The Air Outside Is Hazardous. Here Are 6 Things Every Homeowner Should Do Today

Smoky, hazy outdoor air can travel indoors faster than most homeowners realize. While it’s impossible to make a home completely airtight, there are steps you can take to keep outdoor pollution from impacting your family’s health and comfort. The right filtration approach and a few preventive measures can make a significant difference in your indoor air quality (IAQ).

1. Check the Air Quality Before Opening Anything

Once polluted air gets into your home, it takes time to filter out wildfire smoke, dust, smog, industrial pollution, and other types of pollutants. Because of this, it’s a good idea to check the air quality index (AQI) in your area before opening any doors or windows. You can do this through AirNow, a weather app, or local alerts. If the air reaches an unhealthy or hazardous AQI, you should avoid letting outdoor air into the home. 

2. Close and Latch Windows and Exterior Doors

When you close your windows and exterior doors, make sure to latch them completely. This compresses the weatherstripping and creates a better seal. Any small leak can allow smoky, polluted air to enter your home, so don’t forget to close the following openings.

• Attic access points
• Basement windows
• Garage service doors
• Patio doors
• Pet doors

3. Check Your HVAC Filter and Run the Fan

With a forced-air heating, ventilation, and air conditioning (HVAC) system, indoor air circulates through the filter. While the exact timeline varies based on usage and the manufacturer’s requirements, filters should be replaced every 30 to 90 days. They should be changed earlier if they are dirty or clogged.

MERV ratings represent how efficient the filter is at removing contaminants from the air. The higher the number, the more effective it is. For example, MERV 11 filters offer better filtration than lower-rated filters. If your system can handle it, a MERV 13 filter is often recommended for smoke particles. However, higher-efficiency filters should only be used if your system is capable of handling them.

Many HVAC systems have a fan mode that can be switched to “on” or “circulate.” During periods when the AQI is poor, keeping the fan on ensures that pollutants are being constantly removed from the air.

4. Use a Portable HEPA Air Purifier Where People Spend the Most Time

During wildfire season or allergy season, a portable HEPA air purifier can help you clean the air in your bedroom, living room, or another room you use the most. You can also use these devices to make a temporary clean-air room as long as the purifier is appropriately sized for the room. To maintain clean air, you’ll also need to keep the doors and windows closed in that space.

Your purifier can only clean the air properly if it is maintained well. As part of your maintenance process, remember to check the purifier filter regularly and replace dirty filters. 

Ozone-generating air cleaners can release ozone into the air. For your safety, you should generally opt for a HEPA air purifier instead.

5. Pause Systems That Pull Outdoor Air Inside

Some systems, such as whole-house fans, are designed to pull in fresh air from the outdoors. While this is normally safe, it is not ideal when the outdoor air becomes hazardous. Check to make sure the following systems or settings are temporarily turned off until the AQI improves.

• Whole-house fans
• Heat recovery ventilators (HRVs)
• Energy recovery ventilators (ERVs)
• Fresh-air intake settings
• Evaporative coolers

Once the air quality is back to safe levels, you can turn on your normal ventilation settings again.

6. Limit Indoor Pollution Sources and Exhaust Fan Use

Indoor air can also worsen from day-to-day activities. During periods of poor AQI, it’s a good idea to be cautious about the following activities.

• Burning candles or incense
• Aerosol sprays
• Smoking or vaping indoors
• Fireplace or wood stove use
• Harsh cleaning fumes
• Frying or broiling food

Unfortunately, other activities can create negative air pressure and pull in air through leaks. Powerful range hoods, dryers, bathroom fans, and central vacuums can pull in polluted replacement air.

Obviously, there are times when you need to create negative air pressure. If you are cooking or showering, range hoods and bathroom fans help to remove pollutants and moisture from the air. However, you should avoid running them for any longer than necessary when smoke and poor AQI events are present.

Bonus Step: Create One Cleaner-Air Room

If you don’t have a whole-home air purifier, one of the easiest ways to maintain cleaner air during bad AQI days is by creating a clean-air room. When the air quality is poor, you can use this space for sleeping or spending the majority of your time.

In your chosen space, keep the door closed and windows shut. Ideally, you should pick a room that doesn’t have a fireplace. Keep pets, candles, smoke, and strong cleaning products out of the room. Then, turn the HEPA air purifier on to run continuously. 

What Not To Do When Outdoor Air Is Hazardous

When the outdoor air is hazardous, there are a few things you should avoid doing.

• Do not open your windows to air out your home until outdoor conditions improve.
• Do not use a whole-house fan.
• Do not ignore hazy weather or unusual outdoor odors.
• Do not assume that your current HVAC filter is enough to remove all smoke particles.
• Do not run ozone air cleaners.

When Can You Open the House Again?

You can open your home once the outdoor AQI has improved and local officials have removed the air quality alerts. Additionally, the smoke smell or haze needs to be gone as well. Once the air is cleaner, you can ventilate your home and then switch to your normal HVAC and ventilation settings.

FAQs

Should I run my HVAC when the air outside is hazardous?

Yes, it is generally better to recirculate air through your HVAC system when outdoor air is unhealthy. For the best results, make sure to use a clean, compatible filter.

Should I turn off my HRV or ERV during wildfire smoke?

You should temporarily switch it off to reduce the amount of smoke that is coming in from outside. Once the air quality improves outside, you can turn it on again.

Is a box fan filter safe to use?

A properly built DIY box-fan air cleaner can reduce particles in a single room, but it must be assembled securely and monitored while in use. Whenever possible, portable or whole-home air purifiers are generally a better option.

Can indoor air be worse than outdoor air?

Absolutely. Around the world, the World Health Organization estimates over 2.9 million deaths occur per year because of household air pollution. Cooking, dust, cleaning products, smoke, moisture, and poor ventilation can directly impact the air quality in your home.

What is the fastest thing I can do right now?

For an immediate solution to your IAQ issues, close and latch your doors and windows. Then, you should set your HVAC system to circulate the air and verify that the filter is clean and appropriately sized. To make a clean-air room, use a HEPA purifier in a space that has no fireplace and minimal windows.

Protect Your Respiratory Health From Poor Air Quality

While homeowners can’t control what happens with outdoor air quality, checking AQI, sealing openings, running HVAC filtration systems, using HEPA purification, pausing outdoor-air systems, and lowering indoor pollution can reduce the effect outdoor air has on your home.

Concerned about smoke or poor airflow in your home? Schedule an HVAC or home performance inspection to find out how your home manages outdoor air quality events.