Spatial variations in urban air pollution: impacts of diesel bus traffic and restaurant cooking at small scales

AbstractAir pollutant concentrations in urban areas exhibit strong spatial and temporal trends because of variations in land use and source distributions. While traffic is an important urban source of pollutants such as NO2 and particulate matter (PM), other sources can also contribute to observed spatiotemporal patterns. PM exposures are further complicated because urban-scale variations in fine particulate matter mass (PM2.5) concentrations can be decoupled from variations in PM physicochemical properties such as composition and the concentration of ultrafine particles (UFPs). Our goal was to quantify spatial gradients in both pollutant concentrations and PM characteristics over spatial scales ranging from hundreds of meters to several kilometers, along with sources influencing the observed spatial patterns. Continuous air pollutant concentrations were measured with a distributed network that consisted of a low-cost sensor package to measure pollutant gases (CO, NO2, O3, CO2), optical measurements of particulate black carbon (BC) and PM2.5, and UFP using condensation particle counters. The sampling sites were classified according to nearby land use for traffic, population, and restaurant density. Mean concentrations of BC and UFP vary by factors of approximately 4 and 3, respectively, across five typical urban sites in a 16 km2 sampling domain. Differences in traffic volume and composition (e.g., diesel bus activity) can describe some, but not all of the observed spatial an...
Source: Air Quality, Atmosphere and Health - Category: Environmental Health Source Type: research