جودة الهواء في Santa Barbara County

What is the air quality in Santa Barbara?

Santa Barbara is located between the Pacific Ocean and Santa Ynez Mountains just 90 miles northwest of Los Angeles, one of the most polluted cities in the United States. Its location largely establishes the area’s climate and meteorology, which influence how pollution emissions are transported and diffused. Understanding these effects are important to understanding Santa Barbara’s air quality and its challenges in pollution mitigation.

Santa Barbara County is described as a “Mediterranean climate” for its warm, dry summers, and cool, damp winters.¹ Rain storms are infrequent during the period from March to November. The dry conditions of these months often contribute to higher air pollution levels, as there is no rain to tamp down pollutants or humidity to assist with pollution coagulation.

One problematic pollutant for Santa Barbara is ozone, a highly irritating gas pollutant commonly referred to as “smog.” Unlike other criteria pollutants measured by the US Environmental Protection Agency (EPA), ozone is primarily formed in the atmosphere as opposed to being emitted by ground sources directly. Precursor pollutants like nitrogen dioxide (NO₂) and volatile organic compounds (VOCs) as well as temperatures over 84 degrees must be present for ozone to form due to the chemical reactions that only occur with heat and other pollutants. Santa Barbara experiences roughly 30 days a year where temperatures are ideal for ozone formation.² Peak ozone season runs from July to October, when temperatures are the hottest and conditions are driest.

Over the last three decades, ozone levels have greatly declined. When monitoring began with the 1996 to 1998 monitoring period, Santa Barbara county experienced 55.5 unhealthy ozone days annually, far exceeding the federal allowance of 3.2 days.³ In the 2015 to 2017 monitoring period, Santa Barbara met ozone standards for the first time with only 2.3 unhealthy ozone days. The city again achieved attainment in the following 2016 to 2018 monitoring period with 1.7 unhealthy days.

While Los Angeles County was rated as the most polluted city in the US for high ozone days, the Santa Maria-Santa Barbara region fared significantly better, ranking 93rd out of the same 228 metropolitan area study.

In 2015, the EPA announced a plan to lower the current ozone national ambient air quality standards (NAAQS) to the range of 70 ppb to 65 ppb. The standard of 70 ppb was decided, despite studies showing an even lower standard could further reduce adverse effects in the general public. Had the standard been lowered even further to 65 ppb, several air quality monitoring sites in Santa Barbara would be at or above the standard.

Fine particle pollution, or PM2.5, is a pollutant of graver concern in Santa Barbara. PM2.5 describes ambient airborne particles measuring 2.5 microns or smaller in diameter. These particles may be made of ash, dust, dirt, chemicals, or even viruses and bacteria, as they are categorized for their size rather than composition. When inhaled, these fine particles are able to penetrate deep into the lungs, sometimes reaching the circulatory system and causing a number of health effects across the body’s organs.

Santa Barbara’s annual PM2.5 levels in 2018 and 2019 were 8.7 μg/m³ and 8.4 μg/m³ respectively, thus meeting federal targets set at 12 μg/m³ as well as the more stringent World Health Organization target set at 10 μg/m³.

Despite annual PM2.5 averages in the “good” range, a look at short-term PM2.5 across the city reveals a different story. Since 2016, short term PM2.5 pollution (or 24-hour PM2.5 pollution) has been on the rise. From 2009 to 2016, Santa Barbara experienced zero unhealthy PM2.5 days. In the 2015 to 2017 monitoring period, however, the number of unhealthy PM2.5 days rose to 6.2, and rose again in the 2016 to 2018 monitoring period to 6.7.

These increases in short-term PM2.5 in Santa Barbara coincide with increasingly prolonged and severe wildfire seasons. Human-driven climate change is largely to blame, as warmer and drier conditions create longer wildfire seasons.

California’s 2020 wildfire season constituted the most severe in the state’s recorded history, causing pollution levels to far exceed typical ranges. In September, Santa Barbara’s air quality index (AQI) experienced 5 consecutive days of air deemed “unhealthy for sensitive groups” or worse, While 20 out of 30 days that month exceeded “good” standards.

Santa Barbara’s geography, on the coast near the steep Santa Ynez Mountains, contributes to a pollution-trapping weather event known as a “marine inversion.” Normally, air becomes cooler and less dense with gains in altitude. During a marine inversion, the ocean cools surface air to temperatures lower than the air directly above it. When this happens, the warmer denser air suppresses the cool air layer like a lid, preventing normal pollution dispersion. This effect creates low-hanging fog and smog, resulting in a “brown cloud” over Santa Barbara. The nearby mountains exacerbate this effect by preventing inward blowing sea-breezes from moving pollution outward.

Will Santa Barbara rain help air quality from fires?

Rain can improve air quality in Santa Barbara. However, its effect is often overestimated. A number of factors determine just how effective rain is at changing pollution levels, including the size of rain droplets, the size and concentration of pollutants, and cloud altitude.

When rain falls, it attracts hundreds to thousands of tiny airborne particulates and gas particles in a process called coagulation. The larger the particle, the more effective rain is in tamping it down.

Light rains hardly reduce PM2.5 levels, and reduce PM10 levels by less than 5 percent.⁴ Heavy rains, meanwhile, were found to reduce PM2.5 particles by an average of 8.7 percent, and PM10 particles by up to 30 percent.

