"At a per-passenger-mile basis, rail is about three times as efficient as travel by car, in terms of fuel efficiency, and six times as efficient as travel by air, so there are pretty substantial pollution reduction benefits both in terms of greenhouse gases and other pollutants."

VOA: standard.2010.02.15

he observes,pointing to the very substantial cuts in air pollution emissions during the 2008 summer Olympics in the Beijing metropolitan area.

VOA: standard.2010.04.07

However in the case of Neal Soil Suppliers - where dairy and food effluent was spread over a field - there had been "substantial and serious pollution".

BBC: Gwent Levels waste dumping: David John Neal pleads guilty

"With proper regulation and enforcement, gas provides a very substantial health benefit in reducing air pollution, " compared with coal-fired power plants, said Daniel Schrag, director of Harvard University's Center for the Environment.

WSJ: Celebrity 'fractivists': True advocates or NIMBYs?

Despite measures to cut lead pollution, most adults have substantial levels in their bodies.

BBC: NEWS | Health | Lead exposure link to cataracts