The abundance and inter-relationship of atmospheric peroxyacetyl nitrate (PAN), peroxypropionyl nitrate (PPN), O-3, and NOy during the wintertime in Beijing, China
The abundance and inter-relationship of atmospheric peroxyacetyl nitrate (PAN), peroxypropionyl nitrate (PPN), O-3, and NOy during the wintertime in Beijing, China
复制标题
北京冬季大气过氧乙酰硝酸盐(PAN)、过氧丙酰硝酸盐(PPN)、O-3和NOy的丰度及其相互关系
DOI：
10.1016/j.scitotenv.2020.137388
复制
发表时间：
2020
影响因子：
9.8
通讯作者：
Mu Yujing
中科院分区：
文献类型：
--
作者：
Zhang Gen;Xia Lingjun;Zang Kunpeng;Xu Wanyun;Zhang Fang;Liang Linlin;Yao Bo;Lin Weili;Mu Yujing
北京地区夏季对大气中过氧乙酰基硝酸盐（PAN）和o3含量进行了广泛的测量，但冬季对PAN、过氧丙酰硝酸盐（PPN）和总奇活性氮收支（NOy）丰度及其相互关系的研究相对较少。本文对2012年11月至2013年1月北京市大气中PAN、PPN、O3、NOx和no3进行了测量。与以往夏季相比，冬季PAN的平均值和最大值分别为311.8和1465 pptv， PPN的平均值和最大值分别为52.8和850.6 pptv， O3的平均值和最大值分别为11.6和36.7 ppbv。相比之下，NOy的高水平为94.2和374.9 ppbv，其中NOx是主要成分（75.9%）。夜间臭氧浓度较高的主要原因是西部和西北部的污染源。PAN浓度与夜间从东南方向输送的富PAN气团高度相关，而白天则主要受当地光化学产物的影响。nox和noy的分布主要受白天局地排放和光化学产物的影响，但夜间也受南向气团的影响。PAN与PPN呈显著正相关（R2= 0.9,p< 0.0001），斜率（∆PPN/∆PAN）为0.17，表明人为挥发性有机物（AVOCs）主导了北京地区PAN的光化学形成，PPN/PAN与PAN （>500 pptv）之间的独立关系表明，PAN与PPN在污染气团中快速形成稳定状态。PAN和O3之间的负相关和斜率可能是由于它们在冬季的光化学产物较弱，加上大量的NO源作为O3的局部汇，但由于PAN在低温下的热稳定性增强，因此对PAN的作用要小得多。
Although atmospheric peroxyacetyl nitrate (PAN) and O3have been extensively measured in Beijing during the summertime, the abundances of PAN, peroxypropionyl nitrate (PPN) and the total odd-reactive nitrogen budget (NOy) and their inter-relationship have been studied comparatively less in the winter. Here we measured atmospheric PAN, PPN, O3, NOx, and NOyin Beijing from Nov. 2012 to Jan. 2013. Compared with our previous results in the summertime, much lower levels were observed in the winter, with the mean and maximum values of 311.8 and 1465 pptv for PAN, 52.8 and 850.6 pptv for PPN, and 11.6 and 36.7 ppbv for O3. In contrast, high levels were found as 94.2 and 374.9 ppbv for NOy, with a major constituent of NOx(75.9%). The source to the west and northwest made the significant contribution to the relatively high O3concentrations during nighttime. PAN concentrations were highly related with the PAN-rich air mass transported from the southeast during the nighttime, whereas predominated by local photochemical production during the daylight. The distributions of NOxand NOywere dominated by local emission and photochemical production during daylight but also influenced by air masses transported from south direction during nighttime. Significant positive correlation (R2= 0.9,p< 0.0001) between PAN and PPN with a slope (∆PPN/∆PAN) of 0.17 indicated that anthropogenic volatile organic compounds (AVOCs) dominated the photochemical formation of PANs in Beijing, and the independent relationship between the PPN/PAN ratio and PAN (>500 pptv) implied a steady state between PAN and PPN achieving rapidly in the polluted air masses. Negative correlation and slopes between PAN and O3likely resulted from their weak photochemical productions in the winter, coupled with the large NO sources which acted as a local sink for O3, but much less so for PAN due to its enhanced thermal stability under low temperature.