Wildfire Smoke and Your Health - Filters

Alright! You did it. You are hanging in there. Let’s get to it.

Last time, I suggested you get a better filter for your HVAC. You’re probably thinking “that’s great, but how do I know what filter to choose?” Well, here’s a very quick primer. Air filters are rated using the Minimum Efficiency Reporting Value (MERV).  Basically, the higher the MERV number, the smaller the particle that the filter can catch. For our purposes, the minimum MERV that removes fine particulates from smoke is MERV 13. If you wanna “go big or go home” though, a MERV 17 will get you HEPA levels of removal. Know that a MERV 13 can be effective at removing the fine particulates IF you are recirculating the air through the filter over and over and over. The more times it passes through, the cleaner it will be. Of course, they are so efficient that they will need to be changed frequently thanks to all the stuff that’s accumulating. Here’s a chart to help you understand the MERV rating a little bit better:

MERV Rating	Dust Spot Efficiency	Controlled Contaminant	Typical Setting Used
20	n/a	Small than 0.03 pm particulate size	Cleanrooms
17	n/a	All combustion smoke
15	>95%	Bacteria	Hospitals
13	89-90%	Sneeze droplets	Superior commercial buildings
8	30-35%	3.0-10.0 pm particulate size	Commercial buildings
3	<20%	Dust mites, sanding dust	Residential

http://www.mechreps.com/PDF/Merv_Rating_Chart.pdf

As you can see, upgrading from the typical factory installed filter to higher rating will get you significant improvements in catching the concerning materials in smoke. The last thing I’ll say about MERV filters is that you should probably have a talk with your HVAC technician first. Not all the systems out there can handle a filter with a higher rated MERV. And blowing out your unit would ruin all the work you were trying to do.

Alright, we’ve covered what the pollutants in smoke are and why they aren’t good for you. We’ve covered what you can do to protect yourself. Next time let’s talk about how we measure these pollutants and where you can find that information. As always, go to Idaho Health and Welfare’s site for any more health concerns. You can also find some good links under the “Smoke and Health” tab up top. Take care and see you soon!