Ventilation Improvements

Increasing ventilation can decrease indoor air pollution in your home

  • Open doors and windows to bring in fresh outdoor air when outdoor air quality and weather permit, and it is safe to do so. Promote the movement of air through the building by opening windows or doors on opposite sides of the building and keep internal doors open.
  • If you have a mechanical ventilation system, ensure it is installed, operated, and maintained according to the manufacturer’s instructions. This may involve regular inspection, cleaning and changing filters. 
  • Use a bathroom fan that vents outdoors or open a window (if conditions allow) during and after a shower to exhaust the moisture to the outdoors. Use a range hood or fan that vents outdoors when cooking, which can also generate moisture.  
  • In warm and humid climates, outdoor air that is warmer than indoor air can bring in additional moisture even when its relative humidity is lower. While air conditioning use can reduce humidity, if indoor humidity is consistently above 60%, then a specific dehumidification strategy should be employed. 

It is particularly important to take as many of these steps as possible while you are involved in short-term activities that can generate high levels of pollutants. For example, painting, paint stripping, heating with kerosene heaters, cooking, or engaging in maintenance and hobby activities such as welding, soldering, or sanding. You might also choose to do some of these activities outdoors, if you can and if weather and outdoor air quality permits.

Consider Outdoor Air Quality

Avoid ventilation with outdoor air when outdoor air pollution or pollen is high or during periods of extreme temperatures and humidity. 

  • Check AirNow for current outdoor air quality in your area. In addition, check your local weather for current temperature, humidity and pollen count.

How Does Outdoor Enter a House?

Outdoor air enters and leaves a house by infiltration, natural ventilation and mechanical ventilation.

In a process known as infiltration, outdoor air flows into the house through openings, joints, cracks in walls, floors and ceilings, and around windows and doors. In natural ventilation, air moves through opened windows and doors. Air movement associated with infiltration and natural ventilation is caused by air temperature differences between indoors and outdoors and by wind.

There are many mechanical ventilation devices:

  • Outdoor-vented fans that intermittently remove air from a single room, such as bathrooms and kitchen
  • Air handling systems that use fans and duct work to continuously remove indoor air and distribute filtered and conditioned outdoor air to strategic points throughout the house.
  • Advanced designs of new homes are starting to feature mechanical systems that bring outdoor air into the home. Some of these designs include energy-efficient heat recovery ventilators (also known as air-to-air heat exchangers).

The rate at which outdoor air replaces indoor air is described as the air exchange rate. When there is little infiltration, natural ventilation, or mechanical ventilation, the air exchange rate is low and pollutant levels can increase.

Strategies for Improving Air Quality While Cooking

If you have a range hood over your stove that vents to the outdoors:

  • Turn the range hood on whenever you are cooking.
  • Leave the range hood on for 10–20 minutes after you have finished cooking. 
  • Cook on the back burners when possible to capture more emissions. 
  • Routinely clean surfaces, cooking appliances, and your range hood’s grease filter.

If you do not have a range hood that vents outside or to supplement the performance of your range hood:

  • Open doors and windows to bring in fresh outdoor air when outdoor air quality and weather permit, and it is safe to do so. 
  • Exhaust indoor air to the outdoors, including through kitchen and window exhaust fans. 
  • Filter the air with a portable air cleaner that is the right size for the space and does not produce ozone. 
  • If you have a heating, ventilation, and air conditioning system, use an air filter rated MERV 13 or as high as your system can accommodate.             

Note: Consult a professional if you are unsure how to use these strategies.

 

 

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