Precipitation frequency controls nitrogenous aerosol in a tropical coastal city and its implications for plant carbon sequestration

Xin Zhou; Fajin Chen; Zhiyang Li; Qibin Lao; Chunqing Chen

doi:10.1016/j.chemosphere.2023.138473

Precipitation frequency controls nitrogenous aerosol in a tropical coastal city and its implications for plant carbon sequestration

Chemosphere. 2023 Jun:326:138473. doi: 10.1016/j.chemosphere.2023.138473. Epub 2023 Mar 21.

Authors

Xin Zhou¹, Fajin Chen², Zhiyang Li³, Qibin Lao¹, Chunqing Chen¹

Affiliations

¹ College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang, 524088, China.
² College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang, 524088, China; Key Laboratory of Climate, Resources and Environment in Continental Shelf Sea and Deep Sea of Department of Education of Guangdong Province, Guangdong Ocean University, Zhanjiang, 524088, China; Laboratory for Coastal Ocean Variation and Disaster Prediction, College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang, 524088, China. Electronic address: fjchen@gdou.edu.cn.
³ Guangdong AIB Polytechnic College, Guangzhou, 551507, China.

PMID: 36958498
DOI: 10.1016/j.chemosphere.2023.138473

Abstract

The concentration of nitrogenous aerosols is influenced by air mass transition, local meteorological conditions, local emissions, and the wet removal effect driven by precipitation. Deposited nitrogenous aerosols influence nitrogen availability in the canopy, affecting the amount of plant carbon sequestration. However, the factors controlling nitrogenous aerosol concentrations and their implications for plant carbon sequestration remain unclear. In this study, multiple stable nitrogen isotopes in atmospheric aerosols (δ¹⁵N-TN, δ¹⁵N-NO₃^-, and δ¹⁵N-NH₄⁺) and rainwater (rainwater δ¹⁵N-NO₃^- and rainwater δ¹⁵N-NH₄⁺) in one-year observations were analyzed to explore the main factors controlling nitrogenous aerosol concentrations. The results showed that NO₃^- and NH₄⁺ were the major components of TN, and their concentrations in seasonal patterns were sensitive to frequent rainfall rather than local emissions or external contributions. The concentrations of nitrogenous aerosols were negatively correlated with precipitation frequency, indicating that increased precipitation frequency induced low concentrations of nitrogenous aerosols. Moreover, the positive matrix factorization (PMF) analysis showed that coarse mode NO₃^- was generated in the wet season but not in the dry season, reflecting the removal of precipitation. With the increased precipitation frequency from May to July, 42.4% of aerosol NO₃^- was scavenged into rainwater, indicated by the variations in the δ¹⁵N values of nitrogenous aerosols and rainwater. This result prompted us to calculate the loss of 12.1 ± 3.9 Gg carbon/yr plant carbon sequestration. Our study suggests that nitrogenous aerosols are captured by the high precipitation frequency in tropical areas, decreasing nitrogen availability in the canopy, which might decrease plant carbon sequestration.

Keywords: Nitrogenous aerosol; Precipitation frequency; Rainwater; Stable nitrogen isotope.

MeSH terms

Aerosols / analysis
Air Pollutants* / analysis
Carbon Sequestration
Environmental Monitoring / methods
Nitrogen* / analysis
Seasons

Substances

Nitrogen
Air Pollutants
Aerosols