must easily to meet special needs. The concen- procedure is the same as described in Pec- be controlled within 0.10 C. Permeation tration of standard SO. in air is computed tion 7. tubes are calibrated under a stream of dry as follows: TA1LE I-TYPCAL OALIr.knoN DATA nitrogen to prevent the formation of blis- PrX 103 ters in the walls and sulfuric acid inside C= R+r Concentrations Amnount of SO2 in Abiorbano of the tube. Periodically, about every 4 days, of SOS, pg.ImJ. pg. for 30 liters .rnplo remove the bubbler from the constant tem- C= Concentration of S02, pg./m. perature bath and thoroughly dry the bub- Pr=Permeation rate, u g./min. bler. Remove the permeation tube from the 15 0. 45 0.013 R-Flow rate of diluent air, liters/mn. 25 0.75' v. tw2 bubbler with a Teflon-tipped forcep and r=Flow rate of diluent nitrogen, liters/ 100 3.0 O,(0,1 weigh the tube to the nearest 0.1 mg. Re- min. 200 0.0 (0.170 cord weight and time to the nearest minute. ro0 l;.0 (1,44q Data for a typical calibration curve are listed 0 21.0 0.710 Immediately return tube to bubbler and 1000 3.0 0 , ,Tl in Table I. A plot of the concentration of 1100 IM30 bubbler to bath. Plot gross weight (10. mg. 3 0. W_'f to the inch) against time (1,000 minutes to sulfur dioxide in pg./m. (X-axis) against the inch). Compute the slope of the linear absorbance of the final solution (Y-axis) will SOz,ndi./m.=A XF, portion from the line that best fits the yield a straight line, the reciprocal of the slope of which is the factor for conversion of Where: 3 points. Linear regression is recommended. 5 F=l.lX10 =factor, as derived from equa- Alternately, tubes can be rapidly calibrated absorbance to pzg./m. This factor includes tion in 9.2. the correction for collection efficlency. Any using a coulometric SO2 analyzer operating A=Absorbance of solution for 30 litera of under ideal conditions.2 deviation from linearity at the lower concen- sample and a volume of 25 nil, for the (2) A system designed for the preparation tration range Indicates a change in collec- colored solution. of standard concentrations of sulfur dioxide in the laboratory is shown in Figure 3. (Al- ternately, the apparatus shown in Figure 2 for gravlmetric calibration and field use may be used.) Assemble the apparatus, consist- ing of a water-cooled condenser, a constant- temperature water bath maintained at 200 C., a cylinder containing pure, dry air or .4jj SEPTUM F nitrogen, and appropriate pressure regula- tors, needle valves, and flow meters for FILTER the nitrogen and dry air diluent gas streams. The diluent gases are brought to tempera- CRITICAL ORIFICE FLOW CONTROL ture by passage through a 2-meter copper coil immersed in the water bath. Insert a calibrated permeation tube into the central tube of the condenser maintained at 20- C. by circulating water from the constant-tem- perature bath and pass a stream of air or nitrogen over the tube at a fixed rate of approximately 50 ml./min. Dilute this gas stream to the desired concentration by vary- , "i" TO AIR ing the air flow rate. Normally this flow rate JAtl/, PUMP' can be varied from 1.1 to 15 liters/min. The flow rate of the sampling system determines the lower limit for the flow rate of the INEEDLE VALVE diluent gases. With a tube permeating sul- fur dioxide at a rate of 0.4 pg./min., the range of concentration of sulfur dioxide will be between 27 and 260 pg./ma (o.o1 to IMPINGER 0.14 p.p.m.), a generally satisfactory range for ambient air conditions. When higher FLOSETER concentrations are desired, calibrate and TRAP use longer permeation tubes.

*Available from Metronics, Inc., 3201 Porter Drive, Palo Alto, CA 94304 and Ana- lytical Instrument Developments, Inc., 250 South Franklin Street, West Chester, PA FIluro 1. Sasnpling train. 19380.

FEDERAL REGISTER, VOL 36, NO. 21-SATURDAY, JANUARY 30, 1971 PROPOSED RULE MAKMG

particulate levels are unuually high, a sat- factory amplo my be obtained in 6 to 8 hor or le=s. For determination of dverage cncentrations of su -pnded particulate in ambient air, a standard campiung period of 21 hours is recommended. 2.2 VWelGhts are determined to the nerest CNIA)ZOR mill1gram: air flow rate are determined to - Rn the nearest 0.03 m./mln. (1.0 ft.lmiLn) 14TL'L' times aro determined to the nearest 2 mn. and va concentrations are reported to the neIrest mlcroCram per cubic meter. 3. Interferences. 3.1 Particulate that is oily, such Us photochemical smog or vsocd emolseo may blook the filter and caus-e a rap!d drop in air flow at a nonuniform rate. Dense fog or high humidity can cause the filter to become too wet and severely reduce the air flow through the filter. 3.2 Gl=s1-fiber filters are comparatively insensltive to change in relative humidity. but collected particulate can be hygroscoplc-! 4. Precis on, ccuracij,a d -tability.4.1 At an average m concentration of 112 pg.InL of particulate matter in ambient air the standard deviation is 10 p.I. 3 (correspond- Ing to a relative standard deviation of 9 per- cont); at an average of 39 pg./m.3 the stnd- ard deviation L3 6 rg.Im.S (corresponding to a relative standard deviation of 15 percent). 4.2 The accuracy with which the sampler men-ures the true average concentration de- pends upon the dezree of constant air flow rate maintainedin the sampler. The air flow rate is affected by the concentration and the nature of the dust n the atmosphere, which may clog the filter and significantly reduce the air flow rate. Under these conditions the - 'fl~ce A~arlnfo Dal3*~Bfel gdW error in the mea-ured average concentration may be as much us :t50 percent or more of the true avc=e concentration, depending on the amount of reduction of air flow rate and on the variation of the mass concentrtion ct dust with time during the 21-hour zampling peiod., 5. Apparatu,. 5.1 Sampling. 5.1.1 Sampler-The sampler consists of three units: (1) the face plate and gasket. (2) the filter adapter assembly, and (3) the motor unit. Figure 1 shows an exploded view of these parts, their relationship to each other, and how they are assembled. The sam- must be capable of passing environmen- pler 2 tal air through a 4015 cm. (63 in.!) portion of a clean 20- by 25-cm. (8- by 10-n.) gla- fiber filter at a rate of at least 1.70 mn.fmin. (60 ft.'/min.). The motor must be capable of continuous operation for 21-hou periods with input voltages ranging from 110 to 120 VOlts, 0-C cycles alternating current and must have third-wire safety ground. The housing for the mmtor unit may be of any convenient construction so long as the unit remain air-tIght and leak-free. 'e life of WATM the sampler motor can be extended by lower- by about 10 percent with a ing the voltage * all "buck or b~ot" transf rler between the sampler and power outlet. 5.1 Sampler Shelter-it 13 important that the sampler be properly installed- ina t'lasa3. Nsi-afstia sd-I"-= rl-t~lomxan suitable shelter. The shelter is subjected to extremes of environmental conditions such App'mm= B computed by measuring the mas o f collected a3 high and low temperaturej, extrem of particulate and the volume of ali mpled.PC umidityadalltypes ofairpollutants , PsOOSO n 05Dz n1U=ON Or SUSWZeDED 12 This method is applicable tUimesure- thme reasns the me or the shelter PARTICULATES .(HIGH TOLtVhM =rMOD) ment of the mass concentration of suspended must be chosen carefully. Properly painted 3- rinciple and applioability. 1.1 Air Is particulate In amblent air. This m ethod does exterior plywood or heavy gauge aluminun drawn into a covered housing and through2a not control the flow of air during ,11 pUng EC'To wCIL The sample must, be mounted. filter by means of A hlgh-flow-rate blower at and for this reason is most app)Ucable to vertically in the shelter so that the a flow rate (1.13 to 1.70 m.3fmln4 40 to 60 .trend measurement. The sze of t he sample fiber filter is pallel with the ground. The ft. /mLn.) that allows suspended particles collected Is usually adequate for other shelter must be provided with a roof so that baving diameters of less than 100 pm. analyses. tho filter 3 protected from precipttion and (Stokes equivalent diameter) to pass to the 2. Range and snsftivfty. 2.1 When the debriL The clearance area between the edge filter surface. The particles are ordinarily sampler is operated at an average flow rate collected on a glass-fiber filter within the of 1.70 m.3/min. (CO It./min.) for 21 hours, of the roof and the main housing should be size range of 100 to 0.1 m. diameter. an adequate sample will be obtain ed even In C454-65 cm.' (10 in.').W_10 The maln-hous- 1.2 The mass concentration of suspended an atmosphere having concentratloona of suo- Ing should be rectangular. with dimensions particulate in the ambient air (pg./m.) Is pended particulate as low as 1 pZ.gJm f of 29 by 3B cm. (111 by & In.).

