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進入《TAIPEI TIMES》 Jhongli rain most acidic in Taiwan
Women walk in the rain in Taipei yesterday. Photo: Chien Jung-fong, Taipei Times
By Lin Chia-nan / Staff reporter
Rain samples collected in Taoyuan’s Jhongli District （中壢） last year had a pH of 4.77, the most acidic among all monitoring stations nationwide, an Environmental Protection Administration （EPA） survey showed.
Acid rain is mainly caused by the dissolution of acidic substances in rain, the EPA said, adding that these include carbon dioxide, formic acid and organic acid compounds, some of which are released from natural phenomena.
The agency defines acid rain as precipitation with a pH of 5 or less to focus on the effects of human-caused air pollution on the quality of rain, it said.
Samples collected from 14 stations had an average pH of 5.72, while the Jhongli station was the only one that reported a pH of less than 5, EPA statistics showed.
The nation’s incidence rate of acid rain last year was about 22 percent, but the rate reached 81 percent in Jhongli, followed by Hsinchu with 42 percent, the data showed.
The incidence rates in central and southern Taiwan were between zero and 21 percent, and 11 percent in the east, they showed.
The occurrence of acid rain in Taiwan has diminished, with its major scope of influence — previously encompassing most northern regions — reduced to Taoyuan, the agency said.
The volume of air pollution, which is usually felt to be more severe in central and southern regions, is not directly related to that of acid rain, EPA Air Quality Protection and Noise Control Director-General Tsai Meng-yu （蔡孟裕） said on Saturday when asked about a discrepancy between air pollution and the occurrence of acid rain.
Northern Taiwan experienced more acid rain due to greater rainfall, particularly in the form of drizzle, as drizzle carries more acidic substances, Tsai said.
As the nation’s air quality worsens around October, when the northeasterly monsoon brings overseas pollutants, the EPA is preparing a plan to reduce coal use and increase natural gas use at power plants when poor air quality is forecast, he said.
While state-run Taiwan Power Co （台電） last year started reducing power generation and emissions according to the EPA’s pollution forecasts, the scheme targets only a single power plant in a given region without considering national power demand, he said.
The new plan would aim to reduce coal pollution while ensuring power supply, which has garnered support from the utility and most environmental groups during discussions, Tsai added.
新聞來源：TAIPEI TIMES
