The True Dangers of Seoul Air Pollution

  • 18 min read
Seoul Air pollution

Today Korea’s AQI reached over 250, an amount considered very unhealthy by the American Environmental Protection Agency. ‘Everyone may experience more serious health effects’ to the effect of smoking over ten cigarettes. Even a normal day has an equivalent health toll as smoking 3 cigarettes.¹ This is everything you need to know about Seoul air pollution.

However, rarely does anyone talk about the air. Sure, it is covered by the media at times, but the seriousness of the issue is often avoided. In fact, until recently, coal power plants were still being built. Coal and oil power plants are set to shut down partially when pollution reaches PM2.5 50 µg/m3, but even today the PM2.5 peaked far higher than thatAir pollution leads to seven million premature deaths a year around the world, including 600,000 among children.² David Boyd told of the seriousness of the issue “To put that figure in context, that’s more deaths every year than the combined total of war, murder, tuberculosis, HIV, AIDs and malaria,”.

Watching the media here, it seems more and more common to find articles about air quality. Air quality which is now ‘some of the worst in the world’. It seems like not a day goes by without new articles and warnings arising. As a foreigner in Seoul, it is especially hard to find information in English about the current state of the air in Korea, and how to deal with it. As such, I intend for this post to spread some awareness about the different factors of air pollution, the risks associated with them, and how you can minimise the affects.

Good Resources to Check Air Quality 

Seoul Government Air Quality


Air Korea

What are the Risks Associated With the Rising Air Quality Issue, and How Serious Are They?

Air quality map of East Asia as seen on Berkeley Earth’s Air Quality Real-time Map.

AQI (Air Quality Index) rates air quality on a 0-500 scale. 0-50 representing good air quality, 50-100 moderate, 100-150 unhealthy for sensitive groups, 150-200 unhealthy, 200-300 very unhealthy and 300-500 hazardous.³ In Seoul though, the air has been consistently above the 200 mark this week. An amount which can be detrimental to health over time.

Affects on Health

It is worth mentioning that while short term effects do indeed exist, medium-length exposures (31 days or less) and long term exposure are far more dangerous. If you are a tourist coming to Korea for under 31 days, the air affects will be far less damaging than they will be for a long-term resident.⁴ If you are a short term visitor to Korea, keep an eye on the AQI and wear masks on bad days. However, unless you have a prior heart or lung condition, short-term exposure to the air is unlikely to cause serious issues.

A recent report found that ‘Each 10-µg/m3 elevation in fine particulate air pollution was associated with approximately a 4%, 6%, and 8% increased risk of all-cause, cardiopulmonary, and lung cancer mortality, respectively’.⁵ At the past five day average PM2.5 reading of 77.6 μm/m³, this is a 31% increase in all-cause mortality, 46.6% increase in cardiopulmonary mortality, and a 62% increase in lung cancer mortality. While the general pollution rates are falling, this still presents a significant risk. Especially to those with heart or lung conditions.

Which Mask Should You Wear?

A common misconception is that buying any mask and wearing it will help protect your body from polluted air. This is NOT true. A recent study in China found that ‘Many commercially available face masks may not provide adequate protection, primarily due to poor facial fit. Our results indicate that further attention should be given to mask design and providing evidence-based guidance to consumers.’⁶

N vs KF Rating

When buying a mask in Korea, look for an N or KF rated mask. N ratings are issued by the US National Institute for Occupational Safety and Health and have been extensively tested for effectiveness. ‘The ‘N95’ designation means that when subjected to careful testing, the respirator blocks at least 95 percent of very small (0.3 micron) test particles.’⁷ Meanwhile, an N99 rating means that the respirator blocks at least 99% of very small particles. 

KF rated masks on the other hand are very similar, except that they are rated by the Korean Occupational Safety and Health Agency. The ratings between KF and N are very similar, and in theory a KF 95 mask should perform the same as an N95 mask. However, this study shows that NIOSH rated masks perform better at when it comes to 95+ rated masks.⁸

NIOSH (N) masks VS KFDA (KF masks). Hyejung Jung, Jongbo Kim, Seungju Lee, Jinho Lee, Jooyoun Kim, Perngjy Tsai, Chungsik Yoon. Comparison of Filtration Efficiency and Pressure Drop in Anti-Yellow Sand Masks, Quarantine Masks, Medical Masks, General Masks, and Hankerchiefs. 2014.

How to Wear Respirators

Once you have picked a suitable mask, it is vital that it is fitted properly. Simply putting the mask on is not effective. It has to fit snugly – KF and N rated masks will normally have wire nosepieces and will go under the wearers chin. It is important to note though that ‘N95 respirators are not designed for children or people with facial hair. Because a proper fit cannot be achieved on children and people with facial hair, the N95 respirator may not provide full protection.’ ⁹

When buying a mask, look for the KF and N rating. If there are multiple options, look for the highest rated mask. If there are still multiple choices, look for masks with full head straps (rather than straps that attach to your ears). Masks with wire nose adjustments usually provide good comfort and fit.

