Bay breeze influence on surface ozone at Edgewood, MD during July 2011

Ryan M Stauffer; Anne M Thompson; Douglas K Martins; Richard D Clark; Daniel L Goldberg; Christopher P Loughner; Ruben Delgado; Russell R Dickerson; Jeffrey W Stehr; Maria A Tzortziou

doi:10.1007/s10874-012-9241-6

Bay breeze influence on surface ozone at Edgewood, MD during July 2011

J Atmos Chem. 2015;72(3-4):335-353. doi: 10.1007/s10874-012-9241-6. Epub 2012 Nov 16.

Affiliations

¹ Department of Meteorology, The Pennsylvania State University, University Park, PA 16802 USA.
² Department of Earth Sciences, Millersville University, Millersville, PA 17551 USA.
³ Department of Atmospheric and Ocean Science, University of Maryland, College Park, MD 20742 USA.
⁴ Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20742 USA ; NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA.
⁵ Joint Center of Earth Systems Technology, University of Maryland-Baltimore County, Baltimore, MD 21250 USA.

Abstract

Surface ozone (O₃) was analyzed to investigate the role of the bay breeze on air quality at two locations in Edgewood, Maryland (lat: 39.4°, lon: -76.3°) for the month of July 2011. Measurements were taken as part of the first year of NASA's "Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality" (DISCOVER-AQ) Earth Venture campaign and as part of NASA's Geostationary for Coastal and Air Pollution Events Chesapeake Bay Oceanographic campaign with DISCOVER-AQ (Geo-CAPE CBODAQ). Geo-CAPE CBODAQ complements DISCOVER-AQ by providing ship-based observations over the Chesapeake Bay. A major goal of DISCOVER-AQ is determining the relative roles of sources, photochemistry and local meteorology during air quality events in the Mid-Atlantic region of the U.S. Surface characteristics, transport and vertical structures of O₃ during bay breezes were identified using in-situ surface, balloon and aircraft data, along with remote sensing equipment. Localized late day peaks in O₃ were observed during bay breeze days, maximizing an average of 3 h later compared to days without bay breezes. Of the 10 days of July 2011 that violated the U.S. Environmental Protection Agency (EPA) 8 h O₃ standard of 75 parts per billion by volume (ppbv) at Edgewood, eight exhibited evidence of a bay breeze circulation. The results indicate that while bay breezes and the processes associated with them are not necessary to cause exceedances in this area, bay breezes exacerbate poor air quality that sustains into the late evening hours at Edgewood. The vertical and horizontal distributions of O₃ from the coastal Edgewood area to the bay also show large gradients that are often determined by boundary layer stability. Thus, developing air quality models that can sufficiently resolve these dynamics and associated chemistry, along with more consistent monitoring of O₃ and meteorology on and along the complex coastline of Chesapeake Bay must be a high priority.

Keywords: Bay Breeze; DISCOVER-AQ; Edgewood; Mid-Atlantic; Ozone; Pollution.