Taipei's Air Pollution: Understanding The City's Poor Air Quality

Taipei, Taiwan's capital and largest city, has been facing serious air pollution issues for a long time. The city's topography, surrounded by mountains, contributes to poor air dispersal, trapping pollutants and leading to an unhealthy atmosphere for its residents. The primary sources of air pollution in Taipei are domestic incineration of organic matter, the combustion of fossil fuels, and traffic emissions. Extensive studies conducted between 1993 and 2013 have established a strong link between air pollution, meteorological conditions, and adverse health effects in Taipei.

The combustion of fossil fuels and domestic incineration of organic matter

Taipei, the largest city and capital of Taiwan, has poor air quality due to a combination of factors, including the combustion of fossil fuels and the domestic incineration of organic matter. The topography of Taipei, surrounded by mountains, contributes to the city's air pollution problem by trapping pollutants and preventing their dispersal.

The combustion of fossil fuels, such as coal and oil, releases various gases and particles into the atmosphere, including sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and fine particulate matter (PM2.5 and PM10). According to the National Taiwan University, traffic is the major source of these air pollutants in Taipei, with the annual mean concentration of PM2.5 particles in Taipei City reaching 20 μg/m3, exceeding acceptable limits. The burning of fossil fuels in power plants and industrial facilities located in central Taiwan also contributes to the high levels of air pollution in Taipei.

The domestic incineration of organic matter, including agricultural waste and garbage, is another significant source of air pollution in Taipei. The practice of open burning releases harmful pollutants such as volatile organic compounds (VOCs), particulate matter, carbon monoxide, and toxic air contaminants. These emissions can have adverse effects on human health, particularly respiratory and cardiovascular systems.

To address the air pollution caused by fossil fuel combustion and domestic incineration, Taipei has implemented several measures. The expansion of the Mass Rapid Transit (MRT) system has provided a cleaner alternative to private and public vehicles, helping to reduce emissions from the transportation sector. There is also a push to phase out old two-stroke motorbikes and encourage the use of public transport, electric vehicles, and hybrid vehicles. Additionally, vertical greening initiatives, such as green walls and roof greening, are being explored as sustainable solutions to improve Taipei's air quality.

Air pollution in Taipei has attracted attention from environmental groups and legislators. In 2014, the Taiwan Healthy Air Action Alliance and Taiwanese legislators highlighted that Taipei's air quality was worse than that of other Asian cities, with an annual mean PM10 level of 47.1 micrograms per cubic meter. This has led to calls for further action to reduce emissions and improve air quality in the city.

Topography and poor dispersal of pollutants

Taiwan's topography has been identified as a contributing factor to its poor air quality, specifically in the way it affects the dispersal of pollutants. The country's capital and largest city, Taipei, is surrounded by mountains, as are other industrial centres along the northern and western coasts of Taiwan. The presence of these high mountains inhibits the circulation of air, trapping pollutants and preventing their dispersal.

The effects of this poor dispersal can be seen in the levels of PM2.5 particles in Taipei. Research conducted by the National Taiwan University in March 2015 identified traffic as the major source of these particles, which are microscopic in size. The annual mean concentration of PM2.5 particles in Taipei City and New Taipei City was found to be 20 μg/m3, exceeding the normative limit value of 15 μg/m3. This is three times higher than the standard in the United States and five times higher than the World Health Organization's recommendation.

The concentration of PM2.5 particles is particularly high at ground level in Taipei, with levels up to three stories high being ten to twenty times higher than those found at four stories and above. Levels of other hazardous suspended particles, such as silicon and iron, were found to decrease with increasing altitude. This indicates that the poor dispersal of pollutants caused by Taipei's mountainous topography is particularly detrimental at ground level.

To address the issue of air pollution in Taipei, the Mass Rapid Transit (MRT) system was expanded in 1996, providing a cleaner alternative to private and public vehicles. This expansion has helped to mitigate urban air pollution, especially in the metropolitan area of Taipei City, by lowering emissions from the transportation sector.

Traffic and high levels of nitrogen dioxide

Taipei, Taiwan's capital and largest city, is surrounded by mountains. This topography has been noted as a contributing factor to the city's poor air quality, trapping pollutants.

Traffic is a major source of air pollution in Taipei, particularly in the form of nitrogen dioxide (NO2). Research conducted on PM2.5 particles in Taiwan by the National Taiwan University in March 2015 concluded that traffic was the primary source of air pollutants in Taipei. The annual mean concentration of PM2.5 particles in Taipei City and New Taipei City is 20 μg/m3, while in Kaohsiung, it is 30 μg/m3.