'FEERAL REGISTER, VOL 36, NO. 21-SATURDAY, JANUARY 30, 197t 1508 PROPOSED RULE MAKING

5.1.3 Rotameter-Marked in arbitrary 5 min., connect the rotameter to the nipplo above, measure the true inlet pressure of the units, frequently 0 to 70, and capable of on the back of the sampler, and read the primary standard with this second differen- being calibrated. rotameter ball with rotameter in a vertical tial manometer. Measure atmospheric pres.- 5.1.4 Orifice Calibration Unit-Consisting position. Estimate to the nearest whole num- sure with a barometer. Correct the measured of a metal tube 7.6 cm. (3 in.) ID and 15.9 ber. If the ball is fluctuating rapidly, tip the air volume to true air volume as directed in cm. (6! in.) long with a static pressure tap rotameter and slowly straighten it until the 9.1.1 then obtain true air flow rate, Q, as di- 5.1 cm. (2 in.) from one end. The tube end ball gives a constant reading. Disconnect the rected in 9.1.2. Plot the differential manom- nearest the pressure tap is flanged to about rotameter from the nipple; record the initial eter readings of the orifice unit versues Q. 10.8 cm. (4/ in.) OD with a male thread of rotameter reading and the starting time and 8.1.2 HIgh-Volume Sampler-Assemble a the same size as the inlet end of the. high- date on the filter folder. The rotameter should high-volume sampler with a clean filter in volume air sampler. A single metal plate never be connected to the sampler except place and run for at least 5 mln. Attach a 9.2 cm. (3% in.) in diameter and 0.24 cm. when the flow is being measured. Let the rotameter, read the ball, adjust so that the ( ., in.) thick with a central orifice 2.9 cm. sampler run for the desired time (usually ball reads 65, and seal the adjusting mechan- (1% in.) in diameter is held in place at the 24 hours) and take a final rotameter reading. ism so that It cannot be changed casily. Shut air inlet end with a female threaded ring. The Record the final rotameter reading and end- off motor, remove the filter, and attach the other end of the tube is flanged to hold a ing time and date on the filter folder. Remove orifice calibration unit In its place. Operate loose female threaded coupling, which screws the face plate as described above and care- the high-volume sampler at a serles of differ- on to the inlet of the sampler. An 18-hole fully remove the filter from the holder, touch- ent, but constant, air flows (usually six). Re- metal plate, an integral part of the unit, is ing only the outer edges. Fold the filter cord the reading of the differential nlano- positioned between the orifice and sampler lengthwise so that only surfaces with col- meter on the orifice calibration unit, and re- to simulate the resistance of a clean glass- lected particulate are in contact, and place cord the reading of the rotameter at each fiber filter. in a filter folder. Record on the folder the flow. Convert the differential manometer 5.1.5 Differential Manometer-Capable of filter number, location, and any other fac- reading to mP/mln., Q, then plot rotameter measuring to at least 40 cm. (16 in.) of tors, such as meteorological conditions or reading versus Q. water. razing of nearby buildings, that might affect 8.1.2.1 If the pressure or temperature 5.1.6 Flow Measuring Device-Positive the results. If the sample is defective, void during high-volume sampler calibration Is displacement type; calibrated In cubic meters it at this time. In 6rder to obtain a valid substantially different from the pressure or or cubic feet, to be used as a primary sample, the high-volume sampler must be temperature during orifice calibration, a cor- standard. operated with the same rotameter and tubing rection of the flow rate, Q, may be required. 5.1.7 Barometer-Capable of measuring that were used during its calibration. If the pressures differ by no more than 15 atmospheric pressure to the nearest mm. 7.1.3 Maintenance. percent and the temperatures differ by no 5.1.8 Folders--Manila cardboard folders, 7.1.3.1. Sampler Motor-Replace brushes more than 100 percent (*C.), the error in the 22 by 28 cm. (8! by 11 in.) creased. before they are worn to the point where uncorrected flow rate will be no more than 5.2 Analysis. motor damage can occur. 15 percent. If necessary, obtain the corrected 5.2.1 Balance Room Environment-Main- 7.1.3.2 Face Plate Gasket-Replace when flow rate as directed In Appendix C. This cor- tained at 15 to 35* C. and less than 50 percent the margins of samplers are no longer sharp. rection applies only to oriic meters having a relative humidity. Seal the gasket to the face plate with rubber constant orifice coefficient. The coefficient for 5.2.2 Analytical Balance-Equipped with cement or double-sided adhesive tape. the calibrating orifice described in 0.1.4 has a weighing chamber designed to handle un- 7.1.3.3 Rotanpeter-clean as required, been shown experimentally to be constant folded 20- by 25-cm. (8- by 10-in.) filters using alcohol. over the normal operating range of the high- and having a sensitivity of 0.1 mg. 7.2 Analysis volume sampler (0.6 to 2.2 m.3/mln.; 20 to 78 5.2.3 Light Table-Of the type used to 7.2.1 ft./min.). view X-ray films. Equilibrate the exposed filters for 24 5.2.4 Numbering Machine-Capable of hours in the environment of the balance 9. C lculations. 9.1 Calibration of Orifice. printing identification numbers of 4 to 8 room, then rewelgh. After they are weighed, 9.1.1 Calculate the true air volume mes- digits on the filter. the filters may be saved for detailed chemical ured by the positive displacement primary analysis. 6. Reagents. 6.1 Filter Media-Glass-fiber standard. 8. Calibration. 8.1 Sampling-Since only filters having a collection efficiency of at PdV.=PMV1 least 99 percent for particles of 0.3 AM. a small portion of the total air sampled Paf=Pa-PM passes through the rotameter during meas- diameter, as measured by the DOP test, Combining these relationships: are suitable for the quantitative measure- urement, the rotameter must be calibrated ment of concentrations of suspended particu- against actual air flow with the orifice cali- V=(Pa-P') ' W-). late, although some other medium, such as bration unit. Before the orifice calibration paper, may be desirable for some analyses. unit can be used to calibrate the rotameter, Care must be exercised to prevent use of the orifice calibration unit itself must be V.=Volume of air at atmospheric pre.- filters that contain high background concen- calibrated against the positive displacement sure, mP trations of the pollutant being investigated. primary standard. P.=Barometric pressure, nun. Hg. Careful quality control is required to deter- 8.1.1 Orifice Calibration Unit-Attach the P,=Pressure at inlet of the primary mine background values of these pollutants. orifice calibration unit to the intake end of standard, mm. Hg. P.-Pressuro difference between inlet of 7. Procedure.7.1 Sampling. the positive displacement primary standard primary standard and atmospheric, 7.1.1 Filter Preparation-Place each filter and attach a high-volume motor blower unit to the exhaust end of the primary standard. mm. Hg. on a light table and inspect for pinholes, V-.= Volume measured by primary Connect one end of a differential manometer 3 stand- dark particles, or other imperfections. Filters ard, m. with visible imperfections should not be used. to the differential pressure tap of the orifice calibration unit and leave the other end 9.1.1.1 Conversion Factors: A small brush is useful for removing par- In. water X 73.48 X 103= in. Hg, ticles. Equilibrate the filters to the conditions open to the atmosphere. Operate the high- volume motor blower unit so that a series of In. Hg. X25.4=mm. Hg. of the balance room for 24 hours. Weigh Cubic feetX 0.0284=m.3 the filters to the nearest milligram; record different, but constant, air flows (usually tare weight and filter identification number. six) are obtained for definite time periods. 9.1.2 Calculate flow rate: Record the reading on the differential ma- Do not bend or fold the filter before collec- Va tion of the sample. nometer at each air flow. The different con- stant air flows can be obtained either by 7.1.2 Sample Collection-Open T the shel- placing a series of load plates, one at a time, ter, loosen the wing nuts, and remove the between the calibration unit and the primary Q=Flow rate, m.3/min. face plate from the filter holder. Install a standard or by varying the speed of the sam- T=Tlmo of flow, min. numbered, preweighted, glass-fiber filter in pler motor with a variable speed transformer 9.2 Sample Volume. position (rough side up), replace the face with the No. 18 plate plate without disturbing the filter, and fasten in position. The latter 9.2.1 Convert the initial and final rotam- method is considerably more convenient and eter readings to mP/min. using calibration securely. Undertightening will allow air leak- flexible. Placing the orifice before the inlet age, overtightening will damage the sponge- curve of 8.1.2. reduces the pressure at the inlet of the pri- 9.2.2 Calculate volume of air sampled. rubber face-plate gasket. A very light appli- mary standard below atmospheric; therefore cation of talcum powder may be used on the a correction must be made for the increase in sponge-rubber face-plate gasket to prevent air volume caused by this decreased inlet V=-X

