Cleaner Cars, Cleaner Air

The report analyzes the impact of passenger vehicles manufactured before 2004 in California, finding that while they represent only 19% of registered vehicles, they produce the majority of nitrogen oxides and reactive organic gases. This pollution contributes to the formation of PM2.5, which is linked to significant health issues and premature deaths. The study demonstrates that exposure to this pollution is inequitably distributed, disproportionately affecting Latino, Black, and low-income communities, particularly in Southern California. The authors recommend prioritizing vehicle replacement incentives for disadvantaged populations and expanding non-private transportation alternatives.

• Passenger vehicles manufactured before 2004 produce a disproportionate amount of pollution compared to newer models. Despite making up only 19% of registered vehicles and 12% of miles driven, they are responsible for 73% of all nitrogen oxides exhaust and 64% of reactive organic gases from passenger vehicles.
• Older vehicles have significantly lower fuel efficiency and higher operating costs. Older cars average 23 MPG and older trucks average 17 MPG, whereas new cars and trucks in California average more than 30 MPG and 25 MPG, respectively. Additionally, 20-year-old cars fail Smog Checks twice as often as 10-year-old vehicles.
• Exposure to PM2.5 pollution from older vehicles is inequitably distributed by race, ethnicity, and income. Latino Californians are exposed to concentrations 19% higher than the state average, and Black Californians are exposed to concentrations 12% higher, while White Californians are exposed to 20% lower concentrations. Higher-income households (over $200,000) have 18% lower exposure than the state average.
• The highest concentrations of PM2.5 pollution from older vehicles are located in the southern half of California, specifically in central Los Angeles and Long Beach. In areas with the highest exposure, 67% of residents are Latino and 8% are Black, compared to statewide populations of 40% and 5%, respectively.
• Pollution from older vehicles is estimated to cause between 97 and 421 premature deaths per year in California. These deaths are heavily concentrated in Southern California, with Los Angeles County alone accounting for over one-third of the state total.
• While urban areas have the highest total number of older vehicles, rural areas have a higher proportion of them. In rural Modoc, Trinity, and Sierra counties, over 40% of vehicles are model year 2003 or older.

APA

Beyer, M., Gerrity, A., Partida-López, R., & Reichmuth, D. (2023). Cleaner Cars, Cleaner Air. Union of Concerned Scientists. https://www.ucs.org/sites/default/files/2023-06/cleaner-cars-cleaner-air-report_0.pdf

Chicago

Beyer, Matthew, Ashley Gerrity, Román Partida-López, and David Reichmuth. Cleaner Cars, Cleaner Air. Union of Concerned Scientists, 2023. https://www.ucs.org/sites/default/files/2023-06/cleaner-cars-cleaner-air-report_0.pdf.

Wikipedia

{{cite report |last1=Beyer |first1=Matthew |last2=Gerrity |first2=Ashley |last3=Partida-López |first3=Román |last4=Reichmuth |first4=David |title=Cleaner Cars, Cleaner Air |publisher=Union of Concerned Scientists |date=June 2023 |url=https://www.ucs.org/sites/default/files/2023-06/cleaner-cars-cleaner-air-report_0.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{beyer2023cleaner, author = {Beyer, Matthew and Gerrity, Ashley and Partida-López, Román and Reichmuth, David}, title = {{Cleaner Cars, Cleaner Air}}, institution = {Union of Concerned Scientists}, year = {2023}, month = jun, url = {https://www.ucs.org/sites/default/files/2023-06/cleaner-cars-cleaner-air-report_0.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }