我国城市大气化石源CO2的14C示踪研究进展

Progress of Tracing Fossil Fuel CO by Radiocarbon in Chinese Cities

化石燃料等排放是大气CO2浓度增加的主要原因,而城市是碳排放研究的热点区域。获取化石源CO2(CO2ff)的时空变化特征,可以为政府的宏观决策及参与国际碳减排谈判提供重要的科学数据。近十年来我国科技人员在运用14C示踪城市大气CO2ff的研究方面取得了一些重要进展:通过大气、树轮和一年生植物样品14C的分析,获得了不同时间尺度和空间尺度CO2ff的变化特征,发现北方城市是减排的重点。CO2ff与PM2.5关系的研究表明,控制大气污染物可以同时降低CO2ff排放,存在减排的协同效应。WRF-CHEM模式模拟分析了关中地区CO2ff的传输,并结合Δ14CO2和δ13C对CO2ff的来源进行解析,发现西安CO2ff主要来源于本地燃煤的排放。14C示踪获得的CO2ff浓度与统计的碳排放量变化趋势和幅度基本一致,可以相互校验,保证数据的可靠性。为此建议尽快建立我国城市大气Δ14CO2观测网,投入更多的人力物力推进这项研究,服务于国家碳减排任务。

The main cause of increase in atmospheric CO2 concentration is the carbon emissions from fossil fuel combustions and so on.Cities are regarded as the hot spots of carbon emissions.On the basis of obtaining the levels and spatial-temporal variation characteristics of atmospheric fossil fuel CO2(CO2ff),we can provide scientific data for government policy-making and international negotiations on carbon reductions.In the recent ten years,some important progresses have been achieved in the study of tracing urban atmospheric CO2ff using 14C by Chinese scientists.The variation characteristics of urban CO2ff at different temporal and spatial scales were obtained through the analysis of14 C in air,tree ring and annual plant samples.Our results show that the northern cities are the key points to reduce carbon emissions,and that the CO2ff emissions can be reduced simultaneously by controlling atmospheric pollutant emissions,indicating a synergistic emission reduction.It was found that CO2ff in Xi’an was mainly from local coal-burning emissions with the use of improved WRF-CHEM model andδ13C.Finally,the yearly CO2ff traced by tree-ring 14C in Xi’an showed similar trends and amplitudes with the statistical data of carbon emissions,which indicates that the 14C tracing method and statistical method can be mutually validated to ensure the reliability of the data.In order to promote the 14C trace study to serve the national carbon emission reduction task,we suggest that the urban atmosphericΔ14CO2 observation network should be established as soon as possible,and that this study should be enhanced with more scientists involved in it and more financial resources to support it.