Bay Area commuters can breathe easier riding Caltrain’s new electric trains. According to a new study, Caltrain’s switch from diesel to electric trains in late summer of 2024 dramatically boosted the air quality aboard the commuter rail line.
According to findings released today in the journal Environmental Science and Technology Letters, switching to an electrified system decreased riders’ exposure to the carcinogen black carbon by an average of 89%, greatly reducing ambient black carbon levels both inside and near the San Francisco station.
“The transition from diesel to electric trains occurred over just a few weeks, and yet we saw the same drop in black carbon concentrations in the station as California cities achieved from 30 years of clean air regulations,” said study senior author and CEE Professor Joshua Apte. “It really adds to the case for electrifying the many other rail systems in the U.S. that still use old, poorly regulated diesel locomotives.”
Apte and Cliff estimate that Caltrain’s electrification lowered black carbon exposure, reducing excess cancer deaths by 51 per 1 million riders and 330 per 1 million train conductors. Notably, the U.S. Environmental Protection Agency deems any exposure that raises an individual’s average cancer risk by over one per million as unacceptable.
“If you think about this in the context of the whole of the U.S., where we have millions of people commuting by rail every day, that’s hundreds of cases of cancer that could be prevented each year,” said Cliff, a CEE postdoctoral scholar.
Co-authors of the study include Haley McNamara Byrne and Allen Goldstein of UC Berkeley.
Check out the full feature article on Berkeley News.