Qualité de l’air à Malibu

How is the air quality in Malibu?

Malibu is situated on a narrow 21-mile strip of coastline with a population of 12,645. Despite low emissions and seemingly good odds for pollution dispersion, Malibu ranks as one of the most polluted cities in the US. Its greatest challenge is its proximity to Downtown Los Angeles and the dense regional sprawl home to 10 million residents. Weather conditions, such as frequent marine inversions, and the area’s topography, with steep clay canyons to the west, creates pollution-trapping conditions that can allow emissions to accumulate.

Of the six criteria pollutants measured by the US Environmental Protection Agency (EPA) in real time, ozone and PM2.5 pollution often exist at the riskiest levels. Los Angeles County, of which Malibu is a part, failed to meet federal attainment levels for both pollutants in 2019 according to the annual State of the Air report published by the American Lung Association (ALA).¹

PM2.5 is airborne particulate matter measuring 2.5 microns or smaller. Its defining quality is its size, not its composition, because PM2.5 is able to penetrate deep into the lungs when inhaled, sometimes entering the circulatory system and causing a wide range of short- and long-term health effects.

In 2019, Malibu averaged a PM2.5 concentration of 10.6 μg/m³, thus meeting the US EPA target of 12 μg/m³ but failing to meet the more stringent World Health Organization (WHO) standard of 10 μg/m³.

June (12.9 μg/m³), July (16.9 μg/m³), August (13.5 μg/m³), and November (14.6 μg/m³) all experienced particle pollution levels categorized as US AQI “moderate”, air that poses some risk to sensitive groups including children, the elderly, and people with pre-existing cardiovascular or respiratory health conditions.

Malibu annual air quality ratings smooth over high pollution events where air quality reaches “unhealthy” levels or worse. The federal government uses another measure to tally the number of unhealthy pollution days, allowing no more than an average of 3.2 across three years. During the 2016 to 2018 monitoring period, Los Angeles County experienced 13.8 unhealthy PM2.5 days and was thus marked “non-attainment” for short-term particle pollution.

The pollutant of primary concern in Malibu, however, is not PM2.5 but ozone. Ozone is a highly reactive gas commonly referred to as “smog.” Adverse health effects include coughing, shortness of breath, respiratory infection, inflammation, permanent lung damage, lung cancer, and early death.

The Los Angeles basin has been deemed the smoggiest metropolitan area in the United States for 19 of the last 20 years. Across the 2016 to 2018 monitoring period, L.A. County had 111 unhealthy ozone days – in other words, nearly one-third of days in Los Angeles County have unhealthy ozone levels.

While Malibu air quality fares better than the County average as a result of its coastal location and distance from major pollution emitters, there are still significant risks to health in the air, particularly for the city’s sensitive individuals.

Why is Malibu air quality bad?

Located just 30 miles west of Downtown Los Angeles, a majority of Malibu air pollution comes from its sprawling urban surroundings.

Los Angeles county contains 9 of the 15 most polluted cities in the United States for PM2.5. The cities of Maywood, Walnut Park, Eastvale, Colton, Florence-Graham, and Diamond Bar take spots 2 through 7 on the most polluted list respectively. While Malibu’s own air quality fares better as a result of the city’s small population, low emissions, and coastal location, transboundary pollution greatly contributes to the city’s non-attainment status for PM2.5 and ozone pollution.

Regional wildfires, meanwhile, have been a leading cause for “unhealthy” or worse air pollution spikes in Malibu. A combination of dry conditions, increasingly hot temperatures, highly flammable fuels (such as the volatile Douglas fir and ponderosa pine tree species), an accumulation of forest undergrowth, steep canyons and hills, and strong Santa Ana winds combine to make the area highly susceptible to frequent and severe wildfires.²

In recent years, the 2018 Woolsey Fire, which nearly burned 100,000 acres and became L.A. County’s most destructive fire in recorded history at the time, shrouded Malibu in unhealthy smoke for nearly two weeks.³

In 2020, several smaller fires in the region contributed to Malibu air quality advisories, including the Lake Fire, which burned more than 31,000 acres in the Santa Clarita Valley, and the Holser Fire, which burned more than 3,000 acres south of Lake Piru.⁴

Malibu’s own emissions come primarily from motor vehicles, which produce both PM2.5 and a majority of nitrogen oxides, a precursor pollutant for ozone formation.

Data analyzed during the 2020 COVID-19 pandemic lockdown showed how significant reductions in motor vehicle traffic can be. Measures that shuttered non-essential businesses and encouraged residents to stay at home contributed to Los Angeles’s longest stretch of WHO-target air quality (10 μg/m³) on March 7-28, 2020, and may have additionally resulted in March 2020 becoming Los Angeles’s cleanest air quality month on record.

