Chemosphere,127,70-86,2015 1 2 Compilation and Analysis of Types and Concentrations of Airborne 3 Chemicals Measured in Various Indoor and Outdoor Human 4 Environments 5 6 7 8 9 1 2 10 J. Enrique Cometto-Muñiz and Michael H. Abraham 11 1 12 University of California, San Diego, La Jolla, California, USA and 2 13 Department of Chemistry, University College London, London, UK 14 15 16 17 18 19 20 Address for correspondence: 21 22 J. Enrique Cometto-Muñiz, Ph.D. 23 Research Scientist Emeritus, UCSD 24 8950 Villa La Jolla Drive, Suite C135 25 La Jolla, CA 92037 26 USA 27 28 29 Phone: (858) 622-5832 30 e-mail: [email protected] 31 32 33 34 35 36 37 38 39 40 Running head: Airborne Chemical Concentrations Indoors and Outdoors
41
1
41 Abstract
42
43 The main purpose of this article is to summarize and illustrate the results of a literature search on
44 the types, levels, relative concentrations, concentration spread of individual chemicals, and number of
45 airborne compounds (mostly volatile organic compounds, VOCs) that have been found, measured, and
46 reported both indoors and outdoors. Two broad categories of indoor environments are considered: 1)
47 Home/School, and 2) Commercial spaces. Also, two categories of outdoor environments are considered:
48 1) Non-industrial and 2) Industrial (the latter represented by the vicinity of a pig farm and the vicinity of an
49 oil refinery). The outcome is presented as a series of graphs and tables containing the following statistics:
50 geometric mean, arithmetic mean, median, standard deviation, variance, standard error, interquartile
51 distance, minimum value, maximum value, and number of data (data count) for the air concentration of
52 each reported compound in a given environment. A Supplementary Table allows interested readers to
53 match each single value included in this compilation with its corresponding original reference.
54
55
56 Keywords: Environmental Chemical Exposures - Volatile Organic Compounds (VOC) – Home/School
57 VOC Concentrations – Commercial Buildings VOC Concentrations – Outdoor VOC
58 Concentrations
59
2
59 1. Introduction
60
61 Humans are exposed to a wide variety of airborne chemicals both indoors and outdoors. Acute
62 awareness of such exposures often arises from chemosensory sensations, principally odor, nasal
63 chemesthesis (i.e., nasal pungency or irritation), and ocular chemesthesis (i.e., eye irritation). These
64 human chemosensations are the focus of our research interest (Cometto-Muniz and Abraham, 2008,
65 2010a; Cometto-Muñiz et al., 2010), with special emphasis on the search for quantitative structure-activity
66 relationships in terms of detection thresholds (Abraham et al., 2003; Abraham et al., 2007, 2012; Abraham
67 et al., 2010; Cometto-Muniz and Abraham, 2010b; Cometto-Muniz et al., 2005). In general, no matter what
68 the particular focus might be for the study of environmental chemical exposures, previous knowledge of
69 the kind and levels of airborne compounds that have been found in different types of broad environments
70 constitute an important piece of information. This reasoning led us to mine the scientific literature for data
71 on the types and concentration-ranges of airborne chemicals that have been found and measured in
72 indoor and outdoor environments. The questions addressed include: What compounds have been found in
73 various types of indoor and outdoor environments? At what concentrations where they found? Which
74 compounds are common to different indoor environments and which to different outdoor environments?
75 Which compounds are common between indoor and outdoor environments? For compounds common to
76 two environments, in which are they higher and by what concentration ratio? What spread of
77 concentrations have been reported for a given compound within and across these various environments?
78 This compilation presents the gathered data in the form of illustrative graphs and tables and can serve as
79 a useful and practical information guide for a wide range of investigators interested in the many aspects of
80 the topic.
81
82
83 2. Materials and Methods
84
3
85 Two main databases were used to collect data: PubMed (http://www.ncbi.nlm.nih.gov/pubmed)
86 and Web of Knowledge (https://apps.webofknowledge.com). The search terms entered alone and in
87 combination included, among others: “Air Pollution”, “Air Pollution, Indoor”, “Volatile Organic Compounds”,
88 “Environmental Exposure”, “VOC levels”. Some of these terms were searched on PubMed via the MeSH
89 (Medical Subject Headings) from the NLM (National Library of Medicine) controlled vocabulary thesaurus.
90 From this literature search, 47 references were selected by focusing on those articles tracking a large
91 number of volatiles, typically more than a dozen, and by filtering the results by “Species: Humans”. The set
92 contained quantitative data on the concentration and identity of volatile organic compounds (VOCs), and
93 other airborne chemicals, present in a variety of indoor and outdoor environments. The geographical
94 distribution of the studies was very broad. It included areas and cities in the United States, European
95 Union (north, central and south countries), Japan, China (Hong Kong), Taiwan, Korea, Australia and
96 Argentina (La Plata). The references are listed at the end of this article under the title “Data Sources
97 References”, but readers interested in consulting the specific citation for each single value used in this
98 compilation can do so in a Supplementary Table accessible on the web. These papers constituted the
99 source to calculate the following statistics: geometric mean, arithmetic mean, median, standard deviation,
100 variance, standard error, interquartile distance, minimum value, maximum value, and number of data (data
101 count) for the air concentration of each reported compound in a given environment. The values presented
102 immediately below are geometric means across studies that measured a particular compound in a specific
103 environment (Tables 1 to 4, and Figures 1 to 6). In fact, as a rule, each value reported in a given study
104 was itself an average of a number of measurements. In this review, initial selection of the geometric mean
105 served to minimize the excessive weight on the mean of occasional extreme high or low individual values.
106 Further into the article, when analyzing the range of values reported for each chemical in specific
107 environments (Tables 5 to 7, and Figures 7 to 8), the rest of the statistical parameters mentioned above
108 are introduced.
109
110 3. Results and Discussion
111
4
112 3.1. Indoors
113
114 Indoor environments comprised two broad categories: 1) Home and School, and 2) Commercial.
115 The first category included homes new and old, with and without air quality complaints, homes and
116 schools located in industrial, urban, suburban, residential, semi-rural and rural environments. The second
117 category included car cabins, restaurants (non-smoking, smoking, and both), stores, non-residential
118 spaces (offices and non-offices) and newspaper stands. It did NOT include the air inside a pig farm’s
119 fattening house.
120
121 In the home/school environments, 152 volatiles were measured and reported (Figure 1, left side).
122 22 of them (14%) were present at concentrations ranging from approximately 10 to 200 µg/m3. 44
123 compounds (29%) were present at concentrations ranging from about 3 to 10 µg/m3. Another 44
124 substances (29%) were present at concentrations ranging from 0.55 to about 3 µg/m3. The remaining 42
125 chemicals (28%) were present at concentrations ranging from 0.01 to about 0.55 µg/m3.
126
5 1000 1000 Indoor Home/School GeoMean(!g/m3) Indoor Commercial GeoMean(!g/m3) VOCs 1 to 22 VOCs 1 to 22 g/m3) g/m3) ! ! ( Indoor Home/School ( Indoor Commercial
100 100 Concentration Concentration Mean Mean
10 10 Geometric Geometric Ethanol Toluene Nonanal Xylenes Acetone 3-Carene Ammonia 1-Butanol n-Decane Limonene Isobutane n-Heptane
VOC Ethanol Toluene 2-Propanol Nicotine Acetone Acetic Acid p-Xylene Isoprene m-Xylene Ammonia Ethylacetate
Dodecane VOC Acetaldehyde m/p-Xylene Formaldehyde Ethylacetate Propylene glycol Acetaldehyde Formaldehyde Isobutyl acetate Nonane (n-Nonane) Tetrahydrofuran Dichloromethane Tetrachloroethylene 1,1,1-Trichloroethane 1,2,4-Trichlorobenzene Methyl ethyl ketone (MEK) MTBE (methyl tert-butyl ether) 2-(2-Ethoxyethoxy) ethanol Isobutylketone (diisobutyl ketone) Isopropyl alcohol (Isopropanol) Trichlorofluoromethane (Freon 11)
10 10 Indoor Home/School GeoMean(!g/m3) Indoor Commercial GeoMean(!g/m3) VOCs 23 to 66 VOCs 23 to 66
8 8 g/m3) g/m3) ! !
