Pollution Trends in China from 2000 to 2017: A Multi-Sensor View from Space
Abstract
:1. Introduction
2. Materials and Methods
2.1. Datasets
2.1.1. MODIS and MISR Aerosol Optical Depth and Angstrom Exponent
2.1.2. OMI Absorbing Aerosol Index
2.1.3. OMI SO2 and NO2
2.1.4. OMI/MLS Tropospheric Ozone
2.2. Methods
2.2.1. Trend Estimation
2.2.2. Multiple Regression
3. Results
3.1. AOD Trends
3.2. AAI and AE Trends
3.3. SO2 and NO2 Trends
3.4. Multiple Regression
3.5. Tropospheric Ozone Trends
3.6. Regional Trends
4. Discussions
5. Conclusions
- (1)
- Total aerosol loading in China, especially in the eastern and southern parts, has exhibited a significant decrease of ~0.15–0.3/decade since 2008, after an almost decade-long increase.
- (2)
- This negative trend is accompanied by decreases of SO2 and NO2 during the same period, suggesting reductions in anthropogenic emissions.
- (3)
- NW and NE China, however, exhibit weak positive AOD trends at ~0.1/decade, together with significant positive AAI and negative AE trends. These combined indicate that dust aerosol loading has likely increased and caused a total AOD increase over these two regions.
- (4)
- Multiple regression of AOD against AAI, SO2, and NO2 show overall successful fitting and reasonable spatial distribution of the coefficients, further supporting the inferred compositional changes associated with the AOD trends.
- (5)
- Unlike aerosols, tropospheric ozone exhibits near uniform significant upward trends all over China, implying that ozone pollution control remains a challenging problem.
Funding
Acknowledgments
Conflicts of Interest
Abbreviations
AAI | Absorbing Aerosol Index |
AE | Angstrom Exponent |
AERONET | Aerosol Robotic Network |
AOD | aerosol optical depth |
DJF | December, January, February |
EOS | Earth Observing Systems |
JJA | June, July, August |
MAM | March, April, May |
MISR | Multi-angle Imaging Spectroradiometer |
MLS | Microwave Limb Sounder |
MODIS | Moderate Resolution Imaging Spectroradiometer |
NCP | North China Plain |
NE China | Northeast China |
NW China | Northwest China |
OMI | Ozone Monitoring Instrument |
PBLH | Planetary Boundary Layer Height |
PRD | Pearl River Delta |
SON | September, October, November |
YRD | Yangtze River Delta |
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Li, J. Pollution Trends in China from 2000 to 2017: A Multi-Sensor View from Space. Remote Sens. 2020, 12, 208. https://doi.org/10.3390/rs12020208
Li J. Pollution Trends in China from 2000 to 2017: A Multi-Sensor View from Space. Remote Sensing. 2020; 12(2):208. https://doi.org/10.3390/rs12020208
Chicago/Turabian StyleLi, Jing. 2020. "Pollution Trends in China from 2000 to 2017: A Multi-Sensor View from Space" Remote Sensing 12, no. 2: 208. https://doi.org/10.3390/rs12020208
APA StyleLi, J. (2020). Pollution Trends in China from 2000 to 2017: A Multi-Sensor View from Space. Remote Sensing, 12(2), 208. https://doi.org/10.3390/rs12020208