Aerosol composition at a rural site southeast of London measured by high-resolution mass spectrometry

 
Poster PDF

Authors

Nga Lee Ng — Georgia Institute of Technology
Lu Xu — Georgia Institute of Technology
Matthew Stephen Kollman — Georgia Institute of Technology
John T Jayne — Aerodyne Research, Inc.
Scott C Herndon — Aerodyne Research, Inc.
William Brooks — Aerodyne Research, Inc.
Leah R Williams — Aerodyne Research Inc
Paola Massoli — Aerodyne Research, Inc.
Ed Fortner — Aerodyne Research, Inc.

Timothy B Onasch — Aerodyne Research, Inc.

Category

Field Campaigns

Description

A High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and complementary instrumentation were deployed at a rural site in Detling (southeast of London) during the Clear Air for London (ClearfLo) campaign from January–February 2012. ClearfLo is a collaborative multidisciplinary project to study boundary-layer pollution across London. The HR-ToF-AMS provides quantitative measurement of non-refractory submicron aerosol composition and size distribution with high time resolution. Total mass concentrations and diurnal trends of organics, nitrate, sulfate, ammonium, and chloride at the Detling sampling site are reported. As increasing distance from an urban center is often correlated with increasing photochemical aging, the aerosol mass spectrometry data at the Detling site provide insights into composition of a more oxidized air mass and the evolution of organic aerosols (OA) in the atmosphere. Elemental analyses are performed to determine elemental composition of the bulk OA, including oxygen/carbon (O/C), hydrogen/carbon (H/C), and nitrogen/carbon (N/C) ratios. Positive matrix factorization (PMF) is used to deconvolve the OA into different components, reflecting OA of different sources and/or photochemical processing. Preliminary PMF results are presented to show the relative importance of hydrocarbon-like organic aerosols (HOA) and oxygenated organic aerosols (OOA), which are surrogates of primary and secondary OA, respectively. Other OA components resolved by PMF analysis will also be discussed.