San Diego's Pollution: What's The Main Culprit?

San Diego is one of the most biodiverse areas in the world, but it is also one of the most polluted metropolitan areas in the US. The city's air quality suffers from high levels of ozone pollution, particulate matter, and diesel pollution from trucks and cargo equipment at the Port of San Diego. In addition, stormwater pollution from soaps, fertilizers, and trash contaminates the region's rivers, lakes, and ocean, threatening its diverse wildlife. These issues disproportionately impact minority communities, as state environmental regulations have been found to favour White residents over people of colour.

Stormwater pollution

San Diego is one of the most biodiverse regions in the world, with a diverse population of wildlife, from invertebrates in tide pools to large animals like the California Sea Lion and Mountain Lion. However, stormwater pollution poses a significant threat to these natural environments and the health of the residents.

One of the critical issues with stormwater pollution is the introduction of excess "nutrient" chemicals, such as phosphorus and nitrogen, into water bodies. These chemicals, commonly found in fertilizers, manure, pet waste, and decomposing green waste, are washed into storm drains during rain or over-irrigation. This leads to algae blooms, which can dangerously deplete oxygen levels in the water, creating dead zones, and producing toxic chemicals harmful to humans and animals.

Additionally, stormwater pollution exacerbates the problem of air pollution in San Diego. The region already struggles with high levels of ozone and fine particulate matter (PM2.5) pollution, which have adverse health effects on residents, particularly those with pre-existing heart and lung conditions. Stormwater runoff can carry pollutants from the ground into the air, further aggravating the air quality issues in the area.

To address the issue of stormwater pollution, organizations like Project Clean Water are encouraging residents to take simple actions to reduce pollution, such as pledging to reduce stormwater pollution through their 52 Ways to Love Your Water campaign. By taking collective action and implementing best practices, San Diego can work towards mitigating the impacts of stormwater pollution on its diverse ecosystems and communities.

Racial disparity in pollution exposure

San Diego is one of the most biodiverse areas in the world, with a rich variety of wildlife. However, it is also ranked as the fifth most polluted large metropolitan area in the US. The region faces issues with air pollution, stormwater pollution, and marine inversions, which negatively impact the health of residents and the environment.

While people of all races are affected by San Diego's pollution problem, there is evidence of a racial disparity in pollution exposure. A study by the University of California, San Diego, revealed that California's environmental regulations have systematically favoured White residents over people of colour. This is reflected in the health outcomes of different racial groups. People of colour are over three times more likely than White people to breathe the nation's most polluted air, leading to a higher risk of health issues.

One example of a community grappling with the impacts of pollution is the Barrio Logan neighbourhood, predominantly inhabited by people of colour. Located next to the Port of San Diego, a hub for heavy trucks, cargo equipment, and ships, the area experiences high levels of air pollution. Residents like Emily Villagrana have shared their concerns about the health effects of living in such an environment, including frequent bronchial infections, sinus issues, and consistent itchy noses.

The Environmental Health Coalition (EHC) has been advocating for broad policy shifts to address this disparity. Their efforts led to a significant victory when the Port of San Diego's board of commissioners approved a plan to curb air pollution. The plan mandates that all trucks and cargo handling equipment at the port transition to zero emissions by 2030, faster than the state mandate. This move has been applauded by many residents and activists concerned about the disproportionate impact of pollution on minority communities.

While progress is being made, the racial disparity in pollution exposure in San Diego highlights the need for continued efforts to protect vulnerable communities and ensure environmental justice for all. The clean air plans put forth by the Biden administration and the state of California, such as the mandate for zero-emission trucks, are steps in the right direction. However, more work needs to be done to address the systemic biases that have contributed to this disparity and to ensure that all residents of San Diego have equal access to clean air and a healthy environment.

Ozone pollution

San Diego has been ranked as the fifth most polluted large metropolitan area in the United States. One of the key contributors to the city's poor air quality is ozone pollution.

Ozone is a corrosive gas pollutant composed of three oxygen atoms. It is highly reactive, and prolonged exposure can damage lung tissue, leading to the early ageing of the lungs and the worsening of chronic lung disease. Even short-term exposure can trigger asthma attacks, coughing, and difficulty breathing. These effects are more acute in children, the elderly, and individuals with pre-existing heart and lung conditions. On average, San Diego experiences 43.3 days of unhealthy ozone levels annually, far exceeding the federal target of 3.2 days. This has resulted in an "F" rating by the American Lung Association (ALA).

