Research Projects

Ambient concentrations of ozone and PM2.5 have decreased in the South Coast Air Basin (SoCAB). Concentrations of nitrogen species have, to some extent, also responded to emission control measures. However, concentrations of these pollutants in the San Joaquin Valley Air Basin (SJVAB) have not responded as well to control measures. This raises a key question: Are these different ambient air quality responses to similar regulatory control strategies a result of different atmospheric chemistry regimes? This research proposal would make detailed (speciated) measurements of reactive oxides of nitrogen (NOY) and VOCs for at least a 6 week period during summer in the southern San Joaquin Valley in order to fully assess the chemical reactions (e.g., capture several weekends when NOX concentrations decline by about one-third). The field study would coincide with other CalNex 2010 measurements. These data would be analyzed to characterize the atmospheric chemistry associated with the formation of secondary pollutants during summer in the southern San Joaquin Valley and to assess the performance of chemical mechanisms in air quality models. The results of this and other CalNex 2010 projects will help document any differences in chemical regimes for the formation of secondary pollutants and also guide decisions on how to cost-effectively reduce precursor pollutants to O3, PM2.5, and other secondarily-formed pollutants.