(VOC) Composition of Environmental Tobacco Smoke

International Journal of

Environmental Research and Public Health Article

Correlation between Odor Concentration and Volatile Organic Compounds (VOC) Composition of Environmental Tobacco Smoke (ETS) Miyuki Noguchi, Saya Tanaka, Kaede Watanabe and Akihiro Yamasaki * Faculty of Science and Technology, Seikei University, 3-3-1 Kichijoji-Kitamachi, Musashino, Tokyo 180-8633, Japan; [email protected] (M.N.); [email protected] (S.T.); [email protected] (K.W.) * Correspondence: [email protected]; Tel.: +81-422-37-3887 Academic Editors: Alessandra Cincinelli and Tania Martellini Received: 29 June 2016; Accepted: 29 September 2016; Published: 9 October 2016

Abstract: We examined the correlation between the odor concentration and the chemical composition of environmental tobacco smoke (ETS). Three types of ETS samples were prepared: secondhand smoke (SHS), thirdhand smoke (THS), and field ETS samples from an outside smoking area. The odor concentrations of the ETS, SHS, and THS samples were determined by the triangle-odor-bag method, and the chemical compositions were determined by proton transfer mass spectrometry. The odor concentration of the SHS samples was three or four orders of magnitude higher than that of the field ETS samples, and three orders of magnitude higher than that of the THS samples. The concentration ratios of the constituent chemicals in THS to those in SHS were about 10−4 , corresponding to the ratio of the odor concentration. The concentration ratios of the constituent chemicals in the field ETS samples were much lower than the ratios of the odor concentrations. This suggests that the main contributing components to the odor of the field ETS samples are different from those in SHS and THS. The main contributors of the odor in the field ETS samples could be acetaldehyde, acetonitrile, acetic acid, and other unknown components with a mass-to-charge ratio (m/z) of 39 and 43. Keywords: tobacco smoke; air quality; odor; volatile organic compounds (VOC)

1. Introduction Environmental tobacco smoke (ETS) is a mixture of mainstream tobacco smoke exhaled by smokers and sidestream smoke generated by burning tobacco. ETS contains several thousand chemicals in different forms, such as vapors, particulates, and adsorbed particulates [1–4]. Some of these chemicals are known to cause adverse human health effects, such as asthma and lung cancer. Because of public concerns about these health effects, smoking in public spaces has been banned in many countries, and strict separation of smoking areas is deployed to prevent the unnecessary exposure of non-smokers to secondhand smoke (SHS). Apart from the direct health effects caused by SHS, some of its components possessing a relatively high boiling point adsorb to airborne particles, walls, and cloths; the adsorbed compounds continue to be emitted into the air for a long time. The environmental smoke thus generated is termed thirdhand smoke (THS) [5–9], and concerns have been raised about exposure to THS [7–9], the constituent components of which are different from those of SHS owing to chemical reactions. A number of studies have been published on the chemical composition of ETS, including SHS and THS [10–13]. Characterization of the chemicals involved would assist in evaluating the fundamental risks of human exposure to SHS or THS caused by these hazardous compounds [12]. Some compounds contained in ETS, however, have extremely low olfactory threshold values; for example, the odor threshold value of pyridine is about 3.7 ppb [13]. Such malodorous compounds in ETS may contribute to psychological effects in passive smokers; passive smokers that notice the malodor of ETS should Int. J. Environ. Res. Public Health 2016, 13, 994; doi:10.3390/ijerph13100994

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Int. J. Environ. Res. Public Health 2016, 13, 994

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feel offended, even if the concentration levels are below the threshold values that affect human health. Int. J. Environ. Res. Public Health 2016, 13, 994 2 of 12 Since smoking is not strictly prohibited in public spaces in most countries, smokers and/or providers of passive smokers; passive should smokersbe that notice theabout malodor ETS should feel offended, even if the smoking places for smoking conscious the of detection of tobacco odor by non-smokers. concentration levels are below the threshold values that affect human health. Since smoking is Thus, reducing odor from ETS is a key step in maintaining comfortable living conditionsnot through strictly prohibited in public spaces in most countries, smokers and/or providers of smoking places the separation of smoking areas [13]. Despite intensive work analysis of the constituent components for smoking should be conscious about the detection of tobacco odor by non-smokers. Thus, of ETS [4,11,14–18], there are very few studies focusing on the relationship between odor and the reducing odor from ETS is a key step in maintaining comfortable living conditions through the concentrations chemicals in ETS. Identifying the malodorous components in ETS separation of of odorous smoking areas [13]. Despite intensive work analysis of the constituent components of could lead toETS effective countermeasures to reduce ETS focusing malodor.onBecause volatile organic (VOCs) [4,11,14–18], there are very few studies the relationship betweencompounds odor and the contained in ETS are the main sourcesinofETS. odor [19], thethe contributions of each VOC component to concentrations of odorous chemicals Identifying malodorous components in ETS could lead should to effective countermeasures to reduce However, ETS malodor. Because volatile organic large compounds ETS odor be evaluated quantitatively. because of the extremely numbers of (VOCs) contained in ETS are the sources of odorthe [19], the or contributions of eachchemicals VOC chemicals contained in ETS, it might be main difficult to identify major main contributor of component to ETS odor should be evaluated quantitatively. However, because of the extremely the malodor of ETS. One possible and practical approach is to correlate the composition of malodorous large numbers of chemicals contained in ETS, it might be difficult to identify the major or main components with the odor concentration in ETS. If a given component dominantly contributes to contributor chemicals of the malodor of ETS. One possible and practical approach is to correlate the ETS odor, a correlation should be found between the odor concentration and the concentration of composition of malodorous components with the odor concentration in ETS. If a given component that particular chemical. In to this study, conducted simultaneous measurements of odor and VOC dominantly contributes ETS odor, we a correlation should be found between the odor concentration composition various ETSofsamples, and thechemical. correlations between concentration and chemical and thefor concentration that particular In this study, odor we conducted simultaneous measurements of odor and VOC composition for various ETSobserved samples, and the correlations between composition are demonstrated based on the experimentally results. odor concentration and chemical composition are demonstrated based on the experimentally

