Characterization of fine particulate matter in a coastal urban airshed

There is widespread concern over fine particles and aerosols in the urban atmosphere from a health-related perspective. Owing to recent changes in the air quality standards for particulate matter, an exhaustive study was undertaken to measure PM10, PM2.5, and PM1 within the Corpus Christi urban airshed in South Texas. The results reported here are from an ongoing field experiment in Corpus Christi that began in 1997. This is among the first of its kind in South Texas, with continuous ambient air monitoring at several sites to characterize fine particulate matter concentrations within the region using Tapered Elemental Oscillating Microbalance (TEOM) samplers. An urban monitoring location was chosen as the reference site and concurrent measurements of PM1, PM2.5 and PM10 were also conducted at this site. Filtered samples were gathered for chemical analysis of the particulate matter using a x-ray fluorescence spectrometer and an ion-chromatography unit. The influence of marine and natural aerosols on the urban atmosphere was evaluated. In addition, the influence of various meteorological parameters such as ambient temperature, wind speed, wind direction, and relative humidity on fine particulate mass concentration was evaluated for the study region. A spatial homogeneity in the mass concentration time-series data was noted. During the early morning hours, fine particle concentrations were strongly correlated with the concentrations of the oxides of nitrogen. Elevated levels of PM2.5 concentrations were observed during the recent smoke episodes in South Texas associated with agricultural burning in Mexico and Central America.