AI Overview

 

No, air conditioner filters are not effective at reducing PM2.5. However, you can use a portable air purifier with a HEPA filter to improve indoor air quality. 

Explanation

Air conditioner filters are not designed to remove PM2.5, which are smaller particles that are difficult to see with the naked eye. 

Air filters are usually located near the return air duct and are better at filtering dust, pollen, and other allergens. 

Air filters with a higher MERV rating are better at filtering particles. However, MERV ratings were not developed to measure PM2.5. 

Activated carbon filters are designed to remove chemical pollution and odors, not particulate matter. 

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When indoors, keep doors and windows closed and be aware that the air filters fitted to your residential air conditioners cannot remove PM2.5 from the air. You can use a portable air purifier to improve the indoor air quality. It should have a HEPA (High Efficiency Particulate Air) filter. 

 

https://www.meinhardt.net/news/particulate-matter-2-5-microns-pm2-5-indoor-air-quality-your-health/#:~:text=Minimise%20the%20amount%20of%20time,not%20developed%20to%20measure%20PM2.

On 1/25/2025 at 12:30 PM, fvw53 said:

I live in an apartment opposite Bangkok Golf Club in Pathum Thani where according to AQAir.com the PM2.5 was 180 at 12 noon.

I keep my air conditioner operating the whole day at a setting of 28 C

Recently a bought an Air Quality Detector and it indicates in my apartment a PM.5 value of 29 (also at 12 noon)

Does air conditioning reduce PM2.5  and keep the dust in the filter?

 

Yes 

5 hours ago, SanSaiExPat said:

How often do you all have a guy come out and clean your A/C unit and what to you pay?  500 baht?

Every 6 months / 1500 Baht for two air conditioners

2 hours ago, newbee2022 said:

Yes 

 Not all AC units are designed to remove PM2.5 effectively. To specifically target PM2.5, look for units with specialized filtration or consider a dedicated air purifier.

2 hours ago, newbee2022 said:

Does air conditioning reduce PM2.5  and keep the dust in the filter?

Not all AC units are designed to remove PM2.5 effectively. To specifically target PM2.5, look for units with specialized filtration or consider a dedicated air purifier.

27 minutes ago, Nemises said:

Not all AC units are designed to remove PM2.5 effectively. To specifically target PM2.5, look for units with specialized filtration or consider a dedicated air purifier.

Not my post. Sorry 

I stayed in a cheap hotel and took my pm 2.5 meter with my during an escape south. The air quality definitely improved overnight with the AC running. I would suggest others with a meter do a similar test. The air is being blown over a tray capturing the water from the humidity. I think that this can trap PM 2.5 particles.

The only way to find out is to turn the aircon and a PM2.5 meter on and observe. Our aircon doesn't filter PM2.5, but we bought a filter on a roll that we manually put inside the aircon. This seems to help quite a bit, in combination with an air purifier.

On 1/26/2025 at 7:16 AM, msbkk said:

While I do agree that a measuring device would be the correct way it is a fact that a large quantity of black dust is accumulating in the filter instead of my lungs. So it certainly has a visible effect even it might not be perfect. And yes, I do change the filter often, it is not that expensive.

Just an update. I bought an air purifyer (Xiaomi) with built in sensor to check the difference.

Today morning without any filtering of aircon fitted with additional filter paper AQI air quality index 0.38.

When fixing filter paper to 50% of the in built plastic mesh filter of my aircon AQI went down to around 0.22 on mid level fan, not maximum.

The air purifier inproved AQI to around 0.10 on automatic mode, not maximum speed.

 

The filter paper has definitely an effect on air quality it is however not so perfect as the purifier. 

Another update if someone is interested. I did some more testing. Filter paper taped to the aircons can in fact reduce AQI to a low level of 0.10 within a few hours. The air purifier does the same and even lower within a much shorter timeframe. 

As pollution levels are very high at the moment I would like to give another update regarding PM 2.5 filtering. I did some really intensive testing during the last few weeks.

 

First of all filter paper taped to the aircons can bring only a slight improvement with air so bad during this time. I suggest to use them only in addition to air purifiers. For those who use taped filter paper onto the fan I can assure you that it simply does not work when pollution is high. Even the air purifiers have to work hard to bring the AQI levels to green.

 

Summary: buy a decent air purifier, if possible several of them in case you have a house or a  condo with several rooms.