2. Experimental observed results. 2. Experimental 2.1. Preparation of ETS Samples

Three types of ofETS 2.1. Preparation ETSsample Samples gases were prepared for the measurements: (1) secondhand smoke (SHS); (2) thirdhand smoke (THS) desorbed from a plastic bag; (3) air sample from a smoking area Three types of ETS sample gases were prepared for the measurements: (1) secondhand smoke (field ETS). preparation or (THS) sampling methods these ETS samples are as follows. (SHS);The (2) thirdhand smoke desorbed from of a plastic bag; (3) air sample from a smoking area (1) TheETS). SHS sample was or prepared usingofan apparatus schematically shown in Figure 1. (field The preparation samplingby methods these ETS samples are as follows. A tobacco(1) cigarette Seven, produced by Japan Tobaccoschematically Inc., Tokyo, Japan), was burned in The SHS(Mild sample was prepared by using an apparatus shown in Figure 1. A tobacco cigarette Seven, by produced bytube JapantoTobacco Japan), was burned a polypropylene bottle,(Mild connected a plastic a plasticInc., bagTokyo, (volume 2.0 L) placed in in anaacrylic polypropylene bottle, connected by adegassed plastic tube to a plastic with bag (volume 2.0 L) placed in an box (inner volume 6.0 L). The box was beforehand a vacuum pump with anacrylic evacuation box (inner volume 6.0 L). The box was degassed beforehand with a vacuum pump with an rate of 1.0 L/min. The tobacco smoke generated in the polypropylene bottle was introduced into the evacuation rate of 1.0 L/min. The tobacco smoke generated in the polypropylene bottle was plastic bag by the pressure difference between the bottle and the box. After filling the bag with smoke, introduced into the plastic bag by the pressure difference between the bottle and the box. After the valve connecting the bottle with the bag was closed, and the SHS was sampled. In this study, filling the bag with smoke, the valve connecting the bottle with the bag was closed, and the SHS only side stream smoke as smoke the SHS sample gas. Theascomposition of the was sampled. In this(SSS) study,was onlycollected side stream (SSS) was collected the SHS sample gas. chemicals The in SSScomposition may depend smoking and the composition SSS of on thethe chemicals in conditions, SSS may depend on chemical the smoking conditions, of and thecollected chemicalin this composition of SSS collected in this be different from that in the field ETS. method may be different from that in method the fieldmay ETS.

Figure 1. Schematic drawing and a photograph of the tobacco smoke generator.

Figure 1. Schematic drawing and a photograph of the tobacco smoke generator.

(2) The THS was sampled as follows. After sampling SHS by the method mentioned in (1), we evacuated the bag by vacuum pump. Clean dry air was then introduced into the plastic bag from


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a gas cylinder. The plastic bag wasasleft under ambient conditions formethod 30 minmentioned to allow for desorption (2) The THS was sampled follows. After sampling SHS by the in (1), we of volatile components from the bag itself into the clean air. A blank test was performed evacuated the bag by vacuum pump. Clean dry air was then introduced into the plastic bag fromwithout a introduction of SHS, thebag gaseous from bagtosurface were recorded in gas cylinder. The and plastic was leftcomponents under ambientemitted conditions for the 30 min allow for desorption of volatile from the bag itself thewith cleanthe air.surface A blankof test was performed without advance. Note components the smoke components mayinto react the plastic bag, and the THS of SHS, and the gaseous components sampleintroduction collected was specific to the plastic bag used.emitted from the bag surface were recorded in advance. Note the smoke components may react with the surface of the plastic bag, and the THS (3) The field ETS sample was collected at a smoking space located on the campus of sample collected was specific to the plastic bag used. Seikei University, Musashino, Tokyo, Japan. The smoking space is a semi-open place surrounded by (3) The field ETS sample was collected at a smoking space located on the campus of Seikei glass-plate walls Musashino, and a glass-plate ventilation may take placeplace through the open University, Tokyo, roof. Japan.Natural The smoking space is a semi-open surrounded by space between the glass plates without ventilation equipment (Figure 2). The volume of the smoking glass-plate walls and a glass-plate roof. Natural ventilation may take place through the open space area was approximately 25plates m3 (2.4 m × ventilation 3.9 m × 2.7 m). The(Figure field ETS sample in of thethe smoking between the glass without equipment 2). The volume smokingspace area was 3 wasin approximately 25 m (2.4 × 3.9 m ×3.0 2.7L)m). field ETS sample in the space wasfor 6 s collected an odor sampling bagm(volume byThe collecting the ambient airsmoking of a given place in an odora sampling 3.0 L) collectingambient the ambient ofsampled a given place for same with acollected flex pump with flow ratebag of (volume 30 L/min. Asby a control, air air was by the 6 sat with a flex pump with athe flow rate of 30 L/min. As athe control, air was sampled method a location far from smoking area, where odorambient of tobacco smoke was by notthe sensed. same method at a location far from the smoking area, where the odor of tobacco smoke was not The field ETS sampling was conducted three times in July 2013 over different dates and under different sensed. The field ETS sampling was conducted three times in July 2013 over different dates and conditions, with a varying number of smokers (6, 1, and none) in the smoking area. under different conditions, with a varying number of smokers (6, 1, and none) in the smoking area.

