Estimates of non-traditional secondary organic aerosols from aircraft SVOC and IVOC emissions using CMAQ

摘要

Utilizing an aircraft-specific parameterization based on smog chamber data inthe Community Multiscale Air Quality (CMAQ) model with the volatility basisset (VBS), we estimated contributions of non-traditional secondary organicaerosols (NTSOA) for aircraft emissions during landing and takeoff (LTO)activities at the Hartsfield–Jackson Atlanta International Airport. NTSOA,formed from the oxidation of semi-volatile and intermediate volatilityorganic compounds (S/IVOCs), is a heretofore unaccounted component of fineparticulate matter (PM) in most air quality models. We expanded aprerelease version of CMAQ with VBS implemented for the Carbon Bond 2005(CB05) chemical mechanism to use the Statewide Air Pollution Research Center2007 (SAPRC-07) chemical mechanism and added species representing aircraftS/IVOCs and corresponding NTSOA oxidation products. Results indicated thatthe maximum monthly average NTSOA contributions occurred at the airport andranged from 2.4 ng m (34 % from idle and 66 % from non-idleaircraft activities) in January to 9.1 ng m (33 and 67 %) in July.This represents 1.7 % (of 140 ng m) in January and 7.4 % in July(of 122 ng m) of aircraft-attributable PM compared to41.0–42.0 % from elemental carbon and 42.8–58.0 % from inorganicaerosols. As a percentage of PM, impacts were higher downwind of theairport, where NTSOA averaged 4.6–17.9 % of aircraft-attributablePM and, considering alternative aging schemes, was as high as24.0 % – thus indicating the increased contribution ofaircraft-attributable SOA as a component of PM. However, NTSOAcontributions were generally low compared to smog chamber results,particularly at idle, due to the considerably lower ambient organic aerosolconcentrations in CMAQ compared to those in the smog chamber experiments.