ORCID Profile
0000-0002-6165-6500
Current Organisation
Hong Kong University of Science and Technology
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Publisher: Springer Science and Business Media LLC
Date: 18-07-2018
DOI: 10.1007/S00216-018-1239-8
Abstract: Many aromatic compounds (e.g., polycyclic aromatic hydrocarbons (PAHs)) found in atmospheric aerosols are toxic and exist in both unsubstituted and substituted forms. Previous studies have mainly concentrated on investigating unsubstituted PAHs, leaving the substituted compounds largely uncharacterized. This study focuses on detection of both unsubstituted and substituted aromatics in ambient aerosol s les using ultrahigh-resolution mass spectrometry. Aerosol s les collected from roadside, urban, and suburban sites in Hong Kong were characterized by Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) coupled with atmospheric pressure photoionization (APPI) or electrospray ionization (ESI). In the APPI+ mode, 166 aromatic CH formulas (i.e., formulas containing C and H only and with a double bond equivalent (DBE) of 4 or higher) were determined through molecular formula calculations based on an accurate m/z determination. Among the determined aromatic CH formulas, 141 are possible alkylated monocyclic aromatic hydrocarbon (MAH) or PAH formulas, and account for ≥ 45% of the total intensity by aromatic CH+ formulas. Both APPI+ and ESI+ are effective in detecting nitroaromatics (i.e., CHO
Publisher: American Chemical Society (ACS)
Date: 23-01-2003
DOI: 10.1021/ES020622F
Abstract: A laboratory intercomparison of organic carbon (OC) and elemental carbon (EC) measurements of atmospheric particulate matter s les collected on quartz filters was conducted among eight participants of the ACE-Asia field experiment The intercomparison took place in two stages: the first round of the intercomparison was conducted when filter s les collected during the ACE-Asia experiment were being analyzed for OC and EC, and the second round was conducted after the ACE-Asia experiment and included selected s les from the ACE-Asia experiment Each participant operated ECOC analyzers from the same manufacturer and utilized the same analysis protocol for their measurements. The precision of OC measurements of quartz fiber filters was a function of the filter's carbon loading but was found to be in the range of 4-13% for OC loadings of 1.0-25 microg of C cm(-2). For measurements of EC, the precision was found to be in the range of 6-21% for EC loadings in the range of 0.7-8.4 microg of C cm(-2). It was demonstrated for three ambient s les, four source s les, and three complex mixtures of organic compounds that the relative amount of total evolved carbon allocated as OC and EC (i.e., the ECOC split) is sensitive to the temperature program used for analysis, and the magnitude of the sensitivity is dependent on the types of aerosol particles collected. The fraction of elemental carbon measured in wood smoke and an extract of organic compounds from a wood smoke s le were sensitive to the temperature program used for the ECOC analysis. The ECOC split for the three ambient s les and a coal fly ash s le showed moderate sensitivity to temperature program, while a carbon black s le and a s le of secondary organic aerosol were measured to have the same split of OC and EC with all temperature programs that were examined.
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.SCITOTENV.2018.12.178
Abstract: Epidemiological evidence linking source-specific ambient particulate matter with aerodynamic diameter <2.5 μm (PM
Location: United States of America
Location: United States of America
No related grants have been discovered for Jian Zhen Yu.