Skip to Content
Streetsblog California home
Streetsblog California home
Log In
Air Quality

Study: Highway Pollution Exposure Could Be Linked to Higher COVID-19 Death Rates

People who live near freeways are subject to higher levels of particulates. Photo of 110/105 junction by Remi Jouan, from Wikipedia

A new nationwide study suggests that people living in neighborhoods with higher levels of fine particulate air pollution are more likely to die from COVID-19 infection than patients who live in areas with cleaner air.

The frightening data from Harvard's T.H. Chan School of Public Health is especially concerning in California, where the people living next to highways, major roads, and polluting industries--and thus subjected to higher levels of pollution--tend to be low-income communities of color.

The Harvard study compares county-level COVID-19 deaths (as of April 4) with each county’s long-term average concentrations of pollution particles smaller than 2.5 micrometers in diameter, also known as PM2.5 or “fine particulate” pollution. The authors found that counties with just one more microgram per cubic meter in their average fine particulate levels had, on average, a fifteen percent higher mortality rate from COVID-19.

The results “underscore the importance of continuing to enforce existing air pollution regulations to protect human health both during and after the COVID-19 crisis,” write the study’s authors. Note, however, that the U.S. EPA has decided to follow exactly the opposite course, and has used the pandemic as an excuse to suspend enforcement of existing regulations.

The study results also underscore the importance of addressing the historical injustices that have put some Californians in a more vulnerable position for all health outcomes. We already know that rates of asthma are higher in many low-income communities of color; we know that air quality is worse in some places in the state than others, and that many of those places are home to disadvantaged communities. It is just another thumb on the scale for these communities that they are more likely to suffer the worst consequences of COVID-19.

State policies on climate change, air quality, and transportation planning address this inequity, although usually as an afterthought. For example, via hard-fought, single-issue legislation that calls for better local air quality monitoring, or broader representation on state decision-making bodies, or via higher scores for transportation projects that benefit disadvantaged communities in one funding program, the ATP.

A 2019 report from the Union of Concerned Scientists [PDF] found that residents in the counties of Los Angeles, San Bernardino, Orange, San Diego, Fresno, and Kern had higher-than-state-average exposure levels to particulates.

Screen Shot 2020-04-07 at 2.14.10 PM

That study also found that African American, Latino, and Asian Californians are exposed to more particulates from cars, trucks, and buses than white Californians. The lowest-income households in the state live in areas with particulate rates that are ten percent or more higher than the state aver­age, while the highest-income residents enjoy pollution rates that are thirteen percent below the state average.

Higher particulate pollution corresponds to higher proportion of people of color

Stay in touch

Sign up for our free newsletter

More from Streetsblog California

The Week In Short Videos

Slip lanes, e-bike incentives, and a bonus video from NYC.

January 16, 2026

Santa Monica Parking Enforcement Vehicles to Use AI Cameras to Ticket Bike Lane Violations

Similar to on-bus AI cameras for bus lanes, but with two new wrinkles: cameras will be on city cars, and will detect bike lane blockers

January 16, 2026

Friday’s Headlines

I never thought about what happens if you violate the same law, on one trip, in multiple jurisdictions.

January 16, 2026

Papan Wants to Draw a Legal Line Between E-Bikes and Electric Motorbikes

Pretty sure the pictured bike should never be referred to as an e-bike.

January 15, 2026

$3 Million Now in the Bank to Support Signature-Gathering Effort for Regional Transit Measure

Transit funding advocates have the money. Now they just need almost 200,000 signatures.

January 15, 2026

Monrovia’s ‘Haiku Park’ is Now Open

Satoru Tsuneishi Park honors the acclaimed poet once incarcerated in an internment camp.

January 15, 2026
See all posts