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

Home , Butanone, Butanone (data page), Methylcyclopentane

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 Abstract

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.

56 Keywords: Environmental Chemical Exposures - Volatile Organic Compounds (VOC) – Home/School

57 VOC Concentrations – Commercial Buildings VOC Concentrations – Outdoor VOC

58 Concentrations

59 1. Introduction

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.

83 2. Materials and Methods

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

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

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

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

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

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

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

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

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

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

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

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

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

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) ! ( ! (

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

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

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

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

) 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

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

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

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

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

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

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

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

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

365 References 366 367 368 Abraham, M.H.; Hassanisadi, M.; Jalali-Heravi, M.; Ghafourian, T.; Cain, W.S.; Cometto-Muniz, J.E., 2003. 369 Draize rabbit eye test compatibility with eye irritation thresholds in humans: a quantitative structure- 370 activity relationship analysis. Toxicol Sci. 76, 384-391. 371 Abraham, M.H.; Sanchez-Moreno, R.; Cometto-Muniz, J.E.; Cain, W.S., 2007. A quantitative structure 372 activity analysis on the relative sensitivity of the olfactory and the nasal trigeminal chemosensory 373 systems. Chem Senses. 32, 711-719. 374 Abraham, M.H.; Sanchez-Moreno, R.; Cometto-Muniz, J.E.; Cain, W.S., 2012. An algorithm for 353 odor 375 detection thresholds in humans. Chem Senses. 37, 207-218. 376 Abraham, M.H.; Sánchez-Moreno, R.; Gil-Lostes, J.; Cometto-Muñiz, J.E.; Cain, W.S., 2010. 377 Physicochemical modeling of sensory irritation in humans and experimental animals. In: Morris JB, 378 Shusterman DJ, eds. Toxicology of the Nose and Upper Airways. New York: Informa Healthcare 379 USA; pp.376-389. 380 American Conference of Governmental Industrial Hygienists, 2008. Threshold Limit Values for Chemical 381 Substances and Physical Agents and Biological Exposure Indices. Cincinnati: ACGIH®. 382 Bercu, J.P.; Dolan, D.G., 2013. Application of the threshold of toxicological concern concept when applied 383 to pharmaceutical manufacturing operations intended for short-term clinical trials. Regul Toxicol 384 Pharmacol. 65, 162-167. 385 Cometto-Muniz, J.E.; Abraham, M.H., 2008. A cut-off in ocular chemesthesis from vapors of homologous 386 alkylbenzenes and 2-ketones as revealed by concentration-detection functions. Toxicol Appl 387 Pharmacol. 230, 298-303. 388 Cometto-Muniz, J.E.; Abraham, M.H., 2010a. Odor detection by humans of lineal aliphatic aldehydes and 389 helional as gauged by dose-response functions. Chem Senses. 35, 289-299. 390 Cometto-Muniz, J.E.; Abraham, M.H., 2010b. Structure-activity relationships on the odor detectability of 391 homologous carboxylic acids by humans. Exp Brain Res. 207, 75-84. 392 Cometto-Muniz, J.E.; Cain, W.S.; Abraham, M.H., 2005. Determinants for nasal trigeminal detection of 393 volatile organic compounds. Chem Senses. 30, 627-642. 394 Cometto-Muñiz, J.E.; Cain, W.S.; Abraham, M.H.; Sánchez-Moreno, R.; Gil-Lostes, J., 2010. Nasal 395 chemosensory irritation in humans. In: Morris JB, Shusterman DJ, eds. Toxicology of the Nose and 396 Upper Airways. New York: Informa Healthcare; pp.187-202. 397 398 399 Data Sources References 400 401 Adgate, J.L.; Church, T.R.; Ryan, A.D.; Ramachandran, G.; Fredrickson, A.L.; Stock, T.H., et al., 2004. 402 Outdoor, indoor, and personal exposure to VOCs in children. Environ Health Perspect. 112, 1386- 403 1392. 404 Araki, A.; Kawai, T.; Eitaki, Y.; Kanazawa, A.; Morimoto, K.; Nakayama, K., et al., 2010. Relationship 405 between selected indoor volatile organic compounds, so-called microbial VOC, and the prevalence 406 of mucous membrane symptoms in single family homes. Sci Total Environ. 408, 2208-2215. 407 Araki, A.; Tsuboi, T.; Kawai, T.; Bamai, Y.A.; Takeda, T.; Yoshioka, E., et al., 2012. Validation of diffusive 408 mini-samplers for aldehyde and VOC and its feasibility for measuring the exposure levels of 409 elementary school children. J Environ Monit. 14, 368-374. 410 Barro, R.; Regueiro, J.; Llompart, M.; Garcia-Jares, C., 2009. Analysis of industrial contaminants in indoor 411 air: part 1. Volatile organic compounds, carbonyl compounds, polycyclic aromatic hydrocarbons 412 and polychlorinated biphenyls. J Chromatogr A. 1216, 540-566. 413 Billionnet, C.; Gay, E.; Kirchner, S.; Leynaert, B.; Annesi-Maesano, I., 2011. Quantitative assessments of 414 indoor air pollution and respiratory health in a population-based sample of French dwellings. 415 Environ Res. 111, 425-434. 416 Brown, S.K., 2002. Volatile organic pollutants in new and established buildings in Melbourne, Australia. 417 Indoor Air. 12, 55-63. 418 Bruno, P.; Caselli, M.; de Gennaro, G.; Iacobellis, S.; Tutino, M., 2008. Monitoring of volatile organic

