Fang J, Wang Z, Zhao S, Li Y, Tang Z, Yu D, Ni L, Liu H, Xie P, Da L, et al.Biodiversity changes in the lakes of the Central Yangtze. Frontiers in Ecology and the EnvironmentFrontiers in Ecology and the Environment. 2006;4:369-377.
Tang Z, Wang Z, Zheng C, Fang J. Biodiversity in China's mountains. Frontiers in Ecology and the EnvironmentFrontiers in Ecology and the Environment. 2006;4:347-352.
Some nitrogen-containing organic compounds (NOCs) in PM2.5 aerosols in forest, tunnel, urban, rural, and mixed forest/urban areas in the Lower Fraser Valley (LFV), British Columbia, Canada, were measured to assess their chemical characteristics, temporal and spatial distributions, and origins. The levels of is an element of-caprolactam, isoindole-1,3-dione, benzothiazolone, and N-butyl-benzensulfonamide showed significant differences among the sites, with the highest level at the mixed forest/urban site, indicating that aerosols at this site were impacted by chemical manufacturing activities. N, N-diethyl-m-toluamide (deet) was detected at all locations but was highest in the forest area, demonstrating a widespread usage as an insect repellent in the LFV and at camps at the forest site. Alkyl amides, tracers from wood burning and cooking, ranging from C-6 to C-20 including two unsaturated amides, hexadecenamide, and 9-octadecenamide, were detected at all sites. Three patterns of carbon number distributions of alkyl amides varied with location and time, and were mainly impacted by biomass burning or cooking compared to levoglucosan and cholesterol in the LFV. Ratio of oleamide to stearamide (C-18:1/C-18:0) was discussed as a potential indicator for determining `' age `' or transport range of biomass combustion plumes.
Measurements of cloud condensation nuclei (CCN) were made in downtown Toronto during August and September, 2003. CCN measurements were performed at 0.58% supersaturation using a thermal-gradient diffusion chamber, whereas the aerosol size distribution and composition were simultaneously measured with a TSI SMPS and APS system and an Aerodyne Aerosol Mass Spectrometer (AMS), respectively. Aerosol composition data shows that the particles were predominately organic in nature, in particular for those with a vacuum aerodynamic diameter of <0.25 mu m. In this study, the largest contribution to CCN concentrations came from this size range, suggesting that the CCN are also organic-rich. Using the size and composition information, detailed CCN closure analyses were performed. In the first analysis, the particles were assumed to be internally mixed, the organic fraction was assumed to be insoluble, and the inorganic fraction was assumed to be ammonium sulfate. The AMS time-of-flight data were used for Koohler theory predictions for each particle size and composition to obtain the dry diameter required for activation. By so doing, this closure analysis yielded an average value of CCNpredicted/CCNobserved = 1.12 +/- 0.05. However, several sample days showed distinct bimodal distributions, and a closure analysis was performed after decoupling the two particle modes. This analysis yielded an average value of CCNpredicted/CCNobserved = 1.03 +/- 0.05. A sensitivity analysis was also performed to determine the aerosol/CCN closure if the organic solubility, droplet surface tension, or chamber supersaturation were varied.