If a mask does not have a KF or N rating, don’t buy it. It’s not protecting you from the particles that are actually harmful. Many people in Korea wear facemasks, a mask similar to what you see surgeons wearing. These are to prevent bacteria from spreading in bigger particles and splashes. THEY WILL NOT protect you from small air particles. These masks are often worn by the sick, and they serve a different purpose. 

Another factor which most people forget, or don’t consider, is that respirators are disposable. Typically, they last for 8 hours, and must then be discarded. If you continue wearing them for longer, they will become ineffective. Wearing the same mask for days on end will not protect you. While masks can usually be used for a few days, it depends on a few factors such as the humidity, air quality, and physical exertion. To learn more about the specifics of how long a mask can be work, refer to this post. Masks with replaceable filters can be purchased from Vogmask, Cambridge Mask, and other vendors. These masks can last as 70 hours before a filter replacement is necessary, however each mask is different. Refer to the individual instructions for more information. Learn everything you need to know about fine dust masks.


Look for these when buying a mask:

A KF or N rating. The higher the better.

A full face strap (one that goes around your head, rather than ears)

A nose wire that allows for adjustments.

Remember, these masks are disposable and only last for a few days at the longest. If they aren’t fitted properly, they will be ineffective and won’t work properly. Longer lasting masks with replaceable filters can be purchased for under $30.

Masks such as these 3M masks are highly recommended. N95 Respirator Mask and 3M Particulate Respirator.

Understanding AQI

The readings taken from can be hard to understand at first.

First seeing the air quality readings can be very overwhelming. From the PM 2.5 readings to the carbon monoxide, there is a lot to take in. I have been in this situation before too, and I know how hard it can be to understand everything!

Ozone VS Particle Pollution

To begin with, we can divide the overall AQI readings into two categories:

  • Ozone: People with lung disease, children, older adults, and people who are active outdoors are considered sensitive and therefore at greater risk.
  • Particle pollution: People with heart or lung disease, older adults, and children are considered sensitive and therefore at greater risk.¹⁰

Particle pollution includes both PM2.5 and PM10 readings. The numbers 2.5 and 10 relate to the size of the particles, with 2.5 being particles under 2.5 micrometers. PM10 on the other hand, refers to particles under 10 micrometers. While both PM2.5 and PM10 have negative health affects, PM 2.5 is generally considered to be the more dangerous of the two. It is important to keep an eye on both of these particulate pollution readings. 

PM10 VS PM2.5

‘There is good evidence of the effects of short-term exposure to PM10 on respiratory health, but for mortality, and especially as a consequence of long-term exposure, PM2.5 is a stronger risk factor than the coarse part of PM10 (particles in the 2.5–10 μm range). All-cause daily mortality is estimated to increase by 0.2–0.6% per 10 μg/m³ of PM10 (6,7). Long-term exposure to PM2.5 is associated with an increase in the long-term risk of cardiopulmonary mortality by 6–13% per 10 μg/m³ of PM2.5 (8–10).’¹¹

While PM10 is likely to cause short term difficulties with breathing, the long term affects are less harmful than that of PM2.5. Anyone with a history of respiratory conditions will be even more likely to notice difficulty in breathing with high PM10 concentrations. However, PM10 is not the long-term danger that PM2.5 is.

Ozone pollution includes nitrogen dioxide (NO2), ozone (O3), sulfur dioxide (SO2) and carbon monoxide (CO). These polluters in excess can all pose health threats, especially in long exposures. ‘Ambient air pollution, comprised mainly of nitrogen dioxide, ozone, sulfur dioxide and particulate matter, is directly linked to increased risk of stroke, heart disease, asthma and lung cancer.’ These ozone chemicals are inhaled and decrease the antioxidants on the respiratory tract lining fluids, leading to the oxidants being able to destroy tissue underneath.¹²

At What AQI Should I Wear a Mask?

The AQI table from AQICN.

Different sources have very different AQI levels listed as ‘safe’. The World Health Organisation states these as the guideline values for ‘safe’ air:

Fine Particulate Matter (PM2.5)

10 μg/m3 annual mean

25 μg/m3 24-hour mean

Coarse Particulate Matter (PM10)

20 μg/m3 annual mean

50 μg/m3 24-hour mean¹³

These values are considered very low in Korea, and it is rare for days to go below 35 μg/m³, let alone 10 μg/m³.¹⁴ Countries such as China only consider values above 200 μg/m³ unhealthy. However, the WHO (World Health Organisation) does also admit that no level of fine dust pollution can really be considered ‘safe’.

