California Has 8 of the 10 Most Polluted Cities in the U.S.

Despite ever-stricter air-quality regulations and dropping emissions, the American Lung Association once again finds the state to have some of the worst air in the nation.

1 minute read

April 24, 2018, 1:00 PM PDT

By Katharine Jose


Los Angeles Harbor Freeway

biofriendly / Flickr

As it has many times in its 19-year history, the “State of the Air” survey by the American Lung Association named Los Angeles-Long Beach as the most ozone-polluted city in the nation, reports USA Today.

The only two cities in the top 10 that are not in California are Phoenix (8th) and New York (10th).

The question the article asks, of course, is “Since California is known for its strict environmental regulations, why are so many cities from the state typically on this list?”

It’s similar to a question recently posed by Planetizen’s Irvin David about what he calls the “Southern California Air Quality Paradox:” since emissions are dropping, why is air quality getting worse?

Tuesday, April 24, 2018 in USA Today

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Get top-rated, practical training

For Lease painted on window of vacant commercial space.

2024: The Year in Zoning

Cities and states are leaning on zoning reform to help stem the housing crisis and create more affordable, livable neighborhoods.

January 8, 2025 - Diana Ionescu

Cyclist on bike in green painted bike lane at intersection with three-story buildings in background.

NACTO Releases Updated Urban Bikeway Guide

The third edition of the nationally recognized road design guide includes detailed design advice for roads that prioritize safety and accessibility for all users.

January 8, 2025 - National Association of City Transportation Officials (NACTO)

Close-up of person on bike wearing backpack riding on city street.

Research Affirms Safety of ‘Idaho Stop’

Allowing cyclists to treat stop signs as yield signs does not negatively impact safety and can help people on bikes more effectively navigate roadways.

January 14, 2025 - Streetsblog California

Close-up of person holding hand-written "Affordable Homes Now!" sign.

America’s Housing Crisis: Lessons Ignored and Challenges Ahead

A recent study reveals how decades of policy missteps, demographic shifts, and economic forces fueled America’s housing crisis, leaving millions — especially millennials — struggling amid rising demand, racial disparities, and climate-driven emergencies.

January 19 - USC Today

Homes in Altadena, California with mountains in background on a sunny day.

Altadena’s Resilience: Restoring a Fire-Ravaged Community

The Eaton Fire has devastated Altadena, destroying homes, cultural landmarks, and community institutions, while residents rally to rebuild and preserve the town's rich history, diversity, and neighborly character.

January 19 - NBC News

View up at Chicago elevated train line with train passing and glass high-rises in background.

Chicago Transit Leaders Call for $1.5B Funding Package

Public transit across the Chicagoland region could suffer massive cuts without additional funding.

January 19 - Bloomberg CityLab