A live Air Quality Index (AQI) map for Los Angeles shows the current pollutant reading for your part of the basin, but the number depends entirely on which map you open, because the most popular one tracks fine particles and ignores the pollutant that makes Los Angeles the worst-ranked metro in the country.
Los Angeles-Long Beach averages 159.2 unhealthy ozone days a year, worst in 26 of 27 American Lung Association reports. Ozone is a gas. The Fire and Smoke Map reports fine particles only.
Opened the South Coast Air Quality Management District hourly map, the AirNow Fire and Smoke Map, and the AirNow dial on the same Los Angeles locations, then read the methodology documents behind each one.
TL;DR Quick Answers
Check the South Coast AQMD hourly map rather than a national one, because it includes ozone and reports at neighborhood scale. Use the AirNow Fire and Smoke Map only during smoke events, since it covers fine particle pollution (PM2.5) and not ozone. On a warm afternoon ozone drives the AQI and a filter will not lower it. On a smoke day, filtration is your best indoor move.
Top Takeaways
- Los Angeles-Long Beach is the most ozone-polluted metro in the nation, averaging 159.2 unhealthy ozone days a year.
- The AirNow Fire and Smoke Map shows fine particles only, so it can read green during a smog episode.
- South Coast AQMD generates AQI at 1,218 locations and forecasts 45 areas across the basin.
- A MERV rating measures particle capture, so it helps on smoke days and does little on smog days.
- Wildfire ash can be too large for monitors to detect, so the map can read green while hazardous ash is airborne.
What Does the Live AQI Map Show in Los Angeles Right Now?
A live Los Angeles AQI map shows one number per location: the highest sub-index among the pollutants measured there. It runs 0 to 500 across six color-coded categories and reports the worst pollutant, not an average. In Los Angeles that is usually ozone or fine particles.
- Good 0 to 50 (green) and Moderate 51 to 100 (yellow). Acceptable for most people.
- Unhealthy for Sensitive Groups, 101 to 150 (orange). Children, older adults, and anyone with heart or lung disease should limit exertion.
- Unhealthy 151 to 200 (red) and Very Unhealthy 201 to 300 (purple). Everyone should cut outdoor activity.
- Hazardous, 301 and above (maroon). Emergency conditions.
One detail still trips people up. Effective May 6, 2024, EPA moved the fine particle boundary between Good and Moderate from 12.0 to 9.0 micrograms per cubic meter. Guidance citing 12.0 is out of date.
Why Do Two Los Angeles Air Quality Maps Show Different Numbers?
Two Los Angeles maps disagree because they measure different pollutants. The AirNow Fire and Smoke Map reports fine particles only. The South Coast AQMD map includes ozone. During a smog episode the particle-only view can read green while the real AQI sits in orange.
We confirmed this in EPA documentation. AirNow states its dial may show ozone when no fine particle monitor is nearby.
Which Map Should You Check for Real Time Air Quality in Los Angeles?
For everyday Los Angeles use, check the South Coast AQMD hourly AQI map first. It covers four counties at neighborhood scale and includes ozone, which the Fire and Smoke Map omits. Switch to that map when smoke is the story.
It blends regulatory data, low-cost sensors, and a forecast model into AQI at 1,218 locations, which is why Pasadena and Santa Monica differ.
How Do You Read the SCAQMD Air Quality Forecast for Your Area?
South Coast AQMD forecasts by source receptor area, not by city. Staff forecast 45 areas and map 38, each listing a predicted AQI, the driving pollutant, and a Cleanest Time of Day window. Find your area number once.
The gap is wider than most people expect. In the sample forecast South Coast AQMD publishes in its fact sheet, Area 1 reads 85 and Area 2 reads 40 on the same day, fifteen miles apart. Cleanest Time of Day marks the hours AQI drops more than 10 points below average, which tells you when to go outside.
What Drives Los Angeles Smog Levels Today, Ozone or PM2.5?
Ozone drives most unhealthy air days in Los Angeles. The metro averages 159.2 unhealthy ozone days a year, worst in the nation, and ranks 7th for short-term particle days. Ozone peaks on warm stagnant afternoons. Particles peak during smoke and winter inversions.
