How Meteorology can Determine Ambient Air Pollution Impact on Population of Concerns

Abstract:

Residential wood smoke containing fine particle (PM_2.5) pollution is a common environmental problem during the cold season (typically between October 1^st -March 1^st) in Portland, Oregon. During these five months this ambient air pollution can become harmful to human health, causing and exacerbating respiratory and cardiovascular morbidity. During air stagnation and strong atmospheric inversion events, PM_2.5 pollution gets trapped near the surface causing PM_2.5 concentrations to increase. Such meteorological conditions occur frequently over Portland, especially during the fall and predominantly during evening and overnight hours. However, the complex topography characterizing Portland can impact how the pollution is spatially distributed within the city with some neighborhoods, often neighborhoods with higher concentrations of non-white residents, more impacted by poor air quality than others. This study aims to better understand the spatiotemporal relationship between meteorology, physical geography, and PM_2.5 concentrations in communities of concern across the city of Portland during the winter wood burning season. PM_2.5 data from two Oregon Department of Environmental Quality air monitoring stations are analyzed and compared for the years 2018-2020. One station is located in a neighborhood with a relatively high concentration of communities of concern, especially Latinx households, identified by the Portland Air Toxic Solution study as disproportionally impacted by PM2.5 exposure compared to non-Hispanic whites. This allows for a careful comparison between pollutant concentrations, meteorological conditions, and physical geography (elevation, proximity to wind-sheltered areas, etc.) in two demographically different neighborhoods. Days with elevated concentrations of PM_2.5 (>35 mg/m^3), defined both as daily averages and daily peaks are identified to understand how the environmental landscape, meteorology, demographics, and human behavior are playing a role in the elevated PM_2.5 concentrations. Local-scale measurements of wind and temperature are used to characterize the meteorological conditions associated with these days of elevated PM_2.5 concentrations with an aim to better predict and understand smaller spatial scale variations in pollution across Portland. It is anticipated that results from this study may be used towards reducing the inequities associated with increased winter air pollution on communities of concern in Portland.