California's efforts to clean up diesel engines have helped reduce impact of climate change on state, study finds

(Phys.org) —Reductions in emissions of black carbon since the late 1980s, mostly from diesel engines as a result of air quality programs, have resulted in a measurable reduction of concentrations of global warming pollutants in the atmosphere, according to a first-of-its-kind study examining the impact of black carbon on California's climate.