Environmental exposure disparities in ultrafine particles and PM 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; mass concentrations of PM ≤ 2.5 μm), have not been well studied.

The importance of ammonia for springtime atmospheric new particle formation and aerosol number abundance over the United States.

New particle formation (NPF) and subsequent growth can contribute upwards of 50 % of the global cloud condensation nuclei (CCN) budget. It is also a significant source of ultrafine aerosols (PM) with health implications. Ammonia (NH) can play a significant role in enhancing NPF and contributing to the growth of nucleated particles.

Long-Term Trend of Gaseous Ammonia Over the United States: Modeling and Comparison With Observations.

The concentrations of atmospheric ammonia ([NH]) have been observed to be increasing over the United States in the last decade, especially in Eastern United States. It is important to understand this temporal trend and variation due to the role of NH in particle formation and its ecological effects. Here the long-term trend of [NH] over the United States is investigated using GEOS-Chem, a global 3-D tropospheric chemistry model, and is corroborated with empirical evidence from the Ammonia Monitoring Network.