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Size distributions and formation of dicarboxylic acids in atmospheric particles.
- Source :
-
Atmospheric Environment . 2002, Vol. 36 Issue 13, p2099. 9p. 20 Graphs. - Publication Year :
- 2002
-
Abstract
- The PM2.5 concentrations and the size distributions of dicarboxylic acids in Hong Kong were studied. Eleven sets of daily PM2.5 samples were obtained at a downtown sampling site during the period of 5-16 December 2000 using an R&P speciation PM2.5 sampler. About 6-12% of the total oxalic acid was found in the gas phase in some samples. A good correlation between succinate and sulfate (R² = 0.88) and a moderate correlation between oxalate and sulfate (R² = 0.74) were found. Sampling artifacts of oxalate, malonate and succinate were found to be negligible. A total of 18 sets of 48-96 h size distribution data on dicarboxylic acids, sulfate, nitrate and sodium at an urban site and a rural site from June 2000 to May 2001 were obtained using a Micro-Orifice Uniform Deposit Impactor. Data from both sites show similar size distribution characteristics of the dicarboxylic acids. The condensation mode of oxalate was usually observed at 0.177-0.32 µm. The location of the peak of the droplet mode of oxalate was associated with that of sulfate. When the peak of sulfate in the droplet mode appeared at 0.32-0.54 µm, the peak of oxalate sometimes appeared at 0.32-0).54gm and sometimes shifted to 0.54-1.0 µm. When the peak of sulfate in the droplet mode appeared at 0.54-1.0 µm, the peak of oxalate sometimes appeared at 0.54-1.0 µm and sometimes shifted to 1.0-1.8 µm. Oxalate, succinate and sulfate found in the droplet mode were attributed to in-cloud formation. The slight shift of the oxalate peak from 0.32-0.54 to 0.54-1.0 µm or from 0.54-1.0 to 1.0-1.8 µm was ascribed to minor oxalate evaporation after incloud formation. The maximum peak of malonate sometimes appeared in the droplet mode and sometimes appeared at 3.1-6.2 µm. The formation of malonate is associated to the reactions between sea salt and malonic acid. . [ABSTRACT FROM AUTHOR]
- Subjects :
- *CARBOXYLIC acids
*AIR pollution
Subjects
Details
- Language :
- English
- ISSN :
- 13522310
- Volume :
- 36
- Issue :
- 13
- Database :
- Academic Search Index
- Journal :
- Atmospheric Environment
- Publication Type :
- Academic Journal
- Accession number :
- 8798970
- Full Text :
- https://doi.org/10.1016/S1352-2310(02)00230-3