A haze settles over Shanghai Sunday. The city's air pollution is expected to remain at moderate levels Monday. Photo: Cai Xianmin/GT
The moderate air pollution that Shanghai experienced over the weekend will linger Monday due to the lack of wind, the local pollution monitoring authority said Sunday.
The city's new Air Quality Index (AQI) hit 195 Saturday, nearing the threshold for heavy pollution, before pulling back Sunday.
The Shanghai Environmental Monitoring Center launched the AQI Friday. The index includes three pollutants that were left out of the AQI's predecessor, the Air Pollution Index.
A rise in one of those pollutants, called PM 2.5, was the primary reason why the AQI jumped Saturday, said Wang Qian, a monitor with the Shanghai Environmental Monitoring Center.
PM 2.5 refers to airborne particulates that measure less than 2.5 microns in diameter. Because the particles of dirt and dust are small enough to travel deep into people's lungs, it is considered dangerous to people with respiratory conditions.
The main sources of PM 2.5 are automobile exhaust, chemical plants and roadway dust, Wang told the Global Times. The lack of wind failed to disperse the particles.
Shanghai's AQI had fallen to 124 at 10 pm Sunday, indicating light pollution. The PM 2.5 reading peaked at 120 micrograms per cubic meter in the morning.
The indicator began to drop after 10:00 pm Saturday as the wind began to pick up.
On Sunday, the wind was expected to die down around midnight Monday, which should lower the air quality, Wang said.
The monitoring center suggest residents check the hourly AQI and PM 2.5 readings on its website, rather than the daily readings, which are based on conditions over the previous 24 hours. If the PM 2.5 reading surpasses 150 micrograms per cubic meter in any given hour, residents may want to take precautions, according to the center's website.
Wang reminded residents who are prone to respiratory illnesses, such as children and the elderly, to cut back on outdoor activities when pollution levels are high.
The quality of the air is expected to improve Tuesday when the east winds pick up, Wang said.
The city will experience rain showers Wednesday, which should also reduce the amount of pollutants in the air, the local weather bureau said.
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