News stories from opposite ends of the nation this week illustrate ongoing concerns about diesel-spewing trucks and buses.

In Temecula, Calif., citizens and officials are raising concernsover future diesel emissions related to a proposed new quarry on 135 acres just off Interstate 15 near the San Diego border.

Supporters of the quarry say the project would create much-needed jobs. But critics still doubt the quarry company’s pledge to use modern truck engines that meet stringent federal emission standards on nitrogen oxide and particle emissions.

Members of the Temecula city council are skeptical the standards will be met, despite assurances from the company that they will require truck companies to certify that the trucks’ emissions conform to new standards from the U.S. Environmental Protection Agency.

The California Air Resources Board says particulate pollution from diesel engines can cause cancer, premature death and other health problems.

More than 400,000 diesel engines have been retrofitted to meet the new EPA standards, and new engines can reduce emissions by as much as 90 percent, according to the EPA.

Likewise, the agency is targeting school buses, encouraging bus companies to idle less and use new engine technologies to reduce emissions.

Bus emissions are also the concern of 69-year-old “Miss Penny Morton” of East Baltimore, Md. Morton is blaming her next-door neighbor – a metropolitan bus yard – for the early death of dozens of locals due to cancer or heart and respiratory problems.

She’s circulating a poster with the names and faces of 60 people whom she claims were victims of air pollution from the bus yard over the last 20-30 years, according to The Baltimore Sun.

Researchers have studied the air in Morton’s neighborhood and found that daily particle pollution levels do not exceed the federal limits, although two-week levels were slightly above federal safety thresholds.

But an Ohio State University researcher said the combination of air pollution and stress caused by sources such as noise pollution can have a potent combined effect.

“So if you’ve got the diesel exhaust and at the same time the community is under stress, it definitely is placing them at a higher risk of disease,” he told the Sun.