Indoor Air Cleaners for Removal of Odors and Gases

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Odorous compounds can be emitted from various sources including landfills, concentrated animal feeding operations (CAFOs), cannabis processing facilities, wildfires, high-traffic areas, and wastewater-impacted areas. While the health impacts from particulate components of air pollution from these sources are well-characterized, odorous pollutant compounds can also cause discomfort, headaches, nausea, eye and throat irritation, worsen asthma and other lung conditions, and cause stress and sleep problems. These pollutants can most impact people who are sensitive to chemicals and odors, including people with lung conditions and immune system disorders. Infants, young children, and people over 65 are often more vulnerable to air pollution in general. This webpage provides updated guidance on air cleaning technologies, exposure reduction strategies, and resources for affected communities.

Air Cleaning Technologies for Odors and Gases

Many commonly used residential air cleaners will not effectively remove odors or gaseous pollutants. For example, HEPA filters are very useful for removing particles but cannot remove gases, which pass through the filter material. Several companies do sell models with specialized filters to reduce indoor levels of gaseous pollutants, including VOCs and hydrogen sulfide. Such models can be relatively expensive and specialized so it is important to read marketing materials closely or talk to a sales representative about the type of odors and gaseous pollutants you are concerned about to ensure the air cleaner can remove those chemicals. 

Choosing an air cleaner for particle pollution, odors, and gases

  • Should be CARB certified.  
  • Should have a HEPA filter to also remove the tiniest particles. For more information about particle filtration and properly sizing an air cleaner, please see the link to our FAQ for “Air Cleaning Devices for the Home”.
  • Have an activated charcoal filter to effectively remove hydrogen sulfide and VOCs, such as benzene (US EPA 2018). 
    • Larger quantities of activated charcoal are more effective than small quantities and will last longer. Several devices have carbon beds and filters with 1 to 12 lbs. of activated charcoal.  Thin activated charcoal filters may remove odors for a short period of time but will not remove hydrogen sulfide or reduce high concentrations of VOCs. 
    • The addition of a metal oxide catalyst such as potassium permanganate with activated charcoal filtration can increase the effectiveness at removing gaseous pollutants, such as VOCs and hydrogen sulfide. This is especially important when there is a mixture of VOCs and odors in the air. 
    • Consumers should refer to manufacturer's websites for additional information regarding the removal of specific pollutants.

Best Practices for Using Your Air Cleaner 

  • Many air cleaners have an indicator light that will tell you when to change the filter. Change the filter(s) immediately when indicated. 
  • If the air coming from an air cleaner has a sour or chemical odor, it may indicate that the filter needs to be changed, even if the indicator light is not on. 

Other Tips to Reduce Exposure to Odors and Gas Pollutants

  • Seal gaps in windows and doors to reduce infiltration of odors and gases.
  • During times when odors or smoke are less intense, ventilate and maintain airflow by opening windows or using exhaust fans and in kitchens and bathrooms. Use exhaust fans in kitchens and bathrooms to maintain air exchange.
  • Avoid ozone-generating air purifiers, which can worsen indoor air quality.

More Air Cleaner Information

Resources for Affected Communities

Contact Us

If you have questions about air cleaners or exposure reduction, please contact: aircleaners@arb.ca.gov.