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).
Pollution control effects of environmental policies based on threshold effect model of industrial structure: Taking the Air Pollution Prevention and Control Action Plan as an example