Environmental exposure disparities in ultrafine particles and PM_2.5 by urbanicity and socio-demographics in New York state, 2013–2020

Background: The spatiotemporal and demographic disparities in exposure to ultrafine particles (UFP; number concentrations of particulate matter (PM) with diameter ≤0.1 μm), a key subcomponent of fine aerosols (PM_2.5; mass concentrations of PM ≤ 2.5 μm), have not been well studied. Objective: To quantify and compare the aerosol pollutant exposure disparities for UFP and PM_2.5 by socio-demographic factors in New York State (NYS). Methods: Ambient atmospheric UFP and PM_2.5 were quantified using a global three-dimensional model of chemical transport with state-of-the-science aerosol microphysical processes validated extensively with observations. We matched these to U.S. census demographic data for varied spatial scales (state, county, county subdivision) and derived population-weighted aerosol exposure estimates. Aerosol exposure disparities for each demographic and socioeconomic (SES) indicator, with a focus on race-ethnicity and income, were quantified for the period 2013–2020. Results: The average NYS resident was exposed to 4451 #·cm⁻³ UFP and 7.87 μg·m⁻³ PM_2.5 in 2013–2020, but minority race-ethnicity groups were invariably exposed to greater daily aerosol pollution (UFP: +75.0% & PM_2.5: +16.2%). UFP has increased since 2017 and is temporally and seasonally out-of-phase with PM_2.5. Race-ethnicity exposure disparities for PM_2.5 have declined over time; by −6% from 2013 to 2017 and plateaued thereafter despite its decreasing concentrations. In contrast, these disparities have increased (+12.5–13.5%) for UFP. The aerosol pollution exposure disparities were the highest for low-income minorities and were more amplified for UFP than PM_2.5. Discussion: We identified large disparities in aerosol pollution exposure by urbanization level and socio-demographics in NYS residents. Jurisdictions with higher proportions of race-ethnicity minorities, low-income residents, and greater urbanization were disproportionately exposed to higher concentrations of UFP and PM_2.5 than other NYS residents. These race-ethnicity exposure disparities were much larger, more disproportionate, and unabating over time for UFP compared to PM_2.5 across various income strata and levels of urbanicity.