First Online Observation of Aerosol Total Organic Nitrogen at an Urban Site: Insights Into the Emission Sources and Formation Pathways of Nitrogenous Organic Aerosols

Abstract

Nitrogen (N) is a constituent element of ambient organic aerosol; however, we have limited knowledge of the total quantity of organic N (ON) and its relative importance to aerosol N due to a lack of effective analytical methods for ON. Here, we report first online measurements of ON in particulate matter (PM2.5) in urban Shanghai in summer of 2021 using a newly developed aerosol nitrogen analyzer. ON accounted for an average of 25% of total aerosol N and varied in the range of 5%–64% on the hourly scale. Hourly variations identified four distinct types of ON episodes that occurred in different hours of a day. Analysis aided by concurrently measured source indicative pollutants revealed that vehicular emissions, nocturnal chemistry, daytime photochemistry or combined primary sources, and secondary chemistry could drive up ON under different day‐to‐day atmospheric conditions. Our results help bridge the knowledge gap in the emissions and formation of organic aerosol.

Enhanced Detection of Primary Biological Aerosol Particles Using Machine Learning and Single-Particle Measurement

“…The detection of its existence within aerosols serves as a reliable indicator of emissions resulting from either biomass burning or even biogenic salt particles 39 thereby facilitating the identification and understanding of their origins. Other studies have demonstrated that their analysis, encompassing concurrent measurements of pollutants indicative of sources 40 and samples of cloudwater, 41 has contributed to a broader understanding of the factors contributing to elevated levels of organic nitrates in the atmosphere. The carbonaceous component is a substantial element of particulate matter in the atmosphere, frequently comprising 20−50% of the total aerosol mass.…”

Characterization and Seasonal Variation of PM2.5 Composition in Xi’an, Northwest China: Oxygenated and Nitrogenous Organic Aerosol

“…CHON compounds are key players in the atmospheric nitrogen oxide cycle, contributing significantly to reactive nitrogen budgets . They are abundant in the atmosphere of large cities, often originating from sources such as biomass burning, vehicle emissions, and both day and night-time chemical processes . Nitrogen-containing organic compounds, including nitro-aromatics, are crucial in forming atmospheric brown carbon and profoundly affect its light-absorbing properties. , A substantial portion of these nitrogen-containing organics originate from secondary formation process in which gas-phase precursors are oxidized .…”