Bringing Back Blue Skies

The Taiwan government is implementing a number of plans aimed at further improving air quality.

“When the weather gets cold, the issue of air pollution heats up,” says Tsai Hung-teh, director general of the Environmental Protection Administration’s Department of Air Quality Protection and Noise Control. During the winter months, he notes, the air quality in central and southern Taiwan often registers in the red zone – considered unhealthy – on Taiwan’s Air Quality Index (AQI).

But the situation appears due almost as much to the polluted air sweeping across the Taiwan Strait, carried on prevailing winter winds blowing in from China, as it is to locally produced emissions. In fact, argues Tsai, “the air quality is actually getting better in Taiwan.” He says that Taiwan has significantly reduced many of the most prevalent and dangerous pollutants, including suspended particulates, volatile organic compounds (VOC), and sulfuric oxides (SOX).

Yet these points do not hold much weight with environmentalist activists from Taichung and Kaohsiung, who allude to past industrial policies that spurred first Kaohsiung and then Taichung to develop as manufacturing centers while Taipei served as a corporate, commercial, and political hub with much less polluting industry.

Allen Chen, a marine biologist at Academia Sinica and a prominent figure in Taiwan’s environmental movement, recalls growing up in Taichung before the city became heavily industrialized. “I remember the blue skies and clean air, and I never imagined that smog would become an issue there,” he says. “But now when I visit my parents in Taichung, I can hardly see blue skies anymore. In the last 20 years everything has changed.”

On December 17 last year, simultaneous demonstrations in Kaohsiung and Taichung attracted thousands of marchers under the slogan “One Taiwan, Two Skies,” decrying the poor air quality in those two cities in contrast to the much cleaner air in the Taipei region.

Air quality in Taipei generally falls within global standards for developed countries, with AQI values of 100 or less on a 500-point scale. In the color coding of the system, it routinely measures as green (good) or yellow (within a healthy range).

But elsewhere along Taiwan’s western plain – as far north as Taoyuan and even parts of New Taipei City – the level of pollution is often a serious problem, falling into the red zone or worse.

“In Taichung and Kaohsiung we have really bad air quality in the winter time, particularly on days when we have little wind and lots of sunshine,” explains Lin Hui-chen, a professor of Life Science at Tunghai University in Taichung and a leader in the fight against air pollution. She notes that many pollutants react with sunlight to form new compounds that are sometimes more dangerous than the original forms.

Lin points to industry as the main source of the problem. “In the greater Taichung area we have 11 different industrial parks, and because Taichung is a basin area surrounded on three sides by mountains, if we don’t have wind the local pollutants accumulate in the city,” she says.

Taichung is also the home of the Taichung Power Plant, which at 5.5 gigawatts (GW) is one of the world’s largest coal-fired power plants as well as a large emitter of carbon dioxide (CO2). The facility accounts for nearly 14% of the total power generating capacity of the state-owned monopoly Taiwan Power Co. (Taipower).

Kaohsiung has long been the center of most of Taiwan’s heavy industries, including petrochemicals, steelmaking, and shipbuilding, and also has substantial coal-fired power generating capacity.

Public dissatisfaction over the state of air quality has put pressure on the Tsai Ing-wen administration, which has prioritized the environment in many of its policies, pushing it to make additional efforts to counter air pollution. Taipower was forced to accept a demand from the Taichung City government that the Taichung Power Plant either reduce its annual coal consumption by 24% or shut down.

In addition, the Executive Yuan approved a series of amendments to the Air Pollution Control Act – to be voted on in the legislature in the next session – that will more strictly regulate pollutants at the source, and EPA Minister Lee Ying-yuan has staked his position on the air quality issue, vowing to resign if the air isn’t measurably better next year. “Combatting air pollution is our first priority,” he said in an interview.

However, although many members of the public would be surprised to hear it, leading environmental scientists and the EPA all concur that Taiwan’s air quality has actually improved over the last few years.