Figure 2. A photograph of the smoking space at Seikei University.

Figure 2. A photograph of the smoking space at Seikei University. 2.2. Odor Concentration Measurements

2.2. Odor Concentration Measurements

The odor concentrations of the ETS samples were measured with a sensory test method termed

the odor triangle-odor-bag method method been widely as a test standard odor The concentrations of the[20]. ETSThis samples werehas measured with used a sensory method termed measurement method in Japan, and the resultshas of our odor measurements consistent the the triangle-odor-bag method [20]. This method been widely used as a were standard odor with measurement results from dynamic olfactometry [21]. method in Japan, and the results of our odor measurements were consistent with the results from The measurement procedure was as follows. Six or more volunteers were employed as a panel dynamic olfactometry [21]. group. In this study, six panelists, three female and three male college students in their early The measurement procedure as follows. Six oron more were as a panel twenties, were employed. They was had no special training the volunteers odor detection, andemployed medical ethical group.permission In this study, panelists, and three male college students in their early twenties, was six obtained priorthree to thefemale odor measurement. Three identical bags were prepared for each panelist. Twohad of the bags contained air, and the third contained sample gas to were employed. They no three special training on clean the odor detection, and medicala ethical permission measure odor concentration. The contents of the three bags were sniffed by a panelist to sense the was obtained prior to the odor measurement. Three identical bags were prepared for each panelist. any contained information clean about air, the and content. was asked to point outmeasure the bag odor Two ofodor the without three bags the The thirdpanelist contained a sample gas to containing the sample gas. If the panelist selected the correct bag, the procedure moved to the next concentration. The contents of the three bags were sniffed by a panelist to sense the odor without any stage: Three identical bags were presented, two of which contained clean air and the third information about the content. The panelist was asked to point out the bag containing the sample gas. contained a sample gas diluted with clean air to a pre-determined dilution ratio. The sniff test was If the panelist selected the correct bag, thetheprocedure moved the next stage: identical then repeated. If the panelist indicated correct bag, the testtomoved to the next Three stage, using the bags were presented, contained clean third contained a sample gas diluted sample gas two withof a which higher dilution ratio. Theair testand wasthe repeated if the panelist failed to sense the with clean air to a gas pre-determined ratio. The Theparameter, sniff test was then repeated. the panelist indicated sample or selected onedilution of the controls. Xi, was defined by theIffollowing formula, the correct bag, the test moved to the next stage, using the sample gas with a higher dilution ratio. The test was repeated if the panelist failed to sense the sample gas or selected one of the controls. The parameter, Xi , was defined by the following formula,

Xi =

logM1 + logM0 2

(1)


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where M1 was the maximum (final) dilution ratio at which the panelist correctly indicated the bag containing the sample gas, and M0 was the minimum dilution ratio at which the panel group failed to indicate the bag containing the sample gas. The mean value of Xi was calculated based on the four panelists who gave moderate values out of six panelists, ∑ Xi X=

i

(2)

4

Then the odor concentration, Z, of the sample gas, was finally given by, Z = 10X

(3)

The odor index, OI, was defined by using the odor concentration, OI = 10log10X = 10X

(4)

2.3. VOC Concentration Measurement The concentrations of VOCs composing the gas sample were analyzed by proton transfer mass spectrometry (PTR-MS) (Ionicon Analytik, Innsbruck, Austria). PTR-MS (Proton Transfer Reaction—Mass Spectrometry) is a simultaneous real-time monitoring of volatile (organic) compounds (VOCs) without sample preparation in very low concentrations. The sample gas was introduced to the apparatus and reacted with an excess amount of hydronium ions (H3 O+ ). Protons from the hydronium ions were transferred to the target chemicals (proton transfer reaction, PTR) to form ionic compounds. These ionic compounds were then introduced to mass spectrometry to determine the concentrations. Most of gaseous organic chemicals could be detected by the PTR-MS with a detection limit of about 1 ppt (parts per trillion). The mass spectrometry covers the m/z range from 22 to 220. The operating conditions were as follows. For the calculation of the VOC concentration, we followed the standard or default method provided by the manufacturer (IONICON Analytik [22]) and assumed that the rate constant of the proton transfer reaction was set constant at k = 2.0 × 10−9 cm3 ·s−1 . The pressure, temperature, and voltage of the drift tube were 2.15 mbar, 70 ◦ C, and 600 V, respectively. A quadrupole mass spectrometer was used. The particulates in the sample gas did not affect the concentration analysis. The effect of moisture on the analysis was negligible for all the analyses. We ignored the fragmentation of mass spectra based on the manufacturer’s data Ion fragmentation was not considered according to the manufacture’s data [22]. 3. Results and Discussion 3.1. Odor Concentration and Odor Index Table 1 shows the results of the measurements for the odor concentrations and the odor indices of the various ETS sample gases. Table 1. Odor concentrations of Environmental Tobacco Smoke (ETS) sample gases by the triangle-odor-bag method. Sample Second Hand Smoke (SHS) Third Hand Smoke (THS) Field ETS #1 (18 July); 6 smokers Field ETS #2 (19 July); 1 smoker Field ETS #3 (19 July); no smokers

Odor Concentration 109

2.7 × 3.2 × 105 3.2 × 106 3.2 × 105 3.2 × 105

Odor Index 94 55 65 55 55


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The SHS samples displayed the highest odor concentration, 2 × 109 , and the corresponding odor index was 94. The THS samples had an odor concentration that was four orders of magnitude lower at approximately 105 , equivalent to an odor index of 55. The field ETS samples showed an odor concentration in the range of 105 to 106 , and the highest odor concentration was observed for the field ETS sample collected in the presence of six smokers, the highest number of smokers present during sampling. The odor indices of the field ETS samples were in the range of 55–65. The regulated odor index in a living environment in Japan is in the range of 10–21, which is much lower than the ETS samples tested in this study. 3.2. Composition of the Sample Gases Analyzed by PTR-MS Table 2 shows the concentrations of the components in the ETS samples detected by PTR-MS in order of concentration. The chemicals identified are shown in Table 2 with a superscript. Note that we cannot exclude the possibility that the concentrations are the sum of isobaric and isomeric compounds. In the SHS model, isoprene showed the highest concentration, followed by nicotine. The concentrations of these chemicals are much higher than the published threshold values of the odor detection determined by the triangle-odor-bag method, which is 1.5 ppb for acetaldehyde, 0.5 ppm for formaldehyde, 42 ppm for acetone, 48 ppb for isoprene, and 11 ppb for nicotine [20]. Table 2. Chemicals and their concentrations in the sample gases with the twenty highest concentrations.

m/z

29 31 a 32 33 34 37 38 39 41 42 b 43 45 c 46 47 55 56 57 d 58 59 e 60 61 f 67 68 69 g 70 71 73 75 80 81 82 83

Second Hand Smoke (SHS)

Third Hand Smoke (THS)

Smoking Area #1

Smoking Area #2

6 Smokers

1 Smoker

Smoking Area #3 No Smokers

Concentration (ppb)

Concentration (ppb)

Concentration (ppb)

Concentration (ppb)

Concentration (ppb)

1.55 × 106 9.95 × 105 1.40 × 106 1.57 × 106 1.14 × 106 2.69 × 106 2.48 × 106 9.70 × 105 2.29 × 106 7.63 × 106 1.04 × 106 1.17 × 106 1.87 × 106 2.64 × 106 1.28 × 106 4.10 × 106

2682.8 418.5 1474.1 1806.6 3412.6 3606.7 750.3 363.3 976.9 2451.9 355.9 4296.1 267.7 964.1 332.4 411.1 330.5 248.2

52.0 120.2 13.9 40.6 31.8 94.4 83.1 160.1 20.4 48.5 51.3 97.6 59.3 45.7 20.4 21.0 26.7 17.2

52.4 11 7.9 47.1 41.7 11.1 32 16.7 41.2 39.4 66 19.7 24.7 17.9 17.3 43.4 23.3 19.9 9.2 -

51.5 8.0 7.9 23.0 41.3 6.2 10.5 29.2 28.5 16.1 23.5 12.0 17.1 18.6 15.6 17.6 13.5 -


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Table 2. Cont.

m/z

85

Second Hand Smoke (SHS)

Third Hand Smoke (THS)

Smoking Area #1

Smoking Area #2

6 Smokers

1 Smoker

Smoking Area #3 No Smokers

Concentration (ppb)

Concentration (ppb)

Concentration (ppb)

Concentration (ppb)

Concentration (ppb)

9.81 × 105

-

6 of 12 14.5 91 7.9 7.7 95 83 4.10 ×1.93 106 × 106 248.2 17.2 6 97 - 235.6 - 20.0 85 9.81 ×2.27 105 × 10 106 4.7 87 14.5 124 91 - 7.9 7.7 6.0 6 h 468.8 4.58 × 10 163 6 95 1.93 × 10 6 m/z, Chemicals identified probably as, 97mass-to-charge 2.27 × 10ratio. 235.6with asterisks are 20.0 - a formaldehyde; b acetonitrile; c acetaldehyde; d acrolein; e acetone; f acetic acid; g isoprene; h nicotine. 106 4.7 124 6.0 4.58 × 106 468.8 163 h Int.87 J. Environ. Res. Public-Health 2016, 13, 994 -

Concentration [ppb]

