The US Government is targeting new sources of diesel pollution in an attempt to improve air quality.

Off-road diesel-powered vehicles and machinery such as ferry boats, farm tractors, train locomotives, and dirt movers at construction sites will fall under new regulations issued by the Environmental Protection Agency (EPA).

According to Associated Press, EPA administrator Mike Leavitt believes the control of these types of machines are necessary to comply with federal air quality targets.

According to EPA figures, off-road diesel vehicles machinery accounts for roughly one quarter of all the smog-causing nitrogen oxide and nearly half of the fine soot produced by mobile sources.

"We're now going to take sulphur out of diesel, and add catalytic converters to diesel engines," Mr Leavitt stated.

"The result will be that that black puff of diesel smoke that we've become accustomed to seeing on big trucks and on construction equipment and on buses will be a thing of the past."

Platinum catalysts are used to control harmful exhaust emissions in diesel engines.