The air quality around a particular recording station is measured once daily, called a “station day.” EPA’s Tsai explains that “in 2015 we had 997 unhealthy station days, but in 2017 we only experienced 483 unhealthy station days,” he says, a 50% reduction.

B.J. Tsuang, a professor of environmental engineering at National Chung Hsing University in Taichung and an expert in air pollution, agrees, saying “last year the air quality in Taichung has had a really big improvement.”

The improvement is attributed to a variety of factors, including the government’s decision to reduce the output of its coal-fired power plants during the low-demand winter months and instead to rely heavily on cleaner-burning natural gas. The government has also created incentives for industry to replace oil-burning industrial boilers with natural-gas-powered boilers. Although heavy oil is used in only a small amount of industrial capacity, those plants contribute significantly to pollution levels, according to Tsuang.

Many factories and power plants have added more effective pollution-control mechanisms as well. Even the natural-gas-fired Tung Hsiao power plant switched from simple cycle to combined-cycle natural gas in which heat generated in the initial combustion of gas is recycled through a steam turbine, greatly expanding output without generating more pollutants.

Pollutants found in Taiwan’s air are mostly derived from sources of combustion, primarily the burning of fossil fuels. Sulfur dioxide (SO2) is one example, and is a known health hazard and component of acid rain. Nitrogen dioxide (NO2), which is associated with reduced lung function, forms into nitrate aerosols, a main component of particulate matter in the air. Another such component are volatile organic compounds (VOCs), consisting mostly of methane, plus suspected carcinogens benzene, toluene, and xylene.

NO2 and VOCs react and combine in the presence of ultraviolent light to form ground level ozone (O3), one of the major constituents of photochemical smog. Ozone in the upper layers of the atmosphere is essential for life on earth, but at ground level can “can have a marked effect on human health,” according to the World Health Organization (WHO), and can cause “breathing problems, trigger asthma, reduce lung function and cause lung diseases.”

Carbon monoxide (CO), a dangerous gas, and CO2, the most significant contributor to global climate change, are both also emitted from fossil fuel combustion.

According to EPA data, pollutants including NO2, SO2, CO, and VOCs have all significantly declined in Taiwan’s atmosphere. SO2 has declined by 43% over the past 11 years, while NO2 and CO have declined by around 30% over the same timeframe. NO2 and SO2 levels are now within Taiwan’s EPA-established ambient Air Quality Standards, says Tsai Hung-teh.

Particulate matter (PM) consists of tiny particles of solids or liquids suspended in atmospheric gases, measured on a scale of either 10 micrograms in diameter (PM10) or 2.5 micrograms in diameter (PM2.5). Particulates on the PM10 scale are more apparent to the naked eye but are actually less dangerous as the human body is generally able to block them. As it is far smaller, PM2.5 pollution is able to penetrate the respiratory system and is implicated in heart disease, lung and liver cancer, and COPD (chronic obstructive pulmonary disease, more commonly known as emphysema), along with aggravating conditions such as asthma.

PM2.5 declined 17% between 2013 and 2016, according to the EPA. But at values higher than 15 micrograms/cubic meter (mcg/m3), it remains above Taiwan’s and global standards. The WHO has established guidelines for major air pollutants, and recommends annual mean PM2.5 levels of no more than 10 mcg/m3, or a 24-hour mean of 25 mcg/m3.

“In some areas, the ozone levels don’t meet our ambient air quality standards, as well as PM2.5. These are our main areas of concern,” says the EPA’s Tsai.

Control of PM2.5 is a very complicated matter, because both primary and secondary emissions are involved. NO2, SO2, and VOC can be affected by sunlight and other atmospheric conditions to become PM2.5.

Increased protests

Despite the progress, public protests over air pollution have accelerated, which Tsai Hung-teh credits to rising public awareness of the health effects of air pollution. Tsai considers a key factor in this rising awareness to be the Chinese documentary Under the Dome, released in 2015 but quickly banned by the Chinese Communist Party for its overt criticism of China’s government and state-run enterprises for failing to control air pollution.

“After this documentary, a lot of people became aware of the seriousness of the PM2.5 effects on human health and asked the government to reduce this kind of emission,” he says.

