The rapid growth of economy makes China the largest energy consumer and sulfur dioxide (SO₂) emitter in the world. In this study, we estimated the trends and step changes in the planetary boundary layer (PBL) vertical column density (VCD) of SO₂ from 2005 to 2015 over China measured by the Ozone Monitoring Instrument (OMI). We show that these trends and step change years coincide with the effective date and period of the national strategy for energy development and relocation in northwestern China and the regulations in the reduction of SO₂ emissions. Under the national regulations for the reduction of SO₂ emissions in eastern and southern China, SO₂ VCD in the Pearl River Delta (PRD) of southern China exhibited the largest decline during 2005–2015 at a rate of −7 % yr⁻¹, followed by the North China Plain (NCP) (−6.7 % yr⁻¹), Sichuan Basin (−6.3 % yr⁻¹), and Yangtze River Delta (YRD) (−6 % yr⁻¹). The Mann–Kendall (MK) test reveals the step change points of declining SO₂ VCD in 2009 for the PRD and 2012–2013 for eastern China responding to the implementation of SO₂ control regulation in these regions. In contrast, the MK test and regression analysis also revealed increasing trends of SO₂ VCD in northwestern China, particularly for several hot spots featured by growing SO₂ VCD in those large-scale energy industry bases in northwestern China. The enhanced SO₂ VCD is potentially attributable to increasing SO₂ emissions due to the development of large-scale energy industry bases in energy-abundant northwestern China under the national strategy for the energy safety of China in the 21st century. We show that these large-scale energy industry bases could overwhelm the trends and changes in provincial total SO₂ emissions in northwestern China and contribute increasingly to the national total SO₂ emissions in China. Given that northwestern China is more ecologically fragile and uniquely susceptible to atmospheric pollution than the rest of China, increasing SO₂ emissions in this part of China should not be overlooked and merit scientific research.

To assess the long-term trends of isoprene emissions in northern China and the impact of the Three-North Shelter Forest Program (TNRSF) on these trends, a database of historical biogenic isoprene emissions from 1982 to 2010 was developed for this region using a biogenic emission model for gases and aerosols. The total amount of the biogenic isoprene emissions during the 3 decades was 4.4 Tg in northern China and 1.6 Tg in the TNRSF, with annual emissions ranging from 132 000 to 176 000 t yr⁻¹ and from 45 000 to 70 000 t yr⁻¹, respectively, in the two regions. Isoprene emission fluxes have increased substantially in many areas of the TNRSF over the last 3 decades due to the growing trees and vegetation coverage, especially in the central north China region where the highest emission incline reached to 58 % from 1982 to 2010. Biogenic isoprene emissions produced from anthropogenic forests tended to surpass those produced from natural forests, such as boreal forests in northeastern China. The estimated isoprene emissions suggest that the TNRSF has altered the long-term emission trend in north China from a decreasing trend during 1982 to 2010 (slope = −0.533, R² = 0.05) to an increasing trend for the same period of time (slope = 0.347, R² = 0.014), providing strong evidence for the change in the emissions of biogenic volatile organic compounds (BVOCs) induced by the human activities on decadal or longer timescales.

The Green Revolution (GR) enhances crop yields significantly that contributes greatly to the social and economic development of many less developed countries. However, the increasing crop yields might rise crop residue biomass burning, leading to adverse environmental and health consequences. We assess the impact of crop residue burning associated with the GR-induced growing crop yields on benzo[a]pyrene (BaP) pollution, a congener of polycyclic aromatic hydrocarbons with strong carcinogenicity. We find a significant increasing trend of BaP emission and contamination from crop residue biomass burning from the mid-1960s to 2010s in India, coinciding with the growing crop yields occurring during the GR. Our results reveal that agricultural BaP emission driven lifetime lung cancer risk (ILCR) in India increased 2.6 times from the onset of GR in the mid-1960s to 2014 and the 57% population in India was exposed to the BaP level higher than the India national standard (1 ng m⁻³). We show that the reduction of open crop residue burning during the rice and wheat residue burning period would be a very effective measure to reduce BaP environmental contamination and health risk.