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Atmospheric Oxidation Capacity and Its Impact on the Secondary Inorganic Components of PM 2.5 in Recent Years in Beijing: Enlightenment for PM 2.5 Pollution Control in the Future.
- Source :
- Atmosphere; Aug2023, Vol. 14 Issue 8, p1252, 16p
- Publication Year :
- 2023
-
Abstract
- In recent years, the concentrations of PM<subscript>2.5</subscript> in urban ambient air in China have been declining; however, the strong atmospheric oxidation capacity (AOC) represents challenges to the further reduction of PM<subscript>2.5</subscript> concentration and the continuous improvement of ambient air quality in China in the future, since the overall AOC is still at a high level. For this paper, based on ground observation data recorded in Beijing from 2016 to 2019, the variation in AOC was characterized according to the concentration of odd oxygen (O<subscript>X</subscript> = O<subscript>3</subscript> + NO<subscript>2</subscript>). The concentrations of the primary and secondary components of PM<subscript>2.5</subscript> were analyzed using empirical formulas, the correlation between AOC and the concentrations of secondary PM<subscript>2.5</subscript> and the secondary inorganic components (SO<subscript>4</subscript><superscript>2−</superscript>, NO<subscript>3</subscript><superscript>−</superscript>, NH<subscript>4</subscript><superscript>+</superscript>, and SNA) in Beijing were explored, the impact of atmospheric photochemical reaction activity on the generation of atmospheric secondary particles was evaluated, and the impact of atmospheric oxidation variations on PM<subscript>2.5</subscript> concentrations and SNA in Beijing was investigated. The results revealed that O<subscript>X</subscript> concentrations reached their peak in 2016 and reached their lowest point in 2019. The O<subscript>X</subscript> concentrations followed a descending seasonal trend of summer, spring, autumn, and winter, along with a spatial descending trend from urban observation stations to suburban stations and background stations. The degree of photochemical activity and the magnitude of the AOC have a large influence on the production of atmospheric secondary particles. When the photochemical reaction was more active and the AOC was stronger, the mass concentrations of the secondary generated PM<subscript>2.5</subscript> fraction were higher and accounted for a higher proportion of the total PM<subscript>2.5</subscript> mass concentrations. In the PM<subscript>2.5</subscript> fraction, SNA accounted for 50.7% to 94.4% of the total mass concentrations of water-soluble inorganic ions in the field observations. Higher concentrations of the atmospheric oxidant O<subscript>X</subscript> in ambient air corresponded to a higher sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR), suggesting that the increase in AOC could promote the increase of PM<subscript>2.5</subscript> concentration. Based on a relationship analysis of SOR, NOR, and O<subscript>X</subscript>, it was inferred that the relationship between O<subscript>X</subscript> and SOR and the relationship between O<subscript>X</subscript> and NOR were both nonlinear. Therefore, when establishing PM<subscript>2.5</subscript> control strategies in Beijing in the future, the impact of the AOC on PM<subscript>2.5</subscript> generation should be fully considered, and favorable measures should be taken to properly regulate the AOC, which would be more effective when carrying out further control measures regarding PM<subscript>2.5</subscript> pollution. [ABSTRACT FROM AUTHOR]
- Subjects :
- OXIDATION
SPRING
POLLUTION
ATMOSPHERIC oxygen
AUTUMN
ENLIGHTENMENT
ATMOSPHERIC ammonia
Subjects
Details
- Language :
- English
- ISSN :
- 20734433
- Volume :
- 14
- Issue :
- 8
- Database :
- Complementary Index
- Journal :
- Atmosphere
- Publication Type :
- Academic Journal
- Accession number :
- 170710584
- Full Text :
- https://doi.org/10.3390/atmos14081252