In greater Taipei, the concentration of PM2.5 particles at ground level up to the height of three-story buildings is ten to twenty times higher than at four stories and above. This is attributed to dust and traffic pollution. The normative limit value of PM2.5 in Taiwan is 15 μg/m3, which is higher than the standard in the United States (12 μg/m3) and the World Health Organization's recommended level of less than 10 μg/m3.

Nitrogen dioxide (NO2) is a significant air pollutant in Taipei, with annual concentrations surpassing the European Union's limit of 40 μg/m3. In May 2025, Taipei's NO2 AQI was 34, and in 2020, the nitrogen dioxide level was measured at 24.5 μg/m³. While Taipei's air quality has shown improvement, with a "'Good' level of air pollution reported in late 2020", traffic and high levels of nitrogen dioxide continue to be pressing issues contributing to the city's poor air quality.

Thermal power plants and high PM2.5 particle concentration

Taipei, Taiwan's capital and largest city, has been facing issues with air pollution for a long time. The air quality in Taipei has been deemed to be the worst out of the Four Asian Tigers. The annual mean PM10 level in Taiwan was 54 micrograms per cubic meter, while the annual mean of Taipei was 47.1 micrograms per cubic meter.

One of the significant contributors to Taipei's air pollution is thermal power plants. The Taichung Power Plant (TCPP), located in central Taiwan, is the largest thermal power plant in the country and the second-largest in the world. It provides approximately 19% of Taiwan's electricity. TCPP has been a source of controversy due to its high PM2.5 emissions. While the central government argues that closing TCPP would only marginally improve air quality, local governments and researchers push for emission reductions.

Research has shown that in central Taiwan, thermal power plants are the primary source of fine particles like PM2.5. The annual mean concentration of PM2.5 particles in Taipei City and New Taipei City is 20 μg/m3. Additionally, the concentration of PM2.5 at ground level up to three stories high is ten to twenty times higher than at four stories and above.

The impact of thermal power plants on PM2.5 levels is influenced by various factors. Population density, industrial structure, industrial dust emissions, and road density have been found to correlate with PM2.5 concentrations. The burning of fossil fuels, particularly in power plants, contributes to the formation of sulfur dioxide (SO₂), which can lead to fine particulate matter and harm respiratory health.

Furthermore, Taiwan's topography, including Taipei's mountainous surroundings, contributes to poor dispersal and the trapping of pollutants. Overseas sandstorms and local traffic emissions also play a role in the high PM2.5 concentrations. While rainfall can decrease PM2.5 levels, seasonal variations impact particle concentrations, with higher levels typically seen in winter and spring.

Meteorological factors and health risks

Taipei, the capital of Taiwan, has been facing issues with air pollution for a long time. The city's topography, surrounded by high mountains, contributes to poor air dispersal, trapping pollutants. This is exacerbated during the low-flow river season when large areas of riverbanks become exposed, and wind gusts carry suspended dust towards the city. Domestic combustion, primarily the burning of fossil fuels, and traffic are significant sources of air pollution in Taipei.

The link between air pollution, meteorological conditions, and health risks has been studied extensively in Taipei. Research conducted between 2000 and 2013 found a connection between increased levels of ozone and sulfur dioxide and a higher number of visits by the Emergency Department (ED) to patients with COPD (chronic obstructive pulmonary disease). This relationship was more pronounced during periods of higher air pressure and humidity. These findings provide strong evidence of the impact of air pollution and weather conditions on the health of vulnerable individuals.

The air quality in Taipei can be unhealthy for sensitive groups, including those with respiratory conditions like COPD. During periods of high air pollution, these individuals may experience symptoms such as difficulty breathing and throat irritation. In some cases, even healthy individuals may exhibit similar symptoms with prolonged exposure to polluted air. Therefore, it is recommended to limit outdoor activities and reduce the time spent outside when the air quality is poor.

The impact of air pollution on health is not limited to Taipei but extends to other regions of Taiwan as well. For example, the Linyuan area is considered a health risk zone due to a 30-40% increase in SOx and NOx levels. Additionally, in 2017, the Taiwan Healthy Air Action Alliance launched the "Anti-Air Pollution and Blue Sky Parade" to address the serious air pollution issues in the central and southern regions of the country.

While Taiwan works towards reducing emissions and improving air quality, it is essential for individuals, especially those with pre-existing health conditions, to stay informed about air pollution levels and take necessary precautions to protect their health. This may include monitoring real-time air quality data, installing air purification systems, and adhering to health advisories issued by local authorities.

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