Researchers at the University of California campus at Merced have found that introduction of an urban rail transit system can reduce the level of carbon monoxide pollution and nitrogen oxides in the air.
The 2011 study,”Green Infrastructure: The Effects of Urban Rail Transit on Air Quality,” examined hourly pollution readings in Taipei, Taiway, following the opening of a completely new rail transit system. The public health impacts of the reduction of carbon monoxide of between 5 percent and 15 percent and a reduction in the nitrogen oxides in the air would be an important beneficial aspect of mass transit infrastructure that is often not taken into account by policy makers, according to the study.
Researchers also found that the rail transit system had little detectable impact on ground-level ozone, which is indirectly related to automobile emissions, but whose formation is not completely understood by scientists. The UC Merced scientists also found little evidence suggesting that automobile travelers adjusted their time or route of because of the availability of rail transit.