LAS VEGAS -- Department of Motor Vehicles inspectors have hit the roads to enforce stricter diesel vehicle emissions, backed by steep fines, aimed at cleaning the air in Nevada.
"Implementation of these new standards is one part of cleaning up diesel, which is one part of the pollution picture," DMV spokesman Kevin Malone said.
The new standards, adopted by the Nevada State Environmental Commission, went into effect on Wednesday. They use a standard called "opacity" to measure visible pollutants produced by diesel trucks and buses operating on state highways.
Opacity is a measurement of the amount of light blocked by smoke particles.
Under the new regulation, smoke from diesel vehicles manufactured since 1991 can block no more than 40 percent of the light passing through it.
Diesel engines made between 1977 and 1990 must have no more than 55 percent opacity. Engines built before 1977 must meet an opacity standard of 70 percent.
Formerly, all diesel engines manufactured since 1977 were held to a 70 percent opacity standard.
The department began issuing verbal warnings about the new regulations in October. The fine for failure to correct a first offense within 45 days is $800, and subsequent violations are $1,500.
A Sierra Club official praised the new limits, which bring Nevada in line with opacity standards set by the federal Environmental Protection Agency and neighboring states.
"The stuff in the air that makes us sick ... a lot of that's related to the components of diesel emissions," said Jane Feldman, conservation chairwoman for the Sierra Club southern Nevada chapter. "Attacking diesel is a way to make us healthier."
Daryl Capurro, managing director of the Nevada Motor Transport Association, predicted the tighter regulations will increase truckers' attention to maintenance and rigs belching excessive smoke.
He said the trucking industry worked closely with regulators to develop the new standards.
The DMV estimates that 36 percent of trucks and buses registered in Nevada do not meet the new standards.
Diesel constitutes a small share of the visible air pollutants in the Las Vegas area, which is prone to dust pollution and has drawn EPA oversight to limit airborne particles generated by development of dry desert soils.
Particulate pollution can aggravate respiratory ailments such as asthma, bronchitis, and other heart and lung conditions.
In addition, diesel produces relatively high amounts of nitrogen oxides that react with other compounds to form ozone, which can restrict normal lung function.