How is Los Angeles Air Quality?
Los Angeles air quality exceeded the WHO annual limits on about two-third of days in 2020. Los Angeles air quality averaged nearly over twelve times the daily recommended limit of dangerous PM2.5 pollutants on its worse day in 2020.
Current Air Quality in Los Angeles
67% Of Days in Los Angeles More Polluted Than WHO Target
Los Angeles’s daily air quality levels exceeded the World Health Organization (WHO) annual limit on 67% of days in 2020. Some days in Los Angeles saw air pollution levels reaching “very unhealthy” levels, far above safe levels.

Historical Air Quality Readings for Los Angeles
Is Los Angeles Air Quality Improving?
In the last three years, data shows little improvement in Los Angeles air quality. Although 2019 saw a near 13% improvement from 2018, 2020 levels worsened from 2019 levels.

Why Is the Air Quality Bad Today in Los Angeles?
Weather plays a big role in how the air quality is in Los Angeles each day. The amount of sun can affect how much ozone there is, and wind and rain can affect PM2.5 and particulate air pollution to varying degrees.
Air pollution levels can change quickly, with levels often varying widely throughout the day. Data shows there even appears to be times of the day where air pollution tends to be lower compared to other times.
Below shows how PM2.5 air quality levels around the world tend to vary throughout the day. PM2.5 levels have a tendency to be slightly lower in the afternoon compared to other times of the day. But this is a general trend, Los Angeles PM2.5 AQI levels will not follow this trend every day.

How California Wildfires Affect Los Angeles Air Pollution Levels
Outside of weather, wildfires are another factor that can significantly affect Los Angeles air. The worst wildfires typically occur in the months of June to September.
Read More: How Wildfires in California Affect Air Pollution Levels
Below shows how wildfires in September of 2020 affected air quality levels all across the west coast.
Los Angeles Air Pollution: The Negative Health Effects

This analysis of Los Angeles’s air quality is based on PM2.5 pollution. These are particles smaller than 2.5 microns in diameter that can penetrate deep into the lungs and even enter the bloodstream.
Studies have shown that PM2.5 raises blood pressure, inflammation, and rates of heart attacks and strokes.
WATCH: Why Is PM2.5 So Harmful to Us?
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Protect Your Health in Los Angeles
Despite the harms of PM2.5, placebo-controlled studies of air purifiers have found that removing particulate in the home has positive effects on blood pressure, inflammation, and immune response.
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