(The following story by Chris Bowman appeared on the Sacramento Bee website on September 7.)
SACRAMENTO, Calif. — Extensive air pollution testing has confirmed that the daily spew of locomotive exhaust from Roseville’s Union Pacific Railroad yard is highest for downwind residents, particularly those near the maintenance and repair shops, newly released data show.
The testing gives local officials more leverage to negotiate with Union Pacific for making further emission reductions.
Union Pacific officials said the next round of air test results should show a drop in diesel emissions because of the recent introduction of cleaner locomotive models in the yard.
Experts dispute whether the amount of locomotive soot wafting across Church Street through a neighborhood increased during the 2005-2007 testing.
But results from the three consecutive summers of sampling show diesel exhaust levels consistently and substantially higher in the downwind neighborhood than among homes directly across the yard along the upwind or south side of the J.R. Davis Yard, a 52-track, 6-mile-long facility.
“Overall, there is evidence of substantial impact on the downwind sites,” said Yushuo Chang, who oversees the monitoring for the Placer County Air Pollution Control District.
The monitoring results don’t tell the whole story.
Thomas Cahill, a retired University of California, Davis, atmospheric physicist who serves on the project’s technical advisory committee, said he and his toxicologist son found unexpectedly high levels of lead and toxic metal particles in more limited air sampling they conducted near the yard on their own last year for the Sacramento area chapter of Breathe California, a clean-air advocacy group.
He said the metals likely came from the dust blown off the dirt railyard, where trains have been serviced for at least 100 years.
The Placer air district monitoring also did not include the most toxic diesel exhaust compounds, known as benzo(a)pyrene. The Cahills reported from their sampling that the locomotive exhaust contains 5.5 times more of these compounds than those found in diesel truck exhaust.
The district’s study is focused mainly on locomotive soot. The sampling was limited to the northeast tip of the yard, near the service and repair shops, where diesel concentrations are thought to be highest. The monitors ran only in the summer from 10 p.m. through 5 a.m., when the wind speeds and direction are most consistent.
The sampling results align with earlier computer-model predictions on where the locomotive soot would disperse and at what concentrations. That computer analysis, conducted by the state Air Resources Board, also calculated that there were added risks of lung cancer from breathing the ultra-fine specks: a potential 900-fold increase for lifelong residents of the Church Street neighborhood.
Taken together, the air monitoring results and the cancer risk analysis estimate the area’s excess cancer rates “with a level of confidence rarely achieved in field studies of air pollution sources,” Cahill said.
The air sampling also helps Union Pacific determine whether its pollution controls are getting the most emission reductions for the money, railroad officials said.
The company is financing the project along with state and federal environmental agencies, and it has an engineering consultant on the technical advisory committee.
Though federally regulated as “mobile sources” of pollution, locomotives in a train yard effectively become a “stationary source” like a factory, local air regulators say. Under federal and state air pollution regulations, no factory in the United States would be allowed to spew anywhere near the amount of toxic particles wafting off a railyard.
The congregation of so many idling behemoth engines switching tracks, refueling or undergoing repairs, and the chugging of yard locomotives reassembling cars can create a toxic hot spot for neighboring residents.
The yard that cuts through the heart of Roseville is Union Pacific’s busiest hub west of the Rocky Mountains. It’s also the single largest generator of diesel exhaust in the six-county Sacramento metropolis, according to the state air board.
The Roseville yard monitoring, now in its fourth summer, is the first of its kind in the nation, according to the state air board. Local air regulators and community activists in Los Angeles and San Bernardino counties are following Placer County’s lead in quantifying urban railyard emissions and holding railroads accountable for abating them.
After the state made its cancer risk calculations public in 2004, Union Pacific signed a pact with Placer County to cut the diesel exhaust at least 10 percent by 2008.
Some improvement came in 2006 with the introduction of federally required low-sulfur diesel fuel for locomotives. The company also installed “smart start” devices that have reduced idling – and saved fuel – on approximately 26 “switcher” locomotives that move railroad cars around the yard, said Zoe Richmond, a spokeswoman for the railroad.
Earlier this year, the company replaced four of its oldest and dirtiest switchers with new “Genset” locomotives that run much cleaner, Richmond said. Union Pacific made the upgrade before the old stogies were ready to retire. In exchange, she said, the Placer and Sacramento area smog districts provided $3.2 million or 75 percent of the cost to buy the cleaner models.