419 compounds in non-residential indoor environments. Indoor Air. 18, 250-256. 420 Caselli, M.; de Gennaro, G.; Saracino, M.R.; Tutino, M., 2009. Indoor contaminants from newspapers: 421 VOCs emissions in newspaper stands. Environ Res. 109, 149-157. 422 Chao, C.Y.; Chan, G.Y., 2001. Quantification of indoor VOCs in twenty mechanically ventilated buildings in 423 Hong Kong. Atmos. Environ. 35, 5895-5913. 424 Chien, Y.C., 2007. Variations in amounts and potential sources of volatile organic chemicals in new cars. 425 Sci Total Environ. 382, 228-239. 426 Chikara, H.; Iwamoto, S.; Yoshimura, T., 2009. [Indoor air pollution of volatile organic compounds: 427 indoor/outdoor concentrations, sources and exposures]. Nihon Eiseigaku Zasshi. 64, 683-688. 428 Chmielowiec-Korzeniowska, A., 2009. The concentration of volatile organic compounds (VOCs) in pig 429 farm air. Ann Agric Environ Med. 16, 249-256. 430 Conley, F.L.; Thomas, R.L.; Wilson, B.L., 2005. Measurement of volatile organic compounds in the urban 431 atmosphere of Harris County, Texas, USA. J Environ Sci Health A Tox Hazard Subst Environ Eng. 432 40, 1689-1699. 433 de Blas, M.; Navazo, M.; Alonso, L.; Durana, N.; Iza, J., 2011. Automatic on-line monitoring of atmospheric 434 volatile organic compounds: gas chromatography-mass spectrometry and gas chromatography- 435 flame ionization detection as complementary systems. Sci Total Environ. 409, 5459-5469. 436 Eklund, B.M.; Burkes, S.; Morris, P.; Mosconi, L., 2008. Spatial and temporal variability in VOC levels 437 within a commercial retail building. Indoor Air. 18, 365-374. 438 Fedoruk, M.J.; Kerger, B.D., 2003. Measurement of volatile organic compounds inside automobiles. J 439 Expo Anal Environ Epidemiol. 13, 31-41. 440 Gallego, E.; Roca, X.; Perales, J.F.; Guardino, X., 2009. Determining indoor air quality and identifying the 441 origin of odour episodes in indoor environments. J Environ Sci (China). 21, 333-339. 442 Geiss, O.; Tirendi, S.; Barrero-Moreno, J.; Kotzias, D., 2009. Investigation of volatile organic compounds 443 and phthalates present in the cabin air of used private cars. Environ Int. 35, 1188-1195. 444 Godwin, C.; Batterman, S., 2007. Indoor air quality in Michigan schools. Indoor Air. 17, 109-121. 