Figure 3 shows the PTR-MS spectra of the SHS samples. Various chemicals were detected. m/z, mass-to-charge ratio. Chemicals with asterisks are identified probably as, a formaldehyde; The identified chemicals with the highest areg acrolein (m/z = 57), acetone (m/z = 59), c acetaldehyde; d acrolein ;concentrations e acetone; f acetic acid; h b acetonitrile; isoprene; nicotine. isoprene (m/z = 69), and nicotine (m/z = 163). Figure 4 shows the PTR-MS spectra of the THS Figure 3 shows the PTR-MS spectra of the SHS samples. Various chemicals were detected. The samplesidentified desorbed from the wall the plastic bag intoare theacrolein clean air. the (m/z sample SHS was chemicals with theof highest concentrations (m/zAlthough = 57), acetone = 59), degassed from the plastic bag, a number of chemicals were detected in the THS. The concentration isoprene (m/z = 69), and nicotine (m/z = 163). Figure 4 shows the PTR-MS spectra of the THS desorbed was from10 the3 wall the plastic bag into the clean air. to Although the sample SHS was lower level of samples THS chemicals ppb,ofwhich is approximately three four orders of magnitude degassed from the plastic bag, a number of chemicals were detected in the THS. The concentration than those in the SHS samples. The constituent components with higher concentrations include level of THSacid, chemicals was 103 ppb, which is approximately three to four orders magnitude acetonitrile, acetic acetaldehyde, acetone, acrolein, and isoprene, which are of oxygen-containing lower than those in the SHS samples. The constituent components with higher concentrations compounds with relatively low molecular weights. To clarify the difference between the SHS and include acetonitrile, acetic acid, acetaldehyde, acetone, acrolein, and isoprene, which are THS samples in terms ofcompounds the chemical concentrations, the concentration of each in THS was oxygen-containing with relatively low molecular weights. To clarifychemical the difference plotted between against the its SHS concentration in SHS (Figure 5). We observed a linear correlation between the and THS samples in terms of the chemical concentrations, the concentration of each chemical in THS was plotted against its concentration in SHS (Figure 5). We observed a linear concentrations of chemicals in the SHS and THS samples. Most chemicals are on a line with a slope theand concentrations of chemicals in the SHS Most concentration chemicals of 10−4 ,correlation includingbetween nicotine isoprene, which corresponds to and the THS ratiosamples. of the odor of are on a line with a slope of 10−4, including nicotine and isoprene, which corresponds to the ratio of SHS samples to that of THS samples. Some components displayed a departure from the correlation the odor concentration of SHS samples to that of THS samples. Some components displayed a line, namely acetic acid and acetaldehyde; the ratios of these components in THS were much higher departure from the correlation line, namely acetic acid and acetaldehyde; the ratios of these than their ratios of odor concentration. To clarify these chemicals To from the correlation components in THS were much higher than the theirdeviation ratios of of odor concentration. clarify the line, wedeviation plotted the ratiochemicals of the concentrations in THS and SHS against (Figure 6). In of these from the correlation line, weinplotted the ratiothe of m/z the concentrations ingeneral, −4 , while THSwith and m/z in SHS againsthigher the m/zthan (Figure 6). Inageneral, with m/z10 values higherchemicals than 80 with chemicals values 80 had ratio ofchemicals approximately −4, while chemicals with had alower ratio ofthan approximately values lower than 80because had a ratio m/z values 80 had a10 ratio higher than 10−4m/z . This is presumably ofhigher the fact that than 10−4. This is presumably because of the fact that low molecular weight chemicals have, in low molecular weight chemicals have, in general, lower boiling points, and consequently a higher general, lower boiling points, and consequently a higher tendency to desorb. The contributions of tendency desorb. The contributions of the lowerare, m/z chemicals to the odor concentration are, theto lower m/z chemicals to the odor concentration however, not significant; instead, the odor however, not significant; instead, the odor concentration of the THS samples should be determined concentration of the THS samples should be determined mainly by the chemicals possessing m/z than 100. mainly values by thehigher chemicals possessing m/z values higher than 100. 1.0x10

7

8.0x10

6

6.0x10

6

4.0x10

6

2.0x10

6

isoprene

nicotine acetone acrolein

0.0 40

60

80

100 120 140 160 180 200 220

m/z

3. Proton Transfer Reaction-Mass(PTR-MS) (PTR-MS) spectra of of thethe SHSSHS samples (no dilution). Figure Figure 3. Proton Transfer Reaction-Mass spectra samples (no dilution).

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4.0x103 4.0x10

Concentration [ppb]

Concentration Concentration [ppb] [ppb]

6.0x10

acetaldehyde acetaldehyde aceticacid acid acetic

3

3

acetaldehyde acetonitrile acetonitrile acetic acid

4.0x10

2.0x103 2.0x10

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3

acetonitrile acetone acetone acetone

3

2.0x10

acrolein acrolein isoprene isoprene acrolein

3

isoprene

0.0 0.0

nicotine nicotine nicotine

0.0

40 40

40

60 60

80 100 100 120 120 140 140 160 160 180 180 200 200 80

60

80

100 120 140 160 180 200

m/z m/z m/z

Figure PTR-MS spectraofof ofthe the THS sample. Figure PTR-MSspectra spectra THS sample. Figure 4.4.4. PTR-MS the THS sample. Figure 4. PTR-MS spectra of the THS sample. 4

