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October 3, 2025
Location: SB 156
Time: 12:00 pm
Presenter: Paul Walter
Impacts of Sea Breezes on Coastal Air Quality in the Houston-Galveston-Brazoria Region 2021-2023
Abstract:
Ground-level ozone is a regulated air pollutant, and the Houston-Galveston-Brazoria (HGB) region is in non-attainment with 2015 National Ambient Air Quality Standards for ozone. A series of multi-agency field campaigns were conducted from 2021 to 2023 to measure ozone and its precursors in the HGB region. Measurement platforms include in situ observations from ground sites, mobile labs, boats, and balloons, and remote sensing platforms from the ground sites, aircraft, and satellites. Ozone episodes in the HGB region often occur in post-frontal conditions. In some situations, sea breezes can have an impact on ozone episodes in a coastal urban environment. In such cases in the HGB region, winds overnight and in the early morning have a northerly component, transporting ozone precursors from Houston or other urban and industrial areas out over Galveston Bay and the Gulf. A shallow marine layer confines ozone precursors near the surface, supporting high ozone concentrations from the resulting photochemical ozone production. A bay or gulf breeze circulation in the late morning or afternoon then transports the overwater ozone plume inland, leading to elevated ozone levels at some coastal locations. In some instances, we observe sharp temporal ozone gradients (enhancements) associated with these bay or gulf breezes. Radar observations are used to characterize sea breeze events and complement air quality measurements from the Texas Commission on Environmental Quality (TCEQ) network of monitoring sites and measurements from boats operating in the Houston Shipping Channel, Galveston Bay, and the Gulf. We will discuss the field campaigns, some common features of ozone episodes in the HGB region and observed trends, instances of impacts from sea breezes, and how complementary observations can shed light on such events.
Professor Walter, an associate professor in the Physics and Mathematics departments at St. Edward’s University in Austin, conducts atmospheric research utilizing weather balloons. He obtained his Ph.D. in Physics from the University of Texas at Austin, specializing in numerical relativity. Professor Walter employs a distinctive and collaborative testing methodology in his physics courses at St. Edward’s University.