6 6
4 4
2 2 Indoor Commercial GeoMean( Indoor Home/School GeoMean(
0 0 Xylene Octanal Xylene Heptanal Isoprene p-Xylene n-Octane n-Hexane Nonanal Xylenes Isooctane Dodecane Benzene o-Xylene n-Octane Isopentane Camphene n-Decane n-Hexane 1-Butanol m/p-Xylene Limonene n-Heptane Nitrous acid n-Tridecane n-Undecane Chloroform alpha-Pinene Cyclohexane Acetic Acid 2-Butanone n-Undecane Hexanoic acid Benzaldehyde Cyclohexane alpha-Pinene Ethylbenzene Ethylene glycol n-Butyl acetate 1,3-Butadiene Hexanoic acid Benzaldehyde p-Chlorotoluene Trichloroethene m-Chlorotoluene n-Butyl acetate 1,2-Propanediol Trichloroethylene Furfuryl aldehyde 3-Ethenylpyridine Methylcyclohexane 2-Methyl-1-propanol 2-Ethoxyethylactate 1,1-Dichloropropene Cyclopropylbenzene 2,3-Dimethylpentane 2,4-Dimethylpentane Methylcyclohexane Dichlorofluoromethane Hexaldehyde (Hexanal) 1,2,4-Trimethylbenzene Dichlorodifluoromethane 2,2,4-Trimethylpentane trans-1,2-Dichloroethene Hexaldehyde (Hexanal) 1,2,4-Trimethylbenzene 1,3,5-Trimethylbenzene Methyl ethyl ketone (MEK) Butanal (n-Butyraldehyde) VOC 23-66 Dichlorodifluoromethane Crotonaldehyde (2-Butenal) Hexachloro-1,3-butadiene 1,1,2,2-Tetrachloroethane Propanal (Propionaldehyde) Propanal (Propionaldehyde) Methyl isobutyl ketone (MIBK) 4-Ethyltoluene (p-Ethyltoluene) MTBE (methyl tert-butyl ether) iso-Pentanal (iso-Valeraldehyde) 4-Ethyltoluene (p-Ethyltoluene) 3-Ethyltoluene (m-Ethyltoluene) Methylchloride (chloromethane) Decamethylcyclopentasiloxane Trichlorofluoromethane (Freon 11) 1,4-Dichlorobenzene (p-Dichlorobenzene) 1,4-Dichlorobenzene (p-Dichlorobenzene) 1,2-Dichlorobenzene (o-Dichlorobenzene) 3 1,3-Dichlorobenzene (m-Dichlorobenzene) Indoor Home/School GeoMean(!g/m3) 3 VOCs 67-110 Indoor Commercial GeoMean(!g/m3) VOC 23-66 VOCs 67-96 g/m3) ! g/m3) ! 2 2
1 1 Indoor Home/School GeoMean( Indoor Commercial GeoMean(
0 0 Phenol Glyoxal Styrene Decanal Acrolein Benzene o-Xylene Freon 12 Freon 114 Freon 113 n-Pentane 2-Butanone beta-Pinene Naphthalene Ethylbenzene Methylglyoxal Cycloheptane Butylbenzene n-Tetradecane n-Hexadecane Propylbenzene Chlorobenzene n-Pentadecane 2-Butoxyethanol 2-Methylpentane Isovaleraldehyde Ethylcyclohexane tert-Butylbenzene Tetrachloroethene Methylene chloride 1,1-Dichloroethene Methylcyclopentane 1,2-Dichloropropane Carbon tetrachloride 1,1,1-Trichloroethane Hexachlorobutadiene 1-Methoxy-2-propanol Phenol Styrene 1,2,3-Trimethylbenzene Pyridine Pentanal (Valeraldehyde) 3-Picoline Freon 113 trans-1,3-Dichloropropene Naphthalene Ethylchloride Vinyl chloride Cyclohexanol Acetophenone 2-Ethyltoluene (o-Ethyltoluene) Chlorobenzene 3-Ethyltoluene (m-Ethyltoluene) Bromomethane Benzyl chloride Methylchloride (chloromethane) Trichloroethene Methyl-benzoate 2-Ethyl-1-hexanol 2-Phenoxyethanol Perchloroethylene Methylene chloride 1,2-Dibromoethane 1,1-Dichloroethane 1,2-Dichloroethane 1,1-Dichloroethene 1,2-Dichloroethene Methylbenzaldehyde (Tolualdehyde) Carbon tetrachloride 1,1,2-Trichloroethane
0.6 1,2,3-Trimethylbenzene VOC 67-110 Indoor Home/School GeoMean(!g/m3) VOC 67-96 1,2-Dichlorotetrafluoroethane VOCs 111-152 Methyl isobutyl ketone (MIBK) g/m3) 1,1,2-Trichlorotrifluoroethane (Trichlorotrifluoro !
0.4
0.2 Indoor Home/School GeoMean(
0.0 2-Carene Chloroform Bromoform Acrylonitrile Vinyl acetate Chloroethane Vinyl chloride 1,3-Butadiene 3-Ethylhexane Bromobenzene Benzyl chloride Bromomethane 2-Methylhexane o-Chlorotoluene Tetrahydrofuran 2-Ethoxyethanol Carbon disulfide Isopropylbenzene Trichloroethylene 3-Ethenylpyridine sec-Butylbenzene 2-Methoxyethanol Ethylmethacrylate p-Isopropyltoluene 1,1-Dichloroethane 1,2-Dichloroethane 1,2-Dibromoethane Tetrachloroethylene Methyl methacrylate 1,1,2-Trichloroethane cis-1,2-Dichloroethene 1,2,3-Trichloropropane 1,2,4-Trichlorobenzene 1,2,3-Trichlorobenzene 1,3,5-Trimethylbenzene Bromodichloromethane Dibromochloromethane cis-1,3-Dichloropropene 1-Methyl-2-pyrrolidinone 126 1,1,2,2-Tetrachloroethane 6
VOC 111-152 1,2-Dichlorobenzene (o-Dichlorobenzene) 1,3-Dichlorobenzene (m-Dichlorobenzene)
127 Figure 1. Comparison of VOC concentrations (geometric means) measured in two types of indoor environments:
128 Home/School and Commercial.
129
130 In the commercial environments, 96 volatiles were measured and reported (Figure 1, right side). 22
131 of them (23%) were present at concentrations ranging from approximately 8 to 1,000 µg/m3. 44
132 compounds (46%) were present at concentrations ranging from about 2 to 7 µg/m3. The remaining 29
133 substances (30%) were present at concentrations ranging from 0.30 to about 2 µg/m3.
134
135 There were 74 measured compounds common to both indoor environments: home/school and
136 commercial (Figure 2 and Table 1). Of those, 32 (43%) were higher in home/school, 40 (54%) were higher
137 in commercial, and the remaining 2 were present at similar levels in both environments. From those
138 chemicals higher in home/school environments, only 2 were higher by a factor (i.e., ratio) larger than 10:
139 1-butanol (factor of 25) and trichloroethene (factor of 12), and just one was higher by a factor between 5
140 and 10: nonanal (factor of 6.0). The other 29 chemicals were higher by smaller factors ranging from 1.1 to
141 4.6. In contrast, from those chemicals higher in commercial environments, 5 were higher by factors larger
142 than 10: tetrachloroethylene (factor of 68), 1,2,4-trichlorobenzene (58), tetrahydrofuran (19), 1,3-
143 dichlorobenzene (17), and 1,3,5-trimethylbenzene (13), and as many as 7 were higher by factors between
144 5 and 10: trichloroethylene (factor of 9.7), 3-ethenylpyridine (8.2), 1,2-dibromoethane (7.1), 1,1,1-
145 trichloroethane (6.2), ethanol (5.2), acetone (5.1), and 1,2-dichlorobenzene (5.1). The remaining 28
146 chemicals were higher by smaller factors ranging from 1.2 to 4.8.
147
7
103 Indoor Home/School Geo Mean (!g/m3) Indoor Home/School Geo Mean (!g/m3) Indoor Commercial Geo Mean (!g/m3) Indoor Commercial Geo Mean (!g/m3) g/m3) g/m3) ! VOCs 1 to 37 VOCs 38 to 74 ! 2 10 101
101
100
100 Geometric Mean Concentration ( Geometric Mean Concentration ( -1 10 10-1 Xylene Ethanol Toluene Nonanal Xylenes Phenol Acetone p-Xylene Isoprene n-Octane Styrene 1-Butanol Ammonia n-Hexane n-Decane Limonene n-Heptane Dodecane Benzene o-Xylene Freon 113 m/p-Xylene Acetic Acid n-Undecane Chloroform Ethylacetate 2-Butanone alpha-Pinene Cyclohexane Acetaldehyde Naphthalene Hexanoic acid Formaldehyde Ethylbenzene Vinyl chloride 1,3-Butadiene n-Butyl acetate Benzaldehyde Trichloroethene Chlorobenzene Benzyl chloride Bromomethane Tetrahydrofuran Trichloroethylene 3-Ethenylpyridine Methylcyclohexane Methylene chloride 1,1-Dichloroethene 1,1-Dichloroethane 1,2-Dichloroethane 1,2-Dibromoethane Tetrachloroethylene Carbon tetrachloride 1,1,1-Trichloroethane 1,1,2-Trichloroethane Hexachlorobutadiene 1,2,4-Trimethylbenzene Hexaldehyde (Hexanal) 1,2,4-Trichlorobenzene 1,3,5-Trimethylbenzene 1,2,3-Trimethylbenzene Dichlorodifluoromethane Methyl ethyl ketone (MEK) VOCs (1 to 37) VOCs (38 to 74) 1,1,2,2-Tetrachloroethane Propanal (Propionaldehyde) Methyl isobutyl ketone (MIBK) MTBE (methyl tert-butyl ether) 4-Ethyltoluene (p-Ethyltoluene) 3-Ethyltoluene (m-Ethyltoluene) Methylchloride (chloromethane) Trichlorofluoromethane (Freon 11) 1,2-Dichlorobenzene (o-Dichlorobenzene) 1,4-Dichlorobenzene (p-Dichlorobenzene) 1,3-Dichlorobenzene (m-Dichlorobenzene)
147 Figure 2. Comparison of concentrations (geometric means) for indoor VOCs found in common between
148 Home/School and Commercial environments.
149
8
149 Table 1. Comparison of vapor concentration levels for indoor volatile compounds common to 150 Home/School and Commercial environments (ratios based on geometric means). Compounds are listed in 151 descending magnitude of ratio. Bolded chemicals were higher in their respective environment by a ratio 152 (i.e., factor) larger than 10. 153 Volatiles higher in Home/School Ratio Volatiles higher in Commercial Ratio environments environments 1-Butanol 25 Tetrachloroethylene 68 Trichloroethene 12 1,2,4-Trichlorobenzene 58 Nonanal 6.0 Tetrahydrofuran 19 Methyl isobutyl ketone (MIBK) 4.6 1,3-Dichlorobenzene (m-Dichlorobenzene) 17 Methyl tert-butyl ether (MTBE) 3.9 1,3,5-Trimethylbenzene 13 Acetic acid 3.7 Trichloroethylene 9.7 Trichlorofluoromethane (Freon 11) 3.7 3-Ethenylpyridine (3-Vinylpyridine) 8.2 Formaldehyde 3.6 1,2-Dibromoethane 7.1 n-Decane 3.3 1,1,1-Trichloroethane 6.2 Xylene(s) 2.8 Ethanol 5.2 alpha-Pinene 2.8 Acetone 5.1 Limonene 2.7 1,2-Dichlorobenzene (o-Dichlorobenzene) 5.1 1,4-Dichorobenzene (p- 2.4 1,3-Butadiene 4.8 Dichlorobenzene) Naphthalene 2.3 1,1,2,2-Tetrachloroethane 4.8 n-Butyl acetate 2.2 3-Ethyltoluene (m-Ethyltoluene) 4.4 1,1-Dichloroethene 2.2 Chloroform 4.1 n-Hexane 2.1 Bromomethane 3.9 Ammonia 2.0 Methyl ethyl ketone (MEK) 3.8 Methylcyclohexane 1.9 Toluene 3.0 n-Heptane 1.7 Isoprene 2.4 n-Undecane 1.7 Dodecane 2.3 Benzaldehyde 1.7 1,1-Dichloroethane 2.2 Propanal 1.5 o-Xylene 2.1 4-Ethyltoluene (p-Ethyltoluene) 1.5 2-Butanone 2.0 Carbon tetrachloride 1.5 Benzene 1.9 Acetaldehyde 1.4 1,2-Dichloroethane 1.9 Hexanal 1.3 Vinyl chloride 1.9 n-Octane 1.2 p-Xylene 1.8 Dichlorodifluoromethane 1.1 Hexachlorobutadiene 1.8 Cyclohexane 1.1 m/p-Xylene 1.7 Phenol 1.1 Ethylbenzene 1.6 1,2,3-Trimethylbenzene 1.1 Styrene 1.6 Hexanoic acid 1.0 Benzyl chloride 1.6 1,1,2-Trichloroethane 1.4 Ethylacetate 1.3 1,2,4 Trimethylbenzene 1.3 Methylchloride (Chloromethane) 1.3 Chlorobenzene 1.2 Methylene chloride 1.2 1,1,2-Trichloro-1,2,2-trifluoroethane (Freon 1.2 113) 154 Total: 33 Total:40
9
155
156 When analyzed in terms of chemical families, the commercial environments had, in general, higher
157 concentrations and numbers of halogenated aromatics, halogenated aliphatics, non-halogenated
158 aromatics, and ketones, whereas the home/school environments had higher concentrations and numbers
159 of carboxylic acids, aldehydes, lineal aliphatics, and cyclic aliphatics (Table 2).