The city's geography and climate play a significant role in the accumulation of ozone pollution. San Diego's location on the coast, with its hot, dry summers and mild, wet winters, creates ideal conditions for the formation and build-up of ozone. The city experiences light winds and stagnant air, with little precipitation, which, combined with its position near the Pacific Ocean, leads to temperature inversions. This phenomenon occurs when cooler ground-level air near the ocean becomes trapped by warmer, denser air above, trapping ground-level emissions until normal temperature conditions resume. Additionally, winds blowing in from the west can drive air pollutants inland, further exacerbating the issue.

The impact of ozone pollution is felt disproportionately by minority communities in San Diego. A study from the University of California, San Diego, revealed that California's environmental regulations have systematically favoured White residents over people of colour. For example, the Barrio Logan neighbourhood, home to a significant population of colour, is located next to the Port of San Diego, a hub for heavy trucks, cargo equipment, and ships, exposing residents to high levels of air pollution.

Efforts are being made to address the issue of ozone pollution in San Diego. The Port of San Diego's board of commissioners has approved a plan to curb air pollution, mandating that all trucks and cargo handling equipment switch to zero emissions by 2030. This is a positive step towards improving air quality and ensuring the health and well-being of San Diego's residents.

PM2.5 pollution

San Diego's air quality is impacted by a range of factors, including vehicle emissions, industrial activity, and geographical influences. One of the key contributors to the city's air pollution is fine particulate matter, known as PM2.5. This term refers to a mixture of tiny particles with diverse chemical compositions and sources, encompassing metals, soot, soil, dust, and salt. The presence of PM2.5 in the air has been associated with significant health risks for residents, including an increased likelihood of heart and lung diseases, cancer, and premature mortality.

The American Lung Association (ALA) has given San Diego a "C" rating for 24-hour particle pollution. This grade reflects the city's average of two days per year with unhealthy PM2.5 levels. While San Diego meets the annual attainment levels for PM2.5, it had failed to do so in 2017 and 2018, underscoring the ongoing challenge of maintaining air quality. The months of August through January are typically the most polluted for PM2.5, with November being the month that usually sees the highest concentration.

The impact of PM2.5 pollution is not limited to the environment; it also has significant implications for public health. Sensitive groups, including children, the elderly, and individuals with pre-existing heart and lung conditions, are particularly vulnerable to the adverse effects of PM2.5. They may experience immediate symptoms such as asthma attacks, coughing, and difficulty breathing. Even healthy individuals can be affected with prolonged exposure, emphasising the necessity of limiting outdoor activities during periods of high PM2.5 pollution.

Addressing PM2.5 pollution in San Diego requires a comprehensive approach. While the city has made strides in reducing emissions, more ambitious measures are needed to protect the health of its residents. This includes implementing broad policy shifts, such as transitioning to zero-emission vehicles and equipment, especially in areas with high industrial activity like the Port of San Diego. Additionally, community education and real-time air quality monitoring can empower individuals to make informed decisions to minimise their exposure to harmful pollutants.

Marine inversions

San Diego's location on the coast of the Pacific Ocean gives way to pollution-accumulating weather events known as marine inversions. Marine inversions describe a reversal of normal temperature patterns, where cooler ground-level air near the ocean becomes trapped by warmer, denser air above. This temperature inversion is caused by the ocean cooling the air in the lower atmosphere, which then gets trapped by warmer inland air. The result is the trapping and accumulation of ground-level emissions until normal temperature conditions return.

Light winds blowing in from the west can further aggravate this condition by driving air pollutants and cold surface-level air inland toward the foothills, intensifying the effect of the marine inversion. The unique climate of San Diego, characterised by hot, dry summers and mild, wet winters, also contributes to the occurrence of marine inversions. Light winds, stagnant air, little precipitation, and an abundance of warm days create ideal conditions for the creation and accumulation of ozone pollution.

Ozone is a corrosive gas pollutant composed of three oxygen atoms. Due to its highly reactive nature, prolonged exposure can damage lung tissue, leading to the early ageing of the lungs and the worsening of chronic lung disease. Short-term effects can trigger asthma attacks, coughing, and difficulty breathing, with more acute impacts on sensitive groups, including children, the elderly, and individuals with pre-existing heart and lung conditions. On average, San Diego experiences 43.3 days of unhealthy ozone levels annually, far exceeding the 3.2-day federal target.

In addition to air pollution, San Diego also faces the challenge of stormwater pollution. Soaps from washing cars, fertilizers, herbicides, pesticides, and trash left as litter can introduce harmful chemicals, choking hazards, and objects like mask strings that pose threats to the diverse wildlife in the region. Stormwater pollution can also cause flooding by blocking storm drains and water pathways. Furthermore, excess nutrients, such as phosphorus and nitrogen from fertilizers and manure, can accumulate in waterways, leading to algae blooms that deplete oxygen levels, create dead zones, and produce toxic chemicals harmful to people and animals.

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