PM1.0-Nitrite Heterogeneous Formation Demonstrated via a Modified Versatile Aerosol Concentration Enrichment System Coupled with Ion Chromatography
Particulate nitrite is a critical source of hydroxyl radicals; however, it lacks high-resolution methods due to its low abundance and stability to explore its formation mechanism. In this study, a modified versatile aerosol concentration enrichment system (VACES) coupled with ion chromatography (IC)...
Gespeichert in:
Veröffentlicht in: | Environmental science & technology 2021-07, Vol.55 (14), p.9794-9804 |
---|---|
Hauptverfasser: | , , , , , , , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | Particulate nitrite is a critical source of hydroxyl radicals; however, it lacks high-resolution methods due to its low abundance and stability to explore its formation mechanism. In this study, a modified versatile aerosol concentration enrichment system (VACES) coupled with ion chromatography (IC) was used to measure particulate NO2 – hourly online and achieve a lowered detection limit of 10–3 μg m–3. VACES-IC was used to observe a high- and low-concentration events of PM1.0-NO2 – in Shanghai, corresponding to the ambient-level concentrations of 0.34 and 0.05 μg m–3, respectively. The morning peak concentrations of NO2 – even exceeded 3σ (standard deviation) in the high-concentration event due to the reduction of NO2 by aerosol SO3 2– based on kinetics and regression analysis. This implies that controlling SO2 emissions would be an effective strategy to decrease morning NO2 – concentrations, correspondingly reducing the kinetic formation of SO4 2– by 20.8–34.8%. However, after sunrise, NO2 – formation was primarily attributed to NO2 hydrolysis at pH 4.97–6.14. In the low-concentration event, NO2 hydrolysis also accounted for an overwhelming proportion (∼90%) of NO2 – formation. This work estimates the contribution of different paths to particulate NO2 – formation based on newly established high-resolution measurements. |
---|---|
ISSN: | 0013-936X 1520-5851 |
DOI: | 10.1021/acs.est.1c02373 |