FEDERAL REGISTER, VOL 36, NO. 21-SATURDAY, JANUARY 30, 1971 PROPOSED RULE MAKING 1502

9.3 Calculate mass concentratIon of sus- of Particulates Collected on Glc-s-Fiber I'l- ±0.G percerd fall czaso in the 0-7A m.!no ters," Am. Ind. Hyg. As"'oc. 3. 28, 363 (1007). ranzo.. pended particulate. on ins-trument 6 3. Fortun, S. F. G., "llactora Affecting the 4:2 Accuracy Is dp,ndnt (W -W,) Xl0 Precision of High-Volume Air Sampling." linearity and abcoluto concentration of the Md.S. Thesis. University of Florida, Galnes- calibration Cgaes u.ed. Generally. accuracy Is V ville, Fla.. April 1904. :t1Iprcent of full scale in the G-53 mgm.' SP..=Mass concentration of suspended 4. 1Harrison. W. M., Nader. J. S.. and FoC- range2. particulate. jg./m.2 man. F. S. "Constant Flow Regulators for 4.3 ects of valations in ambient room WI-=Initlal weight of filter, g. High-Volume Air Sampler." Am. Ind. Hyg. temnperature are considerable. Changes as W, =Finai weight of filter, g. Assoc. J.21. 115-120 (190). much ca 0.5 mgjm.Z per C. hve been noted. can ba minimized by operating V=Air volume sampled. m. 5. Pate, J. B.. and Tabor. E. C, "Analyti- The effects 106= Conversion of g. to pg. the analyzer in a controlled-temperature cal Aspects of the Use of Glass-Fiber Filters room. Further. preesure changes between for the Collection and Analyzls of Atmos- 10. Biliography. 1. Robson. C. D., and pan checka rdl cau:,e proportional chan.-e Foster, K. E., "Evaluation of Air"Particulate pherl Particulate Matter." Am. Ind. Hyg. Assoc. J. 23,144-160 (196). In the reading. If cell temparature and pros- Sampling Equipment." Am. Ind. Hyg. Assoc. aure are assumed cons-tant. however zero J.24,404 (1962). 6. Henderson. J. S.. Eighth Conference on drift observed with various instruments Is 2. Tierney, G. P., md Conner, W. D,, "Hy- Methods In Air Pollution and Induutr al Hy- less than :1 percentin2lhours. groscoplo Effects on Weight Determinations giene Studie3 1901, Oalnnd, Calif. G. Appsratus---3.1 Commercillzy canablc IJDI carbon monoxide analyzer. Instruments should ba Installed on location and demon- ctrated. preferably by the manufcturer, to meet or exceed manufacturers speciecations and thoe de-cribed In thIs method. The an- alyzer conslsts of an infrared cource, cample and reference rz cells, a detector capable of sensing dLfferences between levels of Infra- red energy n the two cells, and a control. power cupply, and ampllfler unit. 5.2 Sample. introduction, srjtem. Pump. fl=o control valve, and flowmeter. 6.3 Particlate filter (in-line). To keep sample cell clean, porosity of the filter should be 2 to 10 mcrons. M4 Moisture control For sy-tems with which constant humldlty control is desired. refrigeration units e available with aome commercial instruments. Drying tubes (with sulliclent capacity to operate for 72 hours) containing Indicating ilica gel or equivalent drying agent may be used for short-term sampling. G. Reagnt - .1 Zero gas. Nitrogen or helium contalning Ilc- than 0.1 m-./m.3 car- bon monoxide. 0.2 Calibration gazes. Gases needed for lnearlty checks are determined by the range of operation of Instruments. Calibration 'aes co=ponding to 10, 20,40. and 80 per- cent of full scal are needed. Gases must be provided with certification. or guaranteed 550 L ~ W analyzis of carbon monoxide content. 0.3 Span, gs. The calibration gas corre- 80 percent of full scale may be deflnitions.) spondLng to APPENDXX C 2. Range and sensitivity. (Seo trument. meas- used to span. the In 2.1 Instruments are available that 7. Procedure.7.1 Calibrate the instrument MTUOD FOR eo0nrmUous ar ssURELs=nT OF (0-&D ure In the range of 0 to 48 mg./m. as de:ribed In 8.1. All gases (sample. zero. the range mcct commonly p.pxm.). which Is and span) must be Introduced SPECTROMzTrZ) most calibration, used for urban atmospheric snmpling; Into the entire aalye system. Figure 1 . Pr nciple and applicability. 1.1 'The Instruments measure In additional ranges- chta a typical flow schematic. For --pecific 115 mg./m.' measuring principle makes use of absorption typically 0 to 29 and 0 to instructions, refer to the manu.- full.-cale operating of radiation by CO in the infrared region. 2.2 Sensitivity is 1 percent of facturer's manual. The absorption is measured by a photometer response per 0.6 mg./m)*(0.5 p.p.m.). 3. Interferences. 3.1 The degree of inter- 8. Calibration-8. Calibrationcerre De- 'ith two parallel beams and a selective de- tornlno the linearity of the detector re- varies among individual instrument. tector. A source emits energy in the Infrared ferenco flo, rate and temper- at sponse at the operating region. One beam passes through a reference The effect of carbon dioxide Interference curve or check normal concentrations Is minimal. The pri- ature. Prepare a calibration cell filled with nonabsorbing gas. Both beams the curve furnished with the in-trument. mary interference Is caused by water vapor. pass Into a detector cell, which contains. CO. zero gas and set the zero control no corrective measure, Interference- Introduce The CO in the detector absorbs the nfrrnd With reading of zero. In- from water may be as high as 12 mg./=* to Indicate a recorder radiation only at its characteristic frequen- span e and adjust the cpan control Water vapor Interference may be minimized treduce cies and thus the detector Is sensitive only to value on the recorder by (a) passing the air camplo through sillca to indicate the proper those frequencies. With no CO in the sample s-le (og. on 0-63 mg./n= scale set 46 mg/ gel or simlnr drying agents, (b) maintaining 0 cell, the detector Is balanced for equal ab- (40 p.p=m) standard at 80 percent re- constant humidity in the smplo and call- m. sorption from both .beams. Any CO present until by refriCeration. (o) saturat- corder chart). Recheck zero and span in the sample cell will absorb some of the bration gases necessary. Intro- Ing the air sample and calibration Cases to adjustments are no longer radiation and reduce the amount entering calibration gases and plob, maintaln constant humidity, (d) urlng nar- duce intermediate the detector from that beam. This reduces not row-band optical filters, or (o) combining tho values obtained. If a smooth curve 13 the temperature and hence the pressure in obtained, calibration gass should b stuz- one chamber of the detector, causing a dia- some or all of thee measurca. 3.2 Hydrocarbons at ambient lovels do not pected. phragm to be displaced. This movement Is 0. CaZiuatfoin.O.1 No calculations are in- cause Interferences. Effects of Epecifl hydro- detected electronically and amplified to pro- volved in this procedure since the concentra- carbons are generally rated on the manufac- vide an output signal. tlo L3 determined directly from the calibra, 1.2 The sample introduction pump may turer's zpecification shets for the Individual tIon curve. be bypassed for analysis of gases under pres- analyzer. 0.2 Carbon monoxide concentration in sure, as is sometines done with the calLbra- 4. PrccsiOn, aocuraoj, and atqbiUty. 4.1 mgn.Jn' can b converted to p.pnm as t-on gawes. Precision with standard calibration gase is fallotsel

