A new study published in Environmental science and technology papers It is learned that switching from diesel to electric trains on the Caltraine Commuter Rail Line of San Francisco Bay Area has improved air quality dramatically. Research found that black carbon, contact with riders for a known carcinogen, decreased by 89%on average.
Electrification In addition, there was a significant decrease in black carbon concentrations within and around the San Francisco station.
“Diesel from electric trains occurred within a few weeks, and yet we saw the same decline in black carbon concentrations in the station, as California cities had obtained from 30 years of clean air rules,” Senior writer of the study Joshua Apte, A professor of environmental engineering and environmental health at the University of California, Berkeley. “This actually combines the case to electrify many other railway systems in the US that still uses old, poorly regulated diesel locomotives.”
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Caltraine operates the busiest commuter rail system in Western America, carrying millions of passengers in a year with a 47 mile route between San Francisco and San Jose. During six weeks in August and September 2024, the system retired all 29 of its diesel locomotives and replaced them with 23 new electric trains. The new trains were the culmination of modernization of $ 2.44 billion and the decarbonization project, which was first launched in 2017.
An expert in air quality monitoring, Apte, was motivated to pursue the study after visiting a Caltrane station in August 2024, when electric trains were being introduced long ago.
“I was shocked on how much the station broke like diesel smoke and how much noise this diesel was made from the locomotive racket, away on the platforms, was dumping smoke in the community,” said Apt. “A light bulb went away from my head – I realized that all this would go away in weeks.”
After gaining the support of Caltraine, Apte and Study Lead Writer Samuel Cliff Quickly mobilized, install black carbon detectors at calcrain stations and carry portable air quality detectors in trains. For four weeks, they tracked the rapid improvement in air quality as the old diesel locomotives were replaced by new electric trains.
“Many of these changes are very slowly. It happened in a blink of an eye.” “We had a unique opportunity to catch assistant public health benefits.”
According to the calculation of Apte and Cliff, a decrease in black carbon exposure achieved by electrification of Caltraine cut off additional cancer deaths of 330 per 1 million people for 51 per 1 million people and train conductors for riders.