160
10
160 Table 2. List of volatiles, sorted by chemical type, found at higher concentrations (geometric means) in 161 each of the two Indoor environments selected. Bolded chemicals were higher in their respective 162 environment by a factor (i.e., ratio) larger than 10. 163 Volatiles higher in Home/School environment Volatiles higher in Commercial environment Halogenated Aromatics 1,4-Dichorobenzene (p-Dichlorobenzene) Chlorobenzene Benzyl chloride 1,2-Dichlorobenzene (o-Dichlorobenzene) 1,2,4-Trichlorobenzene 1,3-Dichlorobenzene (m-Dichlorobenzene) Halogenated Aliphatics Trichlorofluoromethane (Freon 11) 1,1,1-Trichloroethane Dichlorodifluoromethane Hexachlorobutadiene Trichloroethene Methylchloride (Chloromethane) 1,1-Dichloroethene Methylene chloride Carbon tetrachloride 1,1,2-Trichloro-1,2,2-trifluoroethane (Freon 113) Chloroform 1,1,2-Trichloroethane 1,1,2,2-Tetrachloroethane 1,1-Dichloroethane Trichloroethylene 1,2-Dichloroethane Bromomethane Tetrachloroethylene Vinyl chloride 1,2-Dibromoethane Non-Halogenated Aromatics Xylene(s)? Toluene Benzaldehyde p-Xylene 4-Ethyltoluene (p-Ethyltoluene) m/p-Xylene Naphthalene 1,2,4 Trimethylbenzene Phenol Benzene 1,2,3-Trimethylbenzene Ethylbenzene o-Xylene 3-Ethyltoluene (m-Ethyltoluene) Styrene 3-Ethenylpyridine (3-Vinylpyridine) 1,3,5-Trimethylbenzene Carboxylic Acids Acetic acid Hexanoic acid Aldehydes Formaldehyde Acetaldehyde Nonanal Propanal Hexanal (Benzaldehyde) Ketones Methyl isobutyl ketone (MIBK) Acetone Methyl ethyl ketone (MEK) 2-Butanone Alcohols 1-Butanol Ethanol 11
Volatiles higher in Home/School environment Volatiles higher in Commercial environment Esters n-Butyl acetate Ethylacetate Ethers Methyl tert-butyl ether (MTBE) Tetrahydrofuran Lineal Aliphatics n-Decane Dodecane n-Heptane Isoprene n-Undecane 1,3-Butadiene n-Hexane n-Octane Cyclic Aliphatics Limonene (Tetrahydrofuran) Alpha-Pinene Methylcyclohexane Cyclohexane Inorganic Ammonia 164
165
12
165
166 3.2. Outdoors
167
168 Outdoor environments comprised two broad categories: 1) Non-industrial and 2) Industrial. The
169 non-industrial environments included urban, residential, and semi-rural spaces. The industrial
170 environments did include the cases of the air in the vicinity of a pig farm and in the vicinity of an oil
171 refinery.
172
173 In the air of non-industrial environments, 54 volatiles were measured and reported (Figure 3, left
174 side). 30 of them (56%) were present at concentrations ranging from 0.80 to 12 µg/m3. The remaining 24
175 compounds (44%) were present at concentrations ranging from 0.02 to 0.71 µg/m3.
176
13
Outdoor Non-industrial Outdoor Industrial
Outdoor Non-Industrial Geom. Mean (!g/m3) Outdoor Industrial Geom. Mean (!g/m3) VOCs 1 to 30 VOCs 1 to 30
102 102 g/m3) ! g/m3) !
1 101 10 Outdoor Ind.Geom. Mean ( Outdoor Non-Ind.Geom. Mean (
0 100 10 Indole Phenol Ethanol Toluene Nonane Ethanol Xylenes Toluene Nonane Methane Nonanal Benzene Acetone 3-Carene n-Octane p-Xylene Benzene o-Xylene 1-Butanol n-Decane n-Hexane n-Octane n-Decane m-Xylene n-Hexane n-Heptane 1-Pentanol n-Pentane n-Heptane 1-Propanol m/p-Xylene Isopentane m/p-Xylene n-Undecane 2-Butanone n-Undecane Cyclobutanol Ethylacetate 2-Butylamine Ethylbenzene Cyclohexane Ethylbenzene 2-Pentylamine Benzaldehyde Dipropyl sulfide n-Butyl acetate Isobutyl acetate 2-Methylpentane Trichloroethylene Methyl mercaptan
VOC (1-30) 2-Methyl-1-propanol Methylcyclopentane Tetrachloroethylene Isopropyl mercaptan Hexanal (Hexaldehyde)
Hexanal (Hexaldehyde) 1,2,3-Trimethylbenzene VOC (1-30) Trichlorotrifluoroethane Butanal (Butyraldehyde) Pentanal (Valeraldehyde)
1 101 10 Outdoor Non-Industrial Geom. Mean (!g/m3) Outdoor Industrial Geom. Mean (!g/m3) VOCs 31 to 54 VOCs 31 to 45 g/m3) ! g/m3)
0 ! 10 100
-1 10 10-1 Outdoor Ind.Geom. Mean ( Outdoor Non-Ind.Geom. Mean (
10-2 10-2 Styrene o-Xylene Tridecane n-Dodecane Naphthalene Phenol Methyl sulfide Styrene Diethyl sulfide 1-Butanol Tridecane Butyl mercaptan Ethyl mercaptan Chloroform d-Limonene n-Dodecane beta-Pinene Naphthalene Methyl ethyl sulfide alpha-Pinene Cyclohexanol Methyl propyl sulfide Acetophenone Carbonyl sulfide (COS) Methyl-benzoate 2-Ethyl-1-hexanol Trichloroethylene Methylene chloride Carbon tetrachloride 1,2,4-Trimethylbenzene p-Ethyltoluene (4-Ethyltoluene) VOC (31-45) 2-Ethyltoluene (o-Ethyltoluene) 3-Ethyl-toluene (m-Ethyltoluene) Methyl isobutyl ketone (MIBK) Isopropyl alcohol (Isopropanol) 2-Ethyltoluene (o-Ethyltoluene) p-Ethyltoluene (4-Ethyltoluene) 3-Ethyl-toluene (m-Ethyltoluene) VOC (31-54) 1,4-Dichlorobenzene (p-Dichlorobenzene) 176 Figure 3. Comparison of VOC concentrations (geometric means) measured in two types of outdoor environments:
177 Non-industrial and Industrial.
178
179
14
179
180 In industrial environments (including the vicinity of the pig house), 45 volatiles were measured and
181 reported (Figure 3, right side). 30 of them (67%) were present at concentrations ranging from 3.3 to 108
182 µg/m3. The remaining 15 compounds (33%) were present at concentrations ranging from 0.10 to 3.1
183 µg/m3.
184
185 There were 23 measured compounds common to both outdoor environments: non-industrial and
186 industrial (Figure 4 and Table 3). All of them but one (ethanol) were higher in the industrial environment.
187 Ethanol was higher in the non-industrial environment by a factor (i.e., ratio) of 2.5. The other 22 chemicals
188 were higher in the industrial environment by factors ranging from 1.3 to 403. From these, 2 substances
189 were higher by a factor larger than 100: trichloroethylene (factor of 403) and phenol (317); 4 substances
190 were higher by a factor larger than 10: hexanal (18), 1-butanol (17), n-hexane (12), and tridecane (11);
191 and 5 substances were higher by a factor between 5 and 10: n-heptane (7.3), benzene (6.3),
192 ethylbenzene (6.0), nonane (5.7), and n-octane (5.1). The remaining 11 substances were higher by
193 smaller factors ranging from 1.3 to 4.8.
194
15
194
102 Outdoor Non-Industrial Geo Mean (!g/m3) Outdoor Industrial Geo Mean (!g/m3) VOCs 1 to 23 g/m3) ! 101
100
10-1 Geometric Mean Concentration (
10-2 Phenol Ethanol Toluene Nonane Styrene o-Xylene Benzene n-Octane n-Hexane n-Decane 1-Butanol Tridecane n-Heptane m/p-Xylene n-Undecane n-Dodecane Naphthalene Ethylbenzene
VOC Trichloroethylene Hexanal (Hexaldehyde) p-Ethyltoluene (4-Ethyltoluene) 2-Ethyltoluene (o-Ethyltoluene) 3-Ethyl-toluene (m-Ethyltoluene)
195
196 Figure 4. Comparison of concentrations (geometric means) for outdoor VOCs found in common between Non-
197 industrial and Industrial environments.
198
199
16
199 Table 3. Comparison of vapor concentration levels for outdoor volatile compounds common to Non- 200 industrial and Industrial environments (ratios based on geometric means). Compounds are listed in 201 descending magnitude of ratio. Bolded chemicals were higher in their respective environment by a ratio 202 (i.e., factor) larger than 10. 203 Volatiles higher in Non-industrial Ratio Volatiles higher in Industrial Ratio environments environments Ethanol 2.5 Trichloroethylene 403 Phenol 317 Hexanal (Hexaldehyde) 18 1-Butanol 17 n-Hexane 12 Tridecane 11 n-Heptane 7.3 Benzene 6.3 Ethylbenzene 6.0 Nonane 5.7 n-Octane 5.1 n-Decane 4.8 m/p-Xylene 4.6 n-Dodecane 4.4 Toluene 4.0 n-Undecane 3.5 p-Ethyltoluene (4-Ethyltoluene) 3.2 2-Ethyltoluene (o-Ethyltoluene) 3.2 Styrene 2.5 3-Ethyl-toluene (m-Ethyltoluene) 1.8 o-Xylene 1.4 Naphthalene 1.3 204
205
17
205
206 3.3 Indoor vs. Outdoor
207
208 All indoor environments were combined and compared with the combined outdoor environments.
209 There were a total of 175 compounds reported and measured indoors (Figure 5, left side). 32 of them
210 (18%) were present at concentrations ranging from 8 to 267 µg/m3. Another 57 compounds (33%) ranged
211 from 2 to 8 µg/m3. Next, 59 compounds (34%) ranged between 0.50 and 2 µg/m3. Finally, 27 compounds
212 (15%) ranged between 0.01 and 0.5 µg/m3.
213
18
213
INDOOR OUTDOOR
Outdoor Geom. Mean (!g/m3) Indoor Geom. Mean (!g/m3) VOCs 1-19 VOCs 1 to 30 g/m3) 2 ! 2 g/m3) 10 (
10 ! ( Concentration Concentration
1 10 101 Mean Mean Geometric Geometric
100 100 Indole Toluene Xylenes Hexanal Methane Acetone Pentanal p-Xylene 3-Carene m-Xylene 1-Pentanol Cyclobutanol 2-Butylamine 2-Pentylamine Dipropyl sulfide Methyl mercaptan 2-Methyl-1-propanol Methylcyclopentane Isopropyl mercaptan Ethanol Toluene Nonanal Nicotine Acetone Heptanal p-Xylene 3-Carene 1-Butanol m-Xylene Ammonia n-Decane Isobutane Limonene n-Heptane Dodecane 2-Propanol Acetic Acid Ethylacetate Acetaldehyde Formaldehyde Ethylene glycol Isobutyl acetate Propylene glycol Dichloromethane Nonane (n-Nonane) VOCs 1-30 (Indoor) 2-Methyl-1-propanol VOCs 1-30 (Indoor) Isopropyl alcohol (Isopropanol) Isobutylketone (diisobutyl ketone) Trichlorofluoromethane (Freon 11)
6 Indoor Geom. Mean (!g/m3) Outdoor Geom. Mean (!g/m3) VOCs 31 to 60 VOCs 20-38 8
5 g/m3) ! g/m3) ( ! (
6 4
3 Concentration
4 Concentration Mean Mean 2
2
1 Geometric Geometric
0 0 Phenol Ethanol Hexane Butanal Decane Nonanal Propanol Benzene o-Xylene n-Octane 1-Butanol n-Pentane n-Heptane Isopentane m/p-Xylene Ethylacetate Cyclohexane Xylene Octanal Hexane Xylenes Isoprene Isooctane n-Undecane Nitrous acid Xylene (p,m) alpha-Pinene Butyl acetate Carbonyl sulfide (COS) Hexanoic acid Trichlorotrifluoroethane 1,2-Propanediol p-Chlorotoluene p-Dichlorobenzene 2-Ethoxyethylactate 1,1-Dichloropropene
1,1,1-Trichloroethane VOCs 1-30 (Indoor) Dichlorofluoromethane 2,2,4-Trimethylpentane Hexaldehyde (Hexanal)
VOCs 1-30 (Indoor) trans-1,2-Dichloroethene Methyl ethyl ketone (MEK) Butanal (n-Butyraldehyde) 2-(2-Ethoxyethoxy) ethanol Crotonaldehyde (2-Butenal) Propanal (Propionaldehyde) MTBE (methyl tert-butyl ether) Decamethylcyclopentasiloxane Dichlorodifluoromethane (Freon 21)
Indoor Geom. Mean (!g/m3) 4 Outdoor Geom. Mean (!g/m3) VOCs 61-90 1.5 VOCs 39-57 g/m3) g/m3) ! ( ! (
3
1.0
2 Concentration Concentration Mean Mean 0.5
1 Geometric Geometric
0 0.0 Glyoxal Nonane Benzene o-Xylene n-Octane Tridecane n-Pentane Isopentane Camphene Undecane 2-Butanone beta-Pinene 2-Butanone Cyclohexane Ethylbenzene Methylglyoxal alpha-Pinene Benzaldehyde Ethylbenzene Methyl sulfide Benzaldehyde Diethyl sulfide n-Butyl acetate Isobutyl acetate 2-Butoxyethanol m-Chlorotoluene 2-Methylpentane Butyl mercaptan Furfuryl aldehyde 2-Ethyl-1-hexanol Methylcyclohexane Methyl ethyl sulfide Cyclopropylbenzene Tetrachloroethylene 2,3-Dimethylpentane 2,4-Dimethylpentane VOCs 1-30 (Indoor) Methyl propyl sulfide 1,2,4-Trichlorobenzene 1,2,4-Trimethylbenzene 1,2,3-Trimethylbenzene
Pentanal (Valeraldehyde)
Hexachloro-1,3-butadiene 19 VOCs 1-30 (Indoor) trans-1,3-Dichloropropene Methyl isobutyl ketone (MIBK) 4-Ethyltoluene (p-Ethyltoluene) 4-Ethyltoluene (p-Ethyltoluene) 3-Ethyltoluene (m-Ethyltoluene) iso-Pentanal (iso-Valeraldehyde) 3-Ethyl-toluene (m-Ethyltoluene)
INDOOR OUTDOOR
2.0 Indoor Geom. Mean (!g/m3) 0.5 Outdoor Geom. Mean (!g/m3) VOCs 91-120 VOCs 58-76 g/m3) ! g/m3) ( !
1.5 ( 0.4
0.3 1.0 Concentration Concentration
0.2 Mean Mean 0.5
0.1 Geometric Geometric 0.0 0.0
VOCs 1-30 (Indoor) Styrene Tridecane Dodecane Chloroform d-Limonene Isopropanol beta-Pinene Phenol Naphthalene Styrene Cyclohexanol Decanal Pyridine Acrolein Acetophenone 3-Picoline Ethyl mercaptan Methyl-benzoate Trichloroethylene p-Dichlorobenzene Naphthalene Methylene chloride 1,3-Butadiene Cycloheptane n-Tetradecane n-Hexadecane Carbon tetrachloride n-Pentadecane Chlorobenzene VOCs 1-30 (Indoor) Tetrahydrofuran Methyl isobutyl ketone 1,2,4-Trimethylbenzene Isovaleraldehyde 2-Ethyl-1-hexanol 3-Ethenylpyridine 2-Phenoxyethanol Ethylcyclohexane Perchloroethylene Tetrachloroethene Methylcyclopentane Tetrachloroethylene Hexachlorobutadiene 1,2,3-Trimethylbenzene Trichlorotrifluoroethane 2-Ethyltoluene (o-Ethyltoluene) 1,1,2,2-Tetrachloroethane 2-Ethyltoluene (o-Ethyltoluene) Methylchloride (chloromethane) 1,2-Dichlorobenzene (o-Dichlorobenzene)
Indoor Geom. Mean (!g/m3) VOCs 121-150
1.0 g/m3) ! ( Concentration 0.5 Mean Geometric
0.0
VOCs 1-30 (Indoor) Freon 12 Freon 114 Freon 113 Chloroform Cyclohexanol Butylbenzene Acetophenone Propylbenzene Benzyl chloride Bromomethane Trichloroethene 2-Methylpentane Trichloroethylene tert-Butylbenzene sec-Butylbenzene 1,2-Dibromoethane Methylene chloride 1,1-Dichloroethene 1,1-Dichloroethane 1,2-Dichloroethane 1,2-Dichloropropane Carbon tetrachloride 1,1,2-Trichloroethane 1-Methoxy-2-propanol cis-1,2-Dichloroethene 1,3,5-Trimethylbenzene Bromodichloromethane cis-1,3-Dichloropropene 1,2-Dichlorotetrafluoroethane Methylbenzaldehyde (Tolualdehyde)
0.5 Indoor Geom. Mean (!g/m3) VOCs 151-175 g/m3) !
( 0.4
0.3 Concentration 0.2 Mean
0.1 Geometric 0.0
VOCs 1-30 (Indoor) 2-Carene Bromoform Acrylonitrile Vinyl acetate Ethylchloride Chloroethane Vinyl chloride 3-Ethylhexane Bromobenzene o-Chlorotoluene 2-Methylhexane 2-Ethoxyethanol Carbon disulfide Methyl-benzoate Isopropylbenzene 2-Methoxyethanol Ethylmethacrylate p-Isopropyltoluene 1,2-Dichloroethene Methyl methacrylate 1,2,3-Trichloropropane 1,2,3-Trichlorobenzene Dibromochloromethane 1-Methyl-2-pyrrolidinone
213 1,3-Dichlorobenzene (m-Dichlorobenzene) 20
214 Figure 5. Comparison of VOC concentrations (geometric means) measured Indoors and Outdoors.
215
216 There were a total of 76 compounds reported and measured outdoors (Figure 5, right side). 19 of
217 them (25%) were present at concentrations ranging from 7 to 108 µg/m3. Another 15 compounds (20%)
218 ranged from 2 to 6 µg/m3. Next, 24 compounds (32%) ranged from 0.50 to 2.0 µg/m3. Finally, 18
219 compounds (24%) ranged from 0.02 to 0.50 µg/m3.
220
221 There were 58 measured compounds in common to both indoor and outdoor environments (Figure
222 6 and Table 4). Of those, only 11 (19%) were higher outdoors whereas 44 (76%) were higher indoors and
223 3 (5%) were at about the same concentration outdoors and indoors. Those at the same concentration
224 were: benzene (at 3.4 µg/m3), carbon tetrachloride (at 0.5 µg/m3), and methyl benzoate (at 0.3 µg/m3).
225 From the 11 compounds that were higher outdoors, two were higher by a factor (i.e., ratio) greater than
226 ten: pentanal (factor of 30) and methylcyclopentane (21). Another two were higher outdoors by a factor
227 between 5 and 10: 2-methyl-1-propanol (factor of 6.6) and the “xylenes” (no specification of isomer in the
228 original sources) (factor of 6.2). The other 7 compounds were higher outdoors by smaller factors ranging
229 from 1.1 to 2.1. Curiously, 5 of the 11 compounds that were higher outdoors than indoors were derivatives
230 of pentane: n-pentane, isopentane, pentanal, methylcyclopentane, and 2-methylpentane. From the 44
231 compounds that were higher indoors, 14 were higher by a factor between 10 and 150: methyl isobutyl
232 ketone (factor of 152), isopropanol (91), ethanol (45), isobutyl acetate (33), p-dichlorobenzene (29),
233 limonene (25), dodecane (24), beta-pinene (21), 1-butanol (19), tridecane (18), styrene (17), naphthalene
234 (15), alpha-pinene (14), and 1,2,4-Trimethylbenzene (13). 7 compounds were higher indoors by a factor
235 between 5 and 10: chloroform (factor of 8.8), butyl acetate, (8.6), n-nonane (8.1), cyclohexanol (7.0), n-
236 undecane (6.2), acetone (5.8), and ethyl acetate (5.3). The other 23 compounds were higher indoors by a
237 factor ranging from 1.2 to 4.3.