It’s hard to identify an exact AQI rating that a mask should be worn at, especially since the the WHO guidelines for long-term exposure are well below what Korea experiences. The AQI site rates 0-50 as ‘healthy’ and that is what is generally believed. I know many people who wear masks only when the air gets worse than 100, and many who wear at 150. For me however, with asthma, anything over 75 begins to cause difficulty with breathing. 

High Risk Groups

If you fit any of the following groups you are more likely to be affected, and will be more affected, than others.¹⁵

  • People with lung diseases, such as asthma, chronic bronchitis, and emphysema, can be particularly sensitive to ozone. They will generally experience more serious health effects at lower levels. Ozone can aggravate their diseases, leading to increased medication use, doctor and emergency room visits, and hospital admissions.
  • Children, including teenagers, are at higher risk from ozone exposure because they often play outdoors in warmer weather when ozone levels are higher, they are more likely to have asthma (which may be aggravated by ozone exposure), and their lungs are still developing
  • Older adults may be more affected by ozone exposure, possibly because they are more likely to have pre-existing lung disease.
  • Active people of all ages who exercise or work vigorously outdoors are at increased risk.
  • Some healthy people are more sensitive to ozone. They may experience health effects at lower ozone levels than the average person even though they have none of the risk factors listed above. There may be a genetic basis for this increased sensitivity.

For more information on the health effects, and information on other substances found in the air (such as carbon monoxide and sulfur dioxide), please refer to the Airnow website.

In the end, it is up to the individual to decide when a mask is required. There is no set level for masks, and everyone is affected differently. Following the guidelines of the table above however, it is recommended to wear a mask above an AQI rating of 100 if you are sensitive, and 150 otherwise. 

What Causes Seoul Air Pollution?

This is a highly controversial question that often results in heated arguments. Often the blame is placed on China. Just as often though, the blame is also placed on Korean domestic pollution. Especially by China. Recently, the South Korean government has approached China with the plan of creating artificial rain over the Yellow Sea to help prevent the pollution in Seoul.  

However, while it is true that much of the bad air comes from China, it isn’t the only cause of the problem:

While the previous argument might suggest that Korea’s own emissions are mostly to blame, other studies have, however, confirmed that China’s emissions have substantially undermined South Korea’s air quality. An older study, conducted between August 2002 and December of 2003, provides solid evidence for transboundary movement of pollution from China to South Korea.. This research found that huge seasonal spikes of airborne chemicals associated with residential biomass and coal-burning ovens in China accounted for as much as 82% of those measured in Seoul, due to prevailing westerly winds blowing pollutants over the Yellow Sea. A more recent study conducted on the Western coast of Seoul from June 2009 to May 2010 also found strong evidence that transboundary pollution from China corrupted South Korea’s air quality.

The process of “source apportionment” (i.e., assigning pollution origination) is, however, an extraordinarily complex and evolving science that relies on sophisticated chemistry, remote sensing, statistics, and modelling. This spring, NASA, in partnership with South Korea, began flying research planes along the Korean coastline to help distinguish foreign pollutants from home-grown ones. Korea’s foreign direct investments (FDI) in China, moreover, are so significant – 6 to 10% of China’s total FDI – that even South Korea’s outsourced emissions are boomeranging back to their shores. Clearly, South Korea and China’s industrial might and the pollution that results is inextricably linked.¹⁶ Other studies have claimed that Chinese air only accounts for 30 to 50% of the pollution in Seoul.

Influence from Neighbouring Countries by KOSAE

Who is Responsible

Whichever number we choose to believe though, Korea is at least partly (and possibly primarily) responsible for the unhealthy air, both due to FDI in China and domestic pollution. The issue with the air pollution coming from China is that it can’t be combated by Korea alone. This is a problem which must be tackled together – as with the proposed rain project.

However, the Korean government is not innocent. A study done by Korea University scientists indicates that policy failures are also to blame. In fact, while pollution has been decreasing, the relative risk of death from exposure to PM2.5 and PM10 particles has increased. While the government may be working on increasing air quality, the health effects are not being targeted.¹⁷

While finding the source of the problem is important, the vital step is to target the health problems and find solutions to the growing issues. Further, even if the majority of the pollution does come from China, Korea has little influence as to what happens in China. Rather, while Korea discusses options with China, it is important that domestic solutions are also being formed. 

