Air Pollution's West Coast Bias: Why?

Several cities on the West Coast of the United States have been reported to have the worst air quality in the world. The air quality in cities like Portland, Oregon, and Seattle, Washington, is hazardous to human health due to the smoke from wildfires. Other factors contributing to poor air quality on the West Coast include temperature inversions, vehicular emissions, demand for energy production through fossil fuels, industrial facilities, and agricultural processing. California's topography, with its large mountain ranges, also plays a role in trapping pollutants and affecting air quality. These factors have led to worsening air pollution on the West Coast, impacting the health and well-being of residents.

Wildfires

California, a state particularly vulnerable to wildfires, has seen a substantial increase in the number of annual burned acres since 1970, with a staggering 3.2 million acres burned in 2020, setting a new state record. The state's topography, characterized by large mountain ranges like the Sierra Nevada and the Coast Ranges, creates a "bowl"-like shape. Temperature inversions trap pollutants in this "bowl," with warmer air acting as a "lid," preventing the dispersal of harmful particulates and soot. This phenomenon is exacerbated in cities like Eugene, Oregon, located in the Willamette Valley, which is sheltered from winds that could otherwise dissipate the pollutants.

The increasing frequency and severity of wildfires on the West Coast can be attributed to various factors, including rising temperatures and drought conditions. Warmer summers contribute to higher ozone levels and PM2.5 concentrations in California. Additionally, the state's large population, significant port industry, and thriving economy generate substantial emissions from traffic, diesel trucks, construction, agriculture, and domestic sources. The combination of these human activities and natural disasters has made California the top state for cities with the worst air pollution in the American Lung Association's "State of Air 2019" report.

To combat the wildfire problem, California's Department of Forestry and Fire Prevention (CAL FIRE) is undertaking the challenging task of clearing volatile forest undergrowth through controlled burning. However, with an estimated 8-10 million acres requiring such treatment, it will take time and effort to bring the situation under control. In the meantime, the West Coast, particularly California, can expect smoky skies and poor air quality during wildfire seasons, posing health risks to residents, especially those with pre-existing respiratory conditions.

Temperature inversions

The city of Eugene in Oregon is another example of a location affected by temperature inversions. Located at the southern end of the Willamette Valley, Eugene is shielded from the winds coming in from the Columbia River, making it more susceptible to temperature inversions. As a result, harmful particulates and soot from car emissions and wood smoke become trapped, leading to poor air quality in the city.

Inversion layers, combined with stagnant air and westerly sea breezes, can create a pollution-trapping effect in California's coastal mountain ranges. Emissions from populous cities like Los Angeles, San Diego, San Jose, and San Francisco are blown inland and become trapped, further contributing to the state's air quality issues.

While temperature inversions play a role in air pollution on the West Coast, other factors also contribute to the problem. Wildfires, for example, have had a significant impact on the air quality in states like California, Oregon, and Washington. The smoke from these fires, combined with fog, has led to hazardous levels of pollution and visibility issues. Additionally, factors such as vehicular emissions, energy production, household energy consumption, and industrial activities contribute to the overall poor air quality in the region.

To address the issue of air pollution caused by temperature inversions and other factors, various efforts are being made. The Oregon Department of Land Conservation and Development, for instance, has implemented rules for participating cities to create "Climate-Friendly Areas," promoting alternatives to car usage and mixed-use development to reduce emissions. Additionally, the California Department of Forestry and Fire Prevention (CAL FIRE) is working to clear volatile forest undergrowth through controlled burns to mitigate the impact of wildfires on air quality.

Vehicular emissions

California, in particular, faces significant air pollution challenges due to its topography. Large mountain ranges like the Sierra Nevada and the Coast Ranges surround the central valleys, creating a "bowl"-like shape. Temperature inversions, where warmer air traps cooler air closer to the ground, act as a "lid" to this bowl, trapping pollutants at ground level and impacting the health of both humans and wildlife.

Cities in California, such as San Jose, San Francisco, and Oakland, struggle to meet national air pollution requirements due to high emissions from road traffic, rail freight, intensive agriculture, and various industries. The metropolitan area of Eugene-Springfield, located in Oregon, also faces poor air quality due to car emissions and wood smoke.