238
21
238
103 Indoor Geom. Mean (!g/m3) Indoor Geom. Mean (!g/m3) 102 Outdoor Geom. Mean (!g/m3) Outdoor Geom. Mean (!g/m3) VOCs 30 to 58 VOCs 1 to 29 g/m3) g/m3) ! ! 102 101
101 100
0 10 10-1 Geometric Mean Concentration ( Geometric Mean Concentration (
-2 10-1 10 Phenol Styrene Ethanol Hexane Toluene Benzene o-Xylene Nonanal Xylenes Acetone p-Xylene Tridecane 3-Carene n-Octane n-Pentane 1-Butanol m-Xylene Limonene n-Heptane Dodecane Chloroform 2-Butanone Isopentane beta-Pinene Naphthalene n-Undecane Xylene (p,m) Ethylbenzene Ethylacetate Cyclohexanol alpha-Pinene Cyclohexane Benzaldehyde Butyl acetate Acetophenone 2-Methylpentane Methyl-benzoate Isobutyl acetate Trichloroethylene 2-Ethyl-1-hexanol Methylene chloride p-Dichlorobenzene Methylcyclopentane Tetrachloroethylene Nonane (n-Nonane) Carbon tetrachloride 2-Methyl-1-propanol 1,2,3-Trimethylbenzene Trichlorotrifluoroethane Hexaldehyde (Hexanal) 1,2,4-Trimethylbenzene VOC Pentanal (Valeraldehyde) VOC Butanal (n-Butyraldehyde) Methyl isobutyl ketone (MIBK) 4-Ethyltoluene (p-Ethyltoluene) 2-Ethyltoluene (o-Ethyltoluene) 3-Ethyltoluene (m-Ethyltoluene) Isopropyl alcohol (Isopropanol)
239 Figure 6. Comparison of concentrations (geometric means) for VOCs found in common between Indoors and
240 Outdoors.
241
242
22
242 Table 4. Comparison of vapor concentrations for volatile compounds common to Indoor and Outdoor 243 environments (ratios based on geometric means). Compounds are listed in descending magnitude of ratio. 244 Bolded chemicals were higher in their respective environment by a ratio (i.e., factor) larger than 10. 245 Volatiles higher in Indoor Ratio Volatiles higher in Outdoor Ratio environments environments Methyl isobutyl ketone 152 Pentanal (Valeraldehyde) 30 Isopropyl alcohol (Isopropanol) 91 Methylcyclopentane 21 Ethanol 45 2-Methyl-1-propanol 6.6 Isobutyl acetate 33 Xylenes 6.2 p-Dichlorobenzene 29 Hexaldehyde (Hexanal) 2.1 Limonene 25 Trichlorotrifluoroethane 1.7 Dodecane 24 Isopentane 1.5 beta-Pinene 21 p-Xylene 1.4 1-Butanol 19 n-Pentane 1.3 Tridecane 18 Phenol 1.2 Styrene 17 2-Methylpentane 1.1 Naphthalene 15 alpha-Pinene 14 1,2,4-Trimethylbenzene 13 Chloroform 8.8 Butyl acetate 8.6 Nonane (n-Nonane) 8.1 Cyclohexanol 7.0 Undecane (n-Undecane) 6.2 Acetone 5.8 Ethylacetate 5.3 3-Ethyl-toluene (m-Ethyltoluene) 4.3 Methylene chloride 4.0 2-Ethyltoluene (o-Ethyltoluene) 3.9 2-Butanone 3.6 n-Heptane 3.4 Benzaldehyde 3.1 4-Ethyltoluene (p-Ethyltoluene) 2.9 Nonanal 2.6 2-Ethyl-1-hexanol 2.6 Toluene 2.5 n-Octane 2.3 m-Xylene 2.2 Ethylbenzene 2.1 Xylene (m/p) 1.9 Cyclohexane 1.8 Trichloroethylene 1.8 Tetrachloroethylene 1.6 3-Carene 1.4 o-Xylene 1.4 Hexane 1.3 1,2,3-Trimethylbenzene 1.3 Acetophenone 1.3 Butanal 1.2 246 247 Total: 44 Total: 11 23
248 3.4. Concentration range of individual chemicals in Indoor Home/School environments
249
250 A concentration range was calculated for those compounds for which there were at least 2 values
251 (n≥2) reported in the literature sources. Figure 7 (left side) shows such compounds for the indoor
252 home/school environment (n = number of values). They are plotted in the same order as in Figure 1 (left
253 side), that is, in decreasing order of geometric mean concentration, but Figure 7 shows, instead, a box plot
254 for each chemical that illustrates the spread of concentrations reported, as explained next: The height of
255 each box encloses 50% of the data, with the median value depicted as a line. Thus, the top (upper
256 quartile, UQ) and the bottom (lower quartile. LQ) of each box mark the limits of ± 25% of the total data.
257 Then, the distance between the upper and lower quartiles (UQ –LQ) represents the interquartile distance
258 (IQD). The lines extending from the top and bottom of each box mark the maximum and minimum value,
259 respectively, within the data set, excluding outliers. Outliers are defined as concentrations whose value is
260 either greater than (UQ + 1.5 * IQD) or less than (LQ – 1.5 * IQD). The outliers are plotted as empty
261 circles. Also, the arithmetic mean of the distribution of all reported concentrations (including outliers) for
262 each chemical is plotted as a filled circle.
263
24
263 264 Indoor Home/School Indoor Commercial
3 10 Arithmetic Mean Aritmetic Mean Indoor Home/School VOCs 1 to 18 Indoor Commercial VOCs 1 to 18
103 2 ) ) 3 3 10 g/m g/m ! ! ( ( 2 1 10 10
100 1 Concentration 10 Concentration
10-1 100 (n=4) ether (n=9) (n=16) (n=21) (n=6) (n=11) (n=2) (n=7) (n=3) (n=2) (n=2) (n=3) (n=2) (n=6) (n=7) (n=2) (n=4) (n=3) (n=8) (n=4) (n=15) (n=2) (n=24) (n=14) (n=17) (n=8) (n=3) (n=13) (n=3) (n=30) (n=2) alcohol (n=3) 11) Acid (n=2) 21) tert-butyl (n=2) (n=4) (n=2) Acetone Nicotine Isoprene p-Xylene Ethanol (MTBE) Acetone Nonanal Toluene m-Xylene 3-Carene Toluene 1-Butanol Dodecane n-Decane n-Nonane Limonene n-Heptane Acetic (Freon Isobutylketone n-Heptane m/p-Xylene Acetaldehyde Ethylacetate alpha-Pinene Dichloromethane Isopropyl Ethylacetate Formaldehyde (Freon (Isopropanol) Methyl Acetaldehyde Formaldehyde 1,1,1-Trichloroethane Tetrachloroethylene Trichlorofluoromethane (diisobutylketone) 1,2,4-Trichlorobenzene Dichlorodifluoromethane
Arithmetic Mean Arithmetic Mean 2 102 Indoor Home/School VOCs 19 to 36 10 Indoor Commercial VOCs 19 to 36 ) 3 ) 3 g/m ! ( g/m
! 1 ( 10 101
100 Concentration Concentration 100
(n=5) (n=2) (n=3) (n=19) (n=3) (n=6) (n=7) (n=8) (n=9) (n=2) (n=9) (n=9) (n=2) (n=2) (n=8) (n=9) (n=2) (n=9) (n=2) (n=2) (n=2) (n=6) (n=8) (n=8) (n=15) (n=10) (n=10) ketone (n=3) (n=10) (n=12) ketone (n=3) tert-butyl (n=2) (n=4) (n=3) 11) Xylene ethyl acetate (n=2) Octanal Butanal Xylene (n=6) p-Xylene Propanal Hexanal n-Octane isobutyl n-Hexane o-Xylene n-Octane Hexaldehyde Propanal n-Decane (MEK) Benzene (methyl (Hexanal) Dodecane ether) (MIBK) Crotonaldehyde n-Undecane (2-Butenal) m/p-Xylene 3-Ethyltoluene n-Undecane Cyclohexane d-Limonene (Freon alpha-Pinene Methyl Methylcyclohexane 1,4-Dichlorobenzene n-Butyl 1,4-Dichlorobenzene Ethylbenzene Trichloroethene (m-Ethyltoluene) Methyl 1,2,4-Trimethylbenzene Trichloroethylene (p-Dichlorobenzene) (Propionaldehyde) Trichlorofluoromethane MTBE (p-Dichlorobenzene)
Arithmetic Mean Arithmetic Mean Indoor Commercial VOCs 37 to 54 Indoor Home/School VOCs 37 to 54
1
) 10 )
1 3 3 10 g/m g/m ! ! ( (
0 100 10 Concentration Concentration
-1 10 10-1 (n=2) (n=2) (n=2) (n=2) (n=2) (n=3) (n=2) (n=2) (n=2) (n=3) (n=3) (n=5) (n=2) (n=2) (n=2) (n=2) (n=7) (n=6) (n=10) (n=7) (n=28) (n=8) (n=8) (n=5)
(n=10) (n=2) (n=2) (n=2) (n=2) (n=15) (n=23) (n=3) (n=3) (n=2) (n=3) Phenol aldehyde Pyridine (n=12) Styrene 1-Butanol Pentanal Chloroform Phenol Methylchloride Acrolein 4-Ethyltoluene Methylchloride 4-Ethyltoluene o-Xylene Benzene n-Pentane Camphene 1,3-Butadiene 1,3-Dichlorobenzene 1,2-Dichlorobenzene Isopentane 2-Butanone n-Tridecane beta-Pinene Benzaldehyde Naphthalene Benzaldehyde Chlorobenzene Ethylbenzene 1,1,2,2-Tetrachloroethane (Valeraldehyde) Furfuryl 1,3,5-Trimethylbenzene 3-Ethenylpyridine (Chloromethane) (p-Ethyltoluene) (o-Dichlorobenzene) (m-Dichlorobenzene) 2-Butoxyethanol 1,1,2-Trichlorotrifluoroethane Perchloroethylene (p-Ethyltoluene) (Chloromethane) 1,2,4-Trimethylbenzene 25
265 266 Indoor Home/School Indoor Commercial
Arithmetic Mean Arithmetic Mean Indoor Home/School VOCs 55 to 74 Indoor Commercial VOCs 55 to 68
1 10 ) 3 ) 3
g/m 0 ! (mg/m 10 ( 100
10-1 Concentration Concentration
-1 -2 10 10 (n=2) (n=6) (n=2) (n=8) (n=8) (n=2) (n=3) (n=5) (n=2) (n=2) (n=2) (n=5) (n=3) (n=4) (n=2) (n=2) (n=2) (n=2) (n=3) (n=23) chloride chloride (n=2) (n=2) tetrachloride (n=3) (n=2) (n=2) tetrachloride (n=2) (n=3) (n=2) (n=5) (n=6) (n=2) (n=2) (n=2) (n=2) Styrene 3-Picoline Chloroform 2-Ethyltoluene 3-Ethyltoluene Naphthalene 1,3-Dichlorobenzene Ethylchloride 1,2-Dichloroethene 1,1-Dichloroethene Methylene 1,2-Dibromoethane 1,2-Dichloroethane n-Hexadecane 1,1-Dichloroethane n-Tetradecane Carbon Tetrachloroethylene n-Pentadecane Carbon Chlorobenzene Methylbenzaldehyde (Tolualdehyde) Bromomethane 1,1,2-Trichloroethane (o-Ethyltoluene) Tetrahydrofuran (m-Dichlorobenzene) 1,2,3-Trichlorobenzene Trichloroethylene Trichloroethene (m-Ethyltoluene) Tetrachloroethene 2-Methylpentane Methylene 1,2,4-Trichlorobenzene 1,3,5-Trimethylbenzene 1,2-Dichlorotetrafluoroethane 267 268 Figure 7. Illustrating the range of VOCs concentrations (n = number of values) reported in Indoor Home/School (left
269 side) and Indoor Commercial (right side) environments. For each chemical the graphs show a box plot (see text for
270 details), the median (line inside the box), the outlier(s) (if any) (empty circles), and the arithmetic mean of all values
271 including outlier(s) (filled circles).
