When air pollution becomes a health equity issue

Poor air quality colliding with existing health inequities exacerbates disease.

It can be difficult for Californians to determine if the gray skies are due to smoke from one of the 8,000 fire-related incidents across the state this year, or from smog, a mixture of air pollutants from factories, construction, gasoline and diesel-powered vehicles, pesticides and more.

Either way, both can cause serious health conditions. Exposure over time can lead to asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis and death.

A Los Angeles County Climate Vulnerability Assessment found that more than half of residents – nearly 5.7 million people – live in a neighborhood that has a high exposure to at least one of five severe climate threats – extreme heat, wildfire, drought, extreme precipitation and sea-level rise.

Air pollution, urbanization, redlining and industrialization all intersect with health equity in a way that harms minority and low-income communities, says Olawale Amubieya, MD, pulmonologist and junior faculty in the Division of Pulmonary and Critical Care Medicine at UCLA Health.

“Policies of the past cut out low-income, minority and urban communities from suburban communities where the traffic and smog are less dense. [These policies] relegated them into areas that are close to industrial plants, which produce more air pollution,” he says. “It really does put these at-risk communities at even higher risk because of the health effects.”

Included in high-risk category are low-income communities with large percentages of racial minorities, people experiencing homelessness, pregnant people, developing children, elderly adults and people with disabilities and chronic conditions.

Neighborhoods in the San Francisco Bay area with higher percentages of people of color face double the rate of pollution-related childhood asthma compared to predominantly white neighborhoods, according to research from March 2021.

Additionally, Black, Latino, Asian American and low-income communities are exposed to substantially more air pollution than other demographic groups in California, a 2019 study shows. People living in dense urban areas like Los Angeles County had higher exposure to traffic pollution compared to the state average.

Dr. Amubieya says when poor air quality collides with the health inequities that already exist, diseases are exacerbated and health issues arise.

Troubling particles

Inhalation and ingestion are the two main ways particulate matter from air pollution enters the body. According to the Environmental Protection Agency, PM is a “complex mixture of extremely small particles and liquid droplets” made up of acids, organic chemicals, metals, and soil or dust particles.

Particulate matter is broken up into different sizes: PM10 is particulate matter that's below the size of 10 micro meters. PM2.5 is smaller than that. The ultra-fine particles are less than 0.1 micro meters.

The size of the particle determines where in the body it will land and how much trouble it will cause, Dr. Amubieya says.

“Long-term exposure to air pollution related to traffic is associated with elevated rates of coronary heart disease, hospitalization and death,” he says. “We also know that air pollution exposure is associated with higher rates of the incidence of COPD and asthma. The more you're exposed to these things, the more that these chronic health issues develop and the more you're likely to succumb to them.”

Air pollution can lead to increased oxidative stress, which is when oxygen splits into single atoms with “free” or unpaired electrons called free radicals. Free radicals, which can cause damage to DNA, are linked with diseases, including cancer, and aging.

Even just one day of bad air pollution, Dr. Amubieya says, can cause some people severe issues.

Studies show that hospitalizations for heart failure, asthma or COPD go up quickly during poor air quality days – whether due to wildfire or smog, he says.

The bigger issue he says, is what air pollution is doing to us on a population level. Some studies have estimated that ambient air pollution is the ninth leading risk factor for global disease burden in the world. Other estimates show that outdoor air pollution is responsible for 3.2 million deaths per year worldwide.


Though California has robust regulations around air pollution, the challenge is that these social inequalities are very entrenched, says Lara Cushing, PhD, MPH, Jonathan and Karin Fielding Presidential Chair in Health Equity at the UCLA Fielding School of Public Health and environmental epidemiologist in the Environmental Health and Sciences Department at UCLA.

“Air pollution is predicted to get worse with climate change and we're certainly seeing that with the fire seasons we've been having the last few years,” she says. “It's kind of an all hands-on-deck-needed scenario if we truly want to narrow the gap and achieve health equity with respect to air pollution.”

That scenario looks like policy and systemic change, says Dr. Cushing, because it is difficult for individuals to control their environment.

“It's pretty hard to control the quality of the air you can breathe. There are some mitigation measures you can take to try to reduce your exposure, such as simply staying inside and trying to create the cleanest air that you can, whether that's in your whole house or just one room.”

Unfortunately, the real long-term solutions are not that we create clean rooms, but that we create clean air – “which is harder to do,” she says.

The ability to mitigate exposures vary with respect to housing conditions. For people unable to purchase air filters, or pay their electricity bill, it’s simply not possible, Dr. Cushing says.

“If you work outside, do you have any control over your work environment? Do you get paid if you take a break?”

More often than not, for many, she says, “you have to work through the smoke or you won't get paid.”

For people with asthma or pre-existing conditions, Dr. Cushing says designating a room where the air can be kept clean can certainly provide some relief. Generally though, she says, personal interventions don’t work that well to reduce exposure for a problem on such a large scale.

This is why she champions government action, she says – because that’s what it will take to reduce air pollution “particularly in socially marginalized communities,” she says. As scientists, Dr. Cushing says, “one of our biggest roles is advocating for better public policy.”

Dr. Amubieya agrees that the best way to prevent and mitigate these health risks are by intervention on a neighborhood and population level.

Governments have attempted interventions like charging people for being in high congestion zones and creating zones where only cars with low emissions are allowed. Other efforts include reducing the amount of traffic-related air pollution produced in those areas.

“These are things that are somewhat controversial, they have their pluses and minuses,” he says. For example, in order to drive in a low emission zone, a person must have a low emission vehicle. This may exacerbate inequities, Dr. Amubieya says, noting the cost of low emissions vehicles or the purchase of a new vehicle altogether.

“So, we have to really think carefully about the intervention,” he says.

Read more about how to reduce air pollution and California’s policies on air quality monitoring.

Learn more about Pulmonology & Critical Care services at UCLA Health and book an appointment with a specialist.