104 10 10 4

acetaldehyde aceticacid acid acetaldehyde acetone acetic acetonitrile acetone acetone isoprene acetonitrile acetonitrile acrolein nicotine isoprene isoprene acrolein acrolein nicotine nicotine

3

10

3

Concentration in THS [ppb]

Concentration Concentration in in THS THS [ppb] [ppb]

103 10

acetaldehyde

acetic acid

2

10 22

10 10

1

10 1

101 10

0

10

0

100 10-1 10 -4

Slope = 10 -1

-2

10-1 10 10 -2

0

1

2

3

4

5

6

7

10 10 10 10 10 10 10 10 -4 Slope==10 10-4 Slope Concentration in SHS [ppb]

8

10

10-2 10

0 1 2 3 4 8 55 SHS66 Figure 5. Correlation between in in77 THS. 100 the 101chemical 102 concentrations 103 10 104 10 10 10and10 10 108 Red points indicate 10 10 10 10 10 10 identified chemicals with the highest concentrations.

ConcentrationininSHS SHS[ppb] [ppb] Concentration

0

Concentration ratio in THS/SHS [-]

10 Figure5.5. Correlation Correlation between between the chemical chemical concentrations concentrations in in SHS SHS and and in inTHS. THS.Red Redpoints pointsindicate indicate Figure concentrations the identified chemicals with the highest concentrations. identified chemicals with the highest concentrations. concentrations. -1 10

acetic acid

00

Concentration Concentration ratio ratio in in THS/SHS THS/SHS [-] [-]

10 10

-2

10

acetaldehyde

-1

10-1 -3 10 10

aceticacid acid acetic

-2 -4 10-2 10 10

acetaldehyde acetaldehyde

-5

-310

10-3 10

0

50

100

150

200

250

m/z -4

10-4ratio of each chemical in THS/SHS plotted against the mass-to-charge ratio Figure 6. Concentration 10 (m/z). The solid line denotes the ratio of the odor concentration of THS to SHS. -5

10-5 10

00

50 50

100 100

150 150

200 200

250 250

m/z m/z

Figure6.6.Concentration Concentrationratio ratioof ofeach eachchemical chemicalin inTHS/SHS THS/SHSplotted plottedagainst againstthe themass-to-charge mass-to-chargeratio ratio each chemical in THS/SHS Figure (m/z).The Thesolid THSto toSHS. SHS. (m/z). solidline linedenotes denotesthe theratio ratioof ofthe theodor odorconcentration concentration of of THS THS to SHS. (m/z).

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Figure 77 shows thethe field ETS samples collected in the area.area. The Figure showsthe thePTR-MS PTR-MSspectra spectraofof field ETS samples collected in smoking the smoking absolute values of the concentrations, approximately 100 ppb for the higher-concentration The absolute values of the concentrations, approximately 100 ppb for the higher-concentration chemicals, were weremuch muchlower lowerthan than SHS or THS samples. In general, the higher concentrations chemicals, thethe SHS or THS samples. In general, the higher concentrations were were observed for samples collected in the presence of six smokers. It should be noted that the observed for samples collected in the presence of six smokers. It should be noted that the order of order of concentrations the odor concentrations thesamples field ETS was theodor order of the odor the odor of the fieldof ETS wassamples similar to thesimilar order oftothe concentrations concentrations in THS. in THS. (a) 200

acetaldehyde Smoking area #1 (6 smokers)

Concentration [ppb]

150 acetonitrile acetone

100

acrolein acetic acid

50

isoprene

0 20

40

60

80

100 120 140 160 180 200 220

m/z

(b) 200

Concentration [ppb]

150

Smoking area #2 (1 smoker)

100 acetonitrile acetaldehyde acrolein acetone

50

acetic acid isoprene

formaldehyde 0 20

40

60

80

100 120 140 160 180 200 220

m/z

(c) 200

Smoking area #3 (No smokers)

Concentration [ppb]

150

100

acetonitrile acetaldehyde

50

acetone acetic acid

formaldehyde 0 20

40

60

80

100 120 140 160 180 200 220

m/z

Figure 7.7.PTR-MS PTR-MSspectra spectra samples. (a) Smoking six smokers; (b) Figure of of thethe fieldfield ETS ETS samples. (a) Smoking area #1area with#1 sixwith smokers; (b) Smoking Smoking areaone #2 smoker; with one(c) smoker; (c) area Smoking area with no smokers. area #2 with Smoking #3 with no#3smokers.

