Is idling in your car bad for you?

If you frequently drive a car, it’s likely that you’ll find yourself idling at some point, with the engine running while you wait. Whether it’s in a drive-through line, picking up takeout, dropping off your kids at school, or simply being stuck in traffic, idling is a common practice. However, it’s important to consider the potential health consequences of idling, not only for yourself but also for those around you.

Both the U.S. Department of Energy (DOE) and the Environmental Protection Agency (EPA) advise against idling, and some schools have even implemented initiatives to discourage it. In certain areas, such as New York City, Massachusetts, Maryland, New Hampshire, New Jersey, Vermont, Hawaii, and parts of California, Colorado, New York, Ohio, and Utah, idling can result in fines.

But why is idling considered harmful, and what are the potential risks? Medical experts provide some insight.

The downsides of idling are multi-fold. Firstly, it reduces your car’s fuel efficiency, leading to increased costs. Additionally, idling contributes to pollution, as highlighted by the DOE. Dr. Inderpal Randhawa, the medical director of the Children’s Pulmonary Institute at MemorialCare Miller Children’s & Women’s Hospital Long Beach in California, explains that idling vehicles emit car exhaust that contains nitrogen oxide, sulfur oxide, ammonia, and ozone. “People started paying attention to these vehicles that are just sitting there, generating pollution,” he says. This pollution can be particularly harmful to individuals waiting outside, such as children waiting for their parents or adults outside stores. Randhawa emphasizes that the exhaust is directly emitted into the airways and lungs of those nearby.

In conclusion, idling in your car not only has economic and environmental implications but also poses potential health risks. It’s crucial to be aware of the consequences and consider alternative practices to minimize idling whenever possible.
Dr. Diane Calello, medical and executive director of New Jersey Poison Information and Education System and associate professor of emergency medicine at Rutgers New Jersey Medical School, warns that while small doses of exposure to idling cars may not be immediately dangerous, it is certainly not as healthy as breathing fresh air.

Dr. Lina Mu, director of the Office of Global Health Initiatives at the University at Buffalo, explains that regular exposure to idling cars can have negative effects on health. The pollutants emitted by these vehicles are known to be harmful and can increase the risk of respiratory illness, cardiovascular diseases, allergies, and even cancer. Mu also emphasizes the impact on children’s health and development, as well as the contribution of pollutants like CO2 to climate change.

The Department of Energy advises caregivers to be particularly mindful of idling while picking up children from school, as vehicle emissions are more concentrated near the ground where children are breathing. Poor air quality can heighten the risk of asthma, and children’s lungs are more vulnerable to damage than those of adults, according to Dr. Daniel Ganjian, a pediatrician at Providence Saint John’s Health Center in Santa Monica, California.

Being inside an idling car does not necessarily offer protection from the pollutants. Mu explains that when inside a running car, individuals are still exposed to polluted air. In fact, some pollutant levels inside a car can be even higher than outside, as emissions from surrounding vehicles in parking lots or pick-up places can enter the car and circulate. However, it is important to note that sitting inside an idling car in an enclosed space, such as a garage, poses the risk of carbon monoxide poisoning.

As for how long it is safe to idle, the article does not provide an answer.
According to the Department of Energy (DOE), idling for more than 10 seconds, which is something most people do, not only uses more fuel but also produces more emissions that contribute to smog and climate change compared to stopping and restarting your engine.

Calello explains that the risks associated with idling increase the longer you sit. “The more you idle, the more exhaust is released,” she says.

However, Randhawa points out that if your vehicle is moving every few seconds, that is not considered idling. “It’s when you’re at a full stop and it’s been going on for a while. If you’re idling in that sense, just turn your vehicle off,” he says. “If all vehicles did that, it would make a big impact.”

All forms of idling are bad, and the longer you idle, the worse it becomes. However, idling in traffic or poorly ventilated spaces like parking garages or under overpasses can be particularly harmful, warns Ganjian.

The type of car you have also plays a role. Calello explains that electric vehicles don’t contribute to idling because they don’t produce exhaust, making idling indoors or outdoors safe for them. Hybrid vehicles automatically shut off the engine when not in motion, and stop-start technology is increasingly available in non-hybrid or non-electric vehicles, effectively eliminating idling when the car is stopped, according to the DOE.

Experts recommend a few things to keep in mind regarding idling. If the weather is not excessively hot or cold, the DOE advises shutting off your car if you plan to be stationary for more than 10 seconds. However, the agency adds that this should not be done in traffic since you never know when you’ll need to move again.
To accurately measure time, Randhawa suggests using 60 seconds as a benchmark instead of relying on 10 seconds. According to him, if you anticipate being parked for more than a minute, it is advisable to turn off your vehicle rather than leaving it idling. It is a common misconception that repeatedly starting and stopping a car uses more fuel, but this is not true.

For parents whose children attend school, they can engage in conversations with administrators about the EPA’s Clean School Bus program. This initiative aims to minimize idling from school buses and offers opportunities to discuss methods to discourage idling during pick-up and drop-off times.

Mu emphasizes the importance of more individuals advocating for reducing car idle time and raising public awareness. By collectively addressing this issue, we can contribute to improving both our environment and public health. As we all share concerns about air quality and climate change, taking action together is a step towards making a positive impact.