Transition in air pollution, disease burden and health cost in China: A comparative study of long-term and short-term exposure

Highlights

• Contrasting trends occurred in PM_2.5- and Ozone-related health impact in 2013–2018.

• Deaths due to long- and short-term exposure of PM_2.5 dropped by 15% and 59%.

• Deaths due to long- and short-term exposure of ozone increased by 36% and 94%.

• Health cost due to long-term exposure was equal to ∼6.9% of national GDP in 2018.

• Health cost of PM_2.5 did not change significantly despite a decrease in attributable deaths.

Abstract

Ambient air pollution is one of the leading environmental risk factors to human health, largely offsetting economic growth. This study evaluated health burden and cost associated with the short-term and long-term exposure of major air pollutants (fine particulate matter [PM_2.5] and ozone [O₃]) during 2013–2018. We developed a database of gridded daily and annual PM_2.5 and O₃ exposure in China at 15 km × 15 km resolution. Then, we estimated the age- and cause-specific premature deaths and quantified related health damage with an age-adjusted value of statistical life (VSL) measure. The health cost estimated in this study captured direct cost, indirect cost and intangible cost of the premature death attributable to ambient PM_2.5 and O₃. We found that the national premature deaths attributable to long-term and short-term exposure to PM_2.5 decreased by 15% and 59%, whereas the national premature deaths attributable to long-term and short-term exposure to O₃ increased by 36% and 94%. Despite a 15% reduction of attributable deaths, the health cost attributable to long-term exposure to PM_2.5 did not change significantly as a result of GDP growth and population aging. On the other hand, the long-term O₃ related health cost in 2018 doubled that in 2013. Our study suggests that while premature deaths fell as a result of China’s clean air actions, the health costs of air pollution remained high. The growing trends of O₃ highlighted the needs for strategies to reduce both PM_2.5 and O₃ emissions, for the sake of public health and social well-being in China.

Introduction

Ambient air pollution is one of the leading risk factors to human health (GBD 2017 Risk Factor Collaborators, 2018), causing substantial economic cost to the society (World Bank, 2016; Yin et al., 2020). Globally, long-term exposure to air pollution contributed to 4.2 million (Cohen et al., 2017) to 8.9 million deaths (Burnett et al., 2018). Among the various air pollutants, fine particulate matter with aerodynamic diameter equal to or smaller than 2.5 μm (PM_2.5) and tropospheric ozone (O₃) are the major contributors to the health impacts (Pope et al., 2002; Jerrett et al., 2009), which represent as a proxy indicator of ambient air pollution in global burden of disease (GBD) projects (Lim et al., 2012; GBD 2017 Risk Factor Collaborators, 2018).

Driven by rapid economic development and urbanization, China has suffered from air pollution problem for decades (Xing et al., 2015; Liu et al., 2020; Lu et al., 2020). In 2013, severe pollution episodes attacked frequently over large areas of the country (Andersson et al., 2015). To improve air quality, the State Council issued the Air Pollution Prevention and Control Action Plan in 2013, which for the first time announced to reduce annual average PM_2.5 concentrations by up to 25% by 2017 (State Council of the People’s Republic of China, 2013). Studies showed that nationwide population-weighted annual PM_2.5 concentration dropped significantly since then (Zheng et al., 2018; Zhang et al., 2019) which averted 0.2 million premature deaths (Xue et al., 2019).

In contrast, clean air actions was not able to stop the increasing trend of ozone pollution (K. Li et al., 2019b). During 2013–2019, the trend of summer maximum 8-h average (MDA8) ozone was 1.9 ppb a⁻¹ across China and 3.3 ppb a⁻¹ in the North China Plain (NCP) (Li et al., 2020). The contrasting trend of the two major air pollutants in recent years led to a transition of PM_2.5-dominating air pollution to PM_2.5- and O₃-dominating condition. Therefore, an overall assessment of the public health burden and economic cost associated with PM_2.5 and O₃ is needed to facilitate the adjustment of clean air policies.

In addition to the species of air pollutants, the exposure duration of air pollution also significantly influences its health damage. Short-term exposure, which varies on a daily or hourly basis, mainly introduces acute effects (Liu et al., 2019). In contrast, the long-term exposure of air pollution is correlated with chronic health damages estimated from cohort studies (Laden et al., 2006; Cai et al., 2016). The distinction in short-term and long-term health effects associated with air pollution could provide detail information for pollution prevention.

The literature has well documented the health impacts associated with long-term exposure of PM_2.5 in China on national or regional scales while the health burden related to short-term exposure has been under explored (Xie et al., 2019; Luo et al., 2020). Most studies on the health burden associated with short-term exposure did not capture spatial variations and coverages in air pollution concentrations or explored only one species of air pollutants. For example, Yao et al. (2020) applied the monitoring data in 338 Chinese cities to estimate the health burden attributable to short-term exposure of multiple air pollutants (including PM_2.5 and O₃), but did not consider the spatial variations of air pollution within cities, and did not include estimates in the rural areas. In contrast, the studies on the PM_2.5-related short-term health impact have better spatial coverages. Xue et al. (2019) applied an optimal estimator of daily PM_2.5 by combining observations, satellite measurements, and simulations to evaluate the health benefits from PM_2.5 reduction during 2013–2017, but the effects of O₃ were not considered.

Health cost associated with air pollution has been recognized as key information input in cost-benefit assessments that facilitate science-based policy in air pollution control. To quantify the health costs, an age-invariant value of statistical life (VSL) or value of statistical life year (VSLY) was widely used to estimate the cost of health risks (World Bank, 2016; J. Li et al., 2019a; Yang et al., 2019). The health cost estimated by VSL/VSLY method reflects not only direct cost (e.g. medical cost) and indirect cost (e.g. productivity loss), but also intangible cost due to painfulness of life loss that was not captured in the cost of illness method. On the other hand, some empirical and theoretical studies argued that both VSL and VSLY vary with people’s age due to relatively shorter life expectancy, life quality and wealth conditions (Alberini et al., 2004; Aldy and Viscusi, 2008; Hammitt, 2013). To capture the effects of health status, life expectancy and wealth condition on VSL, this study adopted age-adjusted VSL valuation method developed by Yin et al. (2020) to estimate the age-specific health cost of air pollution.

So far, there have been plenty of studies evaluating the PM_2.5 air quality improvements and health benefits from the clean air actions during 2013–2017 (Zheng et al., 2017; Ding et al., 2019; Xue et al., 2019; Zhang et al., 2019; Yue et al., 2020), but a study comprehensively depicting the broad picture of the health cost attributable to both long-term and short-term exposure of PM_2.5 and O₃ in China is still not available. To fill such gap in the literature, this study aims to explore both annual and daily patterns of exposure, health burden and economic cost of major air pollutants (PM_2.5 and O₃) from 2013 to 2018. Leveraging the methodology developed in our previous work (Liu et al., 2016; Yin et al., 2020), we evaluate the premature deaths and their costs attributable to both long-term and short-term exposure of PM_2.5 and O₃ during 2013–2018 with newly established dataset of spatial and temporal resolved ground-level PM_2.5 and O₃ concentrations (Kong et al., 2020). The results of this study provide an overall view of the transition in China’s health burden and economic cost associated with air pollution and provided the region-specific policy strategies in the co-control of these two air pollutants.