Figure 8 shows the correlation between the concentrations of the chemicals in the field ETS samples and the SHS samples. A correlation was observed for each field ETS sample, but a better


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Figure 8 shows the correlation between the concentrations of the chemicals in the field ETS samples theRes.SHS was observed for each field ETS sample, but better Int. J.and Environ. Publicsamples. Health 2016, A 13, correlation 994 9 ofa 12 correlation was observed for the samples taken when six smokers were present. Although the ratios 3 to 10−4 , was observed samples taken when six smokers weresamples present. are Although of thecorrelation odor concentration of for thethe field ETS samples to that of the SHS aboutthe 10−ratios of the odor concentration of the field ETS samples to that of the SHS samples are about 10−3 to 10−4, the observed ratios of the concentrations, which can be represented by the slope of the correlation the observed ratios of the concentrations, which can be represented by the slope of the correlation line in Figure 8, were much lower, at about 10−5−5 to −610−6 . This result suggests that the odor of the line in Figure 8, were much lower, at about 10 to 10 . This result suggests that the odor of the field field ETS samples are determined by the different chemicals that determine the odor in SHS and THS. ETS samples are determined by the different chemicals that determine the odor in SHS and THS. We assume that that the the odor concentration samplesisisdetermined determined constituent We assume odor concentrationofofthe the field field ETS ETS samples by by the the constituent chemicals whose concentration ratio samplesisisequivalent equivalent to the ofodor the odor chemicals whose concentration ratiototothat thatin inthe the SHS SHS samples to the ratioratio of the concentration. TheThe chemicals ratiosare areclose close odor concentration concentration. chemicalswhose whoseconcentration concentration ratios to to thethe odor concentration ratio,ratio, such as acetaldehyde, acetonitrile, aceticacid, acid,and andother other unknown unknown components (m/z = 39,=43) such as acetaldehyde, acetonitrile, acetic components (m/z 39,would 43) would significantly contribute to the odor thefield fieldETS ETS samples. samples. Figure thethe correlation between significantly contribute to the odor ofofthe Figure9 shows 9 shows correlation between the concentrations the chemicals theETS fieldsamples ETS samples andinthose in the THS samples. the concentrations of theofchemicals in thein field and those the THS samples. Although it Although it is difficult to compare the strength of the correlations, better correlations were observed is difficult to compare the strength of the correlations, better correlations were observed for the for the concentrations of the chemicals in the field ETS plotted against those in THS rather than concentrations of the chemicals in the field ETS plotted against those in THS rather than those in SHS, those in SHS, especially for the ETS case without smokers. This finding suggests that the especially for the ETS smokers. Thissimilar findingtosuggests that theofcompositions the field compositions of thecase fieldwithout ETS samples are more the composition the THS than of to that ETS samples are more similar to the composition of the THS than to that of the SHS. Because of the SHS. Because the field ETS samples represent a mixture of the SHS and the THS in the the field ETS samples represent a mixture of the SHS and the THS in the smoking area, the higher contribution smoking area, the higher contribution of the SHS can be attributed to the field ETS with the of theincreasing SHS can number be attributed to the field ETS with the increasing number of smokers. of smokers.

Concentrations in the field ETS sample [ppb]

(a) 10

3

10

2

10

1

10

0

Smoking area #1 (6 smokers) acetaldehyde acetonitrile acetone acetic acid isoprene acrolein

10

-1

10

-2

Slope = 10

nicotine

-3

Slope = 10

-4

-6

Slope = 10

Slope = 10 10

-5

-3

10

0

10

1

10

2

3

4

10

10

5

6

10

7

10

8

10

10

Concentrations in SHS [ppb]

(b) 10

3

Concentrations in the field ETS sample [ppb]

Smoking area #2(1 smoker) 10

2

acetonitrile

acetaldehyde acetone isoprene

acetic acid 10

1

10

0

10

acrolein

Slope = 10

-1

-3

nicotine

Slope = 10

-4

Slope = 10 10

-5

Slope = 10

-6

-2

10

0

10

1

10

2

10

3

10

4

10

5

10

Concentrations in SHS [ppb]

Figure 8. Cont.

6

10

7

10

8


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(c) (c)

3

Concentration in the field ETS sample [ppb] Concentration in the field ETS sample [ppb]

10 3 10

Smoking area #3 (No smokers) Smoking area #3 (No smokers)

2

10 2 10

acetonitrile acetonitrileacetaldehyde acetaldehyde acetone acetic acid acetone acetic acid acrolein acrolein isoprene isoprene

1

10 1 10

0

10 0 10

-1

10 -1 10

nicotine -4 nicotine Slope = 10 -4 -6 -3 Slope = 10 Slope = 10 -7 Slope = 10 -6Slope = 10 -3 -5 = 10 -7 Slope = 10 Slope = 10Slope Slope = 10 -5 Slope = 10

-2

10 -2 10

-3

10 0 -3 10 10 0 10

1

2

10 1 10

3

4

5

6

7

10 10 10 10 10 2 3 4 5 6 10 10 10 in SHS 10 [ppb] 10 Concentrations Concentrations in SHS [ppb]

8

10 7 10

10 8 10

Figure 8. Correlation betweenthe theconcentrations concentrations of SHS andand those in the ETS ETS Figure 8. Correlation between ofchemicals chemicalsin in SHS those in field the field Figure 8. Red Correlation betweenthe theidentified concentrations of chemicals in SHSconcentrations. and those in the ETS samples. points indicate chemicals with the highest (a) field Smoking samples. RedRed points indicate the chemicals with withthe thehighest highest concentrations. (a) Smoking samples. indicate theidentified identified concentrations. (a)smokers. Smoking area #1 with sixpoints smokers; (b) Smoking area #2chemicals with one smoker; (c) Smoking area #3 with no area #1 with six smokers; (b) Smoking area #2 with one smoker; (c) Smoking area #3 with no smokers. area #1 with six smokers; (b) Smoking area #2 with one smoker; (c) Smoking area #3 with no smokers.

