Air quality index reached as high as 309 in Southeast Asian city, according to independent provider of global air pollution
The Vietnamese capital Hanoi topped the list of the world's most polluted city on Friday, according to daily weather data.
Data from AirVisual, an independent provider of global air pollution figures, showed the PM2.5 concentration in the air was “currently 13.2 times” the World Health Organization's annual guideline value.
PM2.5 measures the levels of hazardous small particles in the air.
As the air quality was “unhealthy,” the air quality index (AQI) turned brown to 309 at some places, daily Vietnam News reported.
The AQI has a range between zero to 500 — the higher the number, the greater pollution and health impacts it has.
AirVisual has advised people in Hanoi to avoid outdoor exercise, opt to close their windows to avoid dirty outdoor air and wear a mask outdoors.
