U.S. Department of Commerce, National Oceanic and Atmospheric Administration (NOAA): The Aging of Aerosol Nitrate and Implications for the Global Nitrogen Cycle

U.S.

Department of Commerce, National Oceanic and Atmospheric Administration (NOAA): The Aging of Aerosol Nitrate and Implications for the Global Nitrogen Cycle.

We propose a joint laboratory-modeling study to explore the importance of aging of aerosol nitrate to the atmospheric lifecycles of both BVOC-derived SOA and NOy.

Laboratory studies will focus on the kinetics and products of aging reactions, which will be examined by generating nitrate-containing particles in a large environmental chamber, sampling them into a flow reactor to simulate several days of photolytic/oxidative aging, and measuring reactants and products (in the gas and particle phases) with a suite of state-of-the-art analytical instruments.

The focus of these experiments will be on particulate organic nitrates generated from BVOC oxidation (by OH in the presence of NO, or by NO3), though the photolysis of inorganic nitrates, a simpler chemical system, will also be explored.

Such laboratory measurements will provide new constraints on the chemistry of particulate nitrate, which will then be incorporated into a global chemical-transport model (GEOS-Chem).

Results from this model will be tested against field measurements of NOy species, most importantly particulate nitrates (both organic and inorganic), and will provide insight into the impact of this nitrate aging chemistry (e.g., renoxification) on global particulate nitrate loadings and, more generally, the chemistry of the troposphere.