272
26
272
273 Table 5 lists all compounds in Figure 7 (left side) in decreasing size of the ratio between the
274 maximum and the minimum values reported for each chemical (i.e., the concentration range or spread),
275 providing also numerical values for the minimum, maximum, mean, median, standard deviation, variance,
276 and standard error. Out of the 74 compounds, two show a concentration spread (i.e., range) of three
277 orders of magnitude: styrene (range=1,600, n=23) and alpha-pinene (range=1,345, n=21); nine
278 compounds show a concentration spread of two orders of magnitude: beta-pinene (range=490, n=8),
279 benzene (range=486, n=23), trichloroethylene (range=350, n=8), 1,4-dichlorobenzene (range=289, n=19),
280 n-heptane (range=246, n=15), naphthalene (range=179, n=10), 1,2,3-trichlorobenzene (range=140, n=2),
281 o-xylene (range=139, n=15), and toluene (range=107, n=30); and 27 compounds show a concentration
282 spread of one order of magnitude (see Table 5). The remaining 36 compounds show a concentration
283 spread lower than one order of magnitude (Table 5).
284
27
284 Table 5. Statistics of VOC concentrations (µg/m3) measured in Indoor Home/School environments. 285 Variable (Indoor Home/School VOCs) Minimum Maximum Range: Max/Min Mean Median Std Deviation Variance Std Error Styrene (n=23) 0.04 64.0 1,600 6.1 0.9 14.2 202.270 2.97 alpha-Pinene (n=21) 0.20 269.0 1,345 32.8 11.0 62.3 3883.600 13.60 beta-Pinene (n=8) 0.10 49.0 490 9.6 2.8 16.8 283.490 5.95 Benzene (n=23) 0.09 43.7 486 6.1 2.5 9.8 95.910 2.04 Trichloroethylene (n=8) 0.02 7.0 350 1.4 0.3 2.5 6.059 0.87 1,4-Dichlorobenzene (p-Dichlorobenzene) (n=19) 0.50 144.6 289 26.5 4.1 39.3 1545.600 9.02 n-Heptane (n=15) 1.20 295.4 246 34.0 11.0 75.5 5695.800 19.49 Naphthalene (n=10) 0.29 51.8 179 7.1 1.3 15.8 250.300 5.00 1,2,3-Trichlorobenzene (n=2) 0.01 1.4 140 0.7 0.7 1.0 0.966 0.70 o-Xylene (n=15) 0.24 33.5 139 4.6 1.8 8.3 68.986 2.14 Toluene (n=30) 1.60 170.7 107 21.2 14.8 30.2 909.890 5.51 Ethylbenzene (n=28) 0.24 20.0 83 4.0 3.0 4.5 20.593 0.86 1,3,5-Trimethylbenzene (n=2) 0.02 1.6 80 0.8 0.8 1.1 1.248 0.79 Methyl isobutyl ketone (MIBK) (n=4) 0.46 32.7 71 12.6 8.6 15.2 230.740 7.60 Tetrachloroethylene (n=6) 0.02 1.3 65 0.5 0.4 0.4 0.191 0.18 1,2,4-Trimethylbenzene (n=12) 0.14 7.6 54 4.3 4.2 2.2 4.867 0.64 n-Tridecane (n=8) 0.78 40.0 51 7.3 3.0 13.3 177.510 4.71 2-Butanone (n=5) 0.24 11.0 46 4.6 3.0 4.3 18.481 1.92 n-Octane (n=8) 1.30 52.7 41 9.8 2.9 17.5 306.610 6.19 1,3-Dichlorobenzene (m-Dichlorobenzene) (n=2) 0.02 0.7 33 0.3 0.3 0.4 0.198 0.32 Acetic Acid (n=6) 6.80 190.0 28 48.3 21.9 70.1 4920.000 28.64 Methylene chloride (n=6) 0.30 8.2 27 2.5 0.4 3.4 11.743 1.40 Limonene (n=24) 1.90 49.3 26 20.6 19.2 13.1 171.680 2.67 n-Hexane (n=9) 1.50 36.4 24 10.7 7.3 11.0 120.190 3.65 Chloroform (n=8) 0.09 2.1 23 0.9 0.7 0.7 0.553 0.26 n-Nonane (n=14) 1.50 33.5 22 14.3 13.2 8.8 78.294 2.36 1,2,4-Trichlorobenzene (n=2) 0.07 1.4 20 0.7 0.7 0.9 0.884 0.67 n-Decane (n=17) 2.20 41.8 19 19.1 16.0 11.4 129.040 2.76 n-Butyl acetate (n=8) 2.50 47.0 19 16.3 9.0 17.5 305.730 6.18 Dodecane (n=10) 2.22 38.0 17 15.8 7.5 15.0 224.810 4.74 m/p-Xylene (n=15) 1.20 19.0 16 7.5 6.5 5.5 30.796 1.43 Ethanol (n=3) 70.00 860.0 12 340.7 92.0 449.9 202400.000 259.74 Phenol (n=3) 0.61 7.1 12 3.1 1.7 3.5 12.078 2.01 p-Xylene (n=9) 2.60 30.0 12 11.4 7.6 10.8 116.550 3.60 Tetrahydrofuran (n=2) 0.16 1.7 11 0.9 0.9 1.1 1.186 0.77 Trichlorofluoromethane (Freon 11) (n=4) 4.73 50.0 11 25.6 23.8 23.3 544.290 11.67 Formaldehyde (n=16) 12.70 134.0 11 60.5 53.4 34.8 1208.400 8.69 Ethylacetate (n=11) 3.30 34.0 10 16.6 16.7 9.9 98.928 3.00 Acetone (n=8) 9.10 87.1 9.6 35.0 32.8 24.2 587.050 8.57 n-Undecane (n=9) 3.00 24.1 8.0 9.6 8.8 6.2 38.392 2.07 2-Butoxyethanol (n=3) 0.75 5.8 7.7 3.1 2.6 2.6 6.528 1.48 Isopentane (n=2) 1.40 9.5 6.8 5.5 5.5 5.7 32.805 4.05 Pentanal (Valeraldehyde) (n=7) 1.00 5.5 5.5 2.4 1.3 1.8 3.303 0.69 2-Methylpentane (n=3) 0.37 1.8 4.9 1.2 1.5 0.8 0.569 0.44 Crotonaldehyde (2-Butenal) (n=8) 1.60 7.6 4.8 4.8 4.9 1.8 3.385 0.65 1-Butanol (n=8) 35.00 147.6 4.2 66.0 51.4 37.4 1400.800 13.23 n-Pentane (n=2) 1.40 5.8 4.1 3.6 3.6 3.1 9.680 2.20 Tetrachloroethene (n=2) 0.70 2.9 4.1 1.8 1.8 1.6 2.420 1.10 Xylene (n=6) 5.00 18.2 3.6 7.8 5.8 5.1 26.327 2.09 Butanal (n=9) 2.20 8.0 3.6 5.1 4.2 2.2 4.993 0.74 Isobutylketone (diisobutylketone) (n=4) 8.00 27.0 3.4 15.0 12.5 8.3 68.667 4.14 Benzaldehyde (n=7) 2.00 6.2 3.1 3.4 3.0 1.4 1.922 0.52 Octanal (n=2) 4.30 13.0 3.0 8.7 8.7 6.2 37.845 4.35 Camphene (n=2) 1.90 5.2 2.7 3.6 3.6 2.3 5.445 1.65 Nonanal (n=3) 8.10 22.0 2.7 16.0 18.0 7.2 51.203 4.13 3-Carene (n=2) 8.50 23.0 2.7 15.8 15.8 10.3 105.130 7.25 Trichloroethene (n=2) 2.30 6.0 2.6 4.2 4.2 2.6 6.845 1.85 Hexanal (n=10) 5.00 13.0 2.6 7.9 7.5 2.8 7.683 0.88 Chlorobenzene (n=3) 0.68 1.7 2.5 1.3 1.6 0.6 0.316 0.32 4-Ethyltoluene (p-Ethyltoluene) (n=6) 2.26 5.4 2.4 3.3 2.8 1.1 1.302 0.47 3-Ethyltoluene (m-Ethyltoluene) (n=5) 0.97 2.3 2.4 1.5 1.2 0.6 0.347 0.26 Acrolein (n=2) 1.00 2.3 2.3 1.7 1.7 0.9 0.845 0.65 2-Ethyltoluene (o-Ethyltoluene) (n=5) 1.02 2.3 2.3 1.5 1.3 0.5 0.270 0.23 Acetaldehyde (n=9) 11.00 24.3 2.2 17.8 20.0 5.1 26.292 1.71 Methyl ethyl ketone (MEK) (n=2) 3.60 7.4 2.1 5.5 5.5 2.7 7.220 1.90 Cyclohexane (n=2) 2.90 5.2 1.8 4.1 4.1 1.6 2.645 1.15 Methyl tert-butyl ether (MTBE) (n=2) 12.00 19.3 1.6 15.7 15.7 5.2 26.645 3.65 Propanal (n=7) 6.90 10.9 1.6 8.2 8.0 1.3 1.665 0.49 Carbon tetrachloride (n=5) 0.50 0.7 1.4 0.6 0.6 0.1 0.006 0.03 n-Tetradecane (n=2) 1.30 1.7 1.3 1.5 1.5 0.3 0.080 0.20 Methylchloride (Chloromethane) (n=2) 1.49 1.8 1.2 1.6 1.6 0.2 0.048 0.16 n-Pentadecane (n=2) 1.10 1.2 1.1 1.2 1.2 0.1 0.005 0.05 n-Hexadecane (n=2) 1.10 1.1 1.0 1.1 1.1 0.0 0.000 0.00 Methylbenzaldehyde (Tolualdehyde) (n=4) 1.00 1.0 1.0 1.0 1.0 0.0 0.000 0.00 286 28
287 3.5. Concentration range of individual chemicals in Indoor Commercial environments
288
289 A concentration range was calculated for those compounds for which there were at least 2 values
290 reported in the literature sources. Figure 7 (right side) shows the spread of concentrations for such
291 compounds found in the indoor commercial environment (n=number of values). They are plotted in the
292 same order as in Figure 1 (right side), that is, in decreasing order of geometric mean concentration, but
293 Figure 7 presents box plots illustrating the spread of concentrations reported, exactly as explained in the
294 previous section. Table 6 lists these chemicals in decreasing size of the ratio between the maximum and
295 the minimum values reported for each chemical (i.e., the range), providing also numerical values for the
296 minimum, maximum, mean, median, standard deviation, variance, and standard error. Out of 68
297 compounds, six show a concentration spread of two orders of magnitude: acetone (range=241, n=3),
298 alpha-pinene (range=234, n=6), isopropyl alcohol (range=183, n=2), styrene (range=165, n=10),
299 tetrachloroethylene (range=144, n=4), and toluene (range=119, n=13); and thirteen compounds show a
300 concentration spread of one order of magnitude (see Table 6). The remaining 49 compounds show a
301 concentration spread lower than one order of magnitude (Table 6).
