VIENTIANE, April 30 (Xinhua) — Air pollution has become a growing concern in Laos after the concentration of PM 2.5 reached harmful levels, as smoke from seasonal agricultural burning filled the skies.
The concentration of fine dust, known as PM 2.5, which is particulate matter with a diameter of less than 2.5 micrometers, surpasses the safety level, according to a report from the Lao Ministry of Natural Resour