Cleaner Cars, Cleaner Air

The report finds that passenger vehicles manufactured before 2004, while representing only 19% of California's fleet, produce the vast majority of nitrogen oxides and reactive organic gases, contributing to PM2.5 pollution. This pollution disproportionately affects Black and Latino Californians and low-income households, particularly in Southern California and Los Angeles County. The authors recommend prioritizing vehicle replacement incentives for these priority populations and expanding transportation solutions beyond private car ownership.

• Passenger vehicles from model years 1976 to 2003 represent 19% of California's passenger vehicles and 12% of miles driven, but they generate 73% of all nitrogen oxides exhaust and 64% of reactive organic gases from passenger vehicles.
• Exposure to PM2.5 pollution from older vehicles is inequitably distributed by race and ethnicity; Latino Californians are exposed to 19% higher concentrations and Black Californians to 12% higher concentrations than the state average, while White Californians are exposed to 20% lower concentrations.
• Low-income households are disproportionately burdened by older-vehicle pollution. In areas with the highest PM2.5 exposure from these vehicles, over 50% of households earn less than $60,000 annually, compared to 35% in areas with the least exposure.
• The highest concentrations of PM2.5 from older vehicles are located in the southern half of California, specifically central Los Angeles, and correlate with high CalEnviroScreen 4.0 scores.
• Emissions from older vehicles are estimated to cause between 97 and 421 premature deaths per year in California, with the most significant impacts concentrated in Los Angeles County.
• While urban areas have the highest total exposure, rural counties such as Modoc, Trinity, and Sierra have higher proportions of older vehicles, with over 40% being model year 2003 or older.

APA

Union of Concerned Scientists (2023). Cleaner Cars, Cleaner Air. https://www.ucs.org/sites/default/files/2023-06/cleaner-cars-cleaner-air-executive-summary.pdf

Chicago

Union of Concerned Scientists. Cleaner Cars, Cleaner Air. 2023. https://www.ucs.org/sites/default/files/2023-06/cleaner-cars-cleaner-air-executive-summary.pdf.

Wikipedia

{{cite report |author=Union of Concerned Scientists |title=Cleaner Cars, Cleaner Air |date=June 2023 |url=https://www.ucs.org/sites/default/files/2023-06/cleaner-cars-cleaner-air-executive-summary.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{unionofconcernedscientists2023cleaner, author = {{Union of Concerned Scientists}}, 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-executive-summary.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }