资源环境科技发展态势分析平台

Secondary inorganic aerosol (especially SNA: sulfate, nitrate, ammonium) formed from different pathways, account for significant proportions of ambient particulate matter during haze events. For the first time, we quantitatively explored contributions from different SNA formation pathways by an online monitoring AMS instrument and 3-dimension factor analysis PMF3 model, which called “SNA formation pathway apportionment”. Three formation process were identified: NH₄NO₃ heterogeneous phase reactions (NH₄NO₃-heter), (NH₄)₂SO₄ gas phase reactions ((NH₄)₂SO₄-gas), and mixed NH₄NO₃ & (NH₄)₂SO₄ aqueous phase processes (S＆N-aque). Their overall contributions to SNA were 25.7%, 22.1%, and 52.2%, respectively. Moreover, (NH₄)₂SO₄-gas contributed mainly in clean (52.1%); S＆N-aque got highest contribution in haze episode (69.6%); while sulfate gas phase formations were also found in haze stage (10.3%). The quantitative findings from this work provide hard evidence that aqueous phase processes (including sulfate aqueous phase reactions and nitrate gas-particle partition) were major drivers for SNA increasing.