The research by the Korea University scientists also went on to say that the mortality associated with dust was actually greater when the days affected by Asian dust were excluded. Days of Asian dust are generally covered more by the media, and general awareness is greater. More masks are purchased, and activities are restricted. Due to this increased awareness on days of Asian dust, the mortality rate is actually lower than on a day unaffected by the dust.¹⁸

The fact remains that not enough steps have been taken to reduce pollution and fine dust in Korea, and especially Seoul. Only recently has KIHASA (Korean Institute for Health and Science Affairs) developed ‘Korea’s New Comprehensive Plan on Fine Dust and Its Implications for Policy and Research’ with the September 26 measures. These measures are aimed at cutting fine particular emissions by 30% by 2022.¹⁹ The plan outlines steps for a less polluted future. However, the outcome and actual results remain to be seen. The government needs to keep a strong stance towards reducing emissions and needs to remain active in their push to move toward a cleaner future.


Fine particulate emissions have been on the decrease for years. However, the mortality rates associated with them are still climbing. The first steps have been taken to counter the lives taken by fine dust and air pollutants, however, the most important steps are yet to be taken. 

Whether or not the new Korean-Chinese artificial rain works, Korea also needs to focus more on domestic issues. While it is true that China contributes a significant amount of the pollution, many reports point the finger at Korea as being the largest contributor. The best case scenario is that both countries can work together to solve this very serious threat. 

My intention with this post was to help provide a more detailed insight into the air pollution crisis in South Korea, and Seoul. It can be hard to find information (especially in English) regarding the air and fine dust, and I hope that this post can help bring some more understanding to the situation and the causes, effects, and solutions of fine dust. 

If you noticed any inaccuracies in this post please email me at [email protected]. Further, if you have any more questions or comments feel free to either email me, or leave a comment on this post. 

This post contains affiliate links. These links provide me with income at no extra expense to you. 


1. Muller, Richard A. and Elizabeth A. Air Pollution and Cigarette Equivalence.

2. Al Jazeera. South Korea plans artificial rain to reduce Seoul air pollution. 6th March, 2019.

3. U.S. Environmental Protection Agency (2014). A Guide to Air Quality and Your Health.

4. Beverland, I. J., Cohen, G. R., Heal, M. R., Carder, M., Yap, C., Robertson, C., Hart, C. L., … Agius, R. M. (2012). A comparison of short-term and long-term air pollution exposure associations with mortality in two cohorts in Scotland. Environmental health perspectives120(9), 1280-

5. Pope III CA, Burnett RT, Thun MJ, et al. Lung Cancer, Cardiopulmonary Mortality, and Long-term Exposure to Fine Particulate Air Pollution. JAMA. 2002;287(9):1132–1141. doi:10.1001/jama.287.9.1132

6. Cherrie, J. W., Apsley, A., Cowie, H., Steinle, S., Mueller, W., Lin, C., Horwell, C. J., Sleeuwenhoek, A., … Loh, M. (2018). Effectiveness of face masks used to protect Beijing residents against particulate air pollution. Occupational and environmental medicine75(6), 446-452.

7. U.S Food and Drug Administration (May 16th, 2018). Masks and N95 Respirator.

8. Hyejung Jung, Jongbo Kim, Seungju Lee, Jinho Lee, Jooyoun Kim, Perngjy Tsai, Chungsik Yoon (2014). Comparison of Filtration Efficiency and Pressure Drop in Anti-Yellow Sand Masks, Quarantine Masks, Medical Masks, General Masks, and Hankerchiefs, 1000.

9. U.S Food and Drug Administration (May 16th, 2018). Masks and N95 Respirator.

10. U.S. EPA Office of Air Quality Planning and Standards (2014) Air Quality Index – A Guide to Air Quality and Your Health.

11. World Health Organisation (2013). Health effects of particulate matter. Policy implications for countries in eastern Europe, Caucasus and central Asia

12. Bergius, Will (2014). Nitrogen dioxide and ozone: a sinister synergy.

13. World Health Organisation (2018). Ambient (outdoor) air quality and health.


15. U.S. EPA Office of Air Quality Planning and Standards (2014) Air Quality Index – A Guide to Air Quality and Your Health.

16. Mostellar, Donald (2016).Air Pollution’s Hazy Future in South Korea

17. Honghyok Kim, Hyomi  Kim, Jong-Tae Lee (2015). Effects of ambient air particles on mortality in Seoul: Have the effects changed over time?

18. Honghyok Kim, Hyomi  Kim, Jong-Tae Lee (2015). Effects of ambient air particles on mortality in Seoul: Have the effects changed over time?

19. Suehyung Lee (2018). Korea’s New Comprehensive Plan on Fine Dust and ItsImplications for Policy and Research.

2 thoughts on “The True Dangers of Seoul Air Pollution”

  1. Thanks Ethan for the very informative article(s), I had no idea of the extent of air pollution still occurring in the world, we are so lucky here in NZ.

    1. Thank you for leaving a comment! It’s scary to think that while the air pollution here is very bad, it’s not anywhere near as bad as some other places out there.

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