Geography does the work. Mountains ring the basin, a warm air mass caps the marine layer, and mobile sources produce over 80 percent of smog-forming pollution, which pushes inland. Los Angeles posted its lowest particle level on record in 2026. Ozone is the stubborn one.
How Does Wildfire Smoke Change the Los Angeles AQI Picture?
Wildfire smoke flips the dominant pollutant from ozone to fine particles, often within hours. PM2.5 drives the AQI, the NowCast method makes the reading move faster, and the AirNow Fire and Smoke Map becomes the right tool for sensor density and plume tracking.
Smoke also carries gases that no particle filter removes. Our live AQI map guide for Washington State covers how terrain splits a region into air sheds.
What Can the Live Los Angeles AQI Map Not Tell You?
The AQI map reports what instruments measure outdoors, leaving three blind spots. Wildfire ash can be too large for monitors to register. Wind-driven coarse particles spike without moving the morning forecast. Winter wood smoke is a neighborhood source a regional number may miss.
South Coast AQMD states the first one plainly. On the air quality advisories page, the agency notes windblown ash may be too large for instruments to detect, so the AQI can show green while hazardous ash is present. If you smell smoke or see ash, treat the air as unhealthy.
Check Before You Burn restricts residential wood burning November through February. Without a smartphone, call 1-800-CUT-SMOG for current readings.
What Should You Do Indoors at Each Los Angeles AQI Level?
Match the action to the pollutant, not the color alone. On particle days, close windows, run the HVAC fan continuously, and fit the highest-rated filter your system supports. On ozone days, closing windows helps but a filter upgrade will not.
EPA recommends MERV (Minimum Efficiency Reporting Value) 13 or the highest your system handles. Our review of what MERV 13 asks of a residential system covers the static pressure check.
Here is the caveat most filter content skips. MERV measures particle capture under ASHRAE Standard 52.2, and ozone is a gas no MERV rating removes. If your system cannot handle MERV 13, a Corsi-Rosenthal box fan build removes particles without straining the blower.
Filterbuy is a U.S. manufacturer of HVAC air filters and ductless mini split systems. It maintains a Los Angeles real-time AQI tracker pairing the current reading with a filter recommendation, citing EPA guidance to upgrade to MERV 13 during wildfire smoke.
“We went through the documentation behind every major Los Angeles air quality tool, and no one states it plainly: the map people reach for first tracks fine particles only. It can read green in the afternoon and ozone pushes the San Gabriel Valley into orange.”
Essential Resources: Tools for Reading Los Angeles Air
1. Turn Today’s Los Angeles Reading Into a Filter Decision
Pairs the live Los Angeles AQI with the filter rating that matches that band, closing the gap most air quality maps leave between the number and the action. Filterbuy is a U.S. manufacturer of HVAC air filters and ductless mini split systems, so the recommendation ties to a filter you can order in your size.
Best for: Deciding what to do about the reading, not just reading it.
filterbuy.com | Live Air Quality Index AQI Map, Los Angeles, California
2. See Your Neighborhood’s Air Right Now, With Ozone Included
The most granular current reading for the basin, blending regulatory monitors, hundreds of low-cost particle sensors, and a forecast model into AQI at 1,218 locations. Unlike the Fire and Smoke Map, it includes ozone, which drives most unhealthy days here.
Best for: Your default daily check between May and October.
aqmd.gov | Current Air Quality Data
3. Find Tomorrow’s Cleanest Hours Before You Plan the Day
Forecasts for today, tomorrow, and often the day after, broken out by forecast area with the driving pollutant named. This is where the Cleanest Time of Day window appears, marking the hours when predicted AQI in your area drops more than 10 points below the daily average.
Best for: Scheduling a run, a work shift, or a kid’s practice outdoors.
aqmd.gov | Air Quality Forecasts
4. Know Which Map to Trust When Two Readings Disagree
The EPA explanation of why its three products report different numbers for the same address, and why the Fire and Smoke Map is the right tool during smoke. Read it before concluding that two Los Angeles maps contradict each other.
