Model output tracking smoke from agricultural fires in south Florida from October 2022 - May 2023

Smoke from agricultural fires is a potentially important source of fine
particulate matter (PM2.5) in the US. Sugarcane is burned in Florida to
facilitate the harvesting process, with the majority of these fires
occurring in the Everglades Agricultural Area (EAA), where there is only
one regulatory air quality monitor. During the 2022–2023 sugarcane burning
season (October–May), we used public low-cost PurpleAir sensors,
regulatory monitors, and 29 PurpleAir sensors deployed for this study to
quantify PM2.5 from agricultural fires. We found satellite imagery is of
limited use for detecting smoke from agricultural fires in Florida due to
the cloud cover, overnight smoke, and the fires being small and
short-lived. For these reasons, surface measurements are critical for
capturing increases in PM2.5 from smoke, and we used multiple
smoke-identification criteria. During the study period, median 24-hour
PM2.5 concentrations increased by 2.3–6.9 µg m-3 on smoke-impacted days
compared to unimpacted days, with smoke observed on 4–28% of the campaign
days (ranges from the different smoke-identification criteria). Further,
short-term PM2.5 increases were observed over 40 µg m-3 during smoke
events. We contrast the region near the EAA with large populations of
low-income and minoritized groups to the more affluent coastal region. The
inland region experienced more smoke-impacted monitor days than the
Florida east coast region, and there was a higher study-average smoke
PM2.5 concentration in the inland area. These findings highlight the need
to increase air quality monitoring near the EAA.