While these reductions ended as the economy opened back up, they highlight a path to maintaining lower emissions in the long term by transitioning the public to more fuel-efficient, low-emission vehicles.

Where is the fire burning in Malibu?

Malibu air quality is subject to fires burning throughout the region, as smoke can travel hundreds, and even thousands, of miles. Though only a temporary source of air pollution, fires burning in Malibu or surrounding areas can often shape monthly and yearly air pollution levels.

Discover the location and severity of wildfires burning near Malibu by searching IQAir’s air quality map. Active fire data is provided by NASA's Fire Information for Resource Management System (FIRMS) satellite observation. Real-time air quality data here is updated hourly, while active fire data is updated every three hours.

California’s fire season tends to run from July through November, when hot temperatures and dry winds are most frequent. Take care to follow Malibu’s live air quality data during these months to stay aware of pollution spikes and reduce your pollution exposure.

How far can Malibu smoke be seen?

Satellite images have shown visible smoke to travel as far as 600 miles from a burn site.⁵ While the visible smoke fades with distance from a fire, the polluting gases and particle pollution (especially fine particle pollution, PM2.5, and ultrafine particle pollution) often continue to exist in wind currents, although invsible to the human eye.

The IQAir air quality map displays wind speed, wind direction, and heat-mapped PM2.5 data to illustrate the flow of emissions from wildfires to surrounding areas, even when forested locations lack ground-based monitoring stations. Discover the far-reaching impact on air quality from active fires, marked on the map as fire icons. Such observations convey that air quality is not simply a local problem, but a global problem, that must be collectively managed.

Is Malibu air quality improving?

Malibu air quality has improved dramatically in recent decades alongside the greater Los Angeles area. The most significant reductions have been noted for PM2.5 pollution.

Since the 2000 to 2012 monitoring period, annual particle pollution levels for Los Angeles County have fallen roughly 50 percent from 24.4 μg/m³ to 12.7 μg/m³ (in the 2016 to 2018 monitoring period). The number of unhealthy PM2.5 days has seen an even more dramatic drop, falling from an average of 84.2 unhealthy PM2.5 days to 13.8 over the same 16-year period.

Reductions in ozone pollution have been slow and relatively stagnant, with much dramatic action still needed before the region can meet federal attainment. From 2001 to 2003, L.A. County averaged 159.3 unhealthy ozone days. In the most recent monitoring period of 2016 to 2018, that number fell to 111 unhealthy ozone days, still 35 times the US EPA target.

Shifts towards electric vehicles represent one of the most significant opportunities for reducing ozone pollution in Malibu as the leading source of ozone precursor pollutants. Los Angeles mayor Eric Garcetti has pushed a sustainability plan that seeks to increase zero-emission vehicles in the city from 1.4% in 2018 to 25% by 2025, and 100% by 2050.⁶ Such improvements are likely to bring significant air quality reductions in the future.

Beginning in October 2020, Malibu will additionally have the option to source 100 percent of their power from renewable energy sources, according to the Clean Power Alliance (CPA). This option will add roughly 7-9 percent to the base cost of energy provided by Southern California Edison (SCE), though CPA will also be providing lower rates for lower percentages of renewable energy in order to attract those who are interested but concerned about the increased cost.

Setting the precedent for such a transition, all Malibu-owned facilities will be powered by 100-percent renewable energy in the 2019 to 2020 fiscal year.

Renewable energy sources and electric vehicles offer an exciting opportunity for Malibu and Los Angeles to tackle high air pollution levels. In addition to the need for these options to be made available and cost-effective, it is up to residents and businesses to adopt these options. The future of Malibu air quality must be a collective effort.

+ Article Resources

[1] American Lung Association. (2020). State of the air – 2020.
[2] Keeley J. (2008). Relative impact of weather vs. fuels on fire regimes in coastal California. USDA Forest Service.
[3] Cosgrove J. (2019, January 6). Firefighters’ fateful choices: How the Woolsey fire became an unstoppable monster. Los Angeles Times.
[4] Cal Fire. (2020). Incidents.
[5] Murphy P. (2020, August 20). Satellite images show the wildfire smoke making California air quality the worst in the world. CNN.
[6] Roth S. (2019, May 6). Los Angeles sets dramatic new goals for electric cars. The Detroit News.
[7] Jansen. (2020, August 15). Residents to have 100 percent renewable energy option. Canyon News.