Can air conditioners filter out smoke from a room?

The below article talks about air conditioners and smoke if air conditioners could improve poor air quality caused by smoke, along with some frequently asked questions about air conditioners and indoor air quality. 

Can air conditioners filter out smoke from a room?

The truth about filtering smoke from a room is that air conditioners are not capable of doing so. AC filters can remove dust, soot, and other fine particles from an enclosed space, however, most AC filters do not have the capability to filter out heavy smoke from a room in hopes to improve indoor air quality. Heavy smoke compromises a large concentration of extremely fine particles, which could easily travel through an AC’s filter, thus, essentially it would move through the filters and be pumped back into the room. 

How does an Air Conditioner work?

Air conditioning has been used globally to relieve rooms of extreme temperatures that make lives everywhere more comfortable and optimal. Air conditioners essentially would remove the warm air from an enclosed space, and releases it outdoors; while cool air is simultaneously pumped back into the room, thus reducing the room’s temperature. The basic functioning of an air conditioning unit would be to remove heat and humidity from indoors, while a refrigerant or a coolant is used to cool air and pump it into the enclosed space. 

Air conditioners cannot filter out smoke

As mentioned above, air conditioners work by pumping out stale air from the room, and cooling air that is passed back into the room. There are two reasons that smoke cannot be filtered through an air conditioning unit. Namely, not all air conditioning units are fitted with the appropriate filter that could capture fine soot and other carbon contaminants that compromise the smoke, and secondly, smoke particles are quite small, due to which the filters that are present in an air conditioning unit may not be fine enough to capture these particles. Therefore, the particles could theoretically pass through the filters and cycle back into the room. 

While to a  certain extent air conditioners can improve indoor air quality levels, this is not the case when it comes to smoke. Therefore, users must be careful to avoid using an air conditioner unit as a manner of ventilation when burning substances indoors. Especially items such as cigarettes, incense burners, etc. these items have the capability to emit volatile organic compounds that could stay indoors for long periods of time, increasing the inhabitants exposure to these contaminants. Since air conditioners are not capable of filtering out these fine particles, contrary to popular beliefs, inhabitants of the room would essentially be exposed to a constant cycle of contaminants that are not filtered by the air conditioning unit. 

Another common belief is that air conditioner units would bring in air from outdoors, this is not true. For the most part, the air that is used by an air conditioning unit comes from the enclosed space, where the air absorbed is cooled and then pumped out, however, in some cases when the air conditioning unit is not sealed properly or not maintained well, there is a possibility for outdoor contaminants to leak into the indoor space. Therefore, if your air conditioning unit is maintained well and cleaned periodically, it can be used in instances where there may be a wildfire nearby, or large scale vehicular emissions. 

Benefits of air conditioning 

  • Air conditioners usually have unique filters that help them remove dangerous allergens such as pollen, dust, mold spores, etc. from circulating in the air, thus drastically reducing the incidence of allergies in different individuals.
  • Air conditioners are capable of removing excess moisture from your room, therefore reducing the occurrence of mold or mildew. 
  • It stabilizes indoor room temperatures, keeping heat strokes, and other heat-related illnesses far away. 
  • They help reduce dehydration by keeping your body cool, which keeps you from sweating and losing water from your body. 
  • Optimally set air conditioner units could drastically improve ones’ sleep and keep one comfortable, reducing sleep disturbances. 
  • Cleaner air from well-maintained air conditioners has been found to reduce asthma attacks in different individuals.
  • There are fewer insects, bugs, fleas, etc. in your room as the air conditioner filter theoretically would be capable of filtering out these elements. 
  • The closed windows and doors required for optimal functioning of an air conditioner unit, ensure to keep poor outdoor air quality and noise pollution at bay. 

Effects of breathing in smoke

Smoke is emitted through various sources natural and otherwise, such as from wildfires, cigarette burning, incenses, burning of waste, vehicular emissions, etc. and these could have significant impacts on people who are exposed to this. While effects can be short-term or long-term, individuals who are exposed to smoke could experience the following symptoms:

  • Breathing difficulties 
  • Cough 
  • Increased incidences of allergy attacks 
  • Increased incidences of asthma attacks 
  • Wheezing 
  • Itchy and scratchy skin and nasal pathways 
  • Burning sensations in the eye 
  • Runny or stuffy nose 
  • Increased incidences of migraines 
  • Blocked sinuses 
  • Exhaustion 
  • Chest pains 
  • Irregular heart rates 

Frequently Asked Questions (FAQs): Can an air conditioner filter out smoke?

How to protect yourself from long-term exposure to smoke?

  • Ensure that any smoke source is placed outdoors, and if it is indoors, that there is adequate ventilation system set in place to remove the airborne contaminants from the enclosed space. 
  • Avoid unnecessary smoke sources indoors such as cigarette smoking, burning of unhealthy or highly chemical compounds, etc. 
  • When the air conditioner is running, keep the windows and doors closed to ensure that there is no inflow of outdoor contaminants.
  • Ensure to utilise proper ventilation systems so that indoor airborne contaminants are able to be filtered out from the space. 
  • Use a mask like an N95 mask, to avoid breathing in smoke particles 
  • Set up an air filter to clean the air within the enclosed setting
  •  If the air quality worsens due to smoke, consider immediate evacuation 
  • If there is a power outage, open the windows and doors to allow for air ventilation, so as to avoid exposure and subsequent poisoning from contaminants such as carbon monoxide or other volatile organic compounds. 

What is the difference between an air conditioner and an air purifier? Which device improves indoor air quality?

An air conditioner’s main activity is to cool the air within an enclosed space, by absorbing the air in the area, and using a refrigerant or a coolant to decrease the temperature of the air that is pumped back into the enclosed space. An air purifier is solely used to clean out the airborne contaminants in an enclosed space, and thus is equipped with the adequate technology and programming to maintain healthy levels of indoor air quality.

To a certain extent, an air conditioner can improve indoor air quality, but this is not a long-term or a permanent solution for healthy indoor air quality levels. AC filters are capable of capturing larger dust and debris particles, providing a preliminary cleaning of the air, which could improve the indoor air quality levels. However, since an AC was not created for the purposes of maintaining indoor air quality, the efficiency of an AC filter to do the same would vary, and depending on this method would not be a sufficient or efficient method to reducing exposure from harmful indoor airborne contaminants. 

Therefore, it is always best to use an air purifier to regulate indoor air quality levels. An air purifier has been designed for this specific purpose, and is usually fitted with various filters such as a true HEPA filter, that is capable of filtering out fine particles and other contaminants. It is always best to rely on an air purifier for healthier indoor air quality levels, than an air conditioner. 


Anita. (2020, November 18). Do air conditioners filter smoke? Home Upward. Viewed on 01-29-2022.,air%20conditioning%20(AC)%20units