A yellow alert was issued by Chinese meteorological authority indicating dangerous levels of smog in China’s northern and western regions, including major cities like Beijing and Chengdu.
The density of PM2.5 particulates had surpassed 700 micrograms per cubic meter in many parts of the city, much above than the daily safety level of 25 micrograms per cubic meter as considered by the World Health Organization.
What is PM2.5?
PM is the short of Particulate Matter which describes condensed phase (solid or liquid) particles suspended in the atmosphere. Their potential for causing health problems is directly associated with the size of the particles. As per WHO standards, PM less than 2.5 μm in diameter (PM2.5), are more closely linked to adverse health effects than other metrics such as PM10 (particles with a diameter less than 10 μm).