Bay Breeze Impact on Surface Ozone at Two Coastal Sites Along the Chesapeake Bay from 1986-2010
Open Access
- Author:
- Stauffer, Ryan Michael
- Graduate Program:
- Meteorology
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- April 04, 2012
- Committee Members:
- Anne Mee Thompson, Thesis Advisor/Co-Advisor
Jose Dolores Fuentes, Thesis Advisor/Co-Advisor
William F. Ryan, Thesis Advisor/Co-Advisor - Keywords:
- Surface Ozone
Bay Breeze
Climatology
Chesapeake
EPA - Abstract:
- Hourly surface meteorological measurements were coupled with U.S. Environmental Protection Agency (EPA) surface ozone (O3) mixing ratio measurements at Hampton, Virginia and Baltimore, Maryland, two sites along the Chesapeake Bay, to determine the behavior of surface ozone during bay breeze events and quantify the importance of the bay breeze in a manner similar to Martins et al. (2012). Analyses were from the months of May through September for the years 1986 to 2010. The years were split into three groups to account for recent reductions in emissions of nitrogen oxides (NOx): 1986-1994, 1995-2002, and 2003-2010. Each day was marked either as a bay breeze day, a non-bay breeze day, or a rainy/cloudy day based on the meteorological data, and ozone analyses were separated likewise. Eight hour averaged surface ozone values were typically 3 to 5 ppbv higher at Hampton and Baltimore during bay breeze events compared to days without a bay breeze. Average ozone anomalies in the afternoon were highest at both sites during bay breeze days in the study period 2003-2010. In conjunction with an overall lowering of ozone levels, the percentage of total exceedances of the EPA eight hour standard of 75 ppbv of ozone during bay breeze days increased dramatically at Hampton for 2003-2010, while remaining relatively the same at Baltimore. These results suggest that bay breeze circulations are becoming more important to causing pollution events at particular sites in the region, and support the hypothesis of Martins et al. (2012) that highly localized meteorology increasingly drives air quality events at Hampton.