Dynamics of THS-related VOC emissions and concentrations and their differences with audience demographics
The movie theater where the study took place strictly enforces German laws banning indoor smoking in theaters and has not allowed smoking for 15 years. The theater was supplied 100% fresh air for the purposes of this study (i.e., no recirculation), and its air intakes are at or near the roofline (approximately 20+ m above the base of the building), keeping them further away from potential street-level sources. This configuration effectively reduced outdoor SHS exposure and minimized any contribution from other parts of the building during this study. In addition, intake air was passed through a filter (equivalent to MERV 12) and underwent humidity and temperature adjustments.
6, 21, 2 . Through four consecutive days (27 to 30 January 2017) of real-time measurements with online high-resolution MS [i.e., proton transfer reaction–time-of-flight (PTR-TOF) MS], 35 different VOCs previously associated with THS or tobacco smoke were observed at considerable concentrations in the theater, including furanoids, aromatics, aldehydes, alkenes, and nitrogen-containing species, confirmed via offline gas chromatography with MS (GC-MS) as listed in Table 1 22 ). Most changes in these VOC concentrations trended together over the course of each day, punctuated by synchronized, sharp increases of known THS tracers (e.g., 2,5-dimethylfuran, 2-methylfuran, and acetonitrile) and other THS-related VOCs ( Fig. 1 ). These concentration spikes occurred repeatedly at the start of films during audience arrival, concurrent with sharp changes in markers of human occupancy, including decamethylcyclopentasiloxane (D5) and CO
Compounds Average
emission
rate during
THS events
(mg/hour) Emission rate regression
to 2,5-dimethylfuran Emission rate regression
to benzene t test: R-rated versus G-rated
emission rates Mean ± SD* r Slope r Slope t P value† Aromatics Benzene‡§ 3.46 ± 1.79 0.87 4.73 ± 0.73 1.00 1.00 ± 0.00 4.14 0.001 Toluene‡§ 5.91 ± 2.78 0.74 6.14 ± 1.53 0.93 1.42 ± 0.15 2.79 0.009 C 8 aromatics‡§ 4.84 ± 2.11 0.74 5.00 ± 1.26 0.92 1.15 ± 0.14 2.81 0.010 C 9 aromatics‡ 3.12 ± 1.37 0.72 3.28 ± 0.88 0.91 0.77 ± 0.10 4.36 <0.001 C 10 aromatics‡ 0.91 ± 0.42 0.75 1.03 ± 0.25 0.91 0.23 ± 0.03 4.62 <0.001 Phenol‡§ 0.57 ± 0.32 0.85 0.74 ± 0.13 0.77 0.13 ± 0.03 2.60 0.011 Styrene‡§ 0.71 ± 0.35 0.72 0.84 ± 0.22 0.83 0.18 ± 0.03 5.07 <0.001 Benzaldehyde‡ 0.24 ± 0.10 0.59 0.18 ± 0.07 0.57 0.03 ± 0.01 2.98 0.006 Cresols‡§ 0.26 ± 0.14 0.87 0.34 ± 0.05 0.81 0.06 ± 0.01 2.93 0.006 Naphthalene‡§ 0.34 ± 0.16 0.88 0.40 ± 0.06 0.88 0.07 ± 0.01 2.78 0.008 Furanoids Furan 0.43 ± 0.40 0.90 0.90 ± 0.12 0.74 0.14 ± 0.03 1.83 0.045 2-Methylfuran 0.83 ± 0.75 0.98 1.92 ± 0.11 0.85 0.31 ± 0.05 3.15 0.006 2,5-Dimethylfuran§ 0.48 ± 0.36 1.00 1.00 ± 0.00 0.87 0.16 ± 0.02 3.76 0.002 Furfural‡ 0.60 ± 0.36 0.90 0.86 ± 0.11 0.80 0.14 ± 0.03 2.29 0.020 Furfuryl alcohol‡ 0.31 ± 0.14 0.93 0.37 ± 0.04 0.83 0.06 ± 0.01 3.37 0.003 Carbonyls Formaldehyde§ 0.94 ± 0.50 0.87 1.25 ± 0.20 0.83 0.22 ± 0.04 3.84 0.001 Acetaldehyde§ 9.07 ± 6.51 0.90 15.44 ± 2.20 0.84 2.64 ± 0.50 2.86 0.009 Acrolein§ 0.73 ± 0.57 0.94 1.43 ± 0.14 0.87 0.24 ± 0.04 3.31 0.004 Acetone∥ 20.45 ± 10.45 0.69 19.54 ± 6.43 0.72 3.75 ± 1.14 3.06 0.010 Methacrolein 0.61 ± 0.43 0.93 1.10 ± 0.12 0.85 0.18 ± 0.03 3.14 0.004 2,3-Butanedione 1.00 ± 0.68 0.90 1.68 ± 0.23 0.72 0.25 ± 0.07 3.59 0.003 Other Acetonitrile§ 1.20 ± 0.86 0.96 2.24 ± 0.19 0.80 0.35 ± 0.07 3.27 0.004 Acetic acid∥ 8.40 ± 2.21 0.68 5.84 ± 1.99 0.69 1.09 ± 0.36 3.10 0.010 Isoprene 4.55 ± 2.89 0.84 6.81 ± 1.22 0.77 1.15 ± 0.26 2.93 0.006 Monoterpenes‡∥ 2.14 ± 1.91 0.58 2.62 ± 1.05 0.46 0.41 ± 0.23 0.99 0.179 21, 8 aromatics, C 9 aromatics, and C 10 aromatics, consult All compounds reported here have been previously observed in tobacco smoke ( 6 22 ). For the isomer distributions for Caromatics, Caromatics, and Caromatics, consult Fig. 2D *Emission rates were calculated from the THS emission events of 10 R-rated movie showings unless noted otherwise. High SDs indicate high movie-to-movie variability. Emission rates include isomers and ionization products not mentioned above (e.g., methyl vinyl ketone with methacrolein). †P values in bold represent those that are statistically significant (P < 0.05) for the unpaired two-sample t test, evaluating whether the emission rates were higher in the 10 R-rated movie screenings than the five family movies. See section S1 for more details. ‡Compounds were identified with an offline GC-MS method for ≥C 6 compounds using standards and the National Institute of Standards and Technology library. §Hazardous air pollutants (HAPs) as assigned by the EPA or in the case of 2,5-dimethylfuran, showed cytotoxicity in previous studies (1). ∥Emission factors use data from days 1 to 3 for acetone and acetic acid because large non-THS related emissions from cleaning were observed before the start of day 4 for these compounds, which biased calculations. The monoterpenes values exclude the third film on day 1 because of a large non-THS spike after the start of the film.
