我国人为源气态活性氮排放时空变动特征分析

随着粮食和能源需求的增加,农业生产和化石燃料燃烧带来的活性氮污染越来越成为影响我国环境和人民健康的重要因素之一.通过对2000、2005及2010年全国31个省(直辖市、自治区)的人为源气态活性氮排放总量、单位GDP及单位人均排放量的Moran's I指数和GetisOrd G*i指数进行空间分析,探讨了气态活性氮排放及其强度的时空变动特征.结果表明,全国的气态活性氮排放及其强度呈现明显的空间集聚特征.在空间分布特征上,全国活性氮排放表现为高值集聚分布,其热点主要位于华北平原和长江中下游平原地区;排放强度方面则为高值聚集和低值聚集兼备.通过对3个年份的冷热点比较分析发现,排放强度的冷点地区变化较小,热点地区变化较大.其中,单位GDP排放强度方面,冷点地区处于东南沿海地区,热点地区则由西北地区缩小到四川、甘肃两省;而单位人口排放强度方面,冷点地区范围有所缩减,热点地区则由分散转变为集中分布于京津冀及周边的山西、内蒙古和辽宁等.分析人为源气态活性氮时空分布格局和特征及其形成原因,可为评估和减缓气态活性氮排放对生态环境的影响提供科学基础.

Temporal and spatial variation analysis of anthropogenic gaseous reactive nitrogen emissions in China

With the growth in food and energy demand, emissions of reactive nitrogen from agricultural production and fossil fuel combustion has become an important factor that influences the environment and people''s health in China. By using the Moran''s I index and Getis-Ord G^*_i index, we studied the spatial and temporal variation characteristics of anthropogenic gaseous reactive nitrogen emission as well as emission intensity of per unit GDP and per capita of 31 provinces in China for the years of 2000, 2005 and 2010. The result shows that the distribution of gaseous reactive nitrogen and its intensity present obvious characteristics of agglomeration. In term of spatial distribution features, the gaseous Nr emission shows high value clustering, with the hot spots in the North China Plain and the middle and lower reaches of the Yangtze River and the emission intensity in both high value and low value clusters. By comparing the distribution of hot and cold spot during the ten years, it was found that the cold spot area of emission intensity changed little while the hot spot area changed drastically. For the emission of per unit GDP, the cold spot distributed in southeast coastal area, and the hot spot area narrowed from northwest China to Sichuan and Gansu provinces. For the emission of per capita, the cold spot area reduced, while the hot spot distribution changed from dispersion to concentration mainly located in Beijing-Tianjin-Hebei region and the surrounding provinces such as Shanxi, Inner Mongolia and Liaoning. Furthermore, the reasons for the pattern and characteristics of spatial distribution of anthropogenic gaseous Nr emission were discussed. Results of this study can provide scientific basis for assessment and mitigation of the effects of gaseous Nr emission on environment.