Josh Apte
@joshapte.bsky.social
Professor of Environmental Engineering + Environmental Health Sciences, UC Berkeley.
Research: air pollution, health, climate, EJ.
Research: air pollution, health, climate, EJ.
Postscript: the 40-year old diesel locomotives are now retired, but they are not at the end of the line quite yet. Many will be exported to Peru soon to start a new commuter service.
April 16, 2025 at 4:15 PM
Postscript: the 40-year old diesel locomotives are now retired, but they are not at the end of the line quite yet. Many will be exported to Peru soon to start a new commuter service.
Bottom line: electrification can bring huge air quality benefits to rail systems and the communities they run through.
We have dozens of other commuter rail systems that still use mostly older diesel locomotives. We should electrify them ASAP.
We have dozens of other commuter rail systems that still use mostly older diesel locomotives. We should electrify them ASAP.
April 16, 2025 at 4:15 PM
Bottom line: electrification can bring huge air quality benefits to rail systems and the communities they run through.
We have dozens of other commuter rail systems that still use mostly older diesel locomotives. We should electrify them ASAP.
We have dozens of other commuter rail systems that still use mostly older diesel locomotives. We should electrify them ASAP.
The reduction in black carbon at the SF station was so large that we saw the same drop in BC as what California cities achieved from *30 years* of clean air regulation!
April 16, 2025 at 4:15 PM
The reduction in black carbon at the SF station was so large that we saw the same drop in BC as what California cities achieved from *30 years* of clean air regulation!
Over the 6 weeks of the electric transition, there was a clear correlation between days with fewer diesel locomotives idling and days with better air quality near the SF station.
Once the diesel locomotives were retired, we found almost no detectable increment in diesel smoke near the station.
Once the diesel locomotives were retired, we found almost no detectable increment in diesel smoke near the station.
April 16, 2025 at 4:15 PM
Over the 6 weeks of the electric transition, there was a clear correlation between days with fewer diesel locomotives idling and days with better air quality near the SF station.
Once the diesel locomotives were retired, we found almost no detectable increment in diesel smoke near the station.
Once the diesel locomotives were retired, we found almost no detectable increment in diesel smoke near the station.
So, we equipped the SF Caltrain station with instrumentation to detect how much diesel smoke was coming from the locomotives.
April 16, 2025 at 4:15 PM
So, we equipped the SF Caltrain station with instrumentation to detect how much diesel smoke was coming from the locomotives.
Before electrification, the SF Caltrain station was noisy and smoky at nearly any hour of day.
Why? An arcane safety regulation requires that locomotives have a careful safety inspection if they are shut down for too long. So, they usually were just left running.
Why? An arcane safety regulation requires that locomotives have a careful safety inspection if they are shut down for too long. So, they usually were just left running.
April 16, 2025 at 4:15 PM
Before electrification, the SF Caltrain station was noisy and smoky at nearly any hour of day.
Why? An arcane safety regulation requires that locomotives have a careful safety inspection if they are shut down for too long. So, they usually were just left running.
Why? An arcane safety regulation requires that locomotives have a careful safety inspection if they are shut down for too long. So, they usually were just left running.
On diesel trains, smoke would blow straight into the passenger cars. Concentrations of black carbon were nearly as high as what I have measured in New Delhi traffic.
Electric trains were almost 90% cleaner on board!
This brings a meaningful reduction in cancer risk for staff & regular riders.
Electric trains were almost 90% cleaner on board!
This brings a meaningful reduction in cancer risk for staff & regular riders.
April 16, 2025 at 4:15 PM
On diesel trains, smoke would blow straight into the passenger cars. Concentrations of black carbon were nearly as high as what I have measured in New Delhi traffic.
Electric trains were almost 90% cleaner on board!
This brings a meaningful reduction in cancer risk for staff & regular riders.
Electric trains were almost 90% cleaner on board!
This brings a meaningful reduction in cancer risk for staff & regular riders.
We tracked concentrations of black carbon (BC) on-board dozens of diesel and electric trains.
BC is an excellent marker for diesel particulate matter, which is the #1 airborne carcinogen in California.
BC is an excellent marker for diesel particulate matter, which is the #1 airborne carcinogen in California.
April 16, 2025 at 4:15 PM
We tracked concentrations of black carbon (BC) on-board dozens of diesel and electric trains.
BC is an excellent marker for diesel particulate matter, which is the #1 airborne carcinogen in California.
BC is an excellent marker for diesel particulate matter, which is the #1 airborne carcinogen in California.
Caltrain used to operate a fleet of 40-year old diesel-powered trains. Over 6 weeks last summer, these locomotives were swapped for sleek new electric trains.
The rapid transition made it easy for us to quantify the big air quality benefits.
The rapid transition made it easy for us to quantify the big air quality benefits.
April 16, 2025 at 4:15 PM
Caltrain used to operate a fleet of 40-year old diesel-powered trains. Over 6 weeks last summer, these locomotives were swapped for sleek new electric trains.
The rapid transition made it easy for us to quantify the big air quality benefits.
The rapid transition made it easy for us to quantify the big air quality benefits.