The Problem with Diesel

Diesel engines are a major source of particulate and smog-forming pollution. Diesel exhaust is the most potent carcinogen (cancer-causing substance) in air pollution. And because diesel engines are so often operated where people live, play, work or go to school, they pose particular dangers to human health.

EPA recently adopted strong standards for new diesel engines, but because of the slow fleet turnover of existing high-polluting engines used in vehicles and equipment like buses and tractors, the federal standards won't deliver their full promise until 2030 or later.

Two new measures will help close the loopholes for older engines (which can go on polluting for decades) and new stationary diesel engines (until now unregulated).  Thanks to Environmental Defense efforts, EPA recently set the first-ever national emission standards to limit harmful exhaust from diesel engines used in machinery such as electrical generators, compressors, pumps and other stationary equipment.
 
To help reduce unhealthy exhaust from older vehicles, Congress authorized in 2005 (through an amendment to the energy bill) a program that, if fully funded, will provide $1 billion in loans and grants for local initiatives to clean up existing diesel engines. The program covers all types of vehicles, including trucks, ships, locomotives, school buses and tractors. (More on this new national program.)

Solutions

To achieve an 80% reduction in emissions from all diesel engines by 2014, pollution from all on-road, off-road, and stationary diesel engines must be addressed. A national commitment is needed to replace or retrofit all existing diesel machinery within a decade to meet or exceed the protective federal standards for new engines. To maximize public health protections over the next 10 years, a parallel commitment by industry and government to clean up existing engines is needed.

Our 2005 report Cleaner Air for America shows that the value of the health benefits of a national program to lower pollution from today's diesel engines far exceed the cost of investment, by at least 12 to 1. Environmental Defense has also created a handbook that shows what steps the public and private sectors can take to cut diesel pollution from their vehicles by up to 90%.

New EPA Regulations Will Save Thousands of Lives

Diesel engines are the workhorses of the American economy, providing power to almost every type of commercial vehicle as well as many types of electrical generating equipment. But diesel-powered vehicles are among the most dangerous and pervasive sources of air pollution. For example, commercial ships nationwide discharge about 1 million tons of smog-forming nitrogen oxides each year -- as much as millions of cars.

Download our Cleaner Diesel Handbook and help bring cleaner air to your community.

In a welcome move, the U.S. Environmental Protection Agency (EPA) recently announced new regulations to curb harmful diesel exhaust from some nonroad sources, such as tractors and bulldozers. (Read more on the new rules below.)

What Are Nonroad Vehicles?

A nonroad vehicle is, quite literally, a vehicle that does not normally operate on roads. They are also referred to as "off-road" or "off-highway" vehicles. This broad category is comprised of a diverse collection of machines many of which are powered by diesel engines including, but not limited to:

• Locomotives
• Agricultural equipment (i.e., tractors)
• Construction and mining equipment (i.e., graders and back hoes)
• Commercial marine vessels

View our slide show to see various kinds of nonroad machines.

Staggering Pollution from Nonroad Engines

Collectively, nonroad engines -- from gasoline lawn and garden equipment to large diesel construction equipment -- discharge more dangerous fine sooty particles than any other source in the transportation sector. Nonroad diesel engines are in many cases similar to their onroad counterparts, yet without state-of-the-art emission controls they emit sooty particles at dramatically higher levels.

Not only have nonroad emissions been poorly controlled until now, their pollution levels have gone out of control. Since 1980, annual nitrogen oxide (NOx) emissions from all nonroad engines have increased by nearly 25%. These engines discharge a significant portion of the total U.S. NOx emissions. This key ingredient in the formation of smog (ground-level ozone) contributes to acid rain, reduced visibility in urban areas and national parks and the deterioration of coastal estuaries.

In addition, diesel exhaust is associated with cancer and noncancer health effects. Smog and soot trigger asthma attacks and worsen the health of individuals with asthma. Several major international and national health agencies have concluded that diesel particulates are likely carcinogenic, increasing the risk of lung cancer. Indeed, recent data suggests that diesel particulates are the predominant source of cancer risk from air pollution.

Nonroad engines are also responsible for a significant part of nationwide sulfur dioxide pollution, which contributes to harmful particulate pollution, regional haze in national parks and brown clouds in urban centers.

What Is Being Done?

The good news is that EPA has recognized the importance of cleaning up harmful diesel exhaust. Cost-effective engine technologies and emission control technologies combined with cleaner, lower-sulfur diesel fuel, can reduce particulate pollution by 90% or more -- the equivalent to removing about 90% of today's cars, SUVs and light trucks from the road! Tightening emission standards for NOx and PM emissions along with requirements to lower the sulfur content of nonroad diesel fuel are important ground-breaking steps that will help reduce air pollution from the transportation sector.

Specifically, EPA's new rules, which will cut emissions of smog-forming chemicals and fine soot by more than 90 percent, are to be phased in starting in 2008 for the very smallest engines and will be fully implemented by 2015. The final rules for these nonroad diesel engines will slash the sulfur content by more than 99 percent by 2010. They also require low sulfur fuel for commercial shipping and locomotives by 2012.

Newly manufactured large highway trucks and buses and the diesel fuel they use are subject to rigorous rules adopted several years ago that include low sulfur fuel requirements to be achieved in 2006 and strong emission standards to be phased in thereafter. EPA's new final rules announced in May 2004 now also subject many diesel machines classified as "nonroad" to strict federal regulations including those used in construction, industrial, mining and agricultural equipment.

EPA estimates that by 2030, controlling emissions from these nonroad diesels would annually prevent 12,000 premature deaths, over 15,000 heart attacks, 6,000 children's asthma-related emergency room visits, 8,900 hospitalizations and almost a million work-days lost. (To see how your state's air could improve, view our table.)

EPA also announced a new initiative to tighten emission standards for commercial ships and locomotives. The standards being considered would apply to new marine diesels and both new and re-manufactured diesel locomotives. Although diesel locomotives and boats and ships (marine commercial vessels) are included in the broad category of nonroad diesel-powered vehicles, EPA has separate regulatory programs for each of these.

Diesel Retrofit Programs as a Bridge to New Emission Standards

While the national emission standards adopted by EPA will require steep cuts from newly manufactured engines, it will take years to fully realize these clean air benefits. The communities living with diesel pollution cannot wait the years that will pass before dirty diesel engines are scrapped. Retrofit and repower programs have proven successful in spurring the cleanup of high-polluting diesel engines currently in use. These programs should be expanded to provide more immediate public health and environmental protections as a bridge to tougher standards for new engines.

Posted: 17-Sep-2008; Updated: 30-Oct-2008