title: [Transformation Mechanism and Sources of Secondary Inorganic Components in PM2.5 at an Agriculture Site (Quzhou) in the North China Plain in Summer].
abstract: Simultaneously on-line measurements of major water-soluble inorganic ions and gaseous pollutants were performed from June 9 to July 11, 2014 at Quzhou, an agriculture site in the North China Plain using a gas-aerosol collector (GAC) and ion chromatograph (IC), aiming to track the diurnal variation rule of secondary inorganic components and gas-phase precursors as well as their interactions. The transformation mechanism and sources of fine particles (PM2.5) were also discussed. The results showed that these water-soluble ions in PM2.5 and their gas-phase precursors varied regularly. As the dominant ionic components of PM2.5 (accounting for 76.23%), the average concentrations of SO4(2-), NH4(+), NO3(-) were 26.28 μg x m(-3), 18.08 μg x m(-3) and 16.36 μg m(-3) respectively. Among the precursor gases, the NH3, generated from the discharges of local agricultural activities, displayed a significantly higher concentration at an average value of 44.85 μg x m(-3). The average fine sulfate and nitrate oxidation ratios (SOR and NOR) were SOR = 0.60, NOR = 0.30, revealing the remarkable characteristics of secondary pollution. As could be found from the relevant analysis, the NH4(+) of Quzhou showed well relations with NO3(-) and SO4(2-), and the environment here was rich of ammonia. The NH4(+) existed in the form of (NH4)2SO4 and the generation of NO3(-) was limited by the HNO3. From the analysis for the equilibrium of NH4NO3, we observed that the atmospheric environment of Quzhou was adverse to the generation and maintenance of NH4NO3 during the daytime,in contrast with the night. Integrated with the study, the results displayed that the secondary transformation was the main source of fine particles in Quzhou, and the NH3 from field and compost was the significant factor leading to the high value of S-N-A.
authors: Shi-yi
authors: SY
authors: Chen
authors: Li-min
authors: LM
authors: Zeng
authors: Hua-bin
authors: HB
authors: Dong
authors: Tong
authors: T
authors: Zhu
mesh_terms: D000383:Agriculture; D000393:Air Pollutants / Q000032:analysis*; D000641:Ammonia / Q000032:analysis; D002681:China; D004784:Environmental Monitoring; D005740:Gases / Q000032:analysis; D009566:Nitrates / Q000032:analysis; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D012621:Seasons; D013431:Sulfates / Q000032:analysis
chemical_list: D000393:Air Pollutants; D005740:Gases; D009566:Nitrates; D052638:Particulate Matter; D013431:Sulfates; D000641:Ammonia