FEDERAL REGISTER, VOL 36, NO. 21-SATURDAY, JANUAZY 30, 1971 NTo.i1---Pt. It--- 1510 PROPOSED RULE MAKING (maxi- p.p.m. CO=mg. CO/m.PX0.873 Range (minimum)--- 0-58 mg./m.; (0-50) Span drift 3'%l~eeh not to ex- mum). ceed 1%/24 hourv, p.p.m.). ±_ 0.5%. 10. Bibliography. 1. MSA LIRA Infrared Output (minimum)__ 0-10, 100, 1,000, Precision (maxi- Gas and Liquid Analyzer Instruction Book, 5,000 my. full mum). Mine Safety Appliances Co., Pittsburgh, Pa. scale. Operational period 3 days. 2. Beckman Instruction 1635B, Models 8 (minimum). Minimum detectable 0.6 mg./m. (0.5 ± 0.5%, 215A, 315A, and 415A Infrared Analyzers, . sensitivity. p.p.m.). Noise (maximum)--- Beckman Instrument Co., Fullerton, Calif. Lag time (maximum) - 15 seconds. Interference equiva- 1% of full scale, 3. Continuous CO Monitoring System, Time to 90% response 3o seconds. lent (maximum). Model A 5611 Intertech Corp., Princeton, (maximum). Operating tempera- 5-40* 0, N.J. Rise time (90% maxi- 15 seconds. ture range (mini- mum). 4. Bendix-UNOR Infrared Gas Analyzers, mum). 10-100%. Ronceverte, W.Va. Frall time (90% maxi- 15 seconds. Operating humidity 11. Definitions of performance specifica- mumn). range (minimum). 1%, tions used in this method-Range. The mini- Zero drift (maxi- 3%/week not to eX- Linearity (maxi- mum and maximum measurement limits. mum). ceed 1%/24 hours. mum). Output. Electrical signal which is propor- tional to the measurement; intended for con- SAIPLE INTRODUCTION ANALYZER $YSTME nection to readout or data processing devices. Usually expressed as millivolts or milliamps full scale at a given impedence. Full scale. The maximum measuring limit for a given range. Minimum detectable sensitivity. The small- est amount of input concentration that can be detected as the concentration approaches zero. Accuracy. The degree of agreement between a measured value and the true value; usually expressed as _ percent of full scale. Lag time. The time interval from a step change in input concentration at the instru- ment inlet to the first corresponding change in the instrument output. Time to 90 percent response. The time in- terval from a step change in the input-con- centration at the instrument inlet to a read- ing of 90 percent of the ultimate recorded concentration. Rise time (90 percent). The interval be- tween initial response time and time to 90 percent response after a step increase in inlet concentration. Fall time (90 percent). The interval be- tween initial response time and time to 90 percent response time after a step decrease in the Inlet concentration. Zero drift. The change in instrument out- Figure 1. Carbon monoxide analyzir flow diairm. put over a stated time period, usually 24 hours, of unadjusted continuous operation, APPENDIX D 1-cm. cells. At concentrations below 100 ,g./ 5 readings may be quite Im- when the input concentration is zero; us- T.IErHOe FOR DETEES.5IATION OF OXIDANTS in. (0.05 p.p.m.) ually expressed as percent full scale. rOTASSIUB omID precise because of the Instability of oxidants METHD)(NEUTRAL BorBUFFERED iodine at very low concentrations. Span drift. The change in instrument out- ISETISOD)) 2.3 The above limits are based on a molar put over a stated time period, usually 24 hours, of unadjusted continuous operation, 1. Principleand applicability.1.1 A sam- absorptivity of 24,200 liters/mole/cm. when the Input concentration is a stated up- pie of ambient air is drawn through a 3. Interferences. 3.1 Reducing gases such scale value; usually expressed as percent full chromium trioxide scrubber to remove sulfur as sulfur dioxide and hydrogen sulfide give scale. dioxide and then through two absorbers in very serious negative interferences. Sulfur Precision.The degree of agreement between series containing potassium iodide reagent dioxide gives a 100 percent negative Interfer- repeated measurements of the same concen- to collect the oxidants. ence of an equivalent molar concentration of tration and is expressed as the average devia- 1.2 Oxidants are defined by this method ozone. The interference from sulfur dioxide, tion of the single results from the mean. as those compounds capable of liberating even when it is present at amblnt concen- Operational period.The period of time over iodine from a 1 percent potassium Iodide trations, can be eliminated by a properly which the instrument can be expected to op- solution buffered with disodium phosphate conditioned chromium trioxide-scrubber (see erate unattended within specifications. and potassium dihydrogen phosphate. The 6.2, 7.1). Noise. Spontaneous deviations from a mean -Iodine produced in the absorbing reagent is 3.2 The oxidant reading contains a output not caused by input concentration measured spectrophotometrically as the tri- contribution of 10 percent of the molar changes. iodide ion. concentration of NO.. When a chromium trl- Interference. An undesired positive or 1.3 This method is intended for the meas- oxide scrubber Is used, NO Is converted to negative output caused by a substance other urement of total oxidants as ozone in the NO., thus contributing to the oxidant read- than the one being measured. atmosphere. However, the various oxidizing ing to the same extent as NO,. If an oxidant Interference equivalent. The portion of in- species, such as. ozone, nitrogen dioxide, value less NO, is desired, NO + NO, must be dicated input concentration due to the pres- peroxyacetyl nitrate, and peroxides are pres- measured simultaneously and a correetion ence of an interferent. ent in widely varying concentrations and factor of 10 percent of the NO,, coneentra- Operating temperature range. The range react with the reagent at different ratesAlso, tion must be subtracted. of ambient temperatures over which the in- reducing compounds in the atmosphere have 3.3 Glassware should be cleaned with strument will meet all performance specifica- a negative effect on the oxidant reading. chromic acid, since dust or foreign materials tions. Thus the number obtained is a "net" oxidant may interfere. humidity range. The range of value, which describes a condition of the Operating Iodine ambient relative humidity over which the atmosphere and is not the total concentra- 3.4 Direct sunlight will affect the instrument will meet all performance tion of the oxidizing species present, concentration. specifications. 2. Range and sensitivity. 2.1 Concentra- 4. Precision, accuracy, and stability. 4Ai tions of oxidants in the range of about 20 to A+5 percent relative standard deviation Linearity. The maximum deviation between 3 an actual instrument reading and the read- 20,000 gg./m. (0.01 to 10 p.p.m.) can be can be obtained at a concentration of 1,000 ing predicted by a straight line drawn be- determined. pg./m. (0.5 p.p.m.) of ozone. tween upper and lower calibration points. 2.2 At a sampling rate of 2 liters/min. for 4.2 Accuracy cannot be defined, since the 12. Suggested minimum performancespec- 15 min. using 10 ml. absorbing reagent, 20 sensitivity of the potassium iodine reagent 3 ifications for NDIR carbon monoxide ana- Ag./m. (0.01 p.pm.) should produce an ab- varies widely with the different oxidizing lyzers. sorbance of approximately 0.025 measured in species.