302
29
302 Table 6. Statistics of VOC concentrations (µg/m3) measured in Indoor Commercial environments.
Variable (Indoor Commercial VOCs) Minimum Maximum Range: Max/Min Mean Median Std Deviation Variance Std Error Acetone (n=3) 22.9 5510.0 241 1852.2 23.7 3167.70 10035000.000 1828.90 alpha-Pinene (n=6) 0.7 163.9 234 28.8 2.1 66.18 4379.400 27.02 Isopropyl alcohol (Isopropanol) (n=2) 2.7 493.0 183 247.9 247.9 346.69 120200.000 245.15 Styrene (n=10) 0.2 32.9 165 4.8 1.4 9.98 99.638 3.16 Tetrachloroethylene (n=4) 3.0 432.0 144 115.2 13.0 211.33 44660.000 105.67 Toluene (n=13) 6.5 776.5 119 112.3 33.3 208.47 43461.000 57.82 Ethylacetate (n=2) 2.1 135.0 64 68.6 68.6 93.97 8831.200 66.45 1,3,5-Trimethylbenzene (n=3) 0.2 8.8 44 5.6 7.8 4.70 22.120 2.72 1,4-Dichlorobenzene (p-Dichlorobenzene) (n=5) 0.3 13.0 43 5.5 2.4 5.73 32.847 2.56 Ethylbenzene (n=10) 0.6 25.1 42 6.8 5.0 7.33 53.798 2.32 Chloroform (n=5) 0.4 13.5 31 5.6 1.1 6.71 45.023 3.00 4-Ethyltoluene (p-Ethyltoluene) (n=3) 0.3 6.0 20 3.8 5.1 3.06 9.390 1.77 Benzene (n=12) 1.2 23.6 20 8.0 4.9 7.58 57.435 2.19 Dichlorodifluoromethane (Freon 21) (n=3) 2.8 42.9 15 16.3 3.3 23.01 529.400 13.28 Naphthalene (n=3) 0.3 4.3 13 1.7 0.5 2.23 4.990 1.29 o-Xylene (n=9) 1.5 17.3 12 6.5 4.1 5.85 34.192 1.95 1,2,4-Trimethylbenzene (n=6) 1.1 12.2 11 6.3 5.7 5.05 25.550 2.06 Trichloroethylene (n=3) 0.8 8.8 11 5.1 5.6 4.03 16.213 2.32 m/p-Xylene (n=7) 3.9 41.6 11 14.7 6.2 15.05 226.510 5.69 Carbon tetrachloride (n=3) 0.1 0.9 9.0 0.6 0.7 0.41 0.168 0.24 n-Heptane (n=4) 1.8 14.3 7.9 8.0 8.0 5.30 28.087 2.65 Hexaldehyde (Hexanal) (n=3) 2.2 17.0 7.7 8.2 5.4 7.79 60.640 4.50 p-Xylene (n=3) 6.6 46.9 7.1 20.2 7.2 23.10 533.420 13.33 Nicotine (n=2) 5.4 38.3 7.1 21.9 21.9 23.26 541.200 16.45 d-Limonene (n=8) 2.5 17.5 7.0 6.8 5.6 4.64 21.554 1.64 Xylene (n=2) 2.6 14.3 5.5 8.5 8.5 8.27 68.445 5.85 Propanal (Propionaldehyde) (n=2) 2.5 11.9 4.8 7.2 7.2 6.65 44.180 4.70 Isoprene (n=2) 4.5 20.6 4.6 12.6 12.6 11.38 129.610 8.05 1,1-Dichloroethane (n=2) 0.4 1.8 4.5 1.1 1.1 0.99 0.980 0.70 MTBE (methyl tert-butyl ether) (n=3) 2.3 10.0 4.4 4.9 2.4 4.43 19.615 2.56 m-Xylene (n=3) 12.3 50.4 4.1 25.4 13.5 21.66 469.110 12.51 1,1,2,2-Tetrachloroethane (n=2) 1.0 4.0 4.0 2.5 2.5 2.12 4.500 1.50 1,3-Butadiene (n=2) 1.1 4.3 3.9 2.7 2.7 2.26 5.120 1.60 Methylchloride (chloromethane) (n=3) 0.9 3.5 3.9 2.5 3.0 1.38 1.903 0.80 Formaldehyde (n=7) 5.6 21.3 3.8 15.4 17.1 5.55 30.818 2.10 3-Ethenylpyridine (n=2) 1.2 4.4 3.7 2.8 2.8 2.26 5.120 1.60 Dichloromethane (n=2) 14.1 50.2 3.6 32.2 32.2 25.53 651.600 18.05 Trichlorofluoromethane (Freon 11) (n=3) 2.8 9.8 3.5 5.1 2.8 4.04 16.333 2.33 Pyridine (n=2) 0.8 2.6 3.4 1.7 1.7 1.29 1.674 0.92 Methylene chloride (n=3) 0.7 2.2 3.3 1.2 0.8 0.87 0.759 0.50 3-Picoline (n=2) 0.7 2.2 3.3 1.4 1.4 1.09 1.186 0.77 Acetaldehyde (n=6) 7.5 24.4 3.3 13.7 10.4 7.19 51.663 2.93 Dodecane (n=2) 12.0 38.5 3.2 25.3 25.3 18.74 351.120 13.25 1,1,2-Trichlorotrifluoroethane (n=3) 0.9 2.6 2.9 1.6 1.4 0.87 0.763 0.50 Furfuryl aldehyde (n=2) 1.6 4.4 2.8 3.0 3.0 1.98 3.920 1.40 Phenol (n=2) 1.1 2.8 2.5 2.0 2.0 1.20 1.445 0.85 n-Undecane (n=2) 3.0 7.5 2.5 5.3 5.3 3.18 10.125 2.25 3-Ethyltoluene (m-Ethyltoluene) (n=3) 4.5 9.1 2.0 6.4 5.6 2.40 5.770 1.39 1,2,4-Trichlorobenzene (n=2) 12.8 24.5 1.9 18.7 18.7 8.27 68.445 5.85 Methylcyclohexane (n=2) 2.0 3.8 1.9 2.9 2.9 1.27 1.620 0.90 Trichloroethene (n=2) 0.2 0.4 1.9 0.3 0.3 0.14 0.020 0.10 Benzaldehyde (n=2) 1.5 2.3 1.5 1.9 1.9 0.57 0.320 0.40 Perchloroethylene (n=2) 1.4 2.1 1.5 1.8 1.8 0.48 0.231 0.34 Bromomethane (n=2) 1.1 1.6 1.5 1.4 1.4 0.35 0.125 0.25 1,2-Dichlorobenzene (o-Dichlorobenzene) (n=2) 1.6 2.3 1.4 2.0 2.0 0.49 0.245 0.35 1,3-Dichlorobenzene (m-Dichlorobenzene) (n=2) 1.6 2.2 1.4 1.9 1.9 0.42 0.180 0.30 Ethylchloride (n=2) 0.3 0.4 1.3 0.4 0.4 0.07 0.005 0.05 1,1,1-Trichloroethane (n=2) 13.4 17.1 1.3 15.3 15.3 2.62 6.845 1.85 n-Octane (n=2) 3.1 3.9 1.3 3.5 3.5 0.57 0.320 0.40 1,2-Dibromoethane (n=2) 0.9 1.1 1.2 1.0 1.0 0.14 0.020 0.10 Chlorobenzene (n=2) 1.4 1.7 1.2 1.6 1.6 0.21 0.045 0.15 1,1-Dichloroethene (n=2) 0.5 0.6 1.2 0.6 0.6 0.07 0.005 0.05 1-Butanol (n=2) 2.2 2.6 1.2 2.4 2.4 0.28 0.080 0.20 1,2-Dichloroethane (n=2) 0.6 0.7 1.2 0.7 0.7 0.07 0.005 0.05 1,1,2-Trichloroethane (n=2) 0.6 0.7 1.2 0.7 0.7 0.07 0.005 0.05 n-Decane (n=2) 4.4 4.7 1.1 4.6 4.6 0.21 0.045 0.15 1,2-Dichlorotetrafluoroethane (n=2) 0.7 0.7 1.0 0.7 0.7 0.00 0.000 0.00 1,2-Dichloroethene (n=2) 0.4 0.4 1.0 0.4 0.4 0.00 0.000 0.00 303 304 305
306
30
306
307 3.6. Concentration range of individual chemicals in Outdoor Non-industrial environments
308
309 Figure 8 shows the spread of concentrations for compounds found in outdoor non-industrial
310 environments with n≥2 (n=number of values). They are plotted in the same order as in Figure 3, that is, in
311 decreasing order of geometric mean concentration, but Figure 8 presents box plots illustrating the spread
312 of concentrations reported, exactly as explained above. In turn, Table 7 lists these chemicals in
313 decreasing size of the maximum/minimum ratio (i.e., range) and providing additional statistics (minimum,
314 maximum, mean, etc.) as mentioned above. Out of 30 compounds, five show a concentration spread of
315 two orders of magnitude: benzene (range=664, n=10), toluene (range=284, n=10), 1,2,4 trimethylbenzene
316 (range=160, n=3), alpha-pinene (range=140, n=3), and o-xylene (range=112, n=8); and eight compounds
317 show a concentration spread of one order of magnitude: n-octane (range=77, n=5), tetrachloroethylene
318 (range=71, n=3), d-limonene (range=51, n=4), tridecane (range=33, n=3), trichloroethylene (range=30,
319 n=3), 3-ethyltoluene (m-ethyltoluene) (range=23, n=4), styrene (range=17, n=4), and n-heptane
320 (range=16, n=4). The remaining 17 compounds show a concentration spread lower than one order of
321 magnitude (Table 7).
