Los Angeles, California Air Quality
Los Angeles County, California (CA)
↓ Improvingover 10 years
How Los Angeles, California Air Quality Compares
Los Angeles, California's median AQI of 67is 63% worse than the national average of 41. Air quality has improved by 15 AQI points over the past decade. Residents experience an average of 100 unhealthy air days per year, above the national threshold for concern. The primary pollutant of concern is Fine Particulate Matter (PM2.5).
Los Angeles, California Air Quality: The Full Picture
Los Angeles, California (Los Angeles County) holds an AirHistory Air Quality Grade of D (poor, scoring 36 out of 100), built from 10 years of EPA Air Quality System monitoring. Its median AQI fell 15 points between 2014 (82) and 2023 (67), and the five-year median now sits at 75 — inside the "Moderate" band on the EPA scale.
The pollutant driving most of the area's AQI readings is Fine Particulate Matter (PM2.5). In 2023, it set the daily AQI on 203 of 365 monitored days (56% of the year), making it the controlling pollutant for the D grade. The single worst reading logged that year hit an AQI of 210 (Very Unhealthy), while the 90th-percentile day — the level the dirtiest 10% of days reach — came in at 147.
In 2023, Los Angeles County recorded 41 "Good" air days (11% of the 365 days with valid AQI data), 237 "Moderate" days, and 87 days at "Unhealthy for Sensitive Groups" or above. Over the most recent five years on record, monitors logged 501 days that crossed into "Unhealthy for Sensitive Groups" or worse — about 100 per year.
The decade-long trend is improving: median AQI has been dropping by roughly 0.94 points per year. The cleanest year in the record was 2023 (median AQI 67), and the most polluted was 2020 (median AQI 85). Because the data come straight from federally certified EPA monitors, these figures track the California county the monitors physically sit in rather than a city boundary.
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10-Year AQI Trend
The solid line shows the median AQI each year. The dashed line shows the 90th percentile (worst 10% of days). This area has seen measurable air quality improvement over the decade.
Air Quality Day Breakdown
Number of days per year in each EPA AQI category. Green = Good (AQI 0-50), Yellow = Moderate (51-100), Orange = Unhealthy for Sensitive Groups (101-150), Red = Unhealthy or worse (151+).
Year-by-Year Data
| Year | Median AQI | 90th Pct | Max AQI | Good Days | Moderate | Unhealthy+ | Pollutant |
|---|---|---|---|---|---|---|---|
| 2023 | 67 | 147 | 210 | 41 | 237 | 87 | PM2.5 |
| 2022 | 74 | 140 | 209 | 17 | 254 | 94 | Ozone |
| 2021 | 79 | 143 | 281 | 9 | 259 | 97 | PM2.5 |
| 2020 | 85 | 166 | 250 | 35 | 194 | 137 | Ozone |
| 2019 | 72 | 136 | 201 | 34 | 245 | 86 | PM2.5 |
| 2018 | 78 | 130 | 201 | 7 | 250 | 108 | PM2.5 |
| 2017 | 79 | 156 | 224 | 9 | 237 | 119 | PM2.5 |
| 2016 | 77 | 134 | 226 | 7 | 255 | 104 | PM2.5 |
| 2015 | 80 | 151 | 203 | 3 | 230 | 132 | PM2.5 |
| 2014 | 82 | 143 | 205 | 8 | 250 | 107 | PM2.5 |
What This Means for Los Angeles County Residents
Los Angeles, California has received an Air Quality Grade of D (36/100) based on a decade of monitoring data from the EPA's air quality monitoring program. The current median AQI of 67 falls in the "Moderate" range.
Encouragingly, air quality here has been improving, with the median AQI dropping by 15 points over the monitoring period. This trend suggests continued investment in emission controls and cleaner energy.
The primary pollutant affecting this area is Fine Particulate Matter (PM2.5). Over the past 5 years, this area has averaged 100 unhealthy air quality days per year, days when sensitive groups (children, elderly, those with respiratory conditions) should limit outdoor activity. The American Lung Association's State of the Air report provides additional context on long-term health risks from air pollution exposure.
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Frequently Asked Questions
Los Angeles, California has a current median AQI of 67, which falls in the "Moderate" range. The area has received an Air Quality Grade of D (36/100) based on 10 years of EPA monitoring data.
Air quality in Los Angeles, California is improving over the past decade. The median AQI has changed by -15 points from 2014 to 2023.
Los Angeles, California averages 100 unhealthy air quality days per year over the past 5 years. On these days, sensitive groups including children, the elderly, and those with respiratory conditions should limit outdoor activity.
The primary pollutant affecting Los Angeles, California is Fine Particulate Matter (PM2.5). This is the dominant contributor to elevated AQI readings in the Los Angeles County area.
Los Angeles, California averages 100 unhealthy air days per year. With frequent unhealthy air days, asthma patients should use a HEPA air purifier indoors and check AQI before any outdoor activity. The primary pollutant is Fine Particulate Matter (PM2.5), which is a known asthma trigger.
With a median AQI of 67 (Moderate), outdoor exercise in Los Angeles, California is safe most days, though sensitive individuals should check daily AQI before intense workouts. Los Angeles, California averages 100 days per year when athletes should move workouts indoors.