Tired of LA's smoke and smog? Here’s how to find the right air filter for your home

Let’s imagine a common SoCal scenario: You’re getting home. Perhaps it’s wildfire season, with smog looming overhead, or it was a rowdy Fourth of July full of fireworks.

In any case, breathing the air outside just feels gross and heavy on your lungs because, well, it is. What’s best to do in those times is get access to clean air.

Air filters and standalone purifiers at home are one of the more accessible ways for that. Here’s how to find the ones that are right for you.

How the tools help

It all comes down to particle pollution.

These are incredibly small pieces of matter that float around in the air. This has become a daily part of our lives in Southern California — but prolonged exposure to particle pollutants can have serious effects on your health.

If you inhale them, they can affect your breathing and may even be small enough to get into your bloodstream.

These pollutants come into our homes in different sizes, so it’s important to know the strength of your filter or portable purifier. Most devices and inserts will have the ability to filter out large and small particles.

On the small end lies things like virus-size particles, while the larger side can include common allergens, like spores and pollen. The EPA describes the differences through two scales — PM 10 and PM 2.5.

PM 10 is for particulate matter that’s 10 micrometers or smaller, which includes dust and mold. The second group is for fine particles that are 2.5 micrometers or smaller — think tobacco smoke, which can be as small as .01 micrometers, while pet dander can be as large as 100 micrometers. (For context, a grain of sand is about 90 micrometers!)

That means, ideally, whatever device you have in your home should be able to block most of these out.

HEPA filters are considered very strong, and many standalone air purifiers use them.

But for your HVAC system, like central A/C or heaters, that’s where the MERV rating comes in.

What’s a MERV rating?

MERV ratings are the industry standard.

It’s the minimum efficiency reporting values that are used to indicate a filter’s ability to capture particles between 0.3 and 10 micrometers. It ranges from 1 to 16, and the higher the rating, the better the filtration.

These filters also perform best when they’re more than 2 inches thick and changed out frequently (some recommend monthly). Make sure to keep windows closed when these filters are in use in your HVAC, otherwise the filtration effects won’t have much of an effect on your home.

Many HVAC systems can only handle filtration up to a certain point before air pressure builds up. If you slapped the strongest MERV 16 filter on, you’d likely damage your motor because most aren’t set up to support that (and homes don’t usually need it). So before making modifications to your HVAC, make sure to check out your manual and consider talking to a technician.

According to the EPA, most home systems can accommodate up to a MERV 13 filter, which is useful for blocking wildfire smoke and smog.

While MERV is the industry standard, some manufacturers may use their own rating system.

Home Depot, for example, has their own filter performance rating system for ones they sell, and there’s also the microparticle performance rating. Keep in mind these ratings don’t compare one to one, so read the labels of your filter closely to learn what they should block out.

LAist broadcast engineer Rick Esparza and chief engineer Lance Harper contributed to this story.