FEDERAL REGISTER, VOL 36, NO. 21-SATURDAY, JANUARY 30, 1971 PROPOSED RULE MAKING 1511 4-3 Analysis shouldbe completed Immedi- iodlde (K) and 3.2 g. r;-ubUmed iodine MIx thoroughly, and Immediately read the ately after sampling to obtain consistent re- (12) in 10 ml. purified water. hen the aboebnco of Each at 3=2 a-n against un- suits. This is necessary because some oxidants iodine dissolves. transfer the solution to a expocd hea.rbing reagent as the reference. release Iodine slowly to enhance color, while 500-ml. gisa-stoppered volum _tric flak. Di- Calculate the concentratlon of the solutions fading due to slow decomposition of iodine lute to mart with purified water and mix as total tZ. 0, aa follows: may occur. thoroughly. Keep solution In a darh brovn 5. Apparatus-5.1 Absorber. All-glass Im- glas-stoppered bottle aray from light, and Total irg. 0-3= (UI) (96) (V) pingers as shown In Figure 1 are recom- restandardLzo as necesary. Zl=lformallty I ( eo 6.5.2), meg /xnl. mended. These impingers may be purchased 6.5.2 Standardization. Pipet accurately V=Voluma of diluted standard . added. from major glassware suppliers. Two ub- 50 ml. standard amrsnlouz oxide solution Intl ml. (0.5,1,2.3.4). sorbers in series are needed to insure con- a 300-ml. Erlenmoyer flsl:. Acidify slightly plete collection of the sample. with a 1:10 dilution of sulfuric acid. Plot absorbanc3 versus total gg. O. 5.2 Air pump. Capable of drawing 2 liters/ neutralize with Eolid sodium bicarbonate. 8.3 SaMpfing efilcfenj. Sampling effa- rin. through the absorbers. The pump and add about 2 g. exceas. Titrate with the clency In the first- absorber may ba G0-05 should be equipped with a needle valve at standard Iodine solution using 5 ml. starch percent depandinZ upon the Impinger orifice the Inlet side to regulate flow. If a critical solution as indicator. Saturate the colution and the ozone concentration. vhen two ab- orifice (5.7) is used. the pump must be capa- with carbon dioxide at end of titration by sorbers are placed In serics essentially anl ble of maintaining 0.7 atmosphere vacuum. .dding 1 ml. of 1:10 sulfuric acid just ozono I, collected. 5.3 U tube. 140 ml, for the chromium tri- before the end point is reached. 0. Calculationo-.1 Sampling. Correct the oxide scrubber. 6.6 Chromiutm trioxide ccrubber. Dlolve volume of air campled to the volume at 5A Thermometer. Or other temperature- 125 g. chromium trioxide (Cr0) crystals standard conditions of 25* C. and 790 mm. measuring device with an accuracy of t2 C. In 35 ml. concentrated sulfuric aid and Hrg. 5.5 Barometer. Atmospheric, accurate to add to 750 ml. distilled water. Plac a 15- F 298 the nearest mm. Hg. by 25-cm. sheet of a flash-fired gla=-flber 0=VX-x 5.6 Wettest neter. 1 or3 lters/revolution, filter in an oven raclt equipped with glass 700 t+273 5.7 Flowmeter. Calibrated metering device rod attachments to prevent the filter from V,=Volume of air at standard conditions, for measuring flow of 2 liters/min, within touching metal. Saturate the filter with 10 liters _5 percent. A 20-gauge hypodermic needle ml. chromium trioxide solution. Place the V-Volums of air at sampling conditions. 1 in. long acting as a critical orifice can be filter in an oven set at 05-70' C. for 1 liters. used to give a flow of approximately 2 liters/ hour. A freshly prepared filter is brownk, P=Brometrlc pressure of mercury, rm. Tn.n pinl. At the end of this time remove the Hff. 5.8 Drying tube. Containing an indicat- filter and fold every 1.2 cm. along the 15-cm. t=Temperaturo of sample, *C. Ing drying agent to protect flowmeter. dimension in an accordion fashion. While 0.2 Calculate oone concentration In jigl MO.5.9 Prescrubber. Tube filled with granular the sheet is folded. cut the 15-cm. length and charcoal to remove oidants. into 10 equal widths. As each strip is cut. m.satstcofrdcanditlon.. (A) (102) 5.10 VOlumetric ftasl. 25. 100, 500, 1.000 place it in the 140-ml. U-tube. Place fliv g. O/m.=--- - MI cut strips in each tube, rotating alternate V. 5.11 Buret. 50 ml, strips 901 so that folds will not match. Be- A=Total rz,. O read frtom, calibration. 5.12 Pipets. 0.5, 1. 2, 3. 4. 10, 25, and fore the scrubber is used for sampling. con- curve. 50 ml. volumetric. ditlon for soveral hours to oMone at a high 5.13 Erlenmeyer ftasks. 300 ml. concentration from an ozone source Such as 10=conrer-ion of liters to cubic meters. V,=volume sampled at standard condi- 5.14 Ove. Capable of maintaining 105" a UV photolysia lamp. An the filters absorb tona. litera. C. - molsture, scrubbing efficiency is decres3ed. 0.2.1 If desired, concentratiom of oxidant 5.15 Spectrophotometer. Capable of This condition is evident as a green color. ay be calculated as p.p.m. 03 at measuring absorbance at 352 am. Matched Caution: When working with chromium tri- standard conditions of 25 -0. and 760 mm. 1-cm cells should be used. oxide and sulfuric acid. v,ar glovez to pro- Hg. 6. Rjlagents-6.1 Purified water. Used for vent Irritation of the skin. p.pm. Os=(Fbj. 0dm.') (5& 4X10-') all reagents. To distilled or delonized water 7. Procedur--7.1 Sampling. Awemble the Dcrivation of above In an all-glass distillation apparatus, add a apparatus as shown In Figure 1. Use ground- equation: crystal of potassium permanganate and a glass connections upstream from the Im- (1) Total Fg. Os=IVD (meq./ml)x(10 crystal of barium hydroxide, and redistill, pinger. Butt-to-butt connections with Tygon mI.) + (24,000 Fg. 6.2 Absorbing reagent. Dissolve 13.6-g. pc- tubing may be used. Cheek assembled system meq.) 1 tassium dihydrogen phosphate (XHoj), for leaks. Pipet 10 ml. absorbing reagent Into (2) No=Normality of diluted calibration 14.2 g. anhydrous disodlum hydrogen phos- first absorber and place MnO, prezscrbber on standard. phate (NaHP0,) (or 35.8 g. dodecahydrate the sample probe. Draw air through the pre- U1 V salt), and 10.0 g. potassium iodide (KI) in scrubber and the sampling train for 15 min. No= -- (list dilution) X-(2nd ditu- purified water and dilute to 1,00o mL The at 2 lIter/min. If an absorbance reading at F100 25 pH should be 6.8-_-0.2. Store the -olution 352 n.- is obtained, repeat until zero or con- tloa) I. in a glass-stoppered amber bottle n a cool, stant absorbance is obtained. This system (3) Therefore: Total pjg. 03= (N) (96) (V). dark place. It Is stable for several weeks. blank absorbance should be subtracted from 10. Bibliogrphy. 1. Byers. D. H., Saltzman. 63 Standard -enious oxide solution the absorbance of the first absorber when B. . "Determination of Ozone In Air by (0.05 N). Use primary standard grade ar- analyzing for oxidants. Remove the prescrub- 'Neutral and Alkaline Iodide Procedures." senious oxide (As0.). Dry 1 hour at 105* her. Pipet 10 ml. absorbing reagent into each 3. Am. Indust Hyg. Assoc- 19, 251-7 (1958). V. immediately before using. Accuratey absorber. Draw ambient air through the san- 2. Saltzman. B. F., Gi1ber, N., 1odometric weigh 2.4 g. arsenlous oxide from a small piing train at 2 Uters/mln. for 15 min. SMcrodetermlnation of Organic Oxidants ansI glass-stoppered bottle. Dissolve in 25 ml. 1 N 7.2 AnaysIs. Immediately transfer the so- Ozone:' Anal. Chem. 31, 1914-20 (1959). a lutlons from each absorber to separate clean sodium hydroxide n flask or beaker on 3. Mueller, P. X. Terragllo, R. B., and steam bath. Add 25 ml. 1 N sulfuric acid. 1-cm. cells. Determine the absorbance of each Tokiwa, T., "Chemical at 352 nmn. against unepozed absorbing rea- Interferencez In Con- Cool and transfer quantitatively to a 1,000- tinuous Air Analysis." Proc.. 7th Conference mL.volum trio flask, and dilute to volume, gent as the reference. Add the aborbance of NoTE: to o'btan total absorbance. on e thods in Air Pollution Studies, State Solution must be neutral to litmus, the two sqlutlons of California Department of Public Health. not alkaline. Read total pg. 0 from the calibration ourve e'rkeley. California (195). wt.A son (g.) (see 8.2). Norm__tyA__s=_ 8. Calibration,standards, and efficencim- 4. Cohen, L R. Purcell. T. C.. and Altzhul- 49. 8.1 Sampling. The flowmeter must be call- let. A. 0. "Analysis of the Oxidant in Photo- brated with the sampling train aembled chemical Reactions." Ilnvir. Scl. Tech. Vol. 1. 6A Starch inficator solution (02 per- and solution in the absorbers. Connect the No. 3.247 (1W ' 7). cent). Triturate 0.4 g. soluble starch and wet test meter to the arnple probe and call- 5. Saltman, B. B.- Wartbur&. A. F., Jr- approximately 2 rag. mercuric Iodide (pre- brate the flowmeter. "Ab-orption Tube for Removal of Interferng servative) with a little water, add the paste 8.2 Analysis. Pipet 1 ml. standard Iodine Sulfur Dlodde In Analys of Atmo6pherlc rlowly to 200 mL boiling water, Continue solution into a 109-ml. iolumetrio flask Dl- Oxidant." AnsI. Chem. 37, 779 (1905). boiling until the solution Is clear, then lute to mark with absorbing reagent. Prepare 0. Ripley. D. L. Clingenpeel, J. M., and and allow to cool, transfer to glas-stop- tresh before =#-. Into a res of 2-ml. 'Hum. R. W. "Continuous Determination of pered bottle. volumetric flasks, pipet 0.6, 1,2. 3. and 4 ml. Illtrcgen Oxides in Air and Exhaust Gases- 6.5 Standard lod e solution (0.OS N)- of diluted standard iodine solution, and dl- InJ. Air Wat. Poll. Vol. 8. pp. 455-460, 6.51 Preparuton. Dlolve 5.0 g. potassium lute each to the mark with aboorblng reagent. (04).

