Effects of air pollution control policies on PM<sub>2.5</sub> pollution improvement in China from 2005 to 2017: a satellite-based perspective

Abstract

Abstract. Understanding the effectiveness of air pollution control policies is important for future policy making. China has implemented strict air pollution control policies since the 11th Five-Year Plan (FYP). There is still a lack of overall evaluation of the effects of air pollution control policies on PM2.5 pollution improvement in China since the 11th FYP. In this study, we aimed to assess the effects of air pollution control policies from 2005 to 2017 on PM2.5 using satellite remote sensing. We used the satellite-derived PM2.5 of 2005–2013 from one of our previous studies. For the data of 2014–2017, we developed a two-stage statistical model to retrieve satellite PM2.5 data using the Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 6 aerosol optical depth (AOD), assimilated meteorology, and land use data. The first stage is a day-specific linear mixed effects (LME) model and the second stage is a generalized additive model (GAM). Results show that the Energy Conservation and Emissions Reduction (ECER) policy, implemented in the 11th FYP period and focused on SO2 emissions control, had co-benefits with PM2.5 reductions. The increasing trends of PM2.5 pollution (1.88 and 3.14 µg m−3 year−1 for all of China and the Jingjinji region in 2004–2007, p<0.005) were suppressed after 2007. The overall PM2.5 trend for all of China was −0.56 µg m−3 year−1 with marginal significance (p=0.053) and PM2.5 concentrations in the Pearl River Delta region had a big drop (−4.81 µg m−3 year−1, p<0.001) in 2007–2010. The ECER policy during the 12th FYP period was basically an extension of the 11th FYP policy. PM2.5 is a kind of composite pollutant which comprises primary particles and secondary particles such as sulfate, nitrate, ammonium, organic carbon, elemental carbon, etc. Since the ECER policy focused on single-pollutant control, it had shown great limitation for PM2.5 reductions. The PM2.5 concentrations did not decrease from 2010 to 2013 in polluted areas (p values of the trends were greater than 0.05). Therefore, China implemented two stricter policies: the 12th FYP on Air Pollution Prevention and Control in Key Regions (APPC-KR) in 2012, and the Action Plan of Air Pollution Prevention and Control (APPC-AP) in 2013. The goal of air quality improvement (especially PM2.5 concentration improvement) and measures for multi-pollutant control were proposed. These policies led to dramatic decreases in PM2.5 after 2013 (−4.27 µg m−3 year−1 for all of China in 2013–2017, p<0.001).

Effect of changing NO<sub><i>x</i></sub> lifetime on the seasonality and long-term trends of satellite-observed tropospheric NO<sub>2</sub> columns over China

“…The MEIC includes monthly emission profiles for each sector (Li et al, 2017a) and hourly profiles developed at Tsinghua University. We vertically resolve emissions from point sources (power plants and industries) following profiles used in the LOTOS-EUROS model (Manders et al, 2017) and speciate anthropogenic NO x emissions as NO (90 %), NO 2 (9.2 %), and HONO (0.8 %) following Menut et al (2013). GEOS-Chem includes additional NO x emissions from soil and fertilizer use , lightning (Murray et al, 2012), shipping (Vinken et al, 2011;Holmes et al, 2014), and aircraft (Stettler et al, 2011).…”

The Response in Air Quality to the Reduction of Chinese Economic Activities During the COVID‐19 Outbreak

“…One question of interest is the response of the secondary pollutants to such large reduction in the emission of primary pollutants and specifically the impact of these changes on the concentrations of surface ozone (O 3 ). Measurements made in recent years at the monitoring sites of the China Ministry of Ecology and Environment (http://english.mee.gov.cn) have shown that, in response to the efforts made to reduce emissions, surface ozone has increased by typically 1 and 2 ppb per year at urban and background sites (Gao et al, 2017; Ma et al, 2016, 2019; Sun et al, 2016). Li et al (2019) derived for the period 2013–2017 a positive trend in the daily maximum 8‐hour average (MDA8) ozoneof about 10 ppb in the megacity clusters of Beijing and Shanghai and about 2 ppb in the southern region around Guangzhou.…”

Long-Term (2005–2017) View of Atmospheric Pollutants in Central China Using Multiple Satellite Observations

“…As an emerging economic center located between polluted northern China and clean southern China, air quality in central China has been rarely concerned under the background of rapid development. Although recent air pollution such as PM 2.5 in central China (~40-60 µg/m 3 ) is obviously lower than that in northern China (~60-80 µg/m 3 ) [19,20], the magnitude of the atmospheric pollutants in central China is at a high level compared with health standard (e.g., PM 2.5 : 35 µg/m 3 ), which can further be seriously aggravated by [21]. By now, spatial patterns of major atmospheric pollutants in central China and how they change over space and time remain unclear due to few comprehensive observational studies.…”

“…Thus, the long-term trend of aerosol loading derived from MODIS AOD is generally representative of central China. As shown in numerous studies, annual or seasonal mean maps of satellite AOD is usually used to denote particle pollution [19,33]. Different from the consistent distribution between gaseous precursors (NO2 and SO2) and AOD in northern China [15], the hotspots of gaseous pollutants and particles in central China are concentrated in completely different spatial locations of central China.…”