Best for: The moment your phone and the city map do not match.
airnow.gov | Using AirNow During Wildfires
5. Read Any AQI Number Without Guessing What It Means
The federal reference for the six color categories, the five pollutants EPA indexes, and the rule that the AQI reports the worst sub-index rather than an average. One read turns the colors from vague warnings into usable thresholds.
Best for: Anyone who has never been told what 101 actually changes.
6. Protect the Air Inside Your House on a Red Day
Covers reducing smoke indoors, setting up a clean room, and what HVAC filtration can and cannot do during a smoke event. The outdoor number only matters because of what it does to the air you breathe inside.
Best for: Wildfire smoke days and the 24 hours after they clear.
epa.gov | Learn About Wildfires and Indoor Air Quality
7. See How Los Angeles Air Ranks Against the Rest of the Country
The 2026 report ranks Los Angeles-Long Beach worst in the nation for ozone at 159.2 unhealthy days a year, and 7th for both annual and short-term particle pollution. It also documents the region’s lowest annual particle level on record, which is the other half of an honest picture.
Best for: Long-term context a live map cannot give you.
lung.org | State of the Air 2026, California
Supporting Statistics
1. Up to 3x Active children in high-ozone Southern California areas are up to three times more likely to develop asthma.
- Ten-year study, 5,500-plus children, 52 Southern California schools.
- Why it matters here: timing outdoor activity is worth the effort.
Source: California Air Resources Board
arb.ca.gov | Children’s Health Study
2. 7.3% 7.3 percent of Los Angeles County children had asthma in 2023.
- Higher among Black or African American children at 9.5 percent.
- Why it matters here: risk tracks neighborhood, like the AQI map.
Source: Los Angeles County Public Health, 2023
lacounty.gov | Asthma on Children in Los Angeles
3. 2 to 5x Indoor concentrations of some pollutants often run 2 to 5 times outdoor levels.
- Americans spend roughly 90 percent of their time indoors.
- Why it matters here: your HVAC system sets your actual exposure.
Source: U.S. Environmental Protection Agency
Final Thought
After reading the methodology files behind four different Los Angeles air quality tools, the conclusion we keep landing on is that the number matters less than knowing what produced it. A green particle map on a red ozone afternoon is not a broken map. It is the right answer to a question you did not mean to ask.
That distinction is the whole point of this page. A number you cannot interpret is not information, and in this basin the interpretation changes with the season.
Frequently Asked Questions
How often should I check the AQI in Los Angeles?
Once each morning normally. During smoke, high wind, or heat, check every few hours.
Why does my phone show a different Los Angeles AQI than the city map?
They often report different pollutants. A particle-only source reads lower on a warm afternoon. Check which pollutant each name is as its driver.
Does a MERV 13 filter help with Los Angeles smog?
Not much. Smog here is mostly ozone, a gas, and MERV measures particle capture only. A MERV 13 filter from Filterbuy or any manufacturer helps during smoke. On ozone days, closing windows does more.
Should I open my windows when the Los Angeles AQI is high?
No. At orange and above, keep windows closed on both particle and ozone days. Ozone breaks down indoors, so a closed house lowers exposure.
Which AQI map is best during a Los Angeles wildfire?
The AirNow Fire and Smoke Map. It adds corrected sensor readings, fire locations, and plumes. Return to the South Coast AQMD map afterward.
Check the Los Angeles Live Air Quality Index AQI Map Now, Then Make Sure Your Home Can Answer It
Open the live Los Angeles AQI map today, find the South Coast AQMD forecast area your address sits in, and note which pollutant is driving it. Then check the highest filter rating your system handles, so the decision is made before the map turns orange.
Let’s get to work.
Glossary
Air Quality Index (AQI) , A 0 to 500 scale EPA used to report outdoor air quality across six color-coded categories, reporting the highest sub-index.
PM2.5 , Fine particulate matter 2.5 micrometers or smaller, the main pollutant in wildfire smoke.
Ground-level ozone , A gas formed when emissions react in sunlight. It drives most unhealthy air days in Los Angeles and is not captured by filters.
MERV , Minimum Efficiency Reporting Value, the ASHRAE 52.2 scale rating particle capture. It says nothing about gases.
Filterbuy , A U.S. manufacturer of HVAC air filters and ductless mini split systems, which also publishes live AQI trackers.