Qualité de l’air à Berkeley

What is the air quality in Berkeley CA?

Berkeley’s annual air quality index (AQI) score meets the US Environmental Protection Agency (EPA) standard for “good,” indicating that, on average, air is healthy to breathe. Such yearly averages, however, tend to underestimate health risks, as they smooth over daily pollution spikes that can contribute to adverse health effects. It is for this reason that standards have additionally been set for the number of unhealthy air quality days a city is allowed per year.

The 2020 “State of the Air” report released by the American Lung Association (ALA) aggregates data for more than 200 regional areas in the United States and rates these regions according to EPA standards. According to the report, Alameda County, of which Berkeley is a part, was graded an “F” for both short-term PM2.5 and short-term ozone pollution.¹ The “F” rating indicates that Berkeley has exceeded the allowable 3.2 days of unhealthy air quality for each pollutant, calculated as a weighted average over 3 years. In the 2016 to 2018 monitoring period, Alameda County experienced an average of 8.8 unhealthy ozone days a year and 11.2 unhealthy PM2.5 days a year for a total of 20 unhealthy air quality days annually.

These days of heightened air quality in Berkeley cause more acute health effects in sensitive groups, defined as children, the elderly, and those with pre-existing heart and lung disease. In Alameda County, there are an estimated 133,767 residents with asthma, 59,858 with COPD, 86,118 with cardiovascular disease, 230,510 residents over the age of 65, and 342,510 children under the age of 18.

Short-term effects of breathing air pollution include irritation of the airways, coughing, chest pain, heart arrhythmias, and difficulty breathing. Over time, frequent exposure to elevated pollution levels include permanent damage to the heart and lungs, cancer, and early death.

Even in polluted environments, it is possible to breathe clean air. Air quality is ever evolving with the weather, the season, and pollution events. Check Berkeley’s live air quality data at the top of this page to understand current conditions. Readings worse than Good (“green”) indicate that there are moderate or worse risks to breathing the air. Follow the advised health recommendations to reduce your exposure.

How polluted is the area of UC Berkeley?

Berkeley is located on the east shore of the San Francisco Bay, just 10 miles from San Francisco, 7.5 miles from Oakland, and 6 miles from Richmond. Berkeley air quality, and the air quality of the UC Berkeley campus, fares roughly the same as its neighboring cities. In 2019, Berkeley’s air quality index (AQI) was 30, the same AQI as San Francisco and slightly higher than both Oakland’s AQI of 29 and Richmond’s AQI of 27. All cities in the Bay Area had annual AQI levels below 50, thus indicating that overall air quality is healthy.

According to the 2020 State of the Air report, however, the greater region, which encompasses San Jose-San Francisco-Oakland, ranked poorly for short-term air pollution as compared to other regions in the United States. In the 2016 to 2018 monitoring periods, San Jose-San Francisco-Oakland ranked:

• #8 for high ozone days out of 229 US metropolitan areas
• #3 for 24-hour particle pollution out of 216 US metropolitan areas

Use the IQAir Air Quality map to observe heat-mapped air pollution in the region as well as winds which may carry air pollutants to UC Berkeley from nearby emission sources, such as freeways and the Oakland/Berkeley port. Follow data for the McMillan Road, Berkeley air quality monitoring station for the most hyper-local data to the UC Berkeley campus.

How safe is indoor air in Berkeley?

Air pollution is often framed as an outdoor problem. A growing body of scientific evidence, however, indicates that indoor air pollution should be of primary concern, as some pollutant concentrations can far exceed outdoor levels and because the average American spends roughly 90 percent of their day indoors, exacerbating the outsized risk that indoor air pollution poses to health.² Indoor air quality can thus either greatly reduce or increase your overall air pollution exposure depending on the level of control that you have over your indoor air quality.

Indoor air in Berkeley suffers from many of the same pollution sources as outdoor air, such as vehicular and industrial emissions as well as unique indoor pollution sources like building and cleaning materials, smoking, and cooking.

There are also correlations between indoor air and outdoor air. During wildfires, it is estimated that indoor PM2.5 levels will account for 49 to 76 percent of the increases in outdoor PM2.5.³ Conversely, the US EPA estimates that volatile organic compound (VOC) levels are between 2 to 5 times higher indoors than out as a result of higher confinement with products that emit VOCs and CO₂.

The safety of indoor spaces depends on the ventilation and air purification systems in place. Clean indoor environments balance indoor confinement or ventilation (thus lowering CO₂ and VOC levels) while managing the inflow of, and filtering for, harmful particle and gas pollution.

Berkeley was the first city in the nation to require that all new buildings be 100 percent electric beginning January 1, 2020.⁴The new law forbids gas hook-ups to be installed in new houses, apartments, and school and commercial buildings. Currently, 90 percent of California homes rely on gas for domestic heating. By moving to an all-electric plan, fossil fuels will be eliminated as a heating source for buildings in new construction.

When will Berkeley air quality improve?

While long-term trends depict an overall trend of improving air quality in Alameda County, recent years have recorded concerning gains in both PM2.5 and ozone pollution. At present, Berkeley air pollution appears to be on the rise. This comes despite gradual moves toward cleaner energy, more fuel-efficient and low-emission vehicles, and increasingly stringent local and state regulations.

The reason has roots in our changing climate. Warming temperatures are linked to increased short-term ozone and PM2.5 pollution as a result of a prolonged and more severe ozone and wildfires seasons.

In 2019, a relatively mild year for wildfires, November was Berkeley’s most polluted month as a result of the Burris fire in Mendocino and the Kincade Fire in Sonoma County. The PM2.5 average for November 2019 was 14.8 μg/m³, more than 2 times the average of October (7.3 μg/m³) and December (6.7 μg/m³). In 2020, historic California wildfires caused a record stretch of Spare the Air alerts in Berkeley.

Managing the threats of climate change on air quality will require aggressive action. In addition to managing greenhouse gas emissions to slow or reverse current climate trends, the California Department of Forestry and Fire Prevention (CAL FIRE) seeks to thin 8-10 million acres of forest by ‘prescribed burning’ in order to reduce the severity of wildfires.⁵

Moving towards cleaner energy by diminishing reliance on fossil fuels is another key step in improving Berkeley air quality. State and local commitments have been made to achieve 100% renewable electricity by 2045., a goal which must rely on significant emission reductions in the transportation sector.⁶ Between 2000 and 2016, transportation was the only sector to experience increasing air pollution emissions in Berkeley. Moreover, transportation continues to represent the largest air pollution emission source here, responsible for 60 percent of all Berkeley’s air pollution emissions.

In order to facilitate the achievement of these goals, the city of Berkeley released its first Electric Mobility Roadmap in July 2020. The roadmap supports improving the attractiveness and accessibility of driving alternatives like walking, biking, and reliable public transit as well as shifting residents from gas-powered motor vehicles to electric or hybrid options.

In order to reach zero net carbon by 2045, it is estimated that electric vehicles (EV) would need to reach a 25 percent market share by 2025 and a 55 percent market share by 2030, with an ultimate 100 percent share by 2045: an ambitious target. Should such targets be met, however, daily average PM2.5 levels in Berkeley could see as much as a 50 percent drop, offering significant health benefits to the community.

What are the smoke air quality advisories for Berkeley?

Air quality advisories in Berkeley are established when air pollution is, or is forecast, to exceed a US AQI of 100, thus becoming “unhealthy for sensitive groups.” The Bay Area Air Quality Management District (BAAQMD), which is responsible for government monitors in the region, uses this guideline to issue Spare the Air alerts. These alerts indicate that residents should take action to protect their health and reduce their personal emissions.⁷

Spare the Air reports are most often issued for short-term PM2.5 or ozone pollution. PM2.5 advisories are often reported in the later summer, fall and winter as a result of active wildfires and winter woodburning, while ozone advisories are more often reported in the summer when conditions (temperatures greater than 84 degrees) are ideal for ozone formation.

Check live air quality data to determine whether Berkeley is under a Spare the Air advisory. When Berkeley’s AQI exceeds, or is forecast to exceed, 100 (“orange”), a Spare the Air alert is in place. When this happens, follow the recommended health protocol, such as wearing a mask outdoors, limiting outdoor activity, running an air purifier if available, and help play a role in reducing city-wide emissions by driving less and avoiding wood burning or BBQing.

+ Article Resources

[1] American Lung Association. (2020). State of the air – 2020.
[2] US Environmental Protection Agency (EPA). (2020). Report on the environment - indoor air quality.
[3] LBNL Indoor Environment Group. (2020). Wildfires. Lawrence Berkeley National Laboratory.
[4] Delforge P. (2019, July 17). Berkeley Passes Nation’s 1st All-Electric Building Ordinance. National Resources Defense Council.
[5] Helvarg D. (2019, December 20). How will California prevent more mega-wildfire disasters? National Geographic.
[6] City of Berkeley. (2020). City of Berkeley electric mobility roadmap - 2020.
[7] Spare the Air. (2020). What is Spare the Air? Bay Area Air Quality Management District.