Thanks to Don Hester of NCW Home Inspections for sharing with us his thoughts on wildfire smoke and indoor air quality.
As most of us in Leavenworth and Wenatchee have seen, breathed and muddled through, fire season and the related wildfire smoke has been more severe in the last several years.
Wildfires as of Aug 20th, 2018
With air quality reaching “Hazardous levels” it is recommended to stay indoors.
First what are we dealing with?
Wildfire smoke is a complex mixture of various molecules and particulate matter, mainly consisting of carbon dioxide (CO2), water vapor, carbon monoxide (CO), hydrocarbons, organic chemicals, nitrogen oxides (NOX), trace minerals, and particulate matter.
From the Washington State Dept of Health (DOH)
“Particles with diameters less than 10 microns (PM10) are upper respiratory tract and eye irritants. Smaller particles (PM2.5) are the greatest health concern – they can be inhaled deep into the lungs, and can affect respiratory and heart health. Carbon monoxide, a colorless, odorless gas produced by incomplete combustion, is a particular health concern and levels are highest during the smoldering stages of a fire.”
What should we do about wildfire smoke and indoor air quality?
To deal with the outdoor pollution we should stay indoors and close all windows. We now are going to rely on mechanical ventilation to help deal with the air quality. We will want to run our Air Conditioner and close off the fresh air intake.
Most people do not give much thought to their air filters on the HVAC system but now is time to think about them. Upgrading you filter to one with a “Minimum Efficiency Reporting Value” of (MERV) 8 is recommended.
This is where system design and filtration collide. When we increase filtration (MERV Rating) it will put a restriction on the air handler causing it to work harder. Having a larger filter pleat help with air passing through the filter. Ideally, we should have a 2 inch or better pleat. The larger filters such as 4 and 5-inch pleats will give you even better ability to filter your air. We will need to change the filters more often
By using HEPA filters with activated charcoal or alumina, especially those impregnated with potassium permanganate or zeolite will adsorb gases in the smoke, including NOX and some of the volatile organic compounds (VOCs) such as benzene as well as removing fine particulates.
These filters will be more expensive and most likely will need more frequent replacement.
If your system can not keep up or you do not have a central air system, the use of portable high efficiency HEPA air cleaners can be used. These typically run from $100 to $1000 dollars.
From the EPA-
“Room air cleaner units should be sized to provide a filtered airflow at least two to three times the room volume per hour. Most portable units will state on the package the unit’s airflow rate, the room size it is suitable for, its particle removal efficiency, and perhaps its Clean Air Delivery Rate, or CADR. The CADR is a rating that combines efficiency and airflow.”
Fire Camp in Entiat Washington
Lastly you want to keep your home clean, but you do not want to vacuum the house, unless you are using a HEPA-filter equipped vacuum. The activity will stir up more dust and particulates and will just create more indoor air pollution.
Here are a few links to read up on dealing with the wildfire smoke and indoor air quality.
NCW Home Inspections, LLC is a Licensed Washington State Home Inspection service located in Wenatchee Washington