The transition to cleaner, more fuel-efficient vehicles, such as electric cars, can help combat the trend of increasing vehicular emissions and improve air quality on the West Coast. However, it is important to acknowledge that the impacts of congestion and high traffic volumes on air pollution cannot be overlooked. Additional traffic can significantly increase pollutant emissions, especially near large roadways, affecting the health of drivers, commuters, and residents living nearby.

Industrial emissions

Particulate matter, or PM, is of particular concern when it comes to industrial emissions. It includes fine particles of chemicals, soils, smoke, dust, or allergens that can be inhaled and penetrate deep into the lungs, causing serious health issues such as respiratory and cardiovascular diseases. Industrial activities, especially those involving combustion processes, are major sources of PM emissions.

The topography of the West Coast region also plays a role in trapping industrial emissions and contributing to poor air quality. For instance, California's Central Valleys are surrounded by large mountain ranges, creating a "bowl"-like shape. Temperature inversions, where warmer air traps cooler air closer to the ground, act as a "lid" to this bowl, preventing the dispersal of pollutants. This phenomenon is particularly prevalent in cities like Bakersfield, Fresno, and other Californian urban centers, leading to a concentration of pollutants that adversely affect human health and wildlife.

Additionally, the West Coast of North America is not only affected by local industrial emissions but also by pollution drifting across the Pacific Ocean from East Asia, specifically China. A study by scientists from universities in the US, China, and Canada revealed that emissions from China's export-oriented industries contribute to air pollution on the West Coast. As Western companies outsourced manufacturing to Asia, China's emissions from these industries increased significantly. This has impacted both densely populated cities like Los Angeles and sparsely populated areas like British Columbia.

To address the issue of industrial emissions and improve air quality, the Environmental Protection Agency (EPA) in the United States has implemented various measures. They have established federal emissions standards for new motor vehicles, non-road engines, and new industrial equipment. The EPA has also issued the Mercury and Air Toxics Standards, which aim to reduce fine particles and sulfur dioxide emissions from power plants. While these efforts have led to a substantial decrease in the six principal air pollutants since 1970, there is still work to be done to protect the health and well-being of communities affected by industrial emissions on the West Coast.

Domestic emissions

One significant contributor to domestic emissions on the West Coast is vehicle ownership and traffic. The combustion processes of automobiles, trucks, and other vehicles release various contaminants into the air, including nitrogen dioxide (NO2) and particulate matter (PM2.5 and PM10). Los Angeles, for instance, is bounded by mountains, which naturally confine pollutants, and its air quality is severely impacted by diesel engines, ports, motor vehicles, and industries. Similarly, Fresno's air quality is affected by heavy traffic, particularly from diesel trucks, alongside industrial facilities and agricultural dust.

The topography of California further exacerbates the impact of domestic emissions. Large mountain ranges like the Sierra Nevada and the Coast Ranges create a "bowl"-like shape, trapping pollutants in certain areas. Temperature inversions, where warmer air acts as a "lid" to the bowl, prevent the circulation of harmful particulates and soot, leading to poor air quality in cities like Eugene, Oregon, and San Jose, San Francisco, and Oakland in California.

Additionally, domestic emissions are influenced by seasonal variations on the West Coast. During winter in California, the strong bay breeze that typically disperses pollutants in summer ceases. The increased use of furnaces and heat pumps during colder months contributes to a rapid buildup of pollutants with no means of being flushed away.

It's important to note that communities of color and low-income neighborhoods are disproportionately affected by domestic emissions and air pollution. Historical factors such as redlining and industrial site placement have resulted in minority communities being exposed to higher levels of air pollution. This disparity is evident in cities like Los Angeles, where nearly half of the citizens consider air pollution a significant problem, and Birmingham, where Black neighborhoods have worse air quality than nearby white areas.

To address domestic emissions and improve air quality, states like Oregon have implemented initiatives. The Oregon Department of Land Conservation and Development has created rules for participating cities, including the establishment of "Climate-Friendly Areas." These zones promote sustainable practices, such as high-quality public transportation, pedestrian and bicycle routes, and mixed-use centers, ultimately reducing the reliance on cars and, consequently, vehicle emissions.

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