In:
Journal of the Chinese Chemical Society, Wiley, Vol. 65, No. 5 ( 2018-05), p. 578-590
Abstract:
A laboratory study was carried out to investigate the chemical composition of aged aromatic secondary organic aerosol (SOA) formed from the photoxidation of p ‐xylene in the presence of ammonia (NH 3 ). The experiments were conducted by irradiating p ‐xylene/CH 3 ONO/NH 3 air mixtures without and with NO in a home‐made smog chamber. The particulate products of aged p ‐ xylene SOA in the presence of NH 3 were measured by UV–vis spectrophotometry, attenuated total reflectance Fourier transform infrared (ATR‐FTIR) spectroscopy, and aerosol laser time‐of‐flight mass spectrometry (ALTOFMS) coupled with the fuzzy C‐means (FCM) clustering algorithm. The experimental results show that NH 3 does not alter the gas–particle partitioning in the photoxidation of p ‐xylene without NO and that 2,5‐dimethylphenol is the predominant NH 3 ‐aged p ‐xylene SOA without NO. However, NH 3 has a significant promotional effect on the formation of organonitrogen compounds in the OH‐initiated oxidation of p ‐xylene with NO. Organic ammonium salts such as ammonium glyoxylate and p ‐methyl ammonium benzoate, which are formed from NH 3 reactions with gaseous organic acids, were detected as the major particulate organonitrogen products of NH 3 ‐aged p ‐xylene SOA with NO. 1 H ‐Imidazole, 4‐methyl‐1 H ‐imidazole, and other imidazole products of the heterogeneous reactions between NH 3 and dialdehydes of p ‐xylene SOA were newly measured. The possible reaction mechanisms leading to these organonitrogen products are also discussed and proposed. The formation of imidazole products suggests that some ambient particles containing organonitrogen compounds may be the result of this mechanism. The results of this study may provide valuable information for discussing anthropogenic SOA aging mechanisms.
Type of Medium:
Online Resource
ISSN:
0009-4536
,
2192-6549
DOI:
10.1002/jccs.2018.65.issue-5
DOI:
10.1002/jccs.201700249
Language:
English
Publisher:
Wiley
Publication Date:
2018
detail.hit.zdb_id:
2029538-8
