Effects of land-use patterns on PM_2.5 in China's developed coastal region: Exploration and solutions

While land-use models have often been used to determine the spatial distribution of air pollutant concentrations at urban spatial scales, the effects of land use on PM_2.5 concentrations and removal are rarely investigated at regional spatial scales. We studied these effects in Jiangsu Province, which is part of the Yangtze River Delta Urban Agglomeration. Results showed that forest lands and industrial lands had greater effects on the PM_2.5 concentration than did other land-use types. In addition, industrial lands and built-up lands had greater effects on the PM_2.5 concentrations in winter than in summer. The spatiotemporal change in the PM_2.5 concentration was mainly impacted by industrial distribution and development, while the spatiotemporal change in PM_2.5 removal was mainly impacted by forest land distribution and change. Therefore, PM_2.5 removal was generally higher in rural areas than in urban areas. The spatial PM_2.5 concentration slowly increased with net primary productivity (NPP) first and then decreased with NPP, with an inflection point at 19 g C m^-2 a^-1 NPP. However, the spatial PM_2.5 removal per unit area exponentially increased with NPP. The average removal rate of PM_2.5 by forests was about 0.03% in Jiangsu Province, while the absolute removed amount of PM_2.5 was about 3013 tons in 2015. It was concluded that the impact of forests on air quality in terms of PM_2.5 is significant at regional spatial scales. Therefore, scientific trade-offs and decision-making are necessary to maintain forest ecosystem services in order to improve air quality and human health.