2006~2020年广东省大气甲醛排放演变特征

Evolution Characteristics of Atmospheric Formaldehyde Emissions in Guangdong Province from 2006 to 2020

大气甲醛(HCHO)是臭氧(O_(3))和细颗粒物(PM2.5)二次组分的关键前体物,在大气光化学反应和二次污染形成过程中扮演着重要角色,并存在致癌性.然而,当前对大气HCHO排放来源认识存在不足,制约了二次污染形成机制研究和污染防控策略制定.采用排放因子和成分谱结合方法,建立2006~2020年广东省HCHO排放趋势清单,识别了广东省主要HCHO排放来源和排放时空演变特征.结果表明,2006~2020年期间广东省HCHO排放量在3.9~5.6万t区间波动,整体呈现极微弱的下降趋势;生物质燃烧源是广东省重要HCHO排放源,而受到管控措施的显著影响,其排放量占比从2006年的58%降至2020年的27%;溶剂使用源的HCHO排放则逐渐突显,2020年占比增长至28%,并成为广东省首要排放源,其中塑料制品和沥青铺路是主要贡献行业.移动源中以柴油作为燃料的工程机械和货车也是HCHO重要排放来源;虽然珠三角和非珠三角地区对广东省HCHO排放量贡献相当,但空间分布结果表明HCHO排放热点区域分别集中于珠三角中心区域和非珠三角的东西两角,这是由于珠三角主要来源为溶剂使用源和移动源,而非珠三角主要受生物质燃烧源影响.因此,未来应进一步加强珠三角中心区域的工业和移动源减排以及粤西地区的生物质燃烧监管.

Atmospheric formaldehyde,a key precursor for ozone(O_(3))and secondary PM2.5,is carcinogenic and plays an important role in atmospheric photochemistry and the formation of secondary pollution.However,the lack of understanding of the emission sources of atmospheric formaldehyde limits the study on the formation mechanism of secondary pollution and the formulation of pollution control strategies.This study used the emission factor and source profile methods to establish the emission inventories of formaldehyde in Guangdong Province from^(2)006 to 2020 and identified the main emission sources of formaldehyde and spatial and temporal evolution characteristics.The results showed that the formaldehyde emissions in Guangdong Province fluctuated in the range of 39000⁃56000 tons during 2006 to 2020,exhibiting a very weak downward trend.Biomass combustion is an important source of formaldehyde emission in Guangdong Province,of which the contribution decreased from 58%in 2006 to 27%in 2020 owing to effective control measures implemented in Guangdong Province.The solvent use source became the predominant emission source of formaldehyde in 2020 by contributing up to 28%,primarily through plastic products and asphalt paving sources.The construction machinery and trucks fueled by diesel were important contributors of formaldehyde emissions from mobile sources.Although the formaldehyde emissions in the Pearl River Delta and the non⁃Pearl River Delta were equivalent,the spatial distributions showed that formaldehyde emission hotspots were concentrated in the center of the Pearl River Delta and the eastern and western areas of the non⁃Pearl River Delta.This was primarily because the solvent use and mobile sources were the main sources of formaldehyde emissions in the Pearl River Delta,whereas the biomass combustion source was the dominant source in the non⁃Pearl River Delta.Therefore,the formaldehyde emission mitigations of the industrial and mobile sources in the central region of the Pearl River Delta and the biomass combustion source in the western area of Guangdong should be further strengthened in the future.