Understanding the Impact of Meteorology on Air Quality

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Development of regulatory strategies for state-wide attainment of air quality standards for ozone and particulate matter (PM) requires a full understanding of the chemical and physical dynamics of tropospheric ozone. Air Quality Models (AQMs) are powerful tools for the investigation of ozone buildup mechanisms, however, due to the complexity and geographic specificity of such models, they can only be used to simulate a limited number of episodes. Meteorological conditions have a large impact on air quality, and selection of representative scenarios under which air quality standards are exceeded is critical to maximizing the knowledge gained from AQM simulations. We use cluster analysis to determine recurring meteorological states using historical data. Categorization of days of the ozone (or PM) season to meteorological regimes permits identification of representative atmospheric conditions favorable to ozone (or PM) buildup. Additionally, determining the frequency at which different meteorological regimes occur allows prediction of the overall, annual effect of emissions reductions simulated for only a few episodes. Beyond AQM applications, cluster analysis of meteorological regimes may also directly reveal unknown ozone buildup mechanisms.

Our collaborator in this project is Professor J.A. Romagnoli (LSU).

The projects along this research direction are being carried out by Dr. S. Beaver and Angadh Singh (UC Davis) and S. Pakalapati (LSU).

Related Publications

• Pakalapati, S., Beaver, S.,Palazoglu, A., and J.A. Romagnoli, “Sequencing Hourly Wind field Patterns to Determine Meteorological Scenarios Favoring Ozone Exceedance Days around Houston,Texas” Atmospheric Environment , submitted (2007).

• Beaver, S., Palazoglu, A., and Tanrikulu, S.,"Cluster Sequencing to Analyze Synoptic Transitions Affecting Regional Ozone," J. Applied Meteorology and Climatology, in press (2007).

• Beaver, S. and A. Palazoglu, "Cluster Analysis of Hourly Wind Measurements to Reveal Synoptic Regimes Affecting Air Quality," J. of Applied Meteorology and Climatology , 45(12), 1710–1726 (2006).

• Beaver, S. and A. Palazoglu, "A Cluster Aggregation Scheme for Ozone Episode Selection in the San Francisco, CA Bay Area," Atmospheric Environment , 40, 713-725 (2006).

Funding

California Air Resources Board – Central California Ozone Study.

Bay Area Air Quality Management District.