HEALTHYBUILDINGSCIENCE is committed to facilitating the accessibility and usability of its website,, for everyone. HEALTHYBUILDINGSCIENCE aims to comply with all applicable standards, including the World Wide Web Consortium's Web Content Accessibility Guidelines 2.0 up to Level AA (WCAG 2.0 AA). HEALTHYBUILDINGSCIENCE is proud of the efforts that we have completed and that are in-progress to ensure that our website is accessible to everyone.

If you experience any difficulty in accessing any part of this website, please feel free to call us at (415) 785-7986 or email us at [email protected] and we will work with you to provide the information or service you seek through an alternate communication method that is accessible for you consistent with applicable law (for example, through telephone support).

Request an Inspection

Call us at (415) 785-7986 or click the button below to schedule your building health assessment.

Request a Site Visit

Sign up for our Quarterly newsletter

Subscribe to our e-mail newsletter to receive helpful updates and articles from Healthy Building Science.

Sign Up For Newsletter

We value your privacy.
Your email is never shared or sold.

Keeping Your Air Clean During the California Wildfires

by / Thursday, 17 September 2020 / Published in Healthy Building Inspections & Testing, Industrial Hygiene, News

How to Improve the Air Quality in Your Home and Car During Wildfire Season


The smoke season over the past four years has kept us very busy measuring and mitigating wildfire smoke in the air we breathe. On top of California’s extended drought, this year has also delivered extreme heat and massive lighting storms contributing to one of the worst fire seasons in history….during which we are also marinating in the global Covid-19 pandemic.

The Bay Area has the Worst Air Quality in the World

High levels of wildfire smoke exposure are damaging to our health and have been linked to increased flu diagnoses, increased health burden for people of color, and additional stress on recovery for Covid-19 patients. (Further reading on air quality during forest fires from the New York Times ).

Smoke Plume over the West Coast on September 11, 2020

Thankfully there are relatively simple steps you can take to air seal your home and then filter out the particulate pollution in your air.

After closing windows and doors, find and seal the other air leaks in the house. Common temporary approaches include placing a rolled, damp towel at the bottom of doors/windows, hanging cloth curtains over leaky doors/windows, or using painters tape to seal off gaps. Use the same concept as if you were trying to prevent heated or cooled air from leaking out of your house. If you are in an older building with single pane glass, consider taping a sheet of plastic over the windows or use a window shrink film insulator kit.

You can also take more permanent air sealing measures like installing a door sweep, putting gaskets on electric outlets, and air sealing around plumbing penetrations with air sealing tape or expandable foam. If you have central HVAC you can replace the standard filter with a high-efficiency filter (MERV 13 or higher). I could not find these filters in local stores and had to order them online.

Make a “Clean Room” in Your Home

If you can smell the wildfire smoke, or if you are experiencing the symptoms caused by wildfire smoke, it is worth your time to create a clean room. During a wildfire smoke wave, the EPA states everyone can benefit from the filtered air in a clean room, but it may be most helpful for sensitive individuals and younger/older members of the population.


Choose one room in the house large enough for your family to be in comfortably. Close off doors or passageways with cloth curtains. If available, use a HEPA filter sized for the room. Using a particulate counter our team of industrial hygienists has measured that a consumer HEPA air filter will significantly improve air quality in under 30 minutes. You can also make inexpensive but effective air filters at home by combining your standard box fan with a 20-inch x 20-inch x 1-inch MERV 13 filter and some duct tape.


If it is hot, stay cool with fans and air conditioning. If your HVAC system or window air conditioner has a fresh air option, turn it off or close the intake. Avoid activities that create air pollution: smoking cigarettes, using gas or wood-burning stoves, using aerosol products, frying food, burning candles, and vacuuming. Dust surfaces in the clean room with a damp cloth to keep settled particles from getting back into the air.


Upgrade the Air Filters in Your Car

During the last smoke season, I discovered that I could upgrade the cabin filter in my car with a HEPA filter. The cabin air filter removes debris and particles from the outside air. The “air recirculate” setting in most cars also directs air through the filter before re-entering the cabin.

Replacement cabin HEPA filter ordered online


With some determination, I was able to replace the standard cabin filter in three cars – a Mazda, a Honda, and a VW. It did involve removing a panel from under the glove box and then wedging myself into the footwell upside down to reattach the panel. If you need help replacing your filter, check with your local auto repair shop.


The new HEPA filter on the left and the old dirty filter on the right.


Healthy Building Science offers expert industrial hygiene services including air quality testing for particulates, VOCs, aldehydes, and more. If you’re concerned about the air in your home get a free quote for an air quality inspection and air quality testing. We service all of California and focus primarily on counties surrounding the Bay Area.

Leave a Reply



Subscribe to our e-mail newsletter to receive helpful updates and articles from Healthy Building Science.

You have Successfully Subscribed!