TAIPEI (CNA) — Air quality is expected to remain poor in some parts of western Taiwan until next Thursday due to a lack of wind to disperse atmospheric pollutants, the Environmental Protection Administration (EPA) said Wednesday.
The lack of wind is the result of a weakening cold air mass as temperatures across Taiwan rebounded early Wednesday, the EPA said in a press release.
As a result, the Air Quality Index (AQI) is expected to remain on orange alert, meaning unhealthy air for sensitive groups, in areas south of Yunlin, Chiayi and Tainan counties, on Wednesday and Thursday, the EPA said.
The same orange alert will be in place from Feb. 21 to Feb. 26 in most parts of western Taiwan until northeasterly winds arrive next Thursday, it added.
Meanwhile, between Feb. 24 to 26, at nights and early mornings, areas south of Hsinchu and Miaoli counties could see surface temperature inversions that cause air quality in those areas to rise to the most serious red alert level, indicating unhealthy air for the general public, EPA predicts.
Temperature inversion is a reversal of the normal behavior of temperature in the troposphere, in which a layer of cool air at the surface is overlain by a layer of warmer air. Under normal conditions air temperature usually decreases with height.
This phenomenon plays a major role in air quality, especially during the winter. As pollutants from vehicles and industry are emitted into the air, the inversion traps these near the ground, leading to poor air quality.
Based on the forecast poor air quality over the coming week, the EPA said it is taking measures including coordinating with Taiwan Power Company to reduce power generation at its coal-fired Taichung Power Plant and Hsinta Power Plant in Kaohisung.