(a) (a)

3

Concentrations in the fieldfield ETS sample [ppb] Concentrations in the ETS sample [ppb]

10 3 10

Smoking area #1 (6 smokers) Smoking area #1 (6 smokers)

2

10 2 10

acrolein

1

10 1 10

0

10 0 10

nicotine nicotine

-1

10 -1 10

-3

Slope = 10 -3 Slope = 10

-2

10 -2 10

-4


-3

10 -2 -3 10 10 -2 10

-1

0

10 -1 10

1

2

10 10 10 0 1 2 10 10 in THS10 Concentration [ppb] Concentration in THS [ppb]

3

10 3 10

4

10 4 10

(b) (b)

3

10 3 10 Concentration in the field ETS sample [ppb] Concentration in the field ETS sample [ppb]

acetaldehyde acetaldehyde acetone acetonitrile acetic acid acetonitrile acetone isoprene acetic acid acrolein isoprene

Smoking area #2 (1 smoker) Smoking area #2 (1 smoker)

2

10 2 10

1

10 1 10

acetaldehyde acetaldehyde acetone acetonitrile isoprene acetone acetic acid acetonitrile acetic acidacrolein isoprene acrolein

0

10 0 10

nicotine nicotine

-1

10 -1 10

-2

10 -2 10

-3


-3

10 -2 -3 10 10 -2 10

-1

10 -1 10

-4

Slope = 10 -4 Slope = 10 0

1

2

10 10 10 0 1 2 10 10 in THS10[ppb] Concentrations Concentrations in THS [ppb]

Figure 9. Cont.

3

10 3 10

4

10 4 10


11 of 12


11 of 12

(c) 3

10

Smoking area #3 (No smokers)

-3

Slope = 10

2

Concentration in the field ETS [ppb]

10

acetaldehyde

-2

Slope = 10

acetic acid

1

10

acetonitrile acetone

acrolein 0

10

isoprene

-1

nicotine

10

-2

10

-4

Slope = 10 -3

10

-2

10

-1

10

0

10

1

10

2

10

3

10

4

10

Concentrations in THS [ppb]

Figure 9. Correlation betweenthe theconcentrations concentrations of in in THS andand those in the ETS ETS Figure 9. Correlation between ofthe thechemicals chemicals THS those infield the field samples. points indicatethe theidentified identified chemicals chemicals with concentrations. (a) Smoking samples. RedRed points indicate withthe thehighest highest concentrations. (a) Smoking area #1 with six smokers; (b) Smoking area #2 with one smoker; (c) Smoking area #3 with no area #1 with six smokers; (b) Smoking area #2 with one smoker; (c) Smoking area #3 with no smokers. smokers.

4. Conclusions 4. Conclusions In summary, we found a linear correlation between the concentrations of theofconstituent chemicals, In summary, we found a linear correlation between the concentrations the constituent chemicals, represented by m/z, of the SHS and THS samples. The ratios of the concentrations wereto the represented by m/z, of the SHS and THS samples. The ratios of the concentrations were equal theconcentrations ratio of the odor concentrations by the method, triangle-odor-bag ratioequal of theto odor determined by the determined triangle-odor-bag especiallymethod, for the high especially for the high molecular components (m/z 80). Correlations were also betweenof the molecular components (m/z > 80). Correlations were> also observed between theobserved concentrations the concentrations of the constituent chemicals of the field ETS samples and the SHS and THS constituent chemicals of the field ETS samples and the SHS and THS samples. The concentration ratios samples. The concentration ratios were, however, orders of magnitude smaller than the ratio of the were, however, orders of magnitude smaller than the ratio of the odor concentrations. This suggests odor concentrations. This suggests that the chemicals mainly attributable to the odor concentrations that the chemicals mainly attributable to the odor concentrations are different for the field ETS samples. are different for the field ETS samples. In this study, all constituent chemicals inin the by m/z m/zvalues values detected by In this study, all constituent chemicals thesamples sampleswere wererepresented represented by detected PTR-MS. Only a few components were identified; most of the constituent chemicals were not by PTR-MS. Only a few components were identified; most of the constituent chemicals wereidentified. not Future work will focus on identifying rankingand theranking contributions of these chemicals for effective identified. Future work will focus onand identifying the contributions of these chemicals for effective measures of malodor caused by ETS. measures of malodor caused by ETS. Acknowledgments: This study was supportedby by the the Smoking Foundation, Japan. Acknowledgments: This study was supported SmokingResearch Research Foundation, Japan. Author Contributions:Miyuki Miyuki Noguchi and and designed the experiments; Saya Tanaka andTanaka Kaede and Author Contributions: Noguchiconceived conceived designed the experiments; Saya Kaede Watanabe performed the experiments; and Miyukianalyzed Noguchi the data; Watanabe performed the experiments; Akihiro Akihiro YamasakiYamasaki and Miyuki Noguchi theanalyzed data; Akihiro Akihiro Yamasaki wrote the paper. Yamasaki wrote the paper.

Conflicts of Interest: TheThe authors declare Conflicts of Interest: authors declareno noconflict conflict of of interest. interest.

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