Macromodel for assessing residential concentrations of combustion-generated pollutants: Model development and preliminary predictions for CO, NO/sub 2/, and respirable suspended particles

Abstract

I. Introduction II. Model Development III. Summary of Model Input Parameters IV. Selected Model Results V. Single-Source and Regional Results VI. Concl usions and Recommenaa tions Acknowledgments Appendix A: Detailed Description of Model Input Parameters Appendix B: Nine-house Study Appendix C: Selected Graphic Output of Preliminary Model Predictions PREFACEThis report is the first in a series intended to assess residential air-pollution concentrations in the U.S. housing stock. A "macromodel" has been developed to simulate/predict selected residential air-pollution concentration distributions across specified house populations.Combustion pollutants are initially addressed because (1) they are a major class of indoor pollutants with documented adverse health effects at elevated concentrations,the underlying mathematical relationships are somewhat understood, and (3) sufficient input data exist to allow the macromodel to obtain results (i~e.,predictions). This report addresses the macromodel development and preliminary predictions for carbon monoxide, nitrogen dioxide, and respirable suspended particles. Subsequent reports address (1) sensitivity analysis of the macromodel, (2) micro/macro comparisons, and (3) preliminary predictions for organic compounds and sulphur dioxide.i ABSTRACT A simulation model (also call a "macromodel") has been developed to predict residential air pollutant concentration distributions for specified populations. The model inputs include the market penetration of pollution sources, pollution source characteristics (e.g., emission rates, source usage rates), building characteristics (e.g., house volume, air exchange rates), and meteorological parameters (e.g., outside temperature). Four geographically distinct regions of the U.S. have been modeled using Monte Carlo and deterministic simulation techniques. Single-source simulations were also conducted. The highest predicted CO and N02 residential concentrations were associated with the winter-time use of unvented gas and kerosene space heaters. The highest predicted respirable suspended particulate concentrations were associated with indoor cigarette smoking and the winter-time use of non-airtight wood stoves, radiant kerosene heaters, convective unvented gas space heaters, and oil forced-air furnaces. Future field studies in this area should (1) fill information gaps identified in this report, and (2) collect information on the macromodel input parameters to properly interpret the results. It is almost more important to measure the parameters that affect indoor concentration than it is to measure the concentrations themselves. ii I -2Approaches to assess total exposures to air pollutants fall into three categories: (1) personal monitoring (i.e., dosimetry); (2) monitoring of concentrations in the various human environments; and (3) modeling of exposures based on a wide array of information, including pollutant sources, building characteristics, pollutant behavior, and human activities. These approaches can be complementary. Moreover, the ...

Indoor Measurements of Environmental Tobacco Smoke Final Report to the Tobacco Related Disease Research Program

“…Although an exact smoking time and emission rate profile would be needed to correctly model the true week-average ETS concentrations, the steady-state mass balance model can be used to compare, on an equivalent basis, the measured ETS particle and particle tracer concentrations across study weeks and between houses. The steady-state form of the mass balance equation, repeated from Traynor et al, (1989) where C ss = the steady-state particle or particle tracer concentration (µg m -3 ), P = penetration fraction of particles from outdoors (0-1, unitless), C o = the outdoor concentration of particles or particle tracers (µg m -3 ), S = the ETS particle or particle tracer source strength (µg h -1 ), V = the house volume (m 3 ), a = the whole-house air exchange rate (h -1 ), and k = the particle deposition decay rate (h -1 ).…”

“…We have assumed a typical value of 0.08 h -1 for k, the particle deposition rate loss term (Traynor et al, 1989). Although k is particle size dependent, we did not make particle size measurements in the pilot field study, hence we have used a value that represents particle sizes typical of ETS (i.e., particle mass dominating in the aerodynamic diameter range of 0.1 to 1.0 µm).…”

“…Traynor et al, 1989 present a geometric mean value of 0.7 (geometric standard deviation 1.28) for P, based upon measurements of penetration of outdoor particles into residences conducted over a one-year period. In the following analyses the indoor PM 3.5 and PM tracers have been adjusted by subtracting PaC o /(a+k) where P and k are 0.7 and 0.08 h -1 , respectively.…”

A Multichamber Model For Assessing Consumer Inhalation Exposure

“…In contrast to the models in Table 1 that can be used to model specific situations on a one-at-a-time basis, a macromodel (Traynor et al, 1989) has been developed that estimates indoor air distributions across a variety of residences through a combination of deterministic and Monte Carlo simulation techniques in development of distributions for input parameters. With this focus on distributions rather than specific cases, the macromodel is currently restricted to combustion pollutants, a single zone, and steadystate assumptions in predicting average indoor concentrations over a one-week time interval.…”

Indoor Radon and Its Decay Products: Concentrations, Causes, and Control Strategies

“…A major example of this general approach to modeling is the work of Traynor et al (1989), who have constructed a model for assessing residential concentrations of combustion-generated pollutants, in particular CO, N0 2 , and respirable suspended particulates. There is some hope that development of predictive models for the case of radon and other pollutants will be eased by the acquisition of data from the (roughly) SOOO-home national radon survey to be conducted by the EPA.…”