科研成果 by Year: 2009

Emission inventories of sixty-seven speciated non-methane volatile organic compounds (NMVOC) from on-road vehicles in China were estimated for the period of 1980–2005, using seven NMVOC emission profiles, which were summarized based on local and international measurements from published literatures dealing with specific vehicle categories running under particular modes. Results show an exponential growth trend of China's historical emissions of alkanes, alkenes, alkines, aromatics and carbonyls during the period of 1980–2005, increasing from 63.9, 39.3, 6.9, 36.8 and 24.1 thousand tons, respectively, in 1980 to 2778.2, 1244.5, 178.7, 1351.7 and 406.0 thousand tons, respectively, in 2005, which coincided well with China's economic growth. Emission inventories of alkenes, aromatics and carbonyls were gridded at a high resolution of 40 km×40 km for air quality simulation and health risk evaluation, using the geographic information system (GIS) methodology. Spatial distribution of speciated NMVOC emissions shows a clear difference in emission densities between developed eastern and relatively underdeveloped western and inland China. Besides, the appearance and expansion of high-emission areas was another notable characteristic of spatial distribution of speciated NMVOC emissions during the period. Emission contributions of vehicle categories to speciated NMVOC groups showed annual variation, due to the variance in the provincial emissions and in the relative fractions of the seven emission profiles adopted at the provincial level. Highly reactive and toxic compounds accounted for high proportions of emissions of speciated NMVOC groups. The most abundant compounds were isopentane, pentane and butane from alkanes; ethene, propene, 2-methyl-2-butene and ethyne from alkenes and alkines; benzene, toluene, ethylbenzene, o-xylene, and m,p-xylene (BTEX) and 1,2,4-trimethylbenzene from aromatics and formaldehyde, acetaldehyde, benzaldehyde and acetone from 

In Canada approximately 45% of ammonia (NH(3)) emissions are attributed to dairy and beef cattle industries. The present study focused on NH(3) emissions from a beef feedlot with a one-time capacity of 17,220 head. The aim was to improve the Canadian NH(3) emission inventories and air quality forecasting capabilities. A Cessna 207. equipped with a fast-response NH(3)/NO(y) detector and a quadrupole aerosol mass spectrometer, was flown in a grid pattern covering an area of 8 x 8 km centered on a feedlot (800 x 800 m) at altitudes ranging from 30 to 300 m above ground. Stationary ground measurements of NH(3) concentration and turbulence parameters were made downwind of the feedlot. Three flights were conducted under varying meteorological conditions, ranging from very calm to windy with near-neutral stratification. NH(3) mixing ratios up to 100 ppbv were recorded on the calm day, up to 300 m above ground. An average feedlot NH(3) emission rate of 76 +/- 4 mu g m(-2) s(-1) (equivalent to 10.2 g head(-1) h(-1)) was estimated. Characteristics of the measured NH(3) plume were compared to those predicted by a Lagrangian dispersion model. The spatially integrated pattern of NH(3) concentrations predicted and measured agreed but the measured was often more complex than the predicted spatial distribution. The study suggests that the export of NH(3) through advection accounted for about 90% of the emissions from the feedlot, chemical transformation was insignificant, and dry deposition accounted for the remaining 10%. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.