An Assessment of Air Pollution Exposure Information for Health Studies

Abstract

Most studies of air pollution health effects are based on outdoor ambient exposures, mainly because of the availability of population-based data and the need to support emission control programs. However, there is also a large body of literature on indoor air quality that is more relevant to personal exposures. This assessment attempts to merge these two aspects of pollution-related health effects, emphasizing fine particles. However, the basic concepts are applicable to any pollutant. The objectives are to examine sensitivities of epidemiological studies to the inclusion of personal exposure information and to assess the resulting data requirements. Indoor air pollution results from penetration of polluted outdoor air and from various indoor sources, among which environmental tobacco smoke (ETS) is probably the most toxic and pervasive. Adequate data exist on infiltration of outdoor air but less so for indoor sources and effects, all of which have been based on surveys of small samples of individual buildings. Since epidemiology is based on populations, these data must be aggregated using probabilistic methods. Estimates of spatial variation and precision of ambient air quality are also needed. Hypothetical personal exposures in this paper are based on ranges in outdoor air quality, variable infiltration rates, and ranges of indoor source strength. These uncertainties are examined with respect to two types of mortality studies: time series analysis of daily deaths in a given location, and cross-sectional analysis of annual mortality rates among locations. Regressions of simulated mortality on personal exposures, as affected by all of these uncertainties, are used to examine effects on dose-response functions using quasi-Monte Carlo methods. The working hypothesis is that indoor sources are reasonably steady over time and thus applicable only to long-term cross-sectional studies. Uncertainties in exposure attenuate the simulated mortality regression coefficients; correlations between "true" and hypothesized exposures are used to compare their effects. For a given exposure uncertainty level, OPEN ACCESSAtmosphere 2015, 6 1737 attenuation of regression coefficients is similar for both types of simulated mortality studies, but since cross-sectional studies involve indoor sources they are more sensitive, to the point where regression coefficients may be driven to zero. The most pressing need for confirming data is the distribution of indoor sources among cities, especially for ETS.

PM2.5 Characteristics in Qingdao and across Coastal Cities in China

“…When A/F is more than 1, it means that primary sources are predominant; conversely, secondary sources are dominant [38]. In this study, the A/F ratio was high in one year (1.68), indicating that primary emissions were the dominant The maximum and minimum concentrations of NO 3 − appeared in winter and summer, respectively ( Figure 3). Aside from the conversion of NO 2 to HNO 3 and the partition of NO 3 − between the gaseous and particulate phases (which has a strong dependence on temperature and RH [29]), the concentration of ammonia is a key factor in determining nitrate concentration in the atmosphere.…”

“…Atmospheric fine particles are a complicated mixture with an important influence on atmospheric processes, climate change, and human health [1][2][3]. Currently, particle pollution is an urgent environmental issue in China due to its crucial role in the frequent air pollution episodes (e.g., haze).…”

Revisiting the Veterans Cohort Mortality Study: New results and synthesis

“…Using countylevel data for this purpose assumes homogeneity within a county; we thus assume that any local exposure differences in embedded highway configurations will average out. However, the county-average VKT and HAP data basically describe places and not necessarily the exposures of their inhabitants, who likely do not remain in their domicile and neighborhoods and spend most of their time indoors where air quality can be very different (Lipfert 2015). Other studies have focused directly on places such as proximity to vehicular traffic or "green" spaces (Vienneau et al 2017;Villeneuve et al 2012).…”

“…None of the of the published Veterans Cohort papers considered indoor air pollution exposures, which can be important given the large fraction of time typically spent indoors (Lipfert 2015). Substituting outdoor for personal exposure introduces substantial measurement error that is difficult to quantify and may bias risk estimates.…”

The Concentrations and Removal Effects of PM10 and PM2.5 on a Wetland in Beijing

“…The pollution problem is not conducive to the construction of an eco-friendly society and the development of sustainability [1]. The atmospheric particles (particulate matter, PM) have posed a threat to climate change and human health [2][3][4], especially PM 10 and PM 2.5 , which are defined as the particles with aerodynamic diameters of less than 10 µm (PM 10 ) and 2.5 µm (PM 2.5 ), respectively [5]. Thus, reducing the concentration of PM 10 and PM 2.5 or removing them from the atmosphere is considered as the key in improving air quality and promoting sustainability in urban areas.…”