Monitoring history and change trends of ambient air quality in China during the past four decades

Highlights

• First study on monitoring history and air quality change trends in the past 40 years.

• Air quality monitoring work has improved greatly.

• TSP, PM₁₀ and SO₂ showed obvious decreasing trend.

• Lots efforts have been made on air pollution prevention and control.

Abstract

This study summarized the history of ambient air quality monitoring and air pollution prevention and control, and it analyzed the spatiotemporal patterns of ambient air pollutants during 1981–2017 in China. The results showed that monitoring of ambient air quality has changed dramatically in terms of determinants, sampling methods, monitoring extent, and evaluation basis during the previous four decades. Annual average concentrations of total suspended particulates, PM₁₀ and SO₂ have shown obvious decreasing trends during the studied period. These improvements have been closely related to the considerable efforts and various approaches undertaken to prevent and control air pollution. However, although policy implementation has been decisive and, at least in part, it has been enforced effectively, significant challenges remain. Air pollution control cannot be accomplished without a long-term strategy designed to achieve clean air in all parts of China.

Introduction

In the decades since the start of the Reform and Opening-up in 1978, China has experienced rapid industrialization, urbanization, and motorization (Chan and Yao, 2008; Kan et al., 2012; Rohde and Muller, 2015). Consequently, air pollution has become an increasingly severe environmental issue because of the marked growth in energy consumption and the resulting multiple pollutant emissions (Chan and Yao, 2008; Rohde and Muller, 2015). However, in response to the increasing hazard posed by air pollution, the Chinese government has both implemented a series of policies, measures and regulations designed to prevent and control air pollution and adopted certain concrete actions to improve regional air quality (Jin et al., 2016; Wang et al., 2018; Zhang et al., 2011b, 2016b, 2017).

Considerable attention has been given to urban ambient air quality, especially regarding the negative effects of urban air pollution on human health, climate change, and visibility (Huang et al., 2018; Liu et al., 2018; Maji et al., 2018; Zhang et al., 2015). The air quality trend is of primary concern, and recent research has indicated that worldwide trends in ambient air quality typically show reductions in the concentration of certain pollutants, e.g., SO₂ and NO₂ (MEP, 2017, 2018; Zhang et al., 2011b). With growing public awareness of the detrimental effects of air pollution, numerous empirical studies have focused overwhelmingly on the spatiotemporal variations of air pollution, which are vital for evaluation of the health risks associated with human exposure (Kan et al., 2012; Zhang et al., 2011a, 2016a). Previous studies have examined the spatial characteristics of air pollution on scales ranging from the local to the regional scale (Chan and Yao, 2008; Chen et al., 2017; Hu et al., 2014; Liu et al., 2018; Ma et al., 2014; Wang and Fang, 2016; Yang et al., 2018; Zhao et al., 2018b). However, most of studies on ambient air quality conducted in China have focused largely on reasonably small areas or regions (Zhan et al., 2017; Zhang et al., 2011b), e.g., major metropolitan cities such as Beijing (Chen et al., 2015; Zhai et al., 2018), Shanghai (Liu et al., 2016; Wang et al., 2015), and Guangzhou (Chan and Yao, 2008; Wang et al., 2016) and on urban agglomerations such as Jing-Jin-Ji (Chen et al., 2017), the Bohai Rim (Wang and Fang, 2016), and the Yangtze River Delta (Hu et al., 2014). The lack of comprehensive air quality data has meant that systematic nationwide research on the history of air quality monitoring is lacking, and that the spatiotemporal variations of air pollution in China on the national scale, based on ground monitoring data, are not fully understood (Engel-Cox et al., 2013; Zhan et al., 2017). Although the Chinese government does release national reports on quarterly/annual environmental quality or five-year environmental quality (MEP, 2017, 2018; MEE, 2018, 2019a, 2019b, 2019c), reports and studies on the long-term trends of environmental air quality are rare.

The year 2018 marked the 40th anniversary of the Reform and Opening-up in China. Improved understanding and systematic study of the history of the monitoring of ambient air quality, as well as investigation of the temporal changes and spatial distribution patterns of air pollutants, and the measures adopted for control and prevention of air pollution in China, are essential for the formation of effective management strategies regarding urban air pollution control. This study summarized the history of air quality monitoring in China in terms of the determinants monitoring extent, monitoring methods, ambient air quality standards, and requirements regarding data validation. Moreover, the history of the control and prevention of air pollution in China was established and the spatiotemporal patterns of air pollutants since the 1980s were analyzed. The results of this study provide an environmental monitoring history and constitute reliable information on the spatiotemporal patterns of air quality in China that could represent a useful resource for the public and ongoing scientific research.