Taipei, Aug. 5 (CNA) Air quality in Miaoli County and Hsinchu City in northern Taiwan, as well as on the Taiwan-controlled Matsu archipelago (administrated by Lienchiang County) off China's Fujian Province, has deteriorated, according to government data on air pollutant concentrations.
The concentration of PM2.5 in Miaoli County rose by 4.2 micrograms per cubic meter (g/m3), or nearly 20 percent, to 22.8 g/m3 in the first half of the year, from 18.6 g/m3 in the same period of last year, the latest statistics released by the Environmental Protection Administration (EPA) indicate.
The growth was the highest among the 22 counties and cities of Taiwan, followed by a year-on-year surge of 2.9 g/m3 from 21.1 to 24 in Lienchiang County, and a rise of 2.7 g/m3 from 18.5 to 21.2 in Hsinchu City.
Apart from these three places, Taoyuan, Changhua County, Chiayi County and Taichung all recorded higher PM2.5 concentrations in the first six months of the year than in the same period of 2017, the statistics show.
The statistics also indicate that the highest average PM2.5 concentration in Taiwan in the first half of the year was recorded in the northern area covering Taoyuan, Hsinchu and Miaoli.
Asked about that, Chang Shuenn-chin (???), head of the EPA's Department of Environmental Monitoring and Information Management, did not provide details, saying that more analysis is needed to know the reasons.
Observations have to be done for a long period of time to know air quality changes in different areas, Chang said, and such short-term variations may possibly be caused by rainfall.
"Compared with last year, rainfall was relatively low in the first half of the year," said Chang, who also pointed out that geographic locations are another factor affecting air quality.
According to the EPA statistics, Yunlin County recorded Taiwan's highest PM2.5 concentration, which reached 27.8 g/m3 in the January-June period, followed by 27.1 g/m3 in Chiayi City, 27 g/m3 in Nantou County, 26.9g/m3 in Kinmen County, 26.1 g/m3 in Chiayi County, and 25.9 g/m3 in Tainan.
Although Yunlin had the highest PM2.5 concentration in the country, the level has fallen by 2.6 g/m3 from the 30.4 level last year, the tallies show.
PM2.5 refers to atmospheric particulate matter (PM) that have a diameter of less than 2.5 g, which is about 3 percent the diameter of a human hair. PM2.5 and their counterparts PM10, which are particles that are 10 micrometers or less, are also called fine particles.
Fine particles can come from various sources, including power plants, motor vehicles, airplanes, residential wood burning, forest fires, agricultural burning, volcanic eruptions and dust storms. Due to their small size, fine particles tend to stay longer in the air than heavier particles, posing a health risk.
Source: Focus Taiwan News Channel