Wed, Aug 15, 2018 - Page 4 News List

Little rain drives up PM2.5

CHEMICAL CLUES:The average concentrations of sulfur dioxide and nitrogen dioxide did not change from 2016, indicating that pollution output likely did not increase

Staff writer, with CNA

Average concentrations of PM2.5 in industrial parks were higher last year than in 2016, but it was likely not due to an increase in pollutants, the Environmental Protection Administration (EPA) said.

The agency has air quality monitoring stations in five industrial parks, four of which showed a yearly increase in average concentrations of PM2.5 — fine particulate matter that measures 2.5 micrometers or smaller.

The poorer air quality resulted from less rainfall, rather than the generation of more pollution, EPA Department of Air Quality Protection Director Wu Sheng-chung (吳盛忠) said.

“A higher density of PM2.5 does not necessarily mean an increase in pollution, because it is also affected by wind, temperature and rainfall,” Wu said, citing the monitoring station in Kaohsiung’s Cianjhen District (前鎮) as an example.

The station recorded an average PM2.5 concentration of 29.5 micrograms per cubic meter (mcg/m3) last year, up 6.4mcg/m3 from 2016, the biggest increase among the five industrial parks, EPA data showed.

However, the concentrations of sulfur dioxide and nitrogen dioxide — which help create PM2.5 particulates — averaged about the same levels in Cianjhen last year as the year before, suggesting that there was no year-on-year change in the amount of pollutants emitted, Wu said.

However, there was 1,850mm less rainfall in the area during the period, meaning there was less rain to wash away PM2.5, he said.

The dry weather also caused increases in average PM2.5 concentrations at industrial parks in Yunlin County’s Mailiao (麥寮) and Taixi (台西) townships, as well as Miaoli County’s Toufen City (頭份), Wu said.

The average concentration recorded at the Mailiao monitoring station was 27.8mcg/m3 last year, up 2.4mcg/m3 from 2016, while the station in Taisi recorded 25.7mcg/m3, an increase of 0.8mcg/m3.

In Toufen, the PM2.5 concentration averaged 20.1mcg/m3, 1.8mcg/m3 higher than the previous year.

The only industrial park that saw a decrease in PM2.5 concentration was in Changhua County’s Siansi Township (線西), which recorded a year-on-year decrease of 1.9mcg/m3 from 24.4mcg/m3 in 2016.

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