中文摘要：

快速城市化在消耗营养氮元素的同时,直接或间接导致大量人为活性氮流失到大气与水环境中,带来了巨大的生态环境压力和严重的污染问题.本文在定量分析京津冀区域活性氮排放量的基础上,借助数据包络模型分析此区域的氮减排效率,并提出基于氮补偿机制的低氮发展对策.结果表明：2004—2014年,随着城市化程度的提高,活性氮排放呈波动缓慢降低的趋势.河北省一直是京津冀区域的主要氮排放源,其气态与水体氮排放量分别占整个区域的79%~84%和74%~79%.研究期间,京津冀区域活性氮主要来源于农业活动,逐渐转为工业生产与居民生活.城市化对区域各地氮排放强度的影响并不一致,区域年均氮排放强度为5.8 t N·km-2.北京市氮减排效率相对最高,河北省次之,天津市最低.降低河北省氮排放强度与提高天津市氮减排效率是研究区城市低氮化的关键.采用基于协同氮补偿机制的减排策略,有助于三地在氮减排方面上实现互助互补的可持续发展战略.

英文摘要：

The rapid development of urbanization has brought the huge ecological pressure and seri- ous environmental pollution, resulting from direct and indirect emissions of anthropogenic reactive nitrogen to atmosphere and hydrosphere during nitrogen consumption. Based on the quantitative analysis of reactive nitrogen emissions by Beijing-Tianjin-Hebei agglomeration, we constructed an evaluation index for annual reactive nitrogen removal efficiency of this region by employing data en- velopment analysis. Then we attempted to put forward low-nitrogen development countermeasures based on ＇ N offset＇ mechanism for the sustainable development. The results showed that the total reactive nitrogen emissions of Beijing-Tianjin-Hebei agglomeration slightly decreased with fluctuation during urbanization in 2004-2014. Hebei Province was the main contributor to nitrogen emission, occupying 79%-84% and 74%-79% of nitrogen loss to atmosphere and hydrosphere. The main sources of emission were agricultural activities, and then turned to industrial activities and residen- tial livelihood. The impacts of urbanization on reactive nitrogen emission intensity of each region were different. The annual emission intensity of this agglomeration was 5.8 t N · km-2. Beijing City owned the highest of emission reduction efficiency, followed by Hebei Province and Tianjin City. The keys for overall low-nitrogen urbanization were supposed to be the reduction in the emissions in- tensity of Hebei Province and the improvement in emission reduction efficiency of Tianjin City. The countermeasures toward emission reduction, basing on collaborative ＇ N offset＇ mechanism, would contribute to the reciprocity among Beijing-Tianjin-Hebei agglomeration in emission reduction during sustainable development.