Today’s guest blogger is Emma Shlaes, Clean Water Action National Campaigns Associate.

Summer is winding down. When you put your child on the bus for school, or take that one last road trip of the season, you expect that everyone will stay safe and healthy, as long as there are no accidents. But there is a hidden danger lurking around most school buses, highways and too many residential neighborhoods and schools. Dangerous and preventable diesel pollution from buses, trucks and construction vehicles is placing families in harm's way.

Dirty diesel engines emit a mixture of particles, metals and gases called "particulate matter" which include over 40 "hazardous air pollutants" as classified by the U.S. Environmental Protection Agency (EPA) under the Clean Air Act. This mixture can cause a range of health problems. From increased rates of asthma, to lung cancer, stroke and heart attack, diesel pollution contributes to countless illnesses and 21,000 early deaths a year.

In addition to being a serious public health problem, diesel pollution contributes to climate change by emitting a pollutant that’s aptly named “black carbon”. Black carbon soot is approximately 2,000 times more potent as a global warming agent than an equal amount of carbon dioxide (CO2). Over half the black carbon emissions in the U.S. come from diesel engines. Fortunately, black carbon is a short-lived pollutant and does not remain in the atmosphere, so this is one aspect of climate change we can do something about right now.

How do you ask? Available retrofits can reduce diesel particulate matter and black carbon emissions by at least 90% from the 11 million old, dirty diesel engines that are currently used in the U.S. This means an instant reduction of black soot in our atmosphere. Additionally, studies indicate that for every dollar spent on reducing particulate matter pollution from diesel engines, $12 would be avoided in monetized health damages. That translates to improved health for you and your family.

Since 2005, the federal Diesel Emissions Reduction Act (DERA) has been funding retrofits for existing heavy-duty diesel vehicles and engines in every state in the U.S. DERA has enjoyed support by: members of both parties in Congress, the U.S. Conference of Mayors, and industry, labor, environmental and health groups. This important act is set to expire in 2011 and Congress must reauthorize it at the same level of funding if we are to see continued reduction in diesel pollution and the health effects it causes.

Clean Water Action works nationally and in the states to pass policies that will clean up diesel pollution and protect communities. Some states haven’t waited for government protections and funding to take action. For example, Clean Water Action recently helped Rhode Island pass the Clean Construction Law, which requires diesel-burning construction equipment on federally funded projects to be retrofitted to reduce emissions by 2013. Connecticut, Massachusetts, Michigan and New Jersey have also taken action at the state and local level. Find out more.

Clean Water Action works as part of the Diesel Clean-Up Campaign, a nationwide collaboration of organizations committed to reducing diesel emissions 40 percent by the year 2012, 55 percent by 2015 and 70 percent by 2020. You can visit their website at www.dieselcleanup.org