Changes in the Dominant Contributions of Nitrate Formation and Sources During Haze Episodes: Insights From Dual Isotopic Evidence

Journal of Geophysical Research Atmospheres, Journal Year: 2025, Volume and Issue: 130(2)

Published: Jan. 15, 2025

Abstract Inorganic nitrate (NO 3 − ), a crucial component of fine particulate matter (PM 2.5 has not shown consistent decrease, despite an obvious decrease nitrogen oxide (NOx) and PM . The atmospheric oxidation process for formation been deemed key factor in pollution; however, the changes sources pathways during particular haze episode require further investigation. Here, daily dual isotopes (δ 15 N δ 18 O) were used to quantify Qingdao, port city Northern China, from September 2017 February 2018. This study also includes detailed introduction two episodes. O results show that both fractions nocturnal NOx coal combustion lower warmer season higher colder season. increased with increasing under low concentration while significantly changed concentration, dominated by (70.6% ± 9.7%) (66.1% 18.2%), respectively. 1 was attributed smoke transported over long distances, which provided large amount aerosol particles absorb more locally formed gaseous HNO or 2 5 In this episode, meteorological air quality factors, sources, mechanism did obviously change. Haze caused unfavorable factors enhanced local accumulation. As pollution worsened, pathway shifted OH hydrolysis, primary source vehicle exhaust.

Language: Английский

Nontarget Analysis of Organic Aerosol over the South China Sea by Gas Chromatography-Orbitrap Mass Spectrometry

ACS Earth and Space Chemistry, Journal Year: 2024, Volume and Issue: 8(9), P. 1924 - 1932

Published: Aug. 20, 2024

Organic aerosol (OA) over oceans is not well characterized, which hinders our understanding of OA sources, components, atmospheric transformation, and accurate model representations to the global climate marine ecosystem. In this study, chemical composition in 1-year-long samples collected South China Sea was characterized by gas chromatography-Orbitrap mass spectrometry (GC-Orbitrap MS) combined with nontarget analysis. Aromatic compounds contributed most total number identified compounds, esters, polycyclic/monocyclic aromatic hydrocarbons, ketones, phenols as major components. Aliphatic ranked second, followed alicyclic heterocyclic compounds. Specifically, associated continental or air masses exhibited large differences their physicochemical properties. Continental-influenced a high degree oxidation broad range volatilities, especially including low-volatile They were mainly from coal combustion, biomass burning, secondary formation. contrast, marine-influenced low levels relatively primarily oceanic biological activities. Interestingly, although some artificial organics such phthalic acid esters key species continental-influenced OA, they also detected likely due long-range transport air-sea exchange. This study provides insights into composition, status, volatilities highlights between OA.

Language: Английский