BEDPRALREGISTER, VOL 36, NO. 21---ATURDAY, JANUARY 30, 1971 1512 PROPOSED RULE MAKING

1.2 The technique may be applied to a gaseous sample containing low concentra- tions of methane, since the instrument can gases at 5 p.sl. or more pressure or DRYIG sample 'UBF at ambient pressuro. 2. Range and sensitivity, 2.1 The rangeo available on commercial continuous hydro- carbon analyzers are commonly 0 to 10 pp.m. CHROMIIU and 0 to 100 p.pan. A sensitivity of 0.1 p.p.m, 7RIOXIDS SCRUDOERM can be obtained in the 0 to 10 p.p.m. range. 3. interferences. 3.1 Ethane is the hydro- carbon most likely to break through the car- bon column when ambient urban air is sam- pled. Thus, service life of the column Is meas- ured by introducing known concentratlona of ethane in amounts equal to the daily average peak for the sampling zone (ref. 1). This service life has been found to be ns long as 6 days. The column must be purged with helium every 3 days. F19vMa1 $sspIrngirals. 4. Precision, accuracy, and stability, 4,1 Precision Is ±1 percent for successive Identi- APPENDIx E specifications and- those described in this cal samples under identical conditions. method. Generally, hydrocarbon analyzers PART 1: ETHOD FOR CONTINUous MEASURE- 4.2 Accuracy is dependent upon the ac- consist WENT OF HYDROCARBONS (FLAMIE ION ZA- of a regulated fuel and air delivery curacy of standards used to calibrate the TION METHOD) system for the hydrocarbon burner, a regu- instrument. lated sample injection system, electrometer 4.3 At normal temperature, the system is 1. Principle and applicability. 1.1 The for measuring the flame ion current, meter stable. sampling system is an integral part of the readout with connections for a recorder, and 5. Apparatus-5.1 Continuous hydrocar- most commercial total hydrocarbon analyzers a sample pump. ben analyses. The procedure described is for designed to measure continuously the con- 5.2 Recorder. Potentiometeric type, com- the Beckman 108A and 109A analyzers, centration of hydrocarbons (and other or- patible with analyzer with an accuracy of 5.2 Charcoal column. A 5-inch long ganic compounds) in the atmosphere. The 0/5 percent or better. threaded nipple of 1/4-inch pipe packed with sample line is attached to the inlet and the 5.3 Sample, line. Any tubing that Is not 4.5 grams of 9A4 mesh activated charcoal. sample is pumped into a flame ionization a source interferences or an absorbant of hy- Cloth discs contain the charcoal. The freshly detector. A sensitive electrometer coupled drocarbons. Inert materials such as glass, packed tube is blown out forcibly with with a potentiometric recorder detects the stainless steel, and Teflon are recommended. helium for 2 minutes to remove fine dust, increase In ion intensity resulting from the 6. Reagents-6.1 Combustion air. High which otherwise would interfere with the de- introduction into a hydrogen flame of a purity air containing less than 1.3 mg./m.3 tector operation. sample of air containing any organic com- (2 p.phn.) hydrocarbon as methane. 6. Reagents-6.1 Fuel gas. Pure hydrogen pound (e.g. hydrocarbons, aldehydes, alco- 6.2 Fuel. Hydrogen or a hydrogen-inert or a 40 percent hydrogen/60 percent nitro- hols). The response is approximately pro- gas mixture; when ordering specify hydro- gen mixture, relatively hydrocarbon free. A portional to the number of carbon-hydrogen carbon-free gas. A hydrogen generator is hydrogen generator may be used. bonds in the sample. The analyzer is call- strongly advised for safety reasons. 6.2 Air. Water-pumped cylinder air, brated using methane and the results re- 6.3 Zero gas. Less than 0.05 mg./m.; (0.1 6.3 Zero gas. A calibration gas that con- ported as methane equivalents. See adden- p.p.m.) hydrocarbon as methane In air. tains a relatively low amount of hydrocar- dum for 6.4 Span gas. Methane in air correspond- description of method for measure- 3 bons Is required for setting the zero point. ment of methane. ing to 80 percent of full scale, 10.4 mg./m. If the hydrocarbon content of the burner air 1.2 The sample introduction pump may (16.0 p.pm.) for 13 mg./m?. A certified or is sufficiently low and accurately knovn, this be bypassed for analysis of gases under pres- guaranteed analysis is required. gas can be used as the zero gas. sure as is done with calibration gases. 7. Procedure. 7.1 For specific operating 6.4 Span gas. The span gas Is a certified 2. Range and sensitivity. 2.1 The range instructions, see the manufacturer's manual. calibration gas used to set an upscale stand- of the analyzer may be varied so that full 8. Calibration and efficiencies. 8.1 Cali- ardlzation point. scale may be 2.6 mg./m.3 (4 p.pan.) to 1960 brate the instrument at the desired flow rate 6.5 Helium. Cylinder helium (water- neg./m.3 (3,000 p.p.m.) hydrocarbon as and attenuator setting. Introduce zero gas pumped) Is required to recondition the car- methane by varying the attenuation and the and set zero control to indicate proper value bon filter. sample flow rate to the detector. The 13 on the recorder. If a live zero recorder is not 7. Procedure.7.1 Check that all units are mg./m.3 (20 p.p.m.) range is normally for usie'd, it is recommended that the zero set- properly connected according to the diagram. atmospheric sampling. ting be offset at least 5 percent of scale to Turn on fuel gas. Allow fuel pressuro to reach 2.2 Sensitivity is 1 percent of full scale allow for negative zero drift. In this case, proper level according to flow desired. Slowly recorder response. the span setting must also be offset by an open the air cylinder valve. Adjust air pres- 3. Interferences. 3.1 Carbon atoms bound equal amount. Introduce span gas and ad- sure to about 30 p.s.l. Again adjust to ob- just span control to indicate proper value tain desired flow. Check all fittings for leaks. to oxygen, nitrogen, or halogens give reduced on recorder scale (e.g. 0-13 mg./m.3 (0-20 Insert a carbon column In position. Intro- or no response. There is no response to nitro- p.p.m.) sale set a 10.4 mg./m.A (16.0 p.pm.) duce sample and adjust to proper gen, carbon monoxide, carbon dioxide, Or value. If all standard to read 80 percent recorder chart). pressures inside analyzer are proper, turn water vapor. Recheck zero and span until adjustments are on analyzer power switch and ignite burner. 4. Precision accuracy and stability. 4.1 no longer necessary. Since the scale is linear, A small pop indicates that the flame has Ig- Precision Is approximately 0.5 percent full the two-point calibration is valid. nited. The analyzer meter should show an recorder scale on the 13 mg./m.' (20 p.p.m.) 8.1.1 If attenuation upscale deflection. Adjust attenuator to x30 scale. Is varied, some dis- crepancy between the true attenuation and position, and adjust the zero and span* con- 4.2 Accuracy is dependent on instrument the nominal attenuation may exist. The in- trols so that meter reading is between 10 linearity and absolute concentration of the strument should be calibrated using appro- and 60, Proceed to calibration. calibration gases used. Generally, accuracy priate standards at each attenuator setting 8. Calibration, standards, and efficicnclcs. Is + 1 percent of full scale on the 0-13 mg./m.' used. 8.1 Check flow rates with a calibrated bub- range. 9. Calculations. 91.1 The recorder is read ble flow meter so that sample flow corre- 4.3 Zero drift necessitates frequent cali- directly for hydrocarbon concentration. sponds to optimum values. bration. The magnitude of the drift depends 8.2 If the Instrument has just been on the air flow rate, sample flow rate, fuel pART 2: ZTETIOD FOR MEASUREsEsNT Op started, wait at least 3 hours before calibrat- flow rate, ambient temperature changes, IETHANE ing. Open the cylinder shut-off valves on the detector contamination, and electronic drift. 1. Principle and applicability.1.1 The at- span and zero gas cylinders. Observe the Zero drift observations on various instru- mospheric sample is continuously passed sample pressure gauge and adjust to the proper value. Connect the zero gas ments indicate 2 percent/24 hours on the 13 through a treated charcoal column before to the car- mg./m.Oscale. introduction Into the instrument. This col- bon column so that It goes through the col- 5. Apparatus-5.1 Commercially available umn will selectively strip all hydrocarbons umn before passing into the analyzer, Allow total hydrocarbon analyzer. Instruments ob- other than methane and give a specific anal- the instrument to run on zero gas for 5 tained should be installed on location and yses for methane.' The methane level is con- demonstrated preferably by the manufac- tinuously monitored by flame ionization *SEpan control has been added to the Beck- turer to meet or exceed manufacturers techniques. man analyzer for convenience.

