CyanoHABs and CAPs: assessing community-based monitoring of PM _2.5 with regional sources of pollution in rural, northeastern North Carolina

Underserved rural communities in northeastern North Carolina (NC), surrounding the Albemarle Sound, have faced degraded environmental quality from various sources of air and water pollution. However, access to local air quality data is regionally scarce due to a lack of state-run monitoring stations, which has motivated local community science efforts. In January 2022, we co-developed a community-led study to investigate the relationship between fine particulate matter (PM_2.5) and sources of regional air pollution, with a specific focus on previously identified emissions from cyanobacterial harmful algal blooms (CyanoHABs). Using low-cost PurpleAir air quality sensors to quantify PM_2.5 mass, satellite-derived indicators of CyanoHABs, and other publicly available atmospheric and meteorological data, we assessed environmental drivers of PM_2.5 mass in the airshed of the Albemarle Sound estuary during 2022-2023. We found that bias-corrected PurpleAir PM_2.5 mass concentrations aligned with composite data from the three nearest federal reference equivalent measurements within 1 μg m^-3 on average, and that the temporal variation in PM_2.5 was most closely associated with changes in criteria air pollutants. Ultimately, satellite-based indicators of CyanoHABs (<i>Microcystis</i> spp. equivalent cell counts and bloom spatial extent) were not strongly associated with ambient/episodic increases in PurpleAir PM_2.5 mass during our study period. For the first time, we provide local PM_2.5 measurements to rural communities in northeastern NC with an assessment of environmental drivers of PM_2.5 pollution events. Additional compositional analyses of PM_2.5 are warranted to further inform respiratory risk assessments for this region of NC. Despite the lack of correlation between CyanoHABs and PM_2.5 observed, this work serves to inform future studies that seek to employ widely available and low-cost approaches to monitor both CyanoHAB aerosol emissions and general air quality in rural coastal regions at high spatial and temporal resolutions.