445 Gokhale, S.; Kohajda, T.; Schlink, U., 2008. Source apportionment of human personal exposure to volatile 446 organic compounds in homes, offices and outdoors by chemical mass balance and genetic 447 algorithm receptor models. Sci Total Environ. 407, 122-138. 448 Gordon, S.M.; Callahan, P.J.; Nishioka, M.G.; Brinkman, M.C.; O'Rourke, M.K.; Lebowitz, M.D., et al., 449 1999. Residential environmental measurements in the national human exposure assessment 450 survey (NHEXAS) pilot study in Arizona: preliminary results for pesticides and VOCs. J Expo Anal 451 Environ Epidemiol. 9, 456-470. 452 Guo, H.; Kwok, N.H.; Cheng, H.R.; Lee, S.C.; Hung, W.T.; Li, Y.S., 2009. Formaldehyde and volatile 453 organic compounds in Hong Kong homes: concentrations and impact factors. Indoor Air. 19, 206- 454 217. 455 Hippelein, M., 2004. Background concentrations of individual and total volatile organic compounds in 456 residential indoor air of Schleswig-Holstein, Germany. J Environ Monit. 6, 745-752. 457 Kliucininkas, L.; Martuzevicius, D.; Krugly, E.; Prasauskas, T.; Kauneliene, V.; Molnar, P., et al., 2011. 458 Indoor and outdoor concentrations of fine particles, particle-bound PAHs and volatile organic 459 compounds in Kaunas, Lithuania. J Environ Monit. 13, 182-191. 460 Kuntasal, O.O.; Karman, D.; Wang, D.; Tuncel, S.G.; Tuncel, G., 2005. Determination of volatile organic 461 compounds in different microenvironments by multibed adsorption and short-path thermal 462 desorption followed by gas chromatographic-mass spectrometric analysis. J Chromatogr A. 1099, 463 43-54. 464 Lau, W.L.; Chan, L.Y., 2003. Commuter exposure to aromatic VOCs in public transportation modes in 465 Hong Kong. Sci Total Environ. 308, 143-155. 466 Lin, C.C.; Lin, C.; Hsieh, L.T.; Chen, C.Y.; Wang, J.P., 2011. Vertical and diurnal characterization of 467 volatile organic compounds in ambient air in urban areas. J Air Waste Manag Assoc. 61, 714-720. 468 Logue, J.M.; McKone, T.E.; Sherman, M.H.; Singer, B.C., 2011. Hazard assessment of chemical air 469 contaminants measured in residences. Indoor Air. 21, 92-109. 470 Loh, M.M.; Houseman, E.A.; Gray, G.M.; Levy, J.I.; Spengler, J.D.; Bennett, D.H., 2006. Measured 471 concentrations of VOCs in several non-residential microenvironments in the United States. Environ 472 Sci Technol. 40, 6903-6911.

