NTU Scholars Highlight Health Hazards Caused by PM2.5 Air Pollutants

An air pollution research team led by the College of Public Health held a press conference on Mar. 13 to highlight the dangers of air pollution to raise public awareness as well as call for attention among policy-makers. During the conference, COP Dean Wei J. Chen (陳為堅) pointed out that while Taiwan adopted the international PM2.5 control standard in 2012, measures of air pollution management are still in great need of improvement, especially when excessive levels of fine particles pose substantial threats to public health.

PM2.5 is an indicator for assessing health impacts from air pollution through examination of concentrations of fine particulate matter of 2.5 micrometers or less in diameter (PM2.5). Fine particles include smoke, dirt, mould or pollen. PM2.5 is considered the best indicator of the level of health risks from air pollution as the pollutants can be inhaled and accumulated in the respiratory system.

The Word Health Organization ranked Taiwan’s air pollution last among the four East-Asian countries known as the Asian Tigers (i.e. Hong Kong, South Korea, Singapore, and Taiwan). The organization has also time and again highlighted the plight of health concerns related to PM2.5. In light of these concerns, the NTU team looked into Taiwan’s air quality in terms of animal toxicology, epidemiology, environmental monitoring, and policy making.

Upon studying the physiological effects of particulate matter among laboratory rats, Prof. Tsun-Jen Cheng (鄭尊仁) found that fine and ultrafine particles cause damage to the respiratory system upon entrance into the lungs. Affecting the coronary artery and the autonomy of the nervous system, fine particles may lead to the onset of arrhythmia and heart attacks.

Prof. Ta-Chen Su (蘇大成) also discovered that the incidence of cardiovascular inflammation in the blood is related to the inhalation of fine particles. For instance, epidemiological statistics show that the sudden hike in hospitalization for cerebrovascular disease during the winter coincides with short-term increase of air pollutant levels. Statistics also show that the severity of Taipei’s City’s air pollution is highly linked to the thickness of the internal carotid artery, making levels of PM2.5 an important indicator for studying long-term atherosclerosis. Su’s study also suggests that exposure to PM2.5 is detrimental to the development of the infant’s nervous system.

The standard concentration of PM2.5 in Taiwan is set at 15 µg/m³ (micrograms per cubic meter). However, in monitoring Taiwan’s levels of air pollution, CPH Vice-Dean Chang-Chuan Chan (詹長權) and Prof. Chang-Fu Wu (吳章甫) pointed out that the average concentration in Taipei City and New Taipei City is 20 µg/m³ , whereas in Kaohsiung, the average is even higher, sitting at 30 µg/m³ . In greater Taipei, outdoor PM2.5 concentrations below the height of three-stories is also 10 to 20 times higher than the fine particle concentrations found in the air of four-story buildings and above. Levels of other hazardous suspended particles such as silicon and iron also increase significantly with the decline of altitude. Prof. Wu cites dust and traffic pollution as the main sources.

Vice-Dean Chan further noted that Taiwan’s annual PM2.5 standard of 15 µg/m³ established by the United States, it is also much higher than the WHO suggested concentration of 10 µg/m³ . Traffic is the major source of air pollutants in Taipei, whereas in Central Taiwan, fine particles are produced primarily by thermal power plants. Urging authorities to take more proactive actions against air pollution, Chan emphasized the importance of setting emission standards according to the human capacity instead of industrial development. Prioritizing health over development, emission standards should be set by the Environmental Protection Administration in conjunction with the Ministry of Health and Welfare, and not, as in the present, with the Ministry of Economy.