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Health Effects:
Be Idle Free

What You See … and Can’t See … Can Hurt You

Idling can be bad for your health. While children, the elderly, and people with respiratory ailments are most vulnerable to the pollutants from vehicle exhaust, these emissions affect everybody. Pollutants released during idling have been linked to the increased incidence of asthma, allergies, lung and heart disease, and cancer.

Idling emissions include nitrogen oxides (NO2), volatile organic compounds (VOCs), carbon monoxide (CO) and fine particulates (PM2.5). All of these pollutants carry health risks. Carbon monoxide interferes with the blood’s ability to carry oxygen to the brain, heart, and other tissues, causing headaches and fatigue. Ozone, created by chemical reactions between oxygen and nitrogen oxides, can cause inflammation in the lungs, decrease lung capacity, and irritate bronchial passages. VOCs, which along with NO2 contribute to the formation of ozone, have the potential to cause cancer. PM2.5 fine particulates lodge deeply in the lungs, causing respiratory problems and providing an entry point for toxic pollutants into the lungs.

Children are at particular risk because they breathe more rapidly than adults and inhale more air per pound of body weight. Children also spend a considerable amount of time outdoors during the summer and fall, when ozone levels are typically higher. Exposure to these pollutants is associated with increased frequency of childhood illnesses and can contribute to the development of asthma and other respiratory ailments.

Many people do not realize that engines release more harmful emissions when idling than driving. Modern engines are designed to run most efficiently at higher temperatures. Because engines run at a lower temperature when idling, they do not fully combust fuel injected into the combustion chamber. This incomplete combustion releases a chemically complex toxic brew into the air.

Diesel exhaust is especially harmful. The Environmental Protection Agency (EPA) regards these emissions as a major health risk to the public. Scientists have yet to identify a safe level of exposure to diesel exhaust. People who live in urban areas or near major roads and highways suffer a greater incidence of respiratory problems due to the higher concentrations of exhaust in these areas. Diesel emissions from idling school buses pose a danger to children and have been at the heart of idle reduction efforts throughout the country.

Surprisingly, exposure to most auto pollutants, including VOCs and CO, is much higher inside vehicles than outside. Drivers caught in traffic jams on highways, idling outside a school or sitting at drive-through inhale more toxic pollutants than people standing outside the car.

Reducing unnecessary idling reduces exposure to these toxic pollutants and improves the respiratory health not only of sensitive populations but also healthy individuals.