Diesel Exhaust

One of the leading air pollutants of concern in Oregon is diesel exhaust. Diesel engines emit a significant amount of harmful pollutants, including those that contribute to climate change. Some studies suggest diesel soot is the second largest contributor to climate change-second only to CO2. Of the 40 toxic substances in diesel exhaust, the primary health concern is the particulate matter. Particulate matter can be divided into different sizes because of different health impacts:

• Coarse particles are between 2.5 microns and 10 microns in diameter and come mostly from natural sources such as windblown dust or soil
• Fine particles (PM) are less than 2.5 microns in diameter and pose the most health threat. Fine PM comes from combustion or burning activities. Fuel burned in vehicles, trucks, buses and equipment, and in power plants, factories, fireplaces and woodstoves, produce fine PM.

Diesel exhaust is a major contributor of particulate matter; in fact, > 80% of the particulate matter in the exhaust is fine PM.

Why are We Concerned About Particulate Matter?

Fine PM is a health concern because it is toxic and its extremely small size allows it to bypass the body's natural filtration system and lodge deep in the lungs (unlike other substances that can be coughed or sneezed out). Fine PM also attracts other toxic substances in the air, increasing its toxicity delivered to the lungs and other parts of the body.

Numerous studies have linked particulate matter, especially fine particles, with many health problems including:

Premature death
Cancer
Respiratory-related hospital admissions and emergency room visits
Aggravated asthma Acute respiratory symptoms including aggravated coughing and difficult/painful breathing
Chronic bronchitis
Decreased lung function expressed as shortness of breath; and
Work and school absences

Who is Most at Risk from Exposure to Fine Particles?

The Elderly:

• Studies estimate that tens of thousands of elderly people die prematurely each year from exposure to ambient levels of fine particles.
• Studies also show that exposure to fine particles is associated with thousands of hospital admissions each year. Many of these hospital admissions are elderly people suffering from lung or heart disease.

Who is Most at Risk from Exposure to Fine Particles?

Individuals with Preexisting Heart or Lung Disease:

Breathing fine particles can also adversely affect individuals with heart disease, emphysema, and chronic bronchitis by causing additional medical treatment. Inhaling fine particulate matter has been attributed to increased hospital admissions, emergency room visits and premature death among sensitive populations.

Children:

The average adult breathes 13,000 liters of air per day; children breathe 50 percent more air per pound of body weight than adults.

Because children's respiratory systems are still developing, they are more susceptible to environmental threats than healthy adults.

Exposure to fine particles is associated with increased frequency of childhood illnesses, which are of concern both in the short run, and for the future development of healthy lungs in the affected children.

Fine particles are also associated with increased respiratory symptoms and reduced lung function in children, including symptoms such as aggravated coughing and difficulty or pain in breathing. These can result in school absences and limitations in normal childhood activities.

Asthmatics and Asthmatic Children:

More and more people are being diagnosed with asthma every year. Fourteen Americans die every day from asthma, a rate three times greater than just 20 years ago. Children make up 25 percent of the population, but comprise 40 percent of all asthma cases.

Breathing fine particles, alone or in combination with other pollutants, can aggravate asthma, causing greater use of medication and resulting in more medical treatment and hospital visits.

How to Protect Yourself from Diesel

Protecting yourself from diesel is practically impossible. Trucks and buses are everywhere. Diesel exhaust is also released throughout the process of fuel production, refining, distribution and dispensing. There are some ways to reduce risk, such as limiting exercising, especially near major roadways, but the answer is reducing diesel exhaust at the source.

Reducing Diesel Exhaust

There are currently available technologies and methods fleets can use to reduce their diesel exhaust. This allows fleets to take advantage of the benefits of diesel engines--power, durability and efficiency-- by reducing their risk. The three main methods are for fleets to burn less fuel by reducing unnecessary idling, improving vehicle aerodynamics and reducing vehicle top speed; burn cleaner fuel (biodiesel, propane, compressed natural gas), and burn fuel more efficiently, installing advanced exhaust controls; some exhaust controls can reduce diesel exhaust by up to 90%.

Reducing Diesel Exhaust

The Oregon Department of Environmental Quality (DEQ) has worked on many clean diesel projects throughout the state, retrofitting hundreds of school buses with controls reducing school-aged children's exposure to diesel, replacing decades-old engines in towboats, and working with construction companies to use cleaner fuels and control devices. Additionally, the state offers tax credits to help fleets with the cost of retrofitting, and offers grant funding, when available.

The American Lung Association in Oregon supports DEQ's clean diesel work, including legislative efforts and their new Fleet Forward program. The program recognizes public and private fleets that voluntarily reduce their exhaust. To learn more about the clean diesel work DEQ is doing visit DEQ's website: www.deq.state.or.us/aq/diesel/initiative.htm.