Is sitting in your car bad for you?

If you drive a car regularly, chances are you’ll have to sit and wait in it with the engine running at some point. The practice is known as slow walking and it is common to do it at certain times of the day. You might be idle while waiting in line at the drive-thru, picking up an order curbside or dropping off the kids at school, or when you’re stuck in stopped traffic.

While idling is common, it’s not good for the people around your car. O US Department of Energy (DOE) and Environmental Protection Agency (EPA) advise against inactivity and there are even some school initiatives against that. Idle people are also subject to a fine in Some areasincluding New York, Massachusetts, Maryland, New Hampshire, New Jersey, Vermont, Hawaii and parts of California, Colorado, New York, Ohio and Utah.

But why is inactivity so bad and what can happen when you do it? The doctors explain.

The problem of inactivity

There are some things that make inactivity a practice to be avoided. It reduces your car’s fuel economy, ends up costing you money and creates pollution, according to the DOE.

“It all comes down to pollution,” Dr., medical director of the Children’s Pulmonary Institute at MemorialCare Miller Children’s & Women’s Hospital Long Beach in Long Beach, California, tells Yahoo Life. Car exhaust generated by idling often contains nitrogen oxide, sulfur oxide, ammonia and ozone. “People started paying attention to these vehicles that are stopped, generating pollution,” he says. This can be bad for children waiting for their parents to pick them up or for adults standing outside a store. “The exhaust is going straight into the airways and lungs,” highlights Randhawa.

“In small doses, it is not immediately dangerous. But it’s certainly not as healthy as fresh air,” Dr. Diane Calello, medical director and executive of the New Jersey Poison Information and Education System and associate professor of emergency medicine at Rutgers New Jersey Medical School, told Yahoo Life.

Regular exposure to parked cars is not good for your health, Dr., director of the Office of Global Health Initiatives at the University at Buffalo in New York, told Yahoo Life. “All of these pollutants are known to be harmful,” she says, noting that they can increase your risk of developing respiratory illnesses, cardiovascular diseases, allergies and cancer. “These pollutants can affect children’s health and development,” says Mu. “Many pollutants, such as CO2, will worsen climate change.”

The DOE says it’s especially important for caregivers to be mindful of idling when picking up children from school, because vehicle emissions are more concentrated closer to the ground, where children breathe. Poor air quality can increase the risk of asthma, and children’s lungs are more susceptible to damage than adult lungs. Dr.Daniel Ganjianpediatrician at Providence Saint John Health Center in Santa Monica, California, told Yahoo Life.

You are not necessarily protected when you are inside a car that is stopped. “When you are in a stationary car, you are also exposed to polluted air,” says Mu. “Some pollutant levels inside the car are even higher than outside, as emissions from this and surrounding vehicles in the parking lot or collection locations can enter the car and be recirculated.” (Of course, you don’t want to be sitting in a car parked in an enclosed space, like a garage, due to the risk of carbon monoxide poisoning.)

How long can you stay idle?

The DOE says idling for more than 10 seconds — which most people do — uses more fuel and produces more emissions that contribute to air pollution and climate change than stopping and restarting the engine.

In general, risks increase the longer you sit, says Calello. “The longer you idle, the more exhaust is released,” she says.

If your vehicle is moving every few seconds, it is not considered stationary, adds Randhawa. “It’s when you’re stuck and it’s been going on for a while. If you are stopped in that direction, just turn off the vehicle,” he says. “If all vehicles did this, it would have a huge impact.”

Idling is bad—and it’s worse the longer you sit still—but sitting in traffic or in poorly ventilated spaces like parking lots or overpasses “can be particularly harmful,” says Ganjian.

The type of car matters

Electric vehicles don’t have to worry about contributing to idling, says Calello. “An electric vehicle does not produce exhaust gases, so idling indoors or outdoors is safe,” she says. Hybrid vehicles turn off the engine when not moving, and stop-start technology is increasingly available in vehicles that are not hybrids or electric. This also eliminates idling when the car is stopped, the DOE says.

What can you do

Experts say there are a few things to keep in mind when it comes to inactivity. If it’s not too hot or cold, the DOE says it’s best to turn off your car if you plan to sit in one place for more than 10 seconds. (Just don’t do it in traffic, the agency adds, as you never know when you’ll need to move again.)

Because 10 seconds can be difficult to gauge, Randhawa recommends using 60 seconds as a benchmark. “If you’re in there for more than a minute, turn it off,” he says. “There’s an old notion that starting and stopping a car uses more gas, but that’s not true.”

Parents with children at school can talk to administrators about EPA measures Clean school bus program to reduce idling on school buses or discuss ways to discourage idling in pickup and delivery.

“We need more people to advocate for limiting car idle time and raising public awareness,” says Mu. “While we are all concerned about air quality and climate change, this is something we can all do together to improve our environment and public health.”