Taiwan has also made big changes in the way it measures air pollution. Taiwan had previously used the Pollution Standard Index (PSI) developed by the U.S. EPA. PSI measured the five main pollutants, including NO2, SO2, and VOCs, but didn’t track PM2.5 or ground-based ozone. In 1999 the U.S. EPA switched from the PSI to the AQI, which incorporates measurements of PM2.5 and ozone, and in December 2016 Taiwan followed suit.

“The AQI is more connected to human health,” explains the EPA’s Tsai. It uses a scale of 0-500 – the higher the number, the higher the pollution level and the greater the risk to human health. Taiwan follows the U.S. EPA’s in scale, with the same color-coded, easily followed guide to local air quality conditions (

Green represents an AQI value of 0 to 50, which is “Good,” while yellow represents a value of 51-100, considered within an acceptable range, although vulnerable populations – including the very young, very old, and those with health conditions – might experience some effects. Orange represents the 101-151 range, which is considered unhealthy for sensitive groups. Red depicts AQI values of 151-200, unhealthy for everyone, especially for sensitive populations, while purple represents the range of 201-300, calling for a health alert. The highest category, maroon, for the range of 301-500, constitutes a health emergency.

Air quality is a very local phenomenon and can fluctuate significantly throughout the year and even throughout the day, depending on the weather. A quick check of the Taiwan EPA website throughout the day on January 31 revealed significant fluctuations. Taipei City reached orange levels in several areas during the daytime, while Taoyuan remained in the red throughout the day. Meanwhile, central and southern Taiwan remained mostly yellow and orange throughout the day until the afternoon, when Chiayi and Changhua surged into the red. Taiwan’s eastern counties remained green all day, although Penghu jumped into the red in the late afternoon.

With external sources accounting on average for some 34% annually of Taiwan’s air pollution, and as much as 41.7% during the winter, according to the EPA, Taiwan’s scope for action to combat it is somewhat curtailed.

Combatting locally generated air pollution requires knowing the source, and the EPA’s data offers some surprises.

Regarding PM2.5, some 30-37% derives from mobile sources such as trucks, cars, and scooters, while 27-31% comes from industrial sources, and 32-43% from “stationary sources” such as dust. Although the power generation industry often bears the blunt of the blame for dirty air, in fact it only generates 4.5-9.9%. That is less than trucks, which account for 11.2-16.8%, and less even than the food industry, which is responsible for 10.8-12.2% of total PM2.5.

“Chinese cooking uses lots of oil to fry, and there are at least 70,000 restaurants,” Tsai notes.

Accordingly, the relevant ministries are targeting these major polluting industries for change.

For example, plans to ensure that all restaurants are have proper pollution-control devices in their kitchens are being implemented jointly by the Ministry of Interior, Ministry of Health and Welfare, and the Ministry of Economic Affairs (MOEA), along with local governments.

The government also has a plan to retire 80,000 older-generation diesel trucks from Taiwan’s roadways using a variety of punitive laws and incentives to encourage the shift to newer, greener vehicles. The project will require a multibillion NT dollar budget generated through the commodity tax, which will require the cooperation of the Ministry of Finance. Overall implementation will be in the hands of the Ministry of Transportation and Communication, the Public Construction Commission, and local governments.

Motorscooters are one of many sources of PM2.5 pollution in Taiwan. Photo: CNA

The EPA and MOEA are also collaborating on reducing emissions from power plants and replacing 6,000 oil-fired industrial boilers with natural-gas-fired equipment.

The administration’s goals are ambitious, and include halving the number of unhealthy air quality days by 2019. The EPA emphasizes that while improving air quality is a key goal, achievement of the objective will be a matter of slow, steady progress.

“The public wants to see clean air tomorrow, and will not be satisfied until they look at the skies and see that it’s all clear,” says the EPA’s Tsai. “But it’s a very tough task to reduce all of these pollutants from all kinds of sources. We need a lot of different strategies, and we need time to put more action plans into effect.”