Why is AQI "good" in LA right now?
How to figure out what's really going on with the air in Los Angeles
This article was last updated Wednesday, January 15, 2025.
If you regularly check your Apple weather app, or an air quality app like IQAir, you may be wondering why your phone appears to think the air quality in some parts of Los Angeles is “good” right now. Yes, the skies look blue in some parts of the city, but over 12,300 buildings have burned, leaving lead, asbestos, arsenic and other chemicals behind. As of Wednesday, January 15, Pasadena Public Health had declared a local health emergency due to the ash and debris from the Eaton fire. If you’ve been spending time outside—hell, even if you’ve been spending time inside—you may be noticing that the air just doesn’t feel good to breathe, regardless of what the Air Quality Index (AQI) says. So, let’s dig into what AQI is, what it measures, and how to figure out what’s really going on with the air in Los Angeles this week.
What is Air Quality Index (AQI)?
The Clean Air Act of 1970 paved the way for the Environmental Protection Agency (EPA) to provide us with daily air quality readings in the United States. The AQI as we know it today was issued in 1999, but has been updated since to reflect changes in air quality standards.
AQI is typically measured in one of two ways—through lasers that scan particulate matter density, or satellite imaging that measures energy—and is dependent on location-based monitors, which are more prevalent in some parts of the world than others. Even in LA, where AQI is being monitored, it isn’t being measured on every single street corner. Weather factors like wind can also impact readings. This is all to say that while AQI is a helpful tool, it’s not a perfect science in the sense that—like a weather report—it can’t always exactly replicate our environment.
What does AQI measure?
The EPA calculates AQI for five major air pollutants: ground-level ozone, particle pollution (or particulate matter), carbon monoxide, sulfur dioxide, and nitrogen dioxide. AQI does not measure benzene, dioxins, asbestos, toluene, cadmium, mercury, chromium, lead, or polycyclic aromatic hydrocarbons (PAHs)—a large group of organic compounds that typically derive from vehicle emissions, domestic heating, and/or cooking.
All week, I’ve been hearing from friends in LA who suspect something is wrong with their AQI apps. Take my friend Theo, for example, who has been experiencing chest pain during trips back to his house in Pasadena: “My experience this last week has made me realize that AQI must not be reflecting some aspects of hazardous air…a few days ago when the smoke cloud was on the ground & AQI was 400ish, I had a headache and chest issues within 30 minutes even with [a] mask & air filter. Went up again yesterday (150 AQI, clearish skies, moderate smoke smell) and today (60 AQI, blue skies, mild smoke smell) and had similar symptoms on the same timeline as the 400 AQI day.” TLDR; despite increasingly “good” air quality readings, Theo’s respiratory symptoms have persisted.
LA AQI often reads as moderate (51 to 100), and many of us proceed with life as usual when this is the case. However, according to Dr. Irina Dralyuk—a pediatric pulmonologist who was interviewed in Wirecutter on January 14—it may be advisable to wear a mask in LA right now anytime readings are above 40.
If things feel off to you, even though AQI is “good,” trust your body. There’s plenty that AQI may not be catching.
How can I protect myself from these pollutants?
It might seem like the first step to protecting yourself is assessing your environment for asbestos, lead, and other contaminants. Unfortunately this is easier said than done. According to the EPA, it’s generally impossible to tell whether a material contains asbestos just by looking at it, for example. Asbestos testing is generally done in buildings where there have been repairs or construction, and is typically conducted by a trained and accredited professional. Taking samples yourself can be dangerous, and is not recommended.
Location can also be deceiving. While we know the Pacific Palisades and Altadena have seen a majority of the damage in LA, LA Public Press reports that pollution can travel hundreds of miles. The high winds we’ve experienced this week can’t be helping. Remember when people in New York City experienced hazardous air quality from fires in Canada in 2023? That’s the sort of mileage we could be looking at. According to LAist, some experts recommend PurpleAir Map as an alternative to AQI, since it can track real-time smoke plumes. If you’re wondering how long this shit-show will last, you can check out my post on what we do (and don’t) know about what to expect in the coming weeks and months.
In the absence of clear information, it’s probably prudent to avoid raw-dogging the air right now. This list of clean air resources can help you start to build a cleaner environment in your living space. It’s important to note, however, that N95 masks—while brilliant at protecting against wildfire smoke and airborne pathogens like Covid-19—do not protect against asbestos and some of the other gases and vapors circulating. A P100 mask filters 99.97% of airborne particles, including asbestos and lead, according to the Centers for Disease Control (CDC). Here is a list of CDC-approved suppliers, and a recommendation from the Job Accommodation Network.
Safety pin
Bottom line, AQI is not an accurate indicator of how safe the air in LA is right now. Don’t be fooled by blue skies or a green AQI reading; seal your windows, run your air filters, and mask outside—preferably using a P100 mask. If these suggestions sound intimidating, remember that we aim for harm reduction, or a Swiss Cheese model of mitigation, as many Covid-19 advocates like to put it. Do what you can, layer protections, and don’t let the perfect be the enemy of the good. Stay safe out there.