The Impact of the Sea Breeze on Particulate Matter Chemical Composition and Concentration in Houston
CHUN-YING CHAO, Wei Li, Yuxuan Wang, Robert Griffin,
Rice University Abstract Number: 229
Working Group: Urban Aerosols
AbstractIt is crucial to understand the factors that control air quality in coastal regions because approximately half of the population of the United States lives in such areas. The local sea-land breeze plays an important role in coastal air quality because it circulates pollutants between coastal/urban and marine areas, potentially causing the accumulation of pollutants. Most previous studies focused on ozone concentration in these areas. However, particulate matter (PM) is another important air pollutant that warrants investigation. To understand the complicated interactions between coastal urban air quality and local sea-land breezes, we analyzed the historical PM data from Houston, Texas, which is the fourth most populous city in the United States. We used k-mean algorithm to analyze wind data from Houston and successfully separated synoptic wind clusters and a local sea breeze cluster. Additionally, we performed principal component analysis (PCA) on PM composition data for June, July, and August 2010-2019 from a monitoring site 5 km south of the industrialized Houston Ship Channel, resulting in the source apportionment of PM for each of the meteorological clusters. The results demonstrate that on southerly wind and local sea breeze days, the PM2.5 concentrations are ~30% higher than under other wind patterns. Under southerly winds, 29% of PM was attributed to road dust and 20% to heavy oil/combustion. In contrast, on days identified as being impacted by sea breezes, 33% of PM was attributed to motor vehicles and 20% to crustal sources and fresh sea salt. This study provides an example of how land-sea breeze can affect PM concentrations and compositions in a coastal city.