Serious air pollution shrouded 14 cities in Northeast China's Liaoning Province on Sunday, with provincial capital Shenyang witnessing a peak reading of the concentration of PM2.5 - airborne particles measuring less than 2.5 microns in diameter - of 1,017 micrograms per cubic meter, the Xinhua News Agency reported.
Experts believed that the phenomenon has resulted primarily from the generation of heating supply for winter.
Based on statistics released by the environmental protection agency of Liaoning Province, the Air Quality Index (AQI) surpassed 300 - the maximum threshold of the Ministry of Environmental Protection's measurement system - in nine cities, while Shenyang and other cities saw an AQI of over 500.
According to China's standards, an AQI of over 300 is defined as "serious pollution," which may harm people's health and cause certain diseases. Children, seniors and the ill are advised to stay home under such conditions, while all others should avoid outdoor activities.
"Air pollution may worsen in winter due to the [need for] heating supply, since most areas in Northeast China still use coal for heating. Burning coal may produce harmful pollutants such as toxic particles and gases," Wang Gengchen, a research fellow at the Institute of Atmospheric Physics at the Chinese Academy of Science, told the Global Times on Sunday.
"China's coal consumption accounted for about 66 percent of primary energy use in 2014," Fang Junshi, head of the coal department of the National Energy Administration was quoted by China Energy News as saying in May.
Wang explained that relatively static atmospheric conditions have slowed and hindered the diffusion of accumulated pollutants, while the burning of stubble fields hass only worsened the level of pollution.
Based on a Ministry of Environmental Protection report received by the Global Times in October, the number of places across China where stubble fields were being burned increased to 862 between October 5 and 17 - 54 more areas than the same period last year - most of which were in northern China.
"If the air quality continues to deteriorate, the local government may launch emergency measures, such as closing schools and controlling traffic," Wang said.
