Environmental Tobacco Smoke Particles Research Articles

Predicting size-resolved particle behavior in multizone buildings

We compare model predictions to measurements of SF 6 and environmental tobacco smoke particle concentrations in a three-room chamber experiment. To make predictions of multi-room aerosol transport and fate, we linked a multizone airflow model (COMIS) with an indoor aerosol dynamics model (MIAQ4). The linked models provide improved simulation capabilities for predicting aerosol concentrations and exposures in buildings. In this application, we found that the multizone air flow model was vital for predicting the inter-room airflows due to temperature differences between the rooms and when air-sampling pumps were operating during the experiment. Model predictions agree well with measurements, as shown by several comparison metrics. However, predictions of airborne ETS concentrations are slightly lower than measurements. This is mostly attributable to under-stating the source release amount, which we specified independently from literature estimates. Model predictions of ETS particle-size distributions agree with measurements; size bins with the peak concentrations are slightly over-predicted initially, but agree thereafter.

Determining Size-Specific Emission Factors for Environmental Tobacco Smoke Particles

Because size is a major controlling factor for indoor airborne particle behavior, human particle exposure assessments will benefit from improved knowledge of size-specific particle emissions. We report a method of inferring size-specific mass emission factors for indoor sources that makes use of an indoor aerosol dynamics model, measured particle concentration time series data, and an optimization routine. This approach provides--in addition to estimates of the emissions size distribution and integrated emission factors--estimates of deposition rate, an enhanced understanding of particle dynamics, and information about model performance. We applied the method to size-specific environmental tobacco smoke (ETS) particle concentrations measured every minute with an 8-channel optical particle counter (PMS-LASAIR; 0.1-2+ micrometer diameters) and every 10 or 30 min with a 34-channel differential mobility particle sizer (TSI-DMPS; 0.01-1+ micrometer diameters) after a single cigarette or cigar was machine-smoked inside a low air-exchange-rate 20 m{sup 3} chamber. The aerosol dynamics model provided good fits to observed concentrations when using optimized values of mass emission rate and deposition rate for each particle size range as input. Small discrepancies observed in the first 1-2 hours after smoking are likely due to the effect of particle evaporation, a process neglected by the model. Size-specific ETS particle emission factors were fit with log-normal distributions, yielding an average mass median diameter of 0.2 micrometers and an average geometric standard deviation of 2.3 with no systematic differences between cigars and cigarettes. The equivalent total particle emission rate, obtained integrating each size distribution, was 0.2-0.7 mg/min for cigars and 0.7-0.9 mg/min for cigarettes.

Environmental tobacco smoke particles in multizone indoor environments

Environmental tobacco smoke (ETS) is a major source of human exposure to airborne particles. To better understand the factors that affect exposure, and to investigate the potential effectiveness of technical control measures, a series of experiments was conducted in a two-room test facility. Particle concentrations, size distributions, and airflow rates were measured during and after combustion of a cigarette. Experiments were varied to obtain information about the effects on exposure of smoker segregation, ventilation modification, and air filtration. The experimental data were used to test the performance of an analytical model of the two-zone environment and a numerical multizone aerosol dynamics model. A respiratory tract particle deposition model was also applied to the results to estimate the mass of ETS particles that would be deposited in the lungs of a nonsmoker exposed in either the smoking or nonsmoking room. Comparisons between the experimental data and model predictions showed good agreement. For time-averaged particle mass concentration, the average bias between model and experiments was less than 10%. The average absolute error was typically 35%, probably because of variability in particle emission rates from cigarettes. For the conditions tested, the use of a portable air filtration unit yielded 65–90% reductions in predicted lung deposition relative to the baseline scenario. The use of exhaust ventilation in the smoking room reduced predicted lung deposition in the nonsmoking room by more than 80%, as did segregating the smoker from nonsmokers with a closed door.

Deposition of Tobacco Smoke Particles in a Low Ventilation Room

Deposition on indoor surfaces is an important removal mechanism for tobacco smoke particles. We report measurements of deposition rates of environmental tobacco smoke particles in a room-size chamber. The deposition rates were determined from the changes in measured concentrations by correcting for the effects of coagulation and ventilation. The airflow turbulent intensity parameter was determined independently by measuring the air velocities in the chamber. Particles with diameters < 0.25 μm coagulate to form larger particles of sizes between 0.25 and 0.5 μm. The effect of coagulation on the particles > 0.5 μm was found to be negligible. Comparison between our measurements and calculations using the theory of Crump and Seinfeld (1981) showed smaller measured deposition rates for particles from 0.1 to 0.3 μm in diameter and greater measured deposition rates for particles larger than 0.6 μm at three mixing intensities. Comparison of Nazaroff and Cass' model (1989a) for natural convection flow showed good agreement with the measurements for particles > 0.1 μm in diameter; however, measured deposition rates exceeded model predictions by a factor of approximately 4 for particles in size range of 0.05–0.1 μm in diameter. These results were used to predict deposition of sidestream smoke particles on interior surfaces. Calculations predict that in 10 hours after smoking one cigarette, 22% of total sidestream particles by mass will deposit on interior surfaces at 0.03 air change per hour (ACH), 6% will deposit at 0.5 ACH, and 3% will deposit at 1 ACH.

Predicting Regional Lung Deposition of Environmental Tobacco Smoke Particles

Inhalation exposure to environmental tobacco smoke (ETS) particles may increase health risks, but only to the extent that the particles deposit in the respiratory tract. We describe a technique to predict regional lung deposition of environmental tobacco smoke particles. Interpretation of particle size distribution measurements after cigarette combustion by a smoking machine in a test room yields an effective emissions profile. An aerosol dynamics model is used to predict indoor particle concentrations resulting from a specified combination of smoking frequency and building factors. By utilizing a lung deposition model, the rate of ETS mass accumulation in human lungs is then determined as a function of particle size and lung airway generation. Considering emissions of sidestream smoke only, residential exposures of nonsmokers to ETS are predicted to cause rates of total respiratory tract particle deposition in the range of 0.4–0.7 μg / day per kg of body weight for light smoking in a well-ventilated residence and 8–13 μg / day per kg for moderately heavy smoking in a poorly ventilated residence. Emissions of sidestream plus mainstream smoke lead to predicted deposition rates about a factor of 4 higher. This technique should be useful for evaluating health risks and control techniques associated with exposure to ETS particles

Environmental tobacco smoke in commercial aircraft

Environmental tobacco smoke and other pollutants present in both smoking and nonsmoking cabin sections during commercial passenger flights on DC-10 aircraft were determined on four, 5-h smoking flights. The average concentrations of nicotine, 3-ethenylpyridine, CO 2, CO, NO x , NO 2, O 3, PM2.5 and environmental tobacco smoke particles during a flight were determined with a briefcase sampling system. Concentrations of nicotine, 3-ethenylpyridine and CO as well as temperature, humidity and pressure were determined as a function of time during the flight. A model to predict penetration of environmental tobacco smoke from the smoking to the nonsmoking section of the passenger cabin under a variety of flight conditions is derived from the data.

Solanesol: a tracer for environmental tobacco smoke particles

Solanesol, a trisesquiterpenoid alcohol, has been shown to be present in environmental tobacco smoke. Results from the determination of particulate-phase solanesol in environmental tobacco smoke in both chamber and indoor environments show that solanesol is a suitable tracer for the particulate phase of environmental tobacco smoke