Fluxes of reactive organic gases seasonal intercomparison of chemical lifetimes and emissions

Sub–micron particulate matter (PM1) in the New York (NY) metropolitan area
impacts air quality and human health. We characterized refractory black
carbon (BC) and non–refractory (NR) PM1 in Mineola, NY during winter 2024
and NR-PM1 during summer 2023. This study investigated seasonal
differences in PM1, drivers of wintertime PM1 elevated events, and
potential health effects on local communities. Organic aerosol (OA)
dominates both winter (63 %) and summer (86 %) NR–PM1. Primary OA
dominates winter PM1 (57 %) with cooking organic aerosol (COA)
contributing on average 29 %, but up to 81 % of elevated PM1 events. In
summer, OA was impacted by wildfire smoke and biogenic sources; COA
averaged only 9 % of OA, but sporadically enhanced OA and drove several
PM1 events. BC accounted for 6 % of winter PM1. BC coating thickness
increased during wintertime events relative to the campaign average,
although modeled respiratory deposition showed that accompanying size
changes did not shift respiratory deposition away from the alveolar
region. Overall, urban PM1 primarily deposited to the sensitive alveolar
region, with BC–containing particles exacerbating this effect relative to
their uncoated cores. Canadian wildfire events during summer 2023 enhanced
total deposition to the lungs when weighted by mass, with relative
deposition favoring the head airways more than other summer periods. Our
observations demonstrate that cooking is an important local source of PM1
in urban regions throughout the year, and that BC and NR-PM1 from multiple
sources remain a threat to respiratory deposition and community health.