The non-volatile solvent-extractable organic compounds (lipids) of biogenic and anthropogenic origins were isolated from total suspended particulates (TSP) samples collected during the winter months of 1993 in Hong Kong. They were characterized and quantified according to the following classes: n-alkanes, polycychc aromatic hydrocarbons, n-alkanoic acids, n-alkanols, and biomarkers such as triterpanes. Flash column chromatography technique was used to effectively separate the PAH from the samples and a recovery of better than 90% was achieved. It was found that almost all samples contained anthropogenic contributions and the levels were relatively high compared to earlier studies carried out in China [Simoneit et al. (1991) Atmospheric Environment25A, 2111–2129]. The results from the six different sampling stations suggested that mobile combustion sources constituted 39–63% of all the non-volatile solvent-extractable organics. In addition, there is evidence that the contribution of emissions from kitchens is significant due to the characteristic Chinese stir-frying cooking process The six stations can be divided into three different categories: urban, rural and heavily influenced by traffic. The identification, abundance and source of these organic compounds are also discussed.
In September 1994 the chemical and physical properties of aerosol particles over southern California were characterized. Concentrations of particle chemical species were higher near the surface than at higher altitudes. In these particles, measured organic and inorganic water soluble masses were 7 +/- 1% and 75 +/- 12%, respectively, of the dried total particle mass (TPM). Non-sea-salt (nss) SO4=, NO3-, NH4+, and H+ were the major contributors to the mass and ionic equivalence of the particles, The ratio of the soluble organics (SumOrg) to nss SO4= was found to be a function of the TPM, which was similar to the simple relationship found over the northwestern Atlantic Ocean for altitudes <3 km. When the H+ ion was included, there was a good ionic balance between the cations and anions in the particles, The pH of the particles ranged from -2.4 to 0.20 (averaging -0.85). The particle volume size distribution dV/d log D shows distinct features according to the altitude and location of sample collection, In urban plumes, dV/d log D was significantly higher than at high altitudes and had a consistent accumulation mode peaking at 0.24 mu m. For all samples, nss SO4= and NH4+ comprised 59% of the accumulation mode particle mass on average. Samples showed two groups with high and low NH4+/nss SO4= ratios of 0.85 and 0.01, respectively. For the first group the low ambient relative humidities indicate that NH4+ and nss SO4= were in crystallized ammonium sulfate and letovicite in equilibrium with solution, while the second group was probably close to H2SO4 droplets. On the basis of these compositions the refractive index eta was found to be about 1.5 for the first group and <1.4 for the second group. The water contents of the NH4+ - nss SO4= particles were estimated to be 35 +/- 24%, leading to an average ratio of H2O/nss SO4= = 0.9 +/- 1.2.