Fine aerosol bulk composition measured on WP-3D research aircraft in vicinity of the Northeastern United States ? results from NEAQS

• Main Authors: Peltier, R. E., Sullivan, A. P., Weber, R. J., Brock, C. A., Wollny, A. G., Holloway, J. S., de Gouw, J. A., Warneke, C.
• Other Authors: School of Earth and Atmospheric Sciences Atlanta, Georgia Institute of Technology Atlanta, NOAA Earth System Research Laboratory (ESRL), National Oceanic and Atmospheric Administration (NOAA), Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado Boulder -National Oceanic and Atmospheric Administration (NOAA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2007
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Canada; Yukon; Alaska
• Online Access: https://hal.science/hal-00302626; https://hal.science/hal-00302626/document; https://hal.science/hal-00302626/file/acpd-7-3073-2007.pdf

International audience During the New England Air Quality Study (NEAQS) in the summer of 2004, airborne measurements were made of the major inorganic ions and the water-soluble organic carbon (WSOC) of the submicron (PM 1.0 ) aerosol. These and ancillary data are used to describe the overall aerosol chemical characteristics encountered during the study. Fine particle mass was estimated from particle volume and a calculated density based on measured particle composition. Fine particle organic matter (OM) was estimated from WSOC and a mass balance analysis. The aerosol over the northeastern United States (U.S.) and Canada was predominately sulfate and associated ammonium, and organic components, although in unique plumes additional ionic components were also periodically above detection limits. In power generation regions, and especially in the Ohio River Valley region, the aerosol tended to be predominantly sulfate (~60% ?g ?g ?1 ) and apparently acidic, based on an excess of measured anions compared to cations. In all other regions where sulfate concentrations were lower and a smaller fraction of overall mass, the cations and anions were balanced suggesting a more neutral aerosol. In contrast, the WSOC and estimated OM were more spatially uniform and the fraction of OM relative to PM mass largely influenced by sources of sulfate. The study median OM mass fraction was 40%. Throughout the study region, sulfate and organic aerosol mass were highest near the surface and decreased rapidly with increasing altitude. The relative fraction of organic mass to sulfate was similar within the boundary layer (altitude less than ~2.5 km), but was significantly higher in the free troposphere (above ~2.5 km). A number of distinct biomass burning plumes from fires in Alaska and the Yukon were periodically intercepted, mostly at altitudes between 3 and 4 km. These plumes were associated with highest aerosol concentrations of the study and were largely comprised of organic aerosol components (~60%).