SHANGHAI’S daily average of PM2.5 pollutants, the tiny particles that are particularly hazardous to health, reached 62 micrograms per cubic meter last year compared with the nation’s standard of 35, according to the city’s environmental protection bureau.

The daily average of PM10, larger inhalable particles, reached 82 micrograms per cubic meter, exceeding the 70 national limit for the fifth year.

Previously, bureau director Zhang Quan said vehicle and factory emissions accounted for 50 percent of the city’s air pollution, followed by dust from construction sites (10.5 percent), power stations (7.3 percent) and straw burning (10 percent). The other 20 percent was from other provinces.