Air Quality, Masks, Filters and You


I’ve been getting a lot of questions lately about air quality, what to do about it, what the best filter is, and how to best keep yourself safe and healthy during bad air quality days in Korea.

Understanding AQI

If all you’re concerned about is understanding what to do about bad air quality, you can feel free to skip this section. However, a rudimentary understanding of what the Air Quality Index (AQI) i will be helpful in your understanding of how to best combat high AQI days. AQI is a measurement of the quality of the air in a geographical location. Essentially, it tells you how good or bad the air is at any given time of day. AWI is broken up into a few different measurements:

  1. An overall AQI score: when you open up an AQI app, (I use IQ Air Visual as it can send me alerts when the air is bad) you will see a total “score”. this score is rated based off of the following points:

  2. PM 2.5: This is the really bad stuff to be breathing in. Particulate Matter (PM) 2.5 refers to the size of the particles in the air. In this case, the particles are 2.5 ug/m^3. How small is this? Small enough to be absorbed into your blood stream. Hence, this is the stuff you want to avoid as it can cause some pretty nasty health defects, more on this below. PM 2.5 comes from cars, coal power plants, industry work.

  3. PM10: This stuff is larger, and more easily filtered. Construction dust, “yellow dust” season, cigarette smoke, and cars.

  4. SO2, NO2, CO2: For all practical purposes, we can lump these 3 gases into the same category; a group of gases that can be harmful to you in high quantities. Gas levels are usually not as much of an issue as PM2.5 are, so I wouldn’t be too concerned in this respect (at lower quantities that is).

As a note, here’s a handy chart for a rough understanding of AQI levels.


Health Affects of High Pollution

Essentially, you want to be breathing in as much clean air as possible. This is a bit of a laundry list and is not intended to fear monger, that being said, it’s important to know what can happen. Possible acute, short term, affects of bad air quality involve:

  • Shortness of breath/difficulty breathing

  • Added stress/potential damage to your respiratory system

Longterm health affects:

  • Aging of lungs (think like smoking a cigarette). Bejing at 85 PM2.5 is equivalent to 4 cigarettes a day, Los Angeles at 12 PM2.5 is 1/2 a cigarette a day.

  • Reduced lung capacity

  • Potential development of asthma, bronchitis, or cancer

  • Shortened lifespan.

For example in India, Air pollution is a leading factor in reducing term of life, ranking above Dietary risks, malnutrition, high blood pressure, and diabetes.


Practical Steps to Improving Air Quality

If you didn’t want to read the background information, here’s the practical information, ie, what can you do to fight bad air quality. There are a few relatively simple ways to reduce your time in bad air quality environments:

  1. Get your house below 10 PM2.5. (WHO Guideline pg 4)

  2. Make sure your work environment is filtered

  3. Wear a particulate mask (pollution mask) on bad air quality days

Improving Air Quality in Your Home

The best way to improve air quality in your home, where you spend a large majority of your time, is to use an air filter 24/7. Yes, it is best to run your air filter all day long so that when you come home, you’ll be prepared for breathing the best air (as well as when you sleep!).

The question now is, what type of air filter do you need?

There are some ridiculously expensive air filters on the market. Do you need a $5000 air filter to improve your air quality? NO. Here’s a secret for you. A HEPA class Filter (the kind you use on your furnace at home) strapped to a box fan does just as good of a job as a hospital grade air filtration system at improving air quality. Don’t believe me? Check out this video by University of Michigan Medicine.

If you watched the video, you’d see that if all you’re looking to do is improve your air quality as cheap as possible, you can do so by purchasing a HEPA class filter and strapping it to a fan. If you want to buy a fancier air filter, you can, but keep in mind the only reasons to pay for a more expensive air filter are:

  1. quieter fan

  2. “auto” fan speeds that turn up and down depending on air quality

  3. A carbon filter to catch smells

Do “plasma wave” or “UV light” purification systems work?

A note about fancy features, as explained above, you only need a HEPA filter strapped to a box fan to improve the AQI in your house. These UV light systems or Plasma Wave systems are all marketing, and could even be detrimental in that they can produce ozone.

What Air Filter Should I Buy?

The most important consideration is the size of your house. My apartment ins roughly 83m^2, so I bought 2 air filters to be able to fully cover the m^2 of my home. Measure your house, buy an air filter (or 2) that will fit the size of your space.

Recommended Air Filters

If you’re budget conscious:

  • A HEPA class filter and any box fan

  • The same set up, but put together already for you: SMART Air

If you want something to look nicer in your home:

  • Buy the cheapest, featureless air filter you can

  • I personally use the Winix AZBE380-HWK (With Plasma wave turned off) & the BlueAir PURE 411. Why do I use these? They’re the cheapest HEPA class filters I could find at the time of purchasing.

Through using both of these air filters (as my house was too large for 1 unit and it was cheaper to buy 2 units), I’ve been able to get my house air quality to >10 PM2.5 everyday. This being said, I’ve only had the chance to measure on a day where the quality was 170 at it’s peak, so take this with a grain of salt.

Air Quality Masks

Now, practically, the best choice fo you is to choose an AQI number that you are comfortable with, and anytime that the air outside is above this number, you should put on a mask when in unfiltered environments. Notice I didn’t say “outside”. Personally, my fiancee’ and I’s number is 100, so any day that is above 100 we will put on a mask when we are in unfiltered environments.

Things to think about when purchasing a mask:

  1. Make sure it is rated for N95 or N99 (Korean equivalent is KF94 KF99). This is a government ranking that designates it filters 95% to 99% of PM2.5 particulate matter under a 100% seal on your face.

  2. Seal to your face, besides the N95 rating, is the most important factor to a mask. if you have leaking air, the mask won’t help much. Facial hair will reduce a mask’s effectiveness (I’m a hypocrite in this respect with a beard, so I use several straps on top of my mask to make sure I’ve got a firm seal on my face).

  3. Try out different styles of masks until you find one that fits you.

I recommend:

  1. 3M Brand masks. They don’t look the prettiest, but they will certainly help reduce the level of particulate you breath in.

  2. If you’re more vain, (I’m in this camp), and don’t want to walk around with a giant white mask on your face, you can try out the Cambridge mask, Vogmask, or Airinum.

A note of the Cloth type masks: Your millage may vary. Keep in mind, particulate filter masks work on static electricity, as well as the type of filter in them. you cannot wash them to “clean” the PM2.5 filter, nor could you use the mask for several months. Most 3M paper masks will be of use for 8h, and most cloth style masks seem to last about 100h from the research I’ve done. To give you a baseline, I spend 150h outside each month going to/from work, tasks after work, and spending weekends out. Essentially, calculate how much time you spend outside, the quality of your air, and judge how long a mask will last based off that. Cost wise, all 3 cloth masks are about the same.

Something cool to know about Seoul subways, If they are a new car, the kind with 6 seats per row instead of 7, they are air filtered when inside the cabins.

Wrapping up

To review practical applications:

  1. Get your home below 10PM2.5 at all times with a HEPA filter and fan running 24/7.

  2. Try to get your workplace filtered. Petition, or bring in your own.

  3. Choose an AQI threshold number (mine is 100) and wear a particulate (pollution) mask when in unfiltered environments.

I hope this helped you understand a lot of the confusion surrounding air quality and how to best protect yourself. If you have further questions, feel free to comment down below.