Dispersion Modeling of Traffic-Related Air Pollutant Exposures and Health Effects among Children with Asthma in Detroit, Michigan

Abstract

Vehicular traffic is a major source of ambient air pollution in urban areas. Traffic-related air pollutants, including carbon monoxide, nitrogen oxides, particulate matter less than 2.5 μm in diameter, and diesel exhaust emissions, have been associated with adverse human health effects, especially in areas near major roads. In addition to emissions from vehicles, ambient concentrations of air pollutants include contributions from stationary sources and background (or regional) sources. Although dispersion models have been widely used to evaluate air quality strategies and policies and can represent the spatial and temporal variation in environments near roads, the use of these models in health studies to estimate air pollutant exposures has been relatively limited. This paper summarizes the modeling system used to estimate exposures in the Near-Roadway Exposure and Urban Air Pollutant Study, an epidemiological study that examined 139 children with asthma or symptoms consistent with asthma, most of whom lived near major roads in Detroit, Michigan. Air pollutant concentrations were estimated with a hybrid modeling framework that included detailed inventories of mobile and stationary sources on local and regional scales; the RLINE, AERMOD, and CMAQ dispersion models; and monitored observations of pollutant concentrations. The temporal and spatial variability in emissions and exposures over the 2.5-year study period and at more than 300 home and school locations was characterized. The paper highlights issues with the development and understanding of the significance of traffic-related exposures through the use of dispersion models in urban-scale exposure assessments and epidemiology studies.

Ambient air pollution per specific land use types and activities in an urbanizing Eastern Caribbean Country, St. Kitts and Nevis

“…With the exception of NO 2 which is likely bimodal in its AM-PM concentration distribution, pollutant levels trended higher in the later hours of the day (after 12 PM) aligning with previous studies as it relates to traffic pollution [83][84][85]. Diurnal significance would however diminish in constructed models.…”

EXPLUME v1.0: a model for personal exposure to ambient O<sub>3</sub> and PM<sub>2.5</sub>

“…The advantage of this approach is that simulation data may cover long time periods to support climate studies or policy applications adjusting for meteorological variability, emissions regulations, and land-use classification. Gaussian dispersion models have often been coupled with population space-time activity data for use in exposure studies (Dias and Tchepel, 2018;Korek et al, 2015;Batterman et al, 2014;Willers et al, 2013). These models, coupled with regional-scale chemistry-transport models, account simultaneously for long-range transport, regional background concentrations, and local features such as traffic emissions over the road network (Soares et al, 2014).…”

“…Regional-scale chemistry-transport models (CTMs) such as CHIMERE (Mailler et al, 2017) or the Community Multiscale Air Quality model (CMAQ; Appel et al, 2014) have achieved resolution of 1 km×1 km with sufficient accuracy to be considered for use in such fine-scale applications (Beevers et al, 2013). Statistical, dynamical, or hybrid downscaling techniques such as kriging (Beauchamp et al, 2015) or subgrid-scale parameterizations (Valari and Menut, 2010) can be applied or coupled to these models to provide concentrations at district level. The use of CTMs instead of highresolution Gaussian or Lagrangian models in an exposure context has several advantages.…”

Allergic disease associations with regional and localized estimates of air pollution

“…However, most studies focus on short-term exposure in children or adolescents (Batterman et al, 2014; Khreis et al, 2016; Urman et al, 2013). Less is known about the prevalence of allergic disease among adults exposed to traffic emissions over an extended period of time.…”