Qualité de l’air à Irvine

Does Irvine have good air quality?

When public records began in 2000, Irvine’s air quality index (AQI) averaged 68 (“moderate”) Irvine AQI has improved dramatically since then, largely as a result of the 1990 amendments to the Clean Air Act that increased air quality monitoring, emission control, and enforcement. In 2019, Irvine’s average AQI was 41 (“good”), a 40 percent improvement from nearly two decades earlier.

Irvine air quality is markedly better than the air quality of its neighbor, Los Angeles, which averaged an AQI of 52 (“moderate”) during the same 2019 monitoring period. Irvine’s improved air quality, compared to Los Angeles’ air quality, is attributable to Irvine’s lower population density. Less density often translates to less traffic congestion and reduced personal emissions.

Irvine’s air quality is typically reported using the air quality index (AQI). The AQI scale ranges from 0–500, where higher values indicate greater pollution concentrations and increased health risks. The AQI formula is a linear equation, so it is possible for the AQI to break 500. Although this is rare, such hazardous levels have been recorded as recently as late 2020 during California’s record-breaking wildfire season. For example, the air quality in Mammoth Lakes, a region in Northern California popular with tourists for outdoor recreation, reached a “beyond index” AQI of 1205 on October 19th, 2020.¹

The AQI formula translates concentration values from six criteria pollutants into an index score. The overall AQI is derived from the pollutant with the highest individual index score. The six key pollutants include two particle sizes, PM2.5 and PM10, and four common gases — ozone (O₃), NO₂, SO₂, and carbon monoxide (CO).

PM2.5 refers to fine particle pollution measuring 2.5 microns or smaller in diameter. These particles include ash, dust, dirt, chemicals, viruses, or bacteria. The near-microscopic size of PM2.5 allows these particles to penetrate the bloodstream upon inhalation, causing far-reaching health effects throughout the body and brain. PM2.5 is often described as the most dangerous pollutant to health because of its small size and abundance.

Ground-level ozone is another harmful pollutant and significant component of smog in big cities. Unlike atmospheric ozone that shields Earth from UV radiation, ground-level ozone does not provide any environmental benefits. Rather, when inhaled, ground-level ozone irritates the eyes and throat, often causing chest pain and coughing. In the long term, ozone exposure can cause permanent lung damage and restrict lung development in young children.

Ozone is known as a “secondary pollutant.” This means that it’s produced when a mix of precursor pollutants like nitrogen dioxide (NO₂) and volatile organic compounds (VOCs) from car exhaust and factories react in sunlight, largely at temperatures above 84 degrees Fahrenheit (°F). For this reason, ozone is more problematic in the summer and early fall seasons when temperatures are highest.

Although Irvine air quality has averaged “good” levels in recent years, Irvine does experience short-term pollution events in which air quality reaches “unhealthy” levels or worse. The Environmental Protection Agency (EPA) allows a maximum of 3.2 high ozone days per year in its “passing” air quality grade. However, Irvine has failed to meet this standard consistently since 1996. Between 2016–2018, Irvine averaged 17 high ozone days per year.

Irvine experiences more unhealthy ozone days than unhealthy PM2.5 days. Irvine only experienced 5.2 days of high particle pollution per year from 2016–2018, just above the EPA’s passing grade of 3.2 days.

Refer to the top of this page for Irvine forecast air quality data and real-time air quality data.

Why is Irvine air quality bad today?

As with many cities, Irvine air pollution stems primarily from vehicle traffic. Fossil fuel combustion in motor vehicles produces PM2.5 as well as nitrogen dioxide (NO₂) and volatile organic compounds (VOCs), which also combine to produce ozone during warm temperatures.

Irvine air quality varies seasonally. While ozone is more common during the summer months when warmer temperatures encourage ozone formation, PM2.5 is more common in the fall and winter due to wildfires and domestic winter wood-burning practices.²

Irvine air quality levels are also influenced by weather conditions. Temperature inversions, for example, contribute to rising pollution levels. During temperature inversions, a layer of warm air higher in the atmosphere prevents cooler ground-level air from dispersing normally, trapping pollution and causing emissions to build. Coastal areas like Irvine can experience inversions when cool ocean air blows inland beneath the warmer air above it.³ Temperature inversions also usually occur on clear nights when the ground cools off more quickly.

Is smog in Irvine, Orange County improving?

Since the 1990s, Irvine air quality has steadily improved due to cleaner, more efficient motor vehicles and stricter industrial emission limits. But Irvine’s air quality may worsen in the future as a result of increased wildfire activity and population growth, which can result in more construction, traffic, and emissions.

Irvine air quality will also be adversely impacted by warming trends. According to a NOAA Global Climate Summary, combined land and ocean temperatures have increased by an average rate of 0.13°F per decade since 1880.⁴ Alarmingly, the average rate of increase has more than doubled to 0.32°F per decade since 1980. This means more days above 84 degrees Fahrenheit and more ozone-related smog.

Wind and rain can both offer a reprieve from Irvine’s high air pollution levels in the short term. Rain and humidity can increase particle density, causing them to fall faster as a result of gravity. Rain also helps to tamp particles down in a process known as coagulation. While mild rain barely reduces PM2.5 levels and decreases larger PM10 particle pollution by less than 5 percent, heavy rain is more effective, reducing PM2.5 by 8.7 percent and PM10 by 30 percent. Although many people often attribute greater benefits to rain because moist air smells fresher, wind is the most effective tool for clearing pollutants out of the air.⁵

Use the Irvine air quality forecast at the top of this page to see the effect of wind and rain on Irvine AQI.

What is Irvine doing to improve air quality?

California has called for all new car sales to be zero-emissions by 2035, aiming for total carbon neutrality by 2045. To take advantage of the large California market, auto manufacturers must abide by strict California emissions standards. In this way, California sets the bar for national emission standards, impacting the entire automotive industry.

Irvine and surrounding cities in California are also witnessing a surge of new solar and wind power. As these clean energy sources decrease in cost and increase in efficiency, renewable energy will become more prevalent.

In 2020, Irvine air quality improved as a result of reduced transportation in response to the COVID-19 pandemic. When COVID-19 lockdowns began in March that year, Irvine saw a drop in traffic congestion and related pollution as telecommuting became more prevalent.

Long-term reductions in transportation even long after COVID-19 lockdowns end are expected to continue even after the pandemic ends. Several large firms with local offices, including Twitter, have restructured to guarantee telecommuting and meet COVID-19 social distancing requirements, meaning that “working from home” may become a permanent feature for some office workers and eliminate the need for traditional commutes.⁶

California’s pollution-conscious vehicle standards, growing renewable energy efficiency, and reduced movement during the COVID-19 pandemic serve as a roadmap for many California cities like Irvine that are working to mitigate air pollution and its negative health consequences.

Is Irvine, CA affected by wildfire smoke?

Seasonal wildfires significantly impact Irvine air quality, especially as wildfire seasons on the West Coast of the United States have become more intense. In 2020, for example, smoke from West Coast wildfires enveloped surrounding states, traveling as far as the Eastern Seaboard via the polar jet stream. Some smoke even made it across the Atlantic as far away as Europe.⁷

Climate change has also altered seasonal wildfires. As temperatures continue to increase, the fire season is expected to grow in length and severity. This will have a negative impact on Irvine AQI, which is correlated with the regional wildfire season.

The air quality impact of West Coast fires could be mitigated by more aggressive forest management. Record-breaking wildfires in 2020 turned California forest management into an especially hot topic. The threat of future wildfires has driven officials to encourage “prescribed burns,” or deliberate, controlled fires that reduce forest underbrush and mitigate the risk of “megafires.”

The California Department of Forestry and Fire Prevention (CAL FIRE) estimates that there are an 8–10 million acres that should be burned, although California currently burns approximately 1 million acres per year.⁸ The significant discrepancy between recommended annual burns and current burn practices means California’s deadly wildfire season is unlikely to improve for years.⁹ To address this issue, Governor Gavin Newsom and the U.S. Forest Service chief signed a memorandum on August 12th, 2020 requiring that the state intentionally burn significantly more forest material.¹⁰

Despite increasing regional wildfires and global warming, Irvine air quality is generally healthy. During 2019, Irvine’s average annual PM2.5 stayed within the WHO’s target range of 0-10 µg/m³. This means that Irvine’s air is generally safe to breathe, although the WHO cautions that no level of air pollution is truly safe to breathe.

While dense wildfire smoke can appear apocalyptic, not all pollution is visible. Use the IQAir Irvine air pollution heat map to find active fires, identify wind patterns, and learn how local air quality is affected in real time. Follow live air quality in Irvine to stay up to date even when pollution is invisible. Taking action when pollution levels are high can greatly reduce one’s risk of adverse health effects.

+ Article Resources

[1] AirNow Interactive Map of Air Quality. (2020). Environmental Protection Agency.
[2] Perkes C. (2016, August 11). Deadly air: Thousands killed in Southern California each year by pollution, report finds. Orange County Register.
[3] Encyclopedia Britannica. (2020). Temperature inversion.
[4] Lindsey R, et al. (2020, August 14). Climate change: Global temperature. National Oceanic and Atmospheric Administration.
[5] Feng X, et al. (2011). Influence of different weather events on concentrations of particulate matter with different sizes in Lanzhou, China. Journal of Environmental Sciences. DOI: 10.1016/S1001-0742(11)60807-3.
[6] Dwoskin E. (2020, October 01). Americans might never come back to the office, and Twitter is leading the charge. The Washington Post.
[7] Money L, et al. (2020, September 15). Smoke from California wildfires reaches the East Coast and Europe. Los Angeles Times.
[8] Scott K. (2020, January 21). Why isn't California using more prescribed burns to reduce fire risk? Ars Technica.
[9] Helvarg D. (2019, December 20). How will California prevent more mega-wildfire disasters? National Geographic.
[10] Weil E. (2020, January 21). Prescribed burns prevent megafires. why don't we use them in California? Massive Science.