473 Massolo, L.; Rehwagen, M.; Porta, A.; Ronco, A.; Herbarth, O.; Mueller, A., 2010. Indoor-outdoor 474 distribution and risk assessment of volatile organic compounds in the atmosphere of industrial and 475 urban areas. Environ Toxicol. 25, 339-349. 476 Nagda, N.L.; Rector, H.E., 2003. A critical review of reported air concentrations of organic compounds in 477 aircraft cabins. Indoor Air. 13, 292-301. 478 Park, J.S.; Ikeda, K., 2006. Variations of formaldehyde and VOC levels during 3 years in new and older 479 homes. Indoor Air. 16, 129-135. 480 Parra, M.A.; Elustondo, D.; Bermejo, R.; Santamaria, J.M., 2009. Ambient air levels of volatile organic 481 compounds (VOC) and nitrogen dioxide (NO2) in a medium size city in Northern Spain. Sci Total 482 Environ. 407, 999-1009. 483 Pegas, P.N.; Alves, C.A.; Evtyugina, M.G.; Nunes, T.; Cerqueira, M.; Franchi, M., et al., 2011. Seasonal 484 evaluation of outdoor/indoor air quality in primary schools in Lisbon. J Environ Monit. 13, 657-667. 485 Raw, G.J.; Coward, S.K.; Brown, V.M.; Crump, D.R., 2004. Exposure to air pollutants in English homes. J 486 Expo Anal Environ Epidemiol. 14 Suppl 1, S85-94. 487 Salonen, H.; Pasanen, A.L.; Lappalainen, S.; Riuttala, H.; Tuomi, T.; Pasanen, P., et al., 2009. Volatile 488 organic compounds and formaldehyde as explaining factors for sensory irritation in office 489 environments. J Occup Environ Hyg. 6, 239-247. 490 Salonen, H.J.; Pasanen, A.L.; Lappalainen, S.K.; Riuttala, H.M.; Tuomi, T.M.; Pasanen, P.O., et al., 2009. 491 Airborne concentrations of volatile organic compounds, formaldehyde and ammonia in Finnish 492 office buildings with suspected indoor air problems. J Occup Environ Hyg. 6, 200-209. 493 Sarigiannis, D.A.; Karakitsios, S.P.; Gotti, A.; Liakos, I.L.; Katsoyiannis, A., 2011. Exposure to major 494 volatile organic compounds and carbonyls in European indoor environments and associated health 495 risk. Environ Int. 37, 743-765. 496 Schlink, U.; Thiem, A.; Kohajda, T.; Richter, M.; Strebel, K., 2010. Quantile regression of indoor air 497 concentrations of volatile organic compounds (VOC). Sci Total Environ. 408, 3840-3851. 498 Son, B.; Breysse, P.; Yang, W., 2003. Volatile organic compounds concentrations in residential indoor and 499 outdoor and its personal exposure in Korea. Environ Int. 29, 79-85. 500 Takigawa, T.; Wang, B.L.; Saijo, Y.; Morimoto, K.; Nakayama, K.; Tanaka, M., et al., 2010. Relationship 501 between indoor chemical concentrations and subjective symptoms associated with sick building 502 syndrome in newly built houses in Japan. Int Arch Occup Environ Health. 83, 225-235. 503 Takigawa, T.; Saijo, Y.; Morimoto, K.; Nakayama, K.; Shibata, E.; Tanaka, M., et al., 2012. A longitudinal 504 study of aldehydes and volatile organic compounds associated with subjective symptoms related to 505 sick building syndrome in new dwellings in Japan. Sci Total Environ. 417-418, 61-67. 506 Vainiotalo, S.; Vaananen, V.; Vaaranrinta, R., 2008. Measurement of 16 volatile organic compounds in 507 restaurant air contaminated with environmental tobacco smoke. Environ Res. 108, 280-288. 508 Weisel, C.P.; Alimokhtari, S.; Sanders, P.F., 2008. Indoor air VOC concentrations in suburban and rural 509 New Jersey. Environ Sci Technol. 42, 8231-8238. 510 Wu, X.M.; Apte, M.G.; Maddalena, R.; Bennett, D.H., 2011. Volatile organic compounds in small- and 511 medium-sized commercial buildings in California. Environ Sci Technol. 45, 9075-9083. 512 Yamaguchi, T.; Nakajima, D.; Ezoe, Y.; Fujimaki, H.; Shimada, Y.; Kozawa, K., et al., 2006. Measurement 513 of volatile organic compounds (VOCs) in new residential buildings and VOCs behavior over time. J 514 UOEH. 28, 13-27. 515 Yao, M.; Zhang, Q.; Hand, D.W.; Perram, D.L.; Taylor, R., 2009. Investigation of the treatability of the 516 primary indoor volatile organic compounds on activated carbon fiber cloths at typical indoor 517 concentrations. J Air Waste Manag Assoc. 59, 882-890. 518 519 520 521 522

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

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