Source Control – keeping contaminants out of your home
Air cleaners – whole home cleaners integrated into your HVAC system
Improved Ventilation – incorporating fresh air
For some indoor air quality problems in the home, source control is the most effective solution. Simply keep the contaminants out of your home.
Another approach to lowering the concentrations of indoor air pollutants in your home is to increase the amount of outdoor air coming indoors.
It may sound funny, but homes need to breathe. Just like with your lungs, your home needs to breathe to make sure that fresh air comes in and dirty air goes out. The air inside your home can build up high levels of moisture, odors, gases, dust, and other air pollutants. To keep the air safe indoors, fresh outdoor air is needed to dilute these indoor pollutants.
To provide good air quality, enough air needs to be brought in and circulated so that it reaches all areas of the home. For almost all homes, windows and structural elements contribute to bringing in fresh air. Many homes have additional mechanical systems to add to the flow. Some sources, such as stoves and bathrooms, need special venting that can remove the pollution they produce. Ventilation above stoves needs to carry the air outside to avoid redistributing pollutants from cooking inside the home.
There are a few different ways air comes into and leaves your home:
Infiltration is when outdoor air flows into buildings through openings, joints, and cracks in walls, floors, and ceilings, and around windows and doors.
Natural Ventilation is when you open doors and windows.
Mechanical Ventilation can include outdoor-vented fans that intermittently remove air from a single room, such as bathrooms and kitchen, to 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.
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.
Opening windows and doors, and operating window or attic fans (when the weather permits) increases the outdoor ventilation rate. Local bathroom or kitchen fans that exhaust outdoors remove contaminants directly from the room where the fan is located and increase the outdoor air ventilation rate.
It is 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, 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.
Most residential forced air-heating systems and air-conditioning systems don’t bring outdoor air into the house mechanically, instead relying on infiltration and natural ventilation to bring outdoor air into the home.
Advanced designs for new homes are starting to add a mechanical feature that brings outdoor air into the home through the HVAC system. Some of these designs include energy efficient heat recovery ventilators to mitigate the cost of cooling and heating this air during the summer and winter.
Whether by infiltration, natural ventilation, or mechanical ventilation, adding fresh air to your home will help to increase your indoor air quality.