Shanghai warned children and the elderly to avoid prolonged or heavy outdoor activities as PM2.5 readings hit seven times the World Health Organization’s recommended level of daily exposure.
The air quality index was 183 as of 9 a.m., signaling “moderate pollution,” the third worst in a six-tier warning system, according to the website of the city’s environmental monitoring center. The level of PM2.5 pollutants was 186.4 micrograms per cubic meter. That compares with the WHO guidelines of 25 over a 24-hour period for the particles, which are smaller than 2.5 microns in diameter and are more dangerous than other particulate matter.
Shanghai saw record levels of smog earlier this month, forcing flight cancellations and prompting the government to issue warnings to keep children indoors and order vehicles off the road. The pollution index surged to a record 482 on Dec. 6, reaching the highest “severe” level, according to the China Daily.