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NOx-mediated Chemistry - Climate Interactions via Atmospheric Aerosols Julie Fry, currently unemployed! (was UC Berkeley, starting at Reed College next week). NO + oxyRO 2. Climate effects?. RONO 2(g). RONO 2. NO x. aerosol. NO 3 + VOCs. Chamber studies of SOA formation
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NOx-mediated Chemistry - Climate Interactions via Atmospheric AerosolsJulie Fry, currently unemployed!(was UC Berkeley, starting at Reed College next week) NO + oxyRO2 Climate effects? RONO2(g) RONO2 NOx aerosol NO3 + VOCs • Chamber studies of SOA formation • AMS organic nitrate standard studies • Modeling regional importance of NOx-mediated SOA formation • Future: Measuring aerosol chemical composition with Hi-Vol samplers & • offline GC-MS, FTIR, NMR; regional modeling (WRF-Chem)
NO3 in Juelich SAPHIR chamber, June 2007 NO3 TD-LIF NO2 TD-LIF inlets
aerosol formation o N2O5 +NO3 +β-pinene Δaerosol DRY Y~50% 60% RH Y~50%
Modeling nitrate partitioning estimated Pvap~6x10-4 Torr Absorptive partitioning model requires Pvap = 4x10-6 Torr
Modeling NO3 + β-pinene Yield(Alkyl nitrates) = 30%
How much aerosol could NO3 + β-pinene make globally? • Mass yield of aerosol from NO3 + β-pinene: ~50% • Global annual β-pinene emissions: ~ 33 Tg yr-1 • Fraction of β-pinene that reacts with NO3, based on relative NO3, O3, and OH lifetimes: ~ 30% • → .3 x .5 x 33 Tg yr-1 = 5 Tg yr-1 SOA source estimates: Kanakidou et al, 2005: 12 – 70 Tg year-1 Goldstein & Galbally, 2007: 510 – 910 Tg year-1