322
31
322 323 324 Outdoor Non-Industrial
Arithmetic Mean Arithmetic Mean 2 10 Outdoor Non-Industrial VOCs 1 to 15 Outdoor Non-Industrial VOCs 16 to 29 ) )
3 0 3 10
1 10 g/m ! ( (mg/m
-1 0 10 10 Concentration Concentration
10-1 10-2 (n=3) (n=3) (n=4) (n=4) (n=3) (n=2) (n=2) (n=4) (n=4) (n=3) (n=4) (n=4) (n=6) (n=4) (n=4) (n=9) (n=4) (n=5) (n=3) (n=8) (n=3) (n=3) (n=10) (n=10) chloride (n=3) (n=2) tetrachloride (n=2) (n=3) (n=3) Styrene Nonane p-Xylene o-Xylene Toluene n-Octane n-Decane n-Hexane Tridecane Benzene n-Heptane Chloroform m/p-Xylene 2-Ethyltoluene d-Limonene n-Dodecane beta-Pinene p-Ethyltoluene 3-Ethyl-toluene Naphthalene Trichloroethylene n-Undecane Methylene 1,4-Dichlorobenzene alpha-Pinene Ethylbenzene Carbon Tetrachloroethylene (o-Ethyltoluene) (4-Ethyltoluene) (m-Ethyltoluene) (p-Dichlorobenzene) 1,2,4-Trimethylbenzene 325 326 Figure 8. Illustrating the range of VOCs concentrations (n = number of values) reported in outdoor Non-Industrial
327 environments. For each chemical the graphs show a box plot (see text for details), the median (line inside the box),
328 the outlier(s) (if any) (empty circles), and the arithmetic mean of all values including outlier(s) (filled circles).
329
330
32
330 Table 7. Statistics of VOC concentrations (µg/m3) measured in Outdoor Non-industrial environments. 331 Variable Minimum Maximum Range: Max/Min Mean Median Std Deviation Variance Std Error Benzene (n=10) 0.06 39.8 664 7.8 2.37 12.87 165.700 4.07 Toluene (n=10) 0.52 147.9 284 20.6 4.84 45.06 2030.000 14.25 1,2,4-Trimethylbenzene (n=3) 0.01 1.6 160 1.0 1.40 0.87 0.750 0.50 alpha-Pinene (n=3) 0.10 14.0 140 4.7 0.11 8.02 64.357 4.63 o-Xylene (n=8) 0.45 50.5 112 8.1 1.04 17.37 301.850 6.14 n-Octane (n=5) 0.32 24.7 77 5.7 0.69 10.67 113.740 4.77 Tetrachloroethylene (n=3) 0.20 14.1 71 4.9 0.30 8.00 63.943 4.62 d-Limonene (n=4) 0.10 5.1 51 1.5 0.35 2.42 5.864 1.21 Tridecane (n=3) 0.01 0.3 33 0.2 0.22 0.16 0.026 0.09 Trichloroethylene (n=3) 0.01 0.3 30 0.2 0.20 0.15 0.022 0.09 3-Ethyl-toluene (m-Ethyltoluene) (n=4) 0.14 3.2 23 1.1 0.43 1.45 2.092 0.72 Styrene (n=4) 0.01 0.2 17 0.1 0.09 0.07 0.004 0.03 n-Heptane (n=4) 0.71 11.7 16 3.8 1.30 5.31 28.236 2.66 Naphthalene (n=4) 0.05 0.4 8.4 0.2 0.08 0.18 0.031 0.09 p-Xylene (n=3) 5.50 39.0 7.1 17.8 8.87 18.44 340.030 10.65 Ethylbenzene (n=9) 0.43 3.0 7.0 1.2 1.15 0.82 0.677 0.27 n-Dodecane (n=4) 0.17 0.9 5.3 0.4 0.30 0.33 0.111 0.17 n-Hexane (n=4) 1.60 7.4 4.6 3.5 2.54 2.65 7.042 1.33 p-Ethyltoluene (4-Ethyltoluene) (n=3) 0.39 1.4 3.7 0.8 0.64 0.55 0.301 0.32 m/p-Xylene (n=6) 2.00 6.9 3.5 3.1 2.40 1.90 3.592 0.77 2-Ethyltoluene (o-Ethyltoluene) (n=3) 0.17 0.6 3.2 0.3 0.21 0.21 0.044 0.12 1,4-Dichlorobenzene (p-Dichlorobenzene) (n=3) 0.10 0.3 3.0 0.2 0.20 0.10 0.010 0.06 n-Undecane (n=4) 0.45 1.3 2.9 1.0 1.14 0.38 0.144 0.19 n-Decane (n=4) 0.81 2.0 2.5 1.3 1.24 0.50 0.254 0.25 Nonane (n=3) 0.70 1.2 1.7 0.9 0.83 0.25 0.062 0.14 Methylene chloride (n=2) 0.20 0.3 1.5 0.3 0.25 0.07 0.005 0.05 beta-Pinene (n=2) 0.10 0.1 1.0 0.1 0.10 0.00 0.000 0.00 Carbon tetrachloride (n=2) 0.50 0.5 1.0 0.5 0.50 0.00 0.000 0.00 Chloroform (n=2) 0.10 0.1 1.0 0.1 0.10 0.00 0.000 0.00 332 333 334
33
334
335 3.7. Concentration range of individual chemicals in Outdoor Industrial environments
336
337 There are many potential kinds of industrial environments since each industry will have its
338 “signature” environment. To try to summarize even some of them is beyond the scope of the present
339 paper. As mentioned under “Outdoors”, this review has included two examples of industrial environments:
340 the vicinity of a pig farm and the vicinity of an oil refinery. Only four of the 45 chemicals reported in these
341 environments (see Figure 3, right side) include two or more measurements (n≥2): toluene (n=2), benzene
342 (n=2), ethylbenzene (n=2) and 1-propanol (n=2). This is too small a sample to provide any further insight.
343
344 4. Concluding Comments
345
346 The present article compiles and analyzes data from the literature on the chemical species,
347 concentrations, and variability of airborne volatiles found and measured in two broad indoor environments:
348 homes/schools and commercial spaces, and in two outdoor environments: non-industrial and industrial
349 (the latter exemplified by the vicinity of a pig farm and the vicinity of an oil refinery). Included in the review
350 are data on mean airborne VOC concentrations collected in two recent comprehensive and informative
351 compilations focused exclusively on indoor spaces: one dealing specifically with residencies (Logue et al.,
352 2011) and the other dealing with residencies and non-residencies (i.e., public buildings) (Sarigiannis et al.,
353 2011). The principal aim of this study is to summarize in illustrative graphs and tables information gathered
354 from the literature, so that investigators addressing the many aspects of human environmental chemical
355 exposures have a centralized source for the types, levels, relative concentrations, concentration spread,
356 and number of volatiles found in these environments. As suggested by one of the reviewers, national and
357 local agencies worldwide should bring together their own available data on public air quality monitoring to
358 guide toxicology and sensory scientists in the prioritization of key compounds and mixtures.
359
34
360 In a number of studies, toxicological limits for individual compounds have been set out (American
361 Conference of Governmental Industrial Hygienists, 2008; Bercu and Dolan, 2013). In the present work we
362 have collected information on the many chemical species found in a given environment. We are using this
363 data to devise a method of assessment of air quality due to mixtures and hope to report on our results in
364 the near future.
365
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522 Figure Legends
523
524 Figure 1. Comparison of VOC concentrations (geometric means) measured in two types of indoor environments:
525 Home/School and Commercial.
526
527 Figure 2. Comparison of concentrations (geometric means) for indoor VOCs found in common between
528 Home/School and Commercial environments.
529
530 Figure 3. Comparison of VOC concentrations (geometric means) measured in two types of outdoor environments:
531 Non-industrial and Industrial.
532
533 Figure 4. Comparison of concentrations (geometric means) for outdoor VOCs found in common between Non-
534 industrial and Industrial environments.
535
536 Figure 5. Comparison of VOC concentrations (geometric means) measured Indoors and Outdoors.
537
538 Figure 6. Comparison of concentrations (geometric means) for VOCs found in common between Indoors and
539 Outdoors.
540
541 Figure 7. Illustrating the range of VOCs concentrations (n = number of values) reported in Indoor Home/School (left
542 side) and Indoor Commercial (right side) environments. For each chemical the graphs show a box plot (see text for
543 details), the median (line inside the box), the outlier(s) (if any) (empty circles), and the arithmetic mean of all values
544 including outlier(s) (filled circles).
545
546 Figure 8. Illustrating the range of VOCs concentrations (n = number of values) reported in outdoor Non-Industrial
547 environments. For each chemical the graphs show a box plot (see text for details), the median (line inside the box),
548 the outlier(s) (if any) (empty circles), and the arithmetic mean of all values including outlier(s) (filled circles).
549
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549 This is a pre-copyedited, author-produced version of an article accepted for publication in Chemosphere
550 following peer review. The version of record Chemosphere,127,70-86,2015 is available online at:
551 http://www.sciencedirect.com/science/article/pii/S004565351500034X - doi:
552 10.1016/j.chemosphere.2014.12.089
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