Major repeated emission events of THS tracers and known tobacco-related compounds, including (A) acetonitrile, (B) furanoids and aldehydes, and (C) aromatics, are observed near the start of R-rated action films, while only minor enhancements are present for family films. (A) includes CO 2 as a marker of human occupancy and displays attendance data from ticket sales (along the top), movie start times (dotted lines), and movie duration (shading). The shading also denotes generic movie category—family movie (Wendy) or R-rated action movie (Resident Evil). Concentrations are shown as 2-min averages. A change in ventilation mode led to the sudden increases in CO 2 at around midnight each night. Figure S5 includes Monday’s data, along with D5, which represents an additional marker for human occupancy changes complementary to CO 2 . ppm, parts per million; ppb, parts per billion.
The increase in THS tracer concentrations was a function of audience demographics for both movie type and movie showtime. While movie rating (G-rated versus R-rated) may not explicitly represent the audience demographic, it was a proxy for both audience age and the likelihood that individuals in the audience were exposed to smoke at some point before entry. A much more pronounced enhancement was observed for the showings of R-rated action movies (e.g., Resident Evil and Irre Helden), while similar abrupt increases were minor and only occasionally present in the family movie screenings, even with large audiences of 70 to 220 people (e.g., Wendy). Concentration spikes due to THS emissions are largest for later showtimes.
et al. (P < 0.01 in one-tailed t tests) ( We determined the overall chemical composition of the emission events during R-rated films ( Fig. 2D ) and calculated each VOC’s effective gas-phase emission rates (hereafter, “emission rates”) for each film by using a box model similar to the one used by Stönner 23 ) (see the Supplementary Materials). THS emission rates are statistically higher for R-rated action movies than for family movies for most THS compounds (< 0.01 in one-tailedtests) ( Table 1 ).
(A) Regressions between emission rates of VOCs commonly found in THS with 2,5-dimethylfuran, a commonly used tracer for THS and environmental tobacco smoke. (B) Observed toluene versus benzene emission rates compared to literature data (see the Supplementary Materials) for tobacco smoke and other sources and environments. (C) Close-up of a single THS emission event, with acetonitrile, benzene, and CO 2 concentrations shown on relative scales for comparison (day 2, 20:20 showing of Resident Evil). Concentrations increase simultaneously; CO 2 comes to steady state because of constant emissions, while acetonitrile and benzene decay as a result of decreased off-gassing from occupants. (D) The average composition of THS-related emissions during THS events, colored by compound type. Isomer speciation is derived from offline TD-GC-MS and may not add up to 100% because of rounding.
2 signal, THS VOC concentrations decay throughout the film because of both the known exponential decay in initial peak THS off-gassing (−1 (23, 1 − 1 e ) in 40 min (for an instantaneous emissions spike). In this study, the observed 63% decay in acetonitrile concentrations from peak THS emissions at the start of the film was 42 to 50 min (fig. S1A). THS VOC concentrations generally increased over the course of multiple R-rated films and the weekend ( In sharp contrast with the respiration-dependent COsignal, THS VOC concentrations decay throughout the film because of both the known exponential decay in initial peak THS off-gassing ( 17 19 ) and their ventilation from the room ( Figs. 1 and 2C ). The effective air exchange rate (AER) reported in previous works at the same theater is 1.5 hour 24 ), which would correspond to a 63% concentration decrease (i.e.,) in 40 min (for an instantaneous emissions spike). In this study, the observed 63% decay in acetonitrile concentrations from peak THS emissions at the start of the film was 42 to 50 min (fig. S1A). THS VOC concentrations generally increased over the course of multiple R-rated films and the weekend ( Fig. 1 ) because of (i) continued off-gassing from the audience throughout the film (albeit at lower rates), (ii) persistent THS repartitioning within the theater room, and/or (iii) insufficient time between THS emission events for ventilation to dilute concentrations back to their initial baseline levels.
Emissions from late arrivals, observed as concentration spikes of THS tracers during films (well after their start), contributed noticeable concentration enhancements multiple times during 4 days of online MS measurements (fig. S1B). These spikes indicate that subsets of audience members can contribute appreciable emissions of THS-related compounds upon entry into the screening room, and the positive pressure of fresh outdoor air supplied to the screening room ensures that these spikes are not the result of air intrusion from other parts of the building. We also observed smaller concentration spikes occurring at the ends of some R-rated films as the audience leaves (fig. S5). These may be attributable to higher breathing rates during departure or agitation of clothes that may have been inaccessible to airflow while seated. In principle, entry/exit by audience members could lead to the resuspension of aerosol/dust containing persistent THS from the theater’s surfaces, or the warming of seats with sorbed persistent THS could cause thermal repartitioning, but the observed THS VOC emissions were minimally affected by these because the large audiences for family films did not produce similar emission spikes.