Environment & Science

When it's smoky in SoCal, here's how to check how healthy the air is

The pyrocumulus created by the Pilot Fire glows pink at sunset as the Pilot Fire burns in the San Bernardino National Forest Sunday afternoon August 7th, 2016.
The pyrocumulus created by the Pilot Fire glows pink at sunset as the Pilot Fire burns in the San Bernardino National Forest Sunday afternoon August 7th, 2016.
Stuart Palley for KPCC

Questions about air quality arise whenever plumes of smoke announce a new wildfire burning in SoCal. Is it safe to go outside? Can I send the kids to school? Should we be wearing face masks?

The Environmental Protection Agency publishes information on particulate and pollution levels around the state, called the Air Quality Index, broken down by zip code. (You can get also find that information using KPCC's Fire Tracker tool.)

Interpreting that data to determine whether the air is safe, however, and also what precautions to take, can sometimes be confusing.

To that end, we've rounded up some useful resources to help you breathe easier during a fire.

What's the Air Quality Index? 

AirNow, a resource developed by the Environmental Protection Agency, determines the Air Quality Index for specific locations by taking five different pollutant measurements into account: ground-level ozone, carbon monoxide, sulfur dioxide, particle pollutants PM2.5, and particle pollutants PM10. The last two are most associated with wildfires.

The way each pollutant gets measured can get very technical, so the AQI translates the numbers into a user-friendly zero to 500 scale, says Violette Roberts, community relations and education manager with the Mojave Desert Air Quality Management District.

The AQI always presents the highest number of the bunch. So if a fire is burning, it's likely the numbers will reflect the measurement of particle pollution.

The Air Quality Index always presents the highest number of the bunch at its top. The index takes five different pollutant measurements into account, and rates their make up on a scale of 0 to 500. When wildfires are burning, particle pollutants PM2.5, and particle pollutants PM10 are usually the top air quality concerns.
The Air Quality Index always presents the highest number of the bunch at its top. The index takes five different pollutant measurements into account, and rates their make up on a scale of 0 to 500. When wildfires are burning, particle pollutants PM2.5, and particle pollutants PM10 are usually the top air quality concerns.

What do the AQI numbers mean? 

Generally, if the AQI rating is between zero and 100, the air is considered to be safe for the majority of people to be active outside. When it gets higher than 100, that's when smoke advisories and air quality warnings begin going out from local air quality management districts. 

Here's a chart with a breakdown of how to interpret the AQI rating in your area, and to determine what activities are safe.  

A screenshot of AirNow's breakdown of how to interpret AQI ratings.
A screenshot of AirNow's breakdown of how to interpret AQI ratings.
AirNow

When air quality is affected by a wildfire, South Coast Air Quality Management District generally suggests a few measures for areas impacted by smoke. Those include:

You may be wondering whether you should be wearing a face mask as a precautionary measure. The short answer is probably not, but if you still want to, make sure it's the right kind and that you're wearing it correctly. More on that here

What are 'particulates'? 

We live in a state where wildfires aren't uncommon, so it's not surprising we hear the term particulates on a regular basis. But what does it mean? During wildfires, the particle pollution, or fine particulate matter is measured in two different ways: PM2.5 and PM10. 

Coarse dust particles: PM10

Fine particles: PM2.5

For more on particle pollution, read up on AirNow.gov

Where can I find the AQI rating for my area?

Depending on where you are located, there are a few different ways you can locate your AQI rating.