FEDERAL REGISTER, VOL 36, NO. 21-SATURDAY, JANUARY 30, 1971 PROPOSED RULE MAKING 1513

to 10 minutes. Disconnect the zero gas and dichromnate-concentrated sulfuric acid clean- 7.2 Analys. Replace any water lost by connect the span gas to the column so that Ing solution and rinse well with distilled evaporation during sampling. Pipet 10 ml. span gas passes through the column before water. Insert the frit in one hole of a two- of the collected sample Into a test tube. Add the analyzer. Allow the instrument to run hole rubber stopper and install the frit in 1.0 ml. hydrogen peroxide solution, 10.0 ml. 5 to 10 minutes. Remove the old bolumn and a tube containing sufficient distilled water sulfanilamide solution, and 1.4; ml. NEDA insert a freshly'purged carbon column. Ob- to cover. Attach a vacuum source to the other solution with thorough mixing after the ad- serve the analysis tag attached to zero-gas hole of the rubber stopper and measure the dition of each reagent. Prepare a blank in the cylinder and note the indicated p.p m Dis- vacuum required to draw the first perceptible same manner using 10 ml. absorbing reagent. connect the span gas and reconnect the zero stream of air bubbles through the frit. Ap- After a 10-min. color development interval, gas, wait until reading has stopped chang- ply the following equation: measure the absorbance at 540 n3m. against ing, then adjust the ZERO control to bring the blank. Read pg. NO.Iml. from standard 30s the recorder pen to the same reading (in maximum pore diameter, pm.= - curve (rectIon 82). p.p.m.) as indicated on analysis tag. Recon- 8. Calibration and efflciencies-.1Sa3m- nect the span gas and adjust the recorder s=Surface tenslon of water In dyneolem. pling. with SPAN control to indicated value in at the test temperature (73 at 181 C., 8.1.1 Calibration of ball float flowmeter. p.p.m. Repeat zero and span adjustment 72 at 251 0., and7l at 31" 0.) Using a wet test meter and a stopwatch, de- until no further adjustments are required. P=Vacuum, mm. Hg. tormine the rates of air flow (ml.!min.) Connect the column back to sample air. 5.1.2 Probe. Teflon or glazs tube with a through the flowmeter at several ball post- Check to see that the sample pressure gauge polypropylene or glass funnel at the end tions. Plot ball positions versus flow rates. reading is still the same as originally set. and a membrane filter to protect the frt. 8.1.2 Calibration of h!,podermic needle. Turn off the zero and span cylinder valves. Replace filter after use with no. more than Connect the calibrated flowmater, the needle - 9. Calculation. 9.1 Meter is read directly five samples. to be calibrated, and the source of vacuum in p.pm. as CH4. 5.1.3 Flow control derice. Calibrated 27- in such a way that the direction of air flow 10. Bibliography. 1. Ortman, G. C., Moni- gauge hypodermic needlez, -ln. long. The through the needle is the same as in the toring Methane in Atmosphere with a Flame 'needle should be protected by a membrane sampling train. Read the position of the ball Ionization Detector, Anal. Chem. 38, 644 filter or fiber glass filter. Change filter after and determine flow rate in ml./mn. from (1966). use with 10 samples. 1306, the calibration chart prepared In 81.1. Reject 2. Beckman Instruction Manual 5.1.4 Air pump. Capable of maintaining a Beckman Instruments, Inc. (1964). all needlea not having flow rates of 190 to flow of 0.2 liter/rain, through the absorber, 210 ml./min. before rampllng AppEDx F and a vacuum of 0.7 atmosphere. 8.2 Calibrationcurve. Dilute 5.0 ml. of the 5.1.5 Calibration equipment. One ball- 1,000 pg. 1105'ml. colution to 200 mI. with AMETHOD FOR DETERL=ATION OF ITROGEN float flowmeter for meaurLng air flowa up DIOXIDE In- THE 7TuosPiEEn absorbing reagent. This solution contains 25 to approximately 275 ml./mln., one stop- Pg. llO=-fml. Pipette 1, 2, 5, and 15 ml. of the (24-Ton SALLMG L-'HOD) watch, and one precision wet test meter, 1 liter/revolution. 25 pg. NO/ml. solution Into 50-. 50-, 100-, 1. Principle and applicability. 1.1 Nitro- 5.2 Analysis. and 250-ml. volumetric flask and dilute to gen dioxide is collected by bubbling air 5.2.1 Volumetric flasks. 50, 100, 200, 250, the mn k with absorbing reagent. The solu- through a sodium hydroxide solution. A di- 500, 1,000 ml. 1 tions contain 0.50, 1.00, 125, and 1.50 pg. lute solution of sodium nitrite is produced, 5.2.2 Graduatedcylinder. 1,000 ml. nOgml., rezpectively. Run standards as in- which need not be analyzed immediately. 5.23 Pipets. 1, 2.5, 10 ml. structed in 7.2 Plot absorbance vs. gg. 1.2 The nitrite ion produced during 52.A Test tube. sampling is determined colorimetrically by 5.2.5 Spectrophotometer or cotorimeter. 8 Efflciencics. An overall average effi- reacting the exposed absorbing reagent with Capable of measuring absorbance at 540 nm. clency of 35 percent was obta ned from test phosphoric acid, sulfanilamide, and N-(1- Band width Is not critical. atmos-pheres having nitrogen dioxide concen- naphthyl) -ethylenediamine dihydrochlorlde. 6. Reagents--6.1 Sampling. trations of 140 pg./m.3 and 200 p../m. by 1.3 The methods of sampling and analysis 6.1.1 Absorbing reagent. Dissolvo 4.0 g. automated anyal.P are applicable to field collection of 24-hour sodium hydroxide and dilute to 1,000 ml. 9. Calculation--9.1 Sampling. samples and return to a central laboratory with distilled water. 9.1.1 Calculate volume of air sampled. for analysis. 6.2 Analysis. FI+F.- 2. Range and sensitivity. 2.1 The range -62.1 Sulfanilamide. Dissolve 20 g. sulfa- V=-XTyXI0" of the analysis Is 0.04 to 1.5 pg. NO_=/ml. For nilamlde in 700 ml. distilled water. Add, with 2 the efficiency stated in section 8.3, 50 ml. mixing, 50 ml. phosphoric acid (85 percent) V=Volume ofair sampled, n.1 absorbing reagent, and a sampling rate of and dilute to 1,000 ml. This solution Is stable F&=L.e'aured flow rate before canpling 200 ml./min. for 24 hours; the range of the for a month If refrigerated. ml./min. method is 20-740 pg./m.; (0.01-0.4 p.p.m.) 6.2.2 NEDA solution. Dissolve 0.5 g. N-(I- F5 =Memosured flow rate after sampling. nitrogen dioxide. naphthyl)-ethylenedlamine dihydrochloride mal./mln. 2.2 A nitrite concentration of 0.04 In distilled water. This solution is stable for T=Timo of sampling, rin. pg. Nc&/ml. will produce an absorbance of a month if refrigerated and protected from 10-0= Conversioln of mL to mA 0.02 with 1-cm. cells. light. 9.2 Calculate the concentration of nitro- 3. Interferences. 3.1 The interference of 6.2.3 Hydrogen peroxide. Dlute 02 ml. gen dioxide as pg. 11Orm/= sulfur dioxide is eliminated by conversion 30 percent hydrogen peroxide to 250 ml. with m. 0.Om) 1 to sulfuric acid with hydrogen peroxide be- distilled water. This solution I- stable for a fore analysisA month If protected from light. 4. Precision, accuracy., and stability. 4.1 62.4 Standard nitrite solution. Dlsolvo VX0.35 V The relative standard deviations are 14.4 sufficient desiccated sodium nitrito (NaNO. 50=Volumo of absorblng reagent uzed in percent and 21.5 percent at nitrogen dioxide assay of 97 percent or greater) and dilute sampling ml. concentrations of 140 pg./m.P (0.072 p.pxn.) with distilled water to 1,000 ml. so that a V=Volume of air sampled, m.s and 200 pg./m. (0.108 p.pm.). These data solution containing 100 1g. ,N /Il. is ob- 0,35=Effclency. are based on 10 samples collected from test tained. The amount of NaNO, to uce is calcu- atmospheres generated with 9.2.1 If desired, concentrtion of nitro- nitrogen dioxide lated as follows: permeation tubes are analyzed by automat- gon dioxido may be calculated as p.p.m. NOz at25 O. and 760mm. ing the procedure with a Technicon G=1.0X1000 Autoanalyzer. p.p.m.= (g. TOs/im) X5.319X10- 4.2 No accuracy data are available. G= Amount of NaNOv g. 10. Bibliography. L Jacobs, IL B. and 4.3 Collected samples are stable for at 1.500 = Gravlmetrlo factor In coverting 11O Hoobliear, S, "Continuous Sampling and least 6 weeks. into aTO_. Ultramicrodetermination of 71troen Dloside 5. Apparatus-5.1 Sampling. See Figure A= Assay, percent. In Air." Anal. Chem., 30 426 (1953). L 7. Proccdure-7.1 Sampling. Assemble the -. Morgan, G. B., Golden, C., and Tabor, 5.1.1 Absorber-Polypropylene tubes 164 sampling train as shown In Flagre L Add E.0., "Now and Improved Procedures for Gas by 32 mm., equipped with polypropylene two- 50 mL absorbing reagent to the absorber. Sampling and Analysis In the National Air port tube closures. Rubber stoppers cannot Dionnect funnel, Inert c4albrmtd flO7- Sampling lework. J. APCA 17 (5) 300-304 be used because high and varying blank meter, and measue flow beforo sampling. If (107). values are obtained. A gas dispersion tube flow rate before rampling Is less than 85 per- 3. Purdue, L. J., Dudley, J7. E., Clements. with a fritted disc of porosity B (70-100 pm. cent of needle calibration, check for Icak or J.B. and Thompson. n. J. "Studies In Air maximum pore diameter) Is used. change filters as necessary. Sample for 24 Sampling for 71trogen Dioxide." L A re- 5.1.1.1 Measurement of maximum pore hours and measure flow at end of sampling Inveotigation of the "Jacobs-Hochhelser Re- diameter of rit.Carefully clean the frit with period. aent. In Prepamtion.

