Why does PM2.5 dust return to be a problem from December to May every year and why do some areas face more PM2.5 dust problems than others? The different intensity of PM2.5 dust is divided into 3 important factors as follows:

1) The severity of PM2.5 pollution in Thailand is alarming, with burning being a significant source.

• Small dust particles. Dust particles smaller than PM2.5 occur in large quantities in all forms of combustion.

• Three sources of combustion that cause PM2.5 dust in Thailand are (1) vehicle fuel combustion, (2) fuel and chemical combustion in various types of manufacturing industries, and (3) burning agricultural landed Included garbage burning and forest fires.

2) Weather

• Weather, particularly wind direction, plays a significant role in exacerbating PM2.5 pollution, underscoring the need for comprehensive solutions

• From December to March, the weather is over in Bangkok. Temperature inversion (temperature inversion) causes the phenomenon of "hood," which is why the amount of air supporting dust decreases. As a result, the dust intensity is even higher.

3) City Planning and Green Space

• Topography and urban planning are other factors affecting concentration, such as cities with thin valleys or with a high density of tall buildings. Dust that occurs or is blown away so they are usually confined to that area. Because the air is not easy to ventilate.

• Dust often occurs in areas with structures concealed above, such as bridges, electric train tracks, etc.

• Increasing green space. It can help alleviate dust problems. Like parks, areas with much green space tend to have better air quality. This is because pollutants and PM2.5 floating in the air often cling to the surface of leaves and trees. The more leaves the tree has, the better it will be at "trapping dust.".

Source: The Operation of "Extinguish Dust" Faculty of Engineering Chulalongkorn University