Let the Air in: Improving Indoor Air Quality

This guide uses the latest technical understanding of the issues. We did our homework. But, following this advice does not guarantee you are safe. It will not necessarily provide complete protection in all situations. Indoor air pollution is tricky. It may still cause health hazards even if you take these steps.

There are three basic strategies to improve indoor air quality:

1. Source Control

2. Improved Ventilation

3. Air cleaners/Filtration

Source Control

You want to improve indoor air quality? Start with the source. Eliminating individual sources of pollution is usually your best bet. You can also work to reduce their emissions. For example, if you have asbestos, you can seal it or enclose it. If you have a gas stove, you can adjust it to release fewer fumes. This approach saves money, too. Increasing ventilation uses more power to heat or cool the air. Source control protects your air without hiking up your energy costs.

Improved Ventilation

You can lower indoor air pollutants just by bringing in more outdoor air. It sounds simple, but you have to do it yourself. Most home heating and cooling systems, like forced air, don’t bring fresh air inside. They just move the old air around. To fix this, open your windows and doors when the weather is nice. You can also run window fans or attic fans. If you have a window air conditioner, keep the vent open. This boosts the outdoor ventilation rate. Also, don’t forget the bathroom and kitchen fans. They exhaust outdoors and remove contaminants right from the room.

You need to be extra careful during short-term projects. Some jobs create high levels of pollutants fast. This includes painting, paint stripping, or sanding. It also happens when you use kerosene heaters or cook a big meal. Even hobbies like welding and soldering foul the air. Take every step you can to vent the room. If the weather permits, do these activities outdoors instead. It is the safest way to go.

Homes are changing. Advanced designs of new homes are much tighter than older ones. They don’t leak air, so they need help to breathe. That is why they are starting to feature mechanical systems. These systems actively bring outdoor air into the home. They don’t just rely on open windows.

One of the best options is the heat recovery ventilator. You might see this listed as an HRV. These are energy-efficient units. They are also known as air-to-air heat exchangers. They pull fresh air in and push stale air out. But they do a cool trick. They use the outgoing air to warm up or cool down the incoming air. This keeps your energy bills low.

You have plenty of choices for this technology. For more information about whole-house ventilation system options, you should do some reading. See the U.S. Dept. of Energy’s website. Look for the “Energy Saver: Whole-House Ventilation” page.

Ventilation is a powerful tool. First, along with shading, it helps control indoor temperatures. Second, it cleans the air. Ventilation helps remove indoor airborne pollutants. It dilutes the stuff that builds up from indoor sources. This reduces the level of contaminants in your house. It is a great way to improve your indoor air quality, or IAQ.

But there is a catch. You need to carefully evaluate when to use ventilation. Look for outdoor sources of pollutants first. If there is smoke or refuse burning nearby, do not open the windows. Bringing that dirty air inside will hurt your air quality, not help it.

Introducing outdoor air is a major factor in promoting good air quality. Air enters a home in several different ways.

1. Natural Ventilation:

   This is air moving through windows and doors.

2. Mechanical Means:

   This happens through outdoor air intakes connected to your HVAC system.

3. Infiltration:

   This is a process where outdoor air flows into the house through leaks. It comes through cracks in the walls, floors, and ceilings. It also sneaks in around windows.

Remember, infiltration occurs in all homes to some extent.

Natural ventilation describes air movement through open windows and doors. If used properly, it can help moderate the indoor air temperature. This is a big help if your home gets too hot. It is perfect for homes without air-conditioning systems. It also saves the day during power outages or brownouts. In those times, using the AC is impossible.

Using natural ventilation improves indoor air quality. It helps by reducing pollutants. You can do this by opening windows and doors. Window shading is another good example.

Standard residential systems have a flaw. Forced air-heating systems do not bring outdoor air into the house mechanically. You have to rely on infiltration to get fresh air. However, advanced designs for new homes solve this. They bring outdoor air in through the HVAC system. Some use heat recovery ventilators. These are energy efficient and mitigate energy costs.

For a deep dive, watch the EPA YouTube channel. Look for the webinar by Dr. William Fisk. He is with the Lawrence Berkeley National Laboratory. The topic is “Do Residential Ventilation Rates Affect Respiratory Health?”

Indoor Air Cleaning Systems/Filtration

Air cleaners come in many types and sizes. You can buy a small table-top model or a complex whole-house system. Performance varies a lot. Some are highly effective at particle removal. Others are much less so, especially the table-top models. Keep in mind that air cleaners are generally not designed to remove gaseous pollutants. You need different tools for that.

An air cleaner’s effectiveness relies on specific factors. One is the percentage efficiency rate. This shows how well it collects pollutants from indoor air. The other is airflow volume. This shows how much air it draws through the cleaning element. It is expressed in cubic feet per minute.

You need a balance to get results. A very efficient collector will not be effective if it has a low air-circulation rate. The same is true for the opposite. A cleaner with a high air-circulation rate is useless if the collector is not efficient. Also, think about the future. The long-term performance depends on maintaining the unit. You must follow the manufacturer’s directions.

The strength of the pollutant source changes everything. It determines effectiveness. Table-top air cleaners are weak. They may not remove enough pollution from strong sources nearby. If you have a sensitivity, be careful. The air cleaner is only helpful if you help it. You must make an effort to remove the source.

Labs proved that houseplants reduce chemicals in small tests. But don’t count on them at home. There is no evidence that a normal amount of plants helps. They simply do not remove significant quantities of pollutants. In fact, they can pose a risk. If they are over-watered, the soil gets too damp. This grows microorganisms. It can really bother allergic individuals.

Right now, the EPA says no to air cleaners for radon. Using them to reduce radon levels is not recommended. The problem is simple. They only partially remove radon decay products. They do not diminish the radon entering the home at all. The effectiveness of these devices is uncertain. The EPA plans to do additional research, though. We are checking to see if they could become a reliable means to handle the health risk.