Sources and formation pathways of organic aerosol in a subtropical metropolis during summer
Journal
Atmospheric Environment
Date Issued
2015-09
Author(s)
Abstract
A field campaign combined with numerical simulations was designed to better understand the emission sources and formation processes of organic aerosols (OA) in a subtropical environment. The field campaign measured total and water soluble organic carbon (OC) in aerosol, as well as its precursor gases in the Taipei metropolis and a nearby rural forest during the summer of 2011. A regional air-quality model modified with an additional secondary organic aerosol (SOA) formation pathway was used to decipher the observed variations in OA, with focus on various formation pathways and the relative contributions from anthropogenic and biogenic sources.According to the simulations, biogenic sources contributed to 60% and 72% of total OA production at the NTU (urban) and HL (rural) sites. The simulated fractions of SOA in total OA were 67% and 79% near the surface of NTU and HL, respectively, and these fractions increased with height and reach over 90% at the 1-km altitude. Estimated from the simulation results, aqueous-phase dicarbonyl uptake was responsible of 51% of OA production in the urban area, while the primary emissions, reversible partitioning of semi-volatile oxidation products, oligomerization of semi-volatile SOA in the particulate phase and acid-enhanced oxidation contributed to 33%, 10%, 5% and 1% respectively; in the rural area, the percentages were 59%, 21%, 13%, 7% and 1%, respectively. Meteorological factors, including large-scale wind direction, local circulation and planetary boundary layer height, all have strong influences on the source contributions and diurnal variations of OA concentration. © 2015 Elsevier Ltd.
Subjects
Anthropogenic aerosol; Aqueous-phase dicarbonyl uptake; Biogenic aerosol; Local circulation; Organic aerosol; Planetary boundary layer height
SDGs
Other Subjects
Air quality; Atmospheric thermodynamics; Balloons; Boundary layer flow; Boundary layers; Carbon; Organic carbon; Rural areas; Urban growth; Anthropogenic aerosols; Aqueous phase; Biogenic aerosols; Organic aerosol; Planetary boundary layers; Aerosols; isoprene; organic carbon; aerosol; air quality; atmospheric modeling; atmospheric pollution; emission; estimation method; height; metropolitan area; pollutant source; subtropical region; urban area; urban pollution; altitude; Article; concentration (parameters); height; local circulation; meteorological phenomena; oligomerization; oxidation; planetary boundary layer height; priority journal; rural area; secondary organic aerosol; simulation; summer; Taiwan; urban area; wind direction; Taipei; Taiwan
Type
journal article