Development of atmospheric acid deposition in China from the 1990s to the 2010s

- Explore spatial and temporal dynamics of wet acid deposition during three decades in China.
- Acid deposition has not deteriorated seriously in China with lower SO42− and higher NO3− deposition.
- Area of severe acid deposition in southern China is shrinking with lower SO2 emissions.
- Moderate acid deposition area is expanding in northern China because of higher levels of industry and transportation.
- China's acid deposition is affected by energy consumption and regulated by rainfall.

Atmospheric acid deposition is a global environmental issue. China has been experiencing serious acid deposition, which is anticipated to become more severe with the country's economic development and increasing consumption of fossil fuels in recent decades. We explored the spatiotemporal variations of acid deposition (wet acid deposition) and its influencing factors by collecting nationwide data on pH and concentrations of sulfate (SO42−) and nitrate (NO3−) in precipitation between 1980 and 2014 in China. Our results showed that average precipitation pH values were 4.59 and 4.70 in the 1990s and 2010s, respectively, suggesting that precipitation acid deposition in China has not seriously worsened. Average SO42− deposition declined from 40.54 to 34.87 kg S ha−1 yr−1 but average NO3− deposition increased from 4.44 to 7.73 kg N ha−1 yr−1. Specifically, the area of severe precipitation acid deposition in southern China has shrunk to some extent as a result of controlling the pollutant emissions; but the area of moderate precipitation acid deposition has expanded in northern China, associated with rapid industrial and transportation development. Furthermore, we found significant positive correlations between precipitation acid deposition, energy consumption, and rainfall. Our findings provide a relatively comprehensive evaluation of the spatiotemporal dynamics of precipitation acid deposition in China over past three decades, and confirm the idea that strategies implemented to save energy and control pollutant emissions in China have been effective in alleviating precipitation acid deposition. These findings might be used to demonstrate how developing countries could achieve economic development and environmental protection through the implementation of advanced technologies to reduce pollutant emissions.

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