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Regional Similarities and NO x ‐Related Increases in Biogenic Secondary Organic Aerosol in Summertime Southeastern United States
Author(s) -
Liu Jun,
Russell Lynn M.,
Ruggeri Giulia,
Takahama Satoshi,
Claflin Megan S.,
Ziemann Paul J.,
Pye Havala O. T.,
Murphy Benjamin N.,
Xu Lu,
Ng Nga L.,
McKinney Karena A.,
Budisulistiorini Sri Hapsari,
Bertram Timothy H.,
Nenes Athanasios,
Surratt Jason D.
Publication year - 2018
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2018jd028491
Subject(s) - aerosol , isoprene , chemistry , fourier transform infrared spectroscopy , sulfate , environmental chemistry , total organic carbon , analytical chemistry (journal) , morning , mass concentration (chemistry) , mass spectrometry , organic chemistry , physics , quantum mechanics , copolymer , polymer , medicine , chromatography
During the 2013 Southern Oxidant and Aerosol Study, Fourier transform infrared spectroscopy (FTIR) and aerosol mass spectrometer (AMS) measurements of submicron mass were collected at Look Rock (LRK), Tennessee, and Centreville (CTR), Alabama. Carbon monoxide and submicron sulfate and organic mass concentrations were 15–60% higher at CTR than at LRK, but their time series had moderate correlations ( r ~ 0.5). However, NO x had no correlation ( r = 0.08) between the two sites with nighttime‐to‐early‐morning peaks 3–10 times higher at CTR than at LRK. Organic mass (OM) sources identified by FTIR Positive Matrix Factorization (PMF) had three very similar factors at both sites: fossil fuel combustion‐related organic aerosols, mixed organic aerosols, and biogenic organic aerosols (BOA). The BOA spectrum from FTIR is similar (cosine similarity > 0.6) to that of lab‐generated particle mass from the photochemical oxidation of both isoprene and monoterpenes under high NO x conditions from chamber experiments. The BOA mass fraction was highest during the night at CTR but in the afternoon at LRK. AMS PMF resulted in two similar pairs of factors at both sites and a third nighttime NO x ‐related factor (33% of OM) at CTR but a daytime nitrate‐related factor (28% of OM) at LRK. NO x was correlated with BOA and LO‐OOA for NO x concentrations higher than 1 ppb at both sites, producing 0.5 ± 0.1 μ g/m 3 for CTR‐LO‐OOA and 1.0 ± 0.3 μ g/m 3 for CTR‐BOA additional biogenic OM for each 1 ppb increase of NO x .