Thu, Feb 12, 2015 page8

• Clear thinking over haze issue

  • By Chan Chang-chuan 詹長權
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  Air pollutant particles smaller than 2.5 micrometers, or PM2.5, are smaller than the cross-section of a strand of hair. Since they are of complex composition, high toxicity, can spread across great distances and last for a long time, PM2.5 have been called the plague of the 21st century.

  People who spend a relatively short amount of time in haze, from a few hours to a few days, or breathe it regularly over a long time, such as months or years, have a higher chance of getting respiratory tract diseases, cardiovascular diseases and lung cancer, which can all lead to death.

  The WHO estimated that for every increase of 10 micrograms of PM2.5 per cubic meter (µg/m3) of air, cardiopulmonary mortality rises by 6 to 13 percent. Those who already suffer cardiopulmonary disease, elderly people and toddlers are especially vulnerable.

  So far there is no evidence that there is such a thing as a safe level of the particulates. In 2005, the WHO published target limits — an annual mean of 10µg/m3 and a daily mean of 25µg/m3 — to set an acceptable public health goal for countries as they formulate policies to control the impact of haze particles on public health.

  The particulate levels across Taiwan are higher than the values suggested by the WHO, especially in central and southern areas, where the levels are often twice or four times higher than the WHO targets. To make things worse, PM2.5 pollutants in southern and central Taiwan are usually accompanied by ozone pollutants, the combination of which increases health risks.

  A lot of domestic research sponsored by the Ministry of Science and Technology and the Environmental Protection Administration has found that haze poses various health risks. National Central University professor Wang Jia-lin (王家麟) and I conducted a series of studies prior to the construction of the Central Taiwan Science Park and we found that in 2006, ozone and haze pollution in the region between Taichung and Nantou County’s Caotun (草屯) and Jhushan (竹山) townships was serious due to the effects of coal-powered energy generation and urban traffic.

  The deteriorating air quality has had a negative effect on the lung functions of outdoor workers and it has increased the risk of people living in Taichung dying due to cardiovascular disease.

  Unfortunately, the park expansion project on Dadu Mountain (大肚山) proposed by the Central Taiwan Science Park Management Bureau selected Taichung — which already suffers from a serious lack of clean air — as the construction site.

  The establishment of this new industrial area will increase the amount of PM2.5 pollutants and ozone precursors output by coal-fired power plants, worsening Taichung’s air quality, which is already heavily polluted by haze and ozone pollution.

  Volatile organic compounds (VOCs) are another major air pollutant in industrial regions. Some VOCs are carcinogenic. A study sponsored by the National Science Council and conducted by National Yang-ming University professor Kuo Hsien-wen (郭憲文), a former colleague of mine at China Medical University, found that commuters in Taichung were exposed to two to 30 times higher VOC concentration levels than commuters in Western countries.

  In addition, commuters were also at a higher risk of getting cancer because of benzene pollutants. Any evaluation of VOC health risks in industrial regions should take into account the already overly high VOC risk in Taichung so that the real risk condition people face can be fully reflected.

  Environmental impact assessments (EIA) and health risk evaluations should be based on scientific methods and objective data. Unfortunately, the evaluators and reviewers of the EIA for the much debated Central Taiwan Science Park expansion project did not fully and sufficiently collect relevant domestic research results and literature as references when making their judgement. This could easily lead to a flawed EIA conclusion based on flawed information.

  From a public health perspective, industrial areas in which the severity of PM2.5 haze is already high should not be used for expansion projects. Using Taichung as an example, the air pollution caused by cars and scooters and the coal-fired Taichung and Mailiao power plants must be considerably reduced before new plans for industrial areas can be implemented.

  Using the US and Switzerland as examples, there have been many successful methods to reduce industrial and transportation pollution since 1980 that have mitigated haze pollution, lowered disease incidence and prolonged life spans, while economic growth continues.

  Such development policies, that promote new economic growth by greatly reducing old sources of pollution, are the right path to safeguarding public health and facilitating Taiwan’s sustainable development.

  Chan Chang-chuan is vice dean of National Taiwan University’s College of Public Health.

  Translated by Ethan Zhan
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