广州市含铁颗粒混合状态及化学特征

Mixing States and Chemical Characteristics of Fe-Containing Particles in Guangzhou

摘要: 本研究利用单颗粒气溶胶质谱仪(SPAMS)于2021年1月1日至31日在广州市对大气中含铁颗粒的化学组成、混合状态、来源及其在污染过程中的演变特征进行了研究。结果表明，含铁颗粒主要分为Fe-BB、Fe-C、Fe-D、Fe-HM、Fe-N、Fe-S、Fe-SN等七种类型，以Fe-N、Fe-SN和Fe-HM三类颗粒为主，这三类颗粒在所有含铁颗粒中数量占比达85%。大部分含铁颗粒与二次无机离子尤其是硝酸盐混合，部分含铁颗粒与生物质燃烧源特征离子有机氮、元素碳、沙尘特征组分或重金属混合。在1月13~16日PM_2.5重污染过程期间，发生了三次PM_2.5突升，分别为污染前期、中期和后期。在污染前期和中期，PM_2.5浓度升高受到来自工业排放和机动车尾气的一次排放的含铁颗粒的影响，在污染后期，受到含铁颗粒上硝酸盐生成的影响。

Abstract: To investigate the particle types, mixing states, sources and evolution during pollution of Fe-containing particles, a single particle aerosol mass spectrometer was used to perform an campaign in Guangzhou from January 1 to 31, 2021. The results showed that the Fe-containing particles were classified as Fe-BB, Fe-C, Fe-D, Fe-HM, Fe-N, Fe-S and Fe-SN, which Fe-N, Fe-SN and Fe-HM was the main types, accounted for 85% of all Fe-containing particles. Most of the Fe-containing particles were mixed with secondary inorganic ions, especially nitrate, and some were mixed with the characteristic ions of biomass combustion of organic nitrogen, elemental carbon, dust characteristic components or heavy metals. During the heavy PM_2.5 pollution event from January 13 to 16, three spikes in PM_2.5 concentrations occurred, which were divided into the early, middle and later stages of pollution. In the early and middle stages of pollution, the increase of PM_2.5 concentration was influenced by Fe-containing particles from primary emissions of industrial and vehicle. In the later stages of pollution, the formation of nitrate was the main driver.