title: Traffic and meteorological impacts on near-road air quality: summary of methods and trends from the Raleigh Near-Road Study.
abstract: A growing number of epidemiological studies conducted worldwide suggest an increase in the occurrence of adverse health effects in populations living, working, or going to school near major roadways. A study was designed to assess traffic emissions impacts on air quality and particle toxicity near a heavily traveled highway. In an attempt to describe the complex mixture of pollutants and atmospheric transport mechanisms affecting pollutant dispersion in this near-highway environment, several real-time and time-integrated sampling devices measured air quality concentrations at multiple distances and heights from the road. Pollutants analyzed included U.S. Environmental Protection Agency (EPA)-regulated gases, particulate matter (coarse, fine, and ultrafine), and air toxics. Pollutant measurements were synchronized with real-time traffic and meteorological monitoring devices to provide continuous and integrated assessments of the variation of near-road air pollutant concentrations and particle toxicity with changing traffic and environmental conditions, as well as distance from the road. Measurement results demonstrated the temporal and spatial impact of traffic emissions on near-road air quality. The distribution of mobile source emitted gas and particulate pollutants under all wind and traffic conditions indicated a higher proportion of elevated concentrations near the road, suggesting elevated exposures for populations spending significant amounts of time in this microenvironment. Diurnal variations in pollutant concentrations also demonstrated the impact of traffic activity and meteorology on near-road air quality. Time-resolved measurements of multiple pollutants demonstrated that traffic emissions produced a complex mixture of criteria and air toxic pollutants in this microenvironment. These results provide a foundation for future assessments of these data to identify the relationship of traffic activity and meteorology on air quality concentrations and population exposures.
authors.affiliation: U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, Research Triangle Park, NC 27711, USA. baldauf.richard@epa.gov
authors.forename: Richard
authors.initials: R
authors.lastname: Baldauf
authors.forename: Eben
authors.initials: E
authors.lastname: Thoma
authors.forename: Michael
authors.initials: M
authors.lastname: Hays
authors.forename: Richard
authors.initials: R
authors.lastname: Shores
authors.forename: John
authors.initials: J
authors.lastname: Kinsey
authors.forename: Brian
authors.initials: B
authors.lastname: Gullett
authors.forename: Sue
authors.initials: S
authors.lastname: Kimbrough
authors.forename: Vlad
authors.initials: V
authors.lastname: Isakov
authors.forename: Thomas
authors.initials: T
authors.lastname: Long
authors.forename: Richard
authors.initials: R
authors.lastname: Snow
authors.forename: Andrey
authors.initials: A
authors.lastname: Khlystov
authors.forename: Jason
authors.initials: J
authors.lastname: Weinstein
authors.forename: Fu-Lin
authors.initials: FL
authors.lastname: Chen
authors.forename: Robert
authors.initials: R
authors.lastname: Seila
authors.forename: David
authors.initials: D
authors.lastname: Olson
authors.forename: Ian
authors.initials: I
authors.lastname: Gilmour
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Cho
authors.forename: Nealson
authors.initials: N
authors.lastname: Watkins
authors.forename: Patricia
authors.initials: P
authors.lastname: Rowley
authors.forename: John
authors.initials: J
authors.lastname: Bang
mesh_terms: D000392:Air Movements; D000393:Air Pollutants / Q000032:analysis; D002248:Carbon Monoxide; D018986:Motor Vehicles; D009657:North Carolina; D013997:Time Factors; D001335:Vehicle Emissions; D014887:Weather
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions; D002248:Carbon Monoxide