京津冀与长三角地区氢氯氟碳化物本底特征

Study on the Background Characteristics of Hydrochlorofluorocarbons in the Beijing-Tianjin-Hebei and the Yangtze River Delta

基于北京上甸子与浙江临安区域大气本底站2011—2019年氢氯氟碳化物(HCFCs)采样观测数据,开展了京津冀与长三角地区6种HCFCs(HCFC-22、HCFC-141b、HCFC-142b、HCFC-124、HCFC-132b和HCFC-133a)本底特征研究。研究结果表明:临安站HCFCs浓度水平和浓度变率比上甸子站明显更高,尤其是HCFC-133a,其浓度及浓度变率均比上甸子站高1个量级,表明长三角地区HCFCs排放量可能较京津冀地区更大。2个站点HCFCs本底浓度基本一致,差异范围为-6.1%~7.1%。上甸子站本底数据占比为26.4%~69.0%,而临安站本底数据占比不足23%。在《关于消耗臭氧层物质的蒙特利尔议定书》的约束下,2个站点多数HCFCs年均浓度呈下降趋势或变化较小。2个站点HCFC-132b浓度相对较低,但2019年相比2018年有明显升高。结合风向进行分析,发现上甸子站HCFC-22、HCFC-141b、HCFC-142b和HCFC-132b高浓度水平主要由西南扇区(北京城区方向)的WSW、SSW及SW方向贡献,而HCFC-124和HCFC-133a在各风向上的浓度和载荷差异较小。临安站HCFC-124高浓度水平主要由SSE和NNE方向贡献,分别对应金华和湖州方向;其他5种HCFCs的高浓度水平主要由东北扇区的ENE方向贡献,对应杭州城区方向。

Based on flask measurements for HCFCs at Shangdianzi and Lin'an regional background stations from 2011 to 2019,ambient mixing ratios of six HCFCs(HCFC-22,HCFC-141b,HCFC-142b,HCFC-124,HCFC-132b and HCFC-133a)in the Beijing-Tianjin-Hebei and the Yangtze River Delta were analyzed.The results showed that the concentration levels and variability of HCFCs at the Lin'an station were significantly higher than those at the Shangdianzi station,especially for HCFC-133a,those of which were an order of magnitude higher than those at the Shangdianzi station.This indicated that the HCFCs emissions in the Yangtze River Delta region could substantially larger than the emissions in the Beijing-Tianjin-Hebei region.The background mixing ratios of most HCFCs at both stations were consistent,with the differences in the range of-6.1%-7.1%.26.4%-69.0%of all valid measurements at the Shangdianzi station were selected as background data,while less than 23%were chosen at the Lin'an station.The annual mean mixing ratios of HCFCs at the two stations showed decreasing trends or small variations under the regulation of the Montreal Protocol.The mean mixing ratios of HCFC-132b in 2019 were obviously higher than those in 2018 at both stations,despite of their smallest mixing ratios among all of HCFCs.The mixing ratios of HCFC-22,HCFC-141b,HCFC-142b,and HCFC-132b at the Shangdianzi station were most enhanced from WSW,SSW,or SW,which were the directions towards downtown Beijing,while anomalies and loadings for all wind directions were relatively small for HCFC-124 and HCFC-133a.The ENE wind direction towards downtown Hangzhou had the most contribution to all HCFCs levels at the Lin'an station except for HCFC-124,the mixing ratios of which were elevated from SSE and NNE towards Jinhua and Huzhou,respectively.