Related Experiment Video
Updated: Aug 10, 2025
Composition and Distribution Analysis of Bioaerosols Under Different Environmental Conditions
Published on: January 7, 2019
[Variations in PM2.5 Composition and Sources During 2020-2021 COVID-19 Epidemic Periods in Nanjing]
Nan Hua1, Yue Shang2, Ming-Jie Xie1
1Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science & Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China.
COVID-19 lockdowns significantly reduced PM2.5 pollution in Nanjing, with traffic emissions showing the most substantial decrease. Secondary nitrate formation dominated PM2.5 sources, highlighting the need to control nitrogen oxides and sulfur dioxide emissions.
Area of Science:
- Atmospheric Chemistry
- Environmental Science
- Air Quality Monitoring
Context:
- COVID-19 pandemic led to unprecedented emission reduction events.
- Nanjing experienced two distinct epidemic control periods (winter 2020, summer 2021).
- PM2.5 chemical composition and sources were analyzed during these periods.
Purpose:
- To investigate the impact of extreme emission reductions on PM2.5 chemical composition and sources.
- To differentiate the influence of traffic emissions versus industrial activities on air quality.
- To identify major PM2.5 contributing factors using the Positive Matrix Factorization (PMF) model.
Summary:
- PM2.5 concentrations, particularly nitrate, ammonium, and sulfate, decreased significantly during COVID-19 control periods.
- Elemental carbon reduction exceeded organic carbon reduction, indicating a greater impact on traffic emissions.
- The Positive Matrix Factorization (PMF) model identified seven sources, with secondary nitrate and sulfate being dominant, though nitrate contribution varied seasonally.
Impact:
- Findings reveal that traffic emissions are highly sensitive to emission control measures.
- Seasonal variations in secondary nitrate formation were observed, influenced by temperature and precursor concentrations.
- Continuous control of nitrogen oxides (NOx) and sulfur dioxide (SO2) is crucial for reducing urban PM2.5 in China.
More Related Videos
05:18Measuring Carbon Content in Airway Macrophages Exposed to Carbon-Containing Particulate Matters
Published on: July 12, 2024
09:33Visualizing Field Data Collection Procedures of Exposure and Biomarker Assessments for the Household Air Pollution Intervention Network Trial in India
Published on: December 23, 2022