FEDEA1. REGISTER, VOL 36, NO. 21-SATURDAY, JANUARY 30, 1971 1514 PROPOSED RULE MAKING

*4-®®~ OD~[~113

[PR Doc.71-1263 Fled 1-29-71;8:45 ami

FEDERAL REGISTER, VOL 36, NO. 21-ATURDAT JANUARY 30 1971. NOTICES 1515

pollutants, including fluorides, poly- 1970 (35 P.R. 4763) in the following doeu- ENVIRONMENTAL PROTECTION cyclic organic matter, and odorous sub- menti: stances, is being conducted, and the list Control Techniques for Carbon Monoxide, AGENCY Nitrog.en Oxide, and Hydrocarbon EmisIons will be revised as the Administrator from Mobile Sources (NAPCA Publication dee= appropriate. Accordingly, there Is No. AP--gi AIR POLLUTION PREVENTION AND hereby established a list of air pollutants Control Technique- for'Nltrogen Oxide CONTROL rniions; from Stationary Sources (NAPCA under section 108(a) (1) of the Act, as Publicantlon No.AP-Ci) List of Air Pollutants; Issuance of Air follows: The control techniques documents were transmitted to the Governor of each State, Quality Criteria LUsr or Am PoLLuvrATs and to the agency in esch State that Is des- Section 108(a)(1) of the Clean Air 1. rTvnoEru OXtaEs ignated by the Governor _ the official State air pollutlon control agency for purposes or Act, as amended December 31, 1970 Pursuant to sections 103 (a) and (d) of the (Public Law 91-604), directs the Ad- Clean Air Act, as amended December 31. the Act. ministrator of the Environmental Pro- 1970 (Public Law 91-C04) notice I-, hereby Pursuant to section 109(a) (2) of the tection Agency to publish, no later than given that the Adniinistratbr of the Environ- Clean Air Act, as amended, there are January 30, 1971, and from time to time mental Protection Agency, after consulta- tion with appropriate advisory commilttce, published in this issue of the FoDa'PA.L thereafter revise, a list that includes each experts, and Federal departments and agen- RtEcmrsn proposed national primary and air pollutant which in his judgment has cles in accordance with section 117(f) of the secondary ambient air quality standards an adverse effect on public health or Act, has today issued the document "Air for nitrogen oxides, which the Adminis- welfare, which is present in the ambient Quality Criteria for Nitrogen Oxides" (EPA trator is required to publish simultane- air as a result of emissions from numer- Publication No. AP-84). As required by the ously with the issuance of air quality cri- ous or diverse mobile or stationary Act, issuance of this document followa the terla and information on control tech- sources, and for which no air quality, inclusion of nitro-gen oxides In the list of air niques. criteria were issued prior to the enact- pollutants published above. Copies of the documents whose issu- ment of the amendments. Within twelve The air quality criteria reflect the late t ance Is announced herein are available scientific knowledge uEeful in Indicating the (12) months from the inclusion of a kind and extent of all identifiable efocts on to the general public from the Superin- pollutant on the. list, the Administrator public health or welfare which may be ex- tendent of Documents, Government is required to issue air quality criteria pected from the presence of nitrogen oxIdes Printing Office, Washington, D.C. 20402. for such pollutant. in varying quantities in the ambient air. WnxLnz D. Rucxzrs~us, The Administrator, after evaluating Notice is further glvin that the informa- Administrator. available information, has concluded that tion on control techniques for nitrogoen ox- nitrogen oxides clearly meet the above ides required to be issued pursuant to section JAr.uAy 25,1971. requirements. Evaluation of other air 108(b) of the Act was Issued on March 19. [FR Doc.71-12G4 Filed 1-29-71;8:45 am]

FEDERAL REGISTER, VOL 36, NO. 21-SATURDAY, JANUARY 30, 1971