As the days get longer and the temperature rises, it seems that welcoming, familiar smell begins to fill the air each afternoon — somebody’s fired up the grill.
It’s a tradition that’s quintessential to summer. It just doesn’t quite feel like summer until you’ve tossed a few burgers (maybe a couple portabella caps for the veggie crowd) on the grill, a cold beer in one hand and tongs in the other. But few of us ever stop to think about the environmental impact of our summer barbeques.
That’s right: your favorite summer pastime comes with consequences beyond eating too many hot dogs before you hop in the pool, but you can take steps to lessen your impact on the environment this summer when you’re planning to head out to the grill and cook up some grub.
First, consider what you’re grilling with. The debate over whether to use charcoal or propane goes far beyond the taste it imparts on your food. A 2009 study by environmental consultant Eric Johnson found that grilling with charcoal leads to a carbon footprint three times that of propane.
There are a number of factors behind why that is. First, as a fuel, propane is produced more efficiently than charcoal. While charcoal is a biomass, which might make it seem cleaner, most of the wood that is heated to created charcoal is converted to gas and emitted into the atmosphere, leaving somewhere between 20 and 35 percent as actual charcoal. Yields of propane, however, are greater than 90 percent, according to Johnson’s research.
John Volckens, a professor in the department of environmental and radiological health sciences at Colorado State University, agrees with Johnson’s work.
“There are a couple reasons why burning biomass residentially in the U.S. is not more environmentally friendly than other forms of cooking,” says Volckens. “One, when we’re burning wood, that form of combustion is not entirely clean — it emits volatile organic chemicals in the atmosphere, and particulate matter in the atmosphere. And we breathe the air that is in and around our homes, and if enough people are burning in an area, pollutant concentrations build up — it’s not insignificant.”
Volckens is leading a study — which received a $1.5 million grant from the Environmental Protection Agency — to look at cook stoves on a global scale, primarily for those in developing countries that don’t have access to natural gas or electrical infrastructure.
“These people are basically starting a campfire in the kitchen to provide a source of energy for food, light and heat for their family, and there are about 3 billion of those people on the planet,” says Volcken. “You can imagine for 3 billion campfires started on the planet each day, that can contribute quite a bit of pollution to the planet. We’re tying to understand the effect that has on climate.”
But Volckens’ team also wants to protect human health. He explains that charcoal grilling contributes to ