Development and uncertainty analysis of a high-resolution NH3 emissions inventory and its implications with precipitation over the Pearl River Delta region, China

摘要

Detailed NH emission inventories are important tounderstand various atmospheric processes, air quality modeling studies, airpollution management, and related environmental and ecological issues. Ahigh-resolution NH emission inventory was developed based onstate-of-the-science techniques, up-to-date information, andadvanced expert knowledge for the Pearl River Delta region, China. Toprovide model-ready emissions input, this NH emissions inventory wasspatially allocated to 3 km × 3 km grid cells using source-basedspatial surrogates with geographical information system (GIS) technology.For NH emissions, 9 source categories and 45 subcategories wereidentified in this region, and detailed spatial and temporal characteristicswere investigated. Results show that livestock is by far the most importantNH emission source by contributing about 61.7% of the totalNH emissions in this region, followed by nitrogen fertilizerapplications (~23.7%) and non-agricultural sources(~14.6%). Uncertainty analysis reveals that theuncertainties associated with different sources vary from source to sourceand the magnitude of the uncertainty associated with a specific sourcemainly depends on the degree of accuracy of the emission factors andactivity data as well as the technique used to perform the estimate. Furtherstudies should give priority to the hog, broiler, goose subsectors of thelivestock source and N fertilizer application source in order to reduceuncertainties of ammonia emission estimates in this region. The validity ofthe NH emissions inventory is justified by the trend analysis of localprecipitation compositions, such as pH values, theCa+NH/SO+ NO ratios, andNH concentrations which are directly or indirectly related toNH emissions.