Relation of wind direction and coal terminal activity patterns with air pollution burden in a community bordering a coal export terminal, Curtis Bay, Maryland, USA.

Residents of Curtis Bay, South Baltimore, Maryland living near an open-air coal terminal have raised concerns about dark dust in their community. Coal particles have been detected in this dark dust, however, the relationship between coal terminal activity and air pollution in Curtis Bay remains unclear. This study aimed to determine how air quality varied in relation to changes in wind direction and observed coal terminal activity. We measured particulate matter (PM₁, PM_2.5, PM₁₀, total suspended particles) and black carbon (BC) concurrently with wind direction and visible coal terminal bulldozer activity (camera-based) at equivalent 1-minute time scales. We used conditional fixed-effects regression models to evaluate relationships between local air pollution and (1) wind direction and (2) visible bulldozer activity on coal piles. From July 5, 2022-July 16, 2023, a ten-node air monitoring network collected 2,121,793 PM and 360,325 BC 1-minute records. When downwind of the coal terminal versus not downwind, PM was 0.66 to 5.3 μg/m³ higher (p < 0.0001) and BC was 0.11 μg/m³ higher (95% CI = 0.10, 0.12). When bulldozer activity was visible versus not visible, PM was 0.49 to 2.2 μg/m³ higher (p < 0.001) and BC was 0.09 μg/m³ higher (95% CI = 0.08, 0.10). The associations between bulldozer activity and air pollutant concentrations were ~ 2.0-2.8 times higher downwind of the coal terminal versus not (all p-interaction < 0.001). PM and BC air pollution was greater in Curtis Bay when downwind of and when bulldozer activity was visible at the coal terminal, and highest when both occurred jointly. Mitigation strategies appear warranted to reduce PM and BC air pollution burden associated with coal terminal activities in Curtis Bay.