摘要
本文基于2021年4月和7月珠江三角洲(珠三角)5个点位的甲醛(HCHO)、其他痕量气体和光解速率系数等在线观测数据结合光化学模型,分析了珠三角城市群HCHO的时空分布、来源贡献以及HCHO对臭氧(O_(3))生成的影响。结果表明,HCHO的变化具有明显的季节性与空间差异性。珠三角城市群HCHO春季平均浓度范围为1.2×10^(−9)—5.1×10^(−9)(V/V),平均值为3.4×10^(−9)(V/V);夏季平均浓度范围为1.0×10^(−9)—5.0×10^(−9)(V/V),平均值为2.5×10^(−9)(V/V);最高浓度出现在鹤山,最低浓度出现在深圳,浓度高低相差近5倍。用基于观测的盒子模型(OBM)计算了HCHO的二次生成浓度,发现HCHO日间观测值中春季以环境残留贡献最大,占比为35.9%—64.5%;夏季则以二次生成为主,占比为31.2%—62.1%。进一步比较了模型在有、无输入HCHO观测浓度两种情景下O_(3)生成速率的差异,发现在不考虑HCHO原位光化学生成影响情况下,HCHO对污染日日间O_(3)净生成平均贡献了33.9%(春季)和11.1%(夏季)。综合而言,HCHO对O_(3)生成具有重要贡献,建议对HCHO的管控在春季应注重一次排放源,加强区域间的联合管控,降低区域残留水平;在夏季则应该对HCHO一次排放源和前体物两手管控。
In this study,the spatiotemporal distribution of formaldehyde(HCHO)in the Pearl River Delta and its sources and impact on ozone(O_(3))formation were analyzed,with application of photochemical models coupled with online observation data.The observations were conducted concurrently at five sites in April and July 2021,and the measured species/parameters include HCHO,major trace gases,and photolysis rate coefficients.The results indicate that HCHO concentrations showed a clear seasonal and spatial variation pattern.From the perspective of seasonal variation,the average concentrations of HCHO in different cities ranged from 1.2×10^(−9) to 5.1×10^(−9)(V/V),with an average of 3.4×10^(−9)(V/V)in spring.In comparison,the average concentrations of HCHO were lower in summer,which ranged from 1.0×10^(−9) to 5.0×10^(−9)(V/V),with an average of 2.5×10^(−9)(V/V).From the perspective of spatial variation,the highest HCHO concentration was shown in Heshan,while the lowest was shown in Shenzhen,with a difference of nearly 5 folds.An observation-based box model(OBM)was applied to quantity the contributions of secondary production to HCHO,and it was identified as the dominating pathway to HCHO in summer(31.2%—62.1%),while environmental residues dominated in spring(35.9%—64.5%).The OBM-calculated net O_(3) production rates with or without HCHO constraints were further compared to quantify the impact of HCHO on O_(3) production.Quantitatively,The net O_(3) production rates decreased by 33.9%and 11.1%in episodes of spring and summer,respectively,without constraints of HCHO.Overall,HCHO played an important role in O_(3) formation.We recommend that the control measures of HCHO should focus on primary emission sources and collaborative control between regions to reduce regional residual levels in spring,and should pay attention to both primary emission sources and HCHO precursor reductions in summer.
作者
周炎
张涛
林玉君
陈多宏
李成柳
ZHOU Yan;ZHANG Tao;LIN Yujun;CHEN Duohong;LI Chengliu(GuangDong Ecological and Environmental Monitoring Center,State Environmental Protection Key Laboratory of Regional Air Quality Monitoring,Guangzhou,510308,China;Guangzhou OnePoint Environmental Consultant Co.,Ltd.,Guangzhou,510220,China)
出处
《环境化学》
CAS
CSCD
北大核心
2022年第7期2356-2363,共8页
Environmental Chemistry
基金
广东省科技计划项目(2019B121202002)
国家重点研发计划课题(2018YFC0213903)资助
关键词
珠江三角洲
甲醛
时空分布
来源
原位生成
臭氧
the Pearl River Delta
formaldehyde
spatiotemporal distribution
source
in-situ production
ozone
