PM (particulate matter) pollution in China
Particulate matter has become an increasing environmental problem in China due to the country’s economic development, rapid urbanization, industrial expansion, and drastic increase in the number of motor vehicles. At the beginning of 2015, 388 cities at or above the prefecture level across China started to monitor and publish their air quality data in accordance with National Ambient Air Quality Standards (NAAQS). In 2015, the lowest and highest 24-hour concentrations of PM2.5 and PM10 in 388 cities were 11 μg/m3 and 125 μg/m3, 24 μg/m3 and 357 μg/m3, respectively. The annual average concentration of PM2.5 and PM10 in the same cities were 50 μg/m3 and 87 μg/m3.
The most developed and highly populated city clusters such as the Beijing-Tianjin-Hebei region (BTH), the Yangtze River Delta (YRD), and the Pearl River Delta (PRD) are exposed to frequent heavy pollution due to their distinct regional characteristics. In 2015, the annual average concentrations of PM2.5 and PM10 in the BTH region were 77 μg/m3 and 132 μg/m3. In particular, BTH and its surrounding areas (including Shanxi, Shandong, Inner Mongolia and Henan) still have the poorest air quality and highest frequency of heavy pollution in the country. In 2015, 70 cities at or above the prefecture level in the region recorded a total of 171 days of heavy or higher-level pollution and issued 154 alerts for heavy air pollution. In addition, the annual average concentrations of PM2.5 and PM10 in YRD were 53 μg/m3 and 83 μg/m3. In PRD, the annual average concentrations of PM2.5 and PM10 were 34 μg/m3 and 53 μg/m3, respectively. The concentrations of PM2.5 in PRD are generally lower than those in the other two largest city clusters in China.
Sulfur dioxide (SO2) and nitrogen oxides (NOx) are key pollutants in ambient air quality. As data from the National Bureau of Statistics of China shows, there were major changes in air pollutant emissions from 2006 to 2014 in China. During that period, SO2 emissions have shown a decrease-increase-decrease trend, and NOx emissions have decreased since 2011, when there was a 29.8% increase over the previous year. The surge in emissions in 2011 may be attributed to changes in China's method of calculating NOx emissions. Starting that year, data on NOx emissions from motor vehicles began to be collected and included in total NOx emissions figures.
There are many sources contributing to increasing air pollutant emissions in China, including the industrial, transport, and residential sectors. According to the National Bureau of Statistics of China, the industrial sector contributed most to the fine particulate matter in China. In 2014, the industrial sector was responsible for 88% of SO2 emissions. The two sectors that contributed the most NOx in 2014 were the industrial and transport (motor vehicle) sectors, which were responsible for about 68% and 30% of the emissions, respectively.
In general, motor vehicles have contributed a significant portion of air pollutants, particularly ambient PM2.5. The contribution of vehicle emissions to PM2.5 in the BTH region in 2013 reached 31.1% (Beijing City), 20% (Tianjin City) and 15.5% (Hebei Province). Similarly, in Hangzhou and Shanghai in the YRD region of China in 2013, vehicle emissions accounted for about 40% and 29.2%, respectively. Vehicle emissions were responsible for 21.7% of the PM2.5 pollution in Guangzhou City.
Air pollution poses an incredible challenge for China. In September 2013, China’s National Action Plan on Air Pollution Control was issued by the State Council. The Action Plan was designed to reduce and prevent air pollution at the national level by 2017. Specifically, it aims to reduce the PM10 concentration by at least 10% by 2017 (taking 2012 as a base year). Moreover, it sets a target that the concentration of PM2.5 in Beijing-Tianjin-Hebei region, Yangtze River Delta, and Pearl River Delta should be decreased by 25%, 20%, and 15%, respectively, by 2017. Furthermore, the 13th Five-Year Plan (FYP) was formally adopted in 2016. According to the 13th FYP, China’s new target is to decrease the PM2.5 concentration by 18% by 2020, in cities that are exceeding the national air quality standard.
CHU Jang Min, Chief Research Fellow, Korea Environment Institute (sinoeco@kei.re.kr)