Approach: To answer these questions, the NOAA WP-3D will make flight legs downwind from urban and point sources of trace gases and aerosol, and measure the mixing ratios of biogenic VOCs during regional surveys.
Approach: Average mass loadings of aerosol will be determined from flights in specific regions and under specific meteorological conditions (pre- and post-frontal), and compared to models.
Approach: What are the significant precursors of organic aerosol? What role do anthropogenic emissions play in the formation of organic aerosol from biogenic precursors? To answer these questions, the NOAA WP-3D will follow air masses from different sources (urban, power plants, forests) as they are processed during the day, at night, with and without the presence of biogenic emissions, and through cumulus and shallow convective clouds.
Approach: The rate at which species are lost by deposition can be estimated using measurements of different hydrocarbon species, which are removed at different rates based on their reactivity with hydroxyl radicals.
Approach: Aerosol extinction, absorption and cloud nucleating properties will be measured from the aircraft for different aerosol types. Correlating the variability in aerosol with inert tracers for different emission sources, e.g. carbon monoxide (CO) for urban emissions, acetonitrile for biomass burning emissions, will help to describe the fraction of aerosol that is controlled by anthropogenic emissions.