TAIPEI (Taiwan News) — Northern and western Taiwan were hit by a thick layer of smog today (Feb. 25), triggering a red alert at 13 weather stations and an orange alert at 26.
Air quality today followed a pattern of worsening conditions over the past few days.
According to the Environmental Protection Administration (EPA), 13 weather stations flashed a red warning for "unhealthy" air quality in Taoyuan County, Hsinchu County, Miaoli County, Taichung County, Changhua County, Nantou County, and Yunlin County. Meanwhile, 26 stations in Chiayi County, Kaohsiung City, and Pingtung County issued orange alerts for air that is "unhealthy for sensitive groups."
The EPA uses a six-color air pollution warning system in which a maroon alert is the most severe, signifying “hazardous” air, followed by purple, red, orange, yellow, and green. According to EPA standards, a red alert runs from 151 to 200 on the Air Quality Index (AQI) scale. AQI levels above 150 are considered “unhealthy for everyone,” and members of sensitive groups may experience adverse effects.
According to the EPA, winds shifted to the east today, and conditions to disperse pollutants in the western half of the country were absent. This morning, the air quality from the northern to central parts of the country rapidly began to worsen, with 13 stations issuing red alerts by 11 a.m.
Polluted Taipei skyline today. (CNA photo)
Due to slow wind speeds and poor horizontal and vertical atmospheric diffusion, conditions are ripe for the accumulation of pollutants. Coastal areas of Taoyuan, Hsinchu, and Miaoli are all being affected by a "leeward vortex," according to the EPA.
Meanwhile, photochemical reactions in the afternoon along with a high ozone concentration will worsen air pollution in Kaohsiung and Pingtung. Fog is also likely in western Taiwan in the evening, affecting visibility.
The EPA predicts that on Friday (Feb. 26), winds will continue to blow in an easterly direction, and wind speeds will remain slow in the western half of the country with poor atmospheric diffusion, resulting in the further accumulation of pollutants.
On Saturday and Sunday (Feb. 27 and 28), winds will shift to the northwest, and air quality in northern and central Taiwan should improve, but the south will be more likely to see poor air quality.
By Monday (March 1), the seasonal northeastern winds will dissipate and air quality in western Taiwan could deteriorate again. However, on Tuesday (March 2), the northeast winds will strengthen, likely improving air quality in central and northern parts of the country, while southern areas could see more pollution.