More important than rain on Santa Barbara air pollution levels, however, is wind. While people often attribute blue skies after a storm to rain, strong winds or moving air is the most effective pollutant-clearing phenomenon.

Use the Santa Barbara air quality forecast at the top of this page to see when wind conditions and rain are predicted, and whether this is expected to reduce Santa Barbara’s AQI levels.

When will air quality improve in Santa Barbara?

Yearly average air quality in Santa Barbara is in the “good” range, indicating that generally air is safe to breathe. Unhealthy air pollution spikes typically occur in the summer and fall months, when warm, dry conditions result in elevated ozone and fine particle pollution (PM2.5).

Still, improvements must be made to further reduce the risk of residents to adverse health effects. According to the 2020 “State of the Air” report, Santa Barbara County was graded a “C” for high ozone days and an “F” for high PM2.5 days. Between spikes in both pollutants, Santa Barbara averages 8.4 unhealthy air pollution days per year.

Climate change will prove a challenge in maintaining clean air. As temperatures warm, wildfires will become increasingly frequent and severe, prompting rises in PM2.5 pollution, while increased temperatures will also accelerate ozone formation and prolong ozone season.

In order to face these challenges, emissions must be further reduced. The biggest and perhaps most easily managed emission source is transportation-related pollution. Motor vehicles such as cars and trucks comprise more than half of the City’s total emissions. Incentivizing and promoting zero- and low-emission vehicles, such as electric and hybrid cars, is one of the state’s top priorities. California Governor Gavin Newsom signed an Executive Order in 2020 calling for all new car sales to be zero-emissions by 2035, aiming for total carbon neutrality in the state by 2045.⁵ In addition to transportation, sourcing energy from increasingly renewable sources provides another opportunity for cleaner air.

Does Santa Barbara have smoke from fire?

In 2020, historic wildfires burning in California, Oregon, and Washington created polluted skies in New York City, NY and Portland, Maine all the way across the country.⁶ Satellite data has confirmed some smoke particles even made it across the Atlantic Ocean, traveling as far as the Netherlands over 5,000 miles away.

While smoke often has the propensity to travel hundreds of miles, not all smoke is able to travel so far. The fires that occurred in September 2020 benefited from two factors. First, the smoke caught a ride on the west-to-east polar jet stream, which moves winds at roughly 110 miles per hour. Second, these fires were record-breaking for their size, increasing smoke density and allowing concentrations to exist at higher levels in farther locations.

Climate change is making fires bigger, which means smoke can travel farther. As the “new normal” includes increasingly long and severe wildfire seasons, short-term PM2.5 pollution spikes are expected to become increasingly frequent.

Not all pollution is visible. Use IQAir’s Santa Barbara air pollution heat map to locate active fires, identify wind patterns, and understand how regional air quality is being affected in real time. Follow live air quality in Santa Barbara 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.

Is air quality in Santa Barbara getting better?

As in most US cities, recent decades have seen air quality improvements in Santa Barbara for both annual PM2.5 and ozone pollution. These improvements occur amidst cleaner and more fuel-efficient motor vehicles and more stringent industrial emission limits.

Despite long-term improving trends, however, recent years show worsening short-term PM2.5 pollution.

Santa Barbara air quality has long been in attainment for short-term PM2.5. In fact, in the 7-year span from 2009 to 2016, Santa Barbara experienced zero unhealthy PM2.5 days. More recently, however, this number has gone up to an average of 6.2 days a year during 2015 to 2017 and 6.7 days a year during 2016 to 2018.

Santa Barbara’s more frequent unhealthy PM2.5 days are primarily the result of wildfires. In 2019 (a relatively mild wildfire year), November was the most polluted month of the year, averaging a PM2.5 concentration of 15.1 μg/m³. During this month, the Cave Fire burned more than 4,000 acres in Santa Barbara’s Santa Ynez Mountains.⁷

Managing the threat of wildfires in a warming climate has prompted action for “prescribed fires,” a practice of (responsibly) burning forest underbrush to reduce the risk of fires in the future. The California Department of Forestry and Fire Prevention (CAL FIRE) estimates that 8-10 million acres in the state should be burned.⁸ Currently, the department is clearing a million acres a year, in an attempt to reach this goal. It will be at least several years before the situation is under control. Until then, California’s wildfires season is likely to cause smoky skies in Santa Barbara for the foreseeable future.

+ Article Resources

[1] Environmental Protection Agency (EPA). (2010). Network assessment of the Santa Barbara Air Pollution Control District ambient air monitoring network.
[2] Current Results. (2020). Santa Barbara temperatures: averages by month.
[3] American Lung Association. (2020). State of the air – 2020.
[4] 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.
[5] City of Santa Barbara. (2020, September 29). Santa Barbara installs 30 new electric vehicle charging stations.
[6] Neilson S. (2020, September 15). Smoke from the West Coast wildfires is causing hazy skies in New York and even reaching as far as the Netherlands. Insider.
[7] Bryson TD. (2019, November 26). Cave Fire in Santa Barbara County threatens homes and forces evacuations. The New York Times.
[8] Helvarg D. (2019, December 20). How will California prevent more mega-wildfire disasters? National Geographic.