Recently, the EPA announced that chronic exposure to diesel exhaust from old buses and trucks were linked to an increased risk of lung cancer.  And while those championing renewable energy praised the report as a call for tougher emissions standards, it appears they may have tooted their horns too soon.  This, according to the Environment and Climate News, which notes that the EPA’s study was based largely on data collected before the 1970 clean air act, rather than an assessment of today’s technology.  If they had researched new diesel engines, they would have found that experts project a 90 percent reduction in exhaust levels – and that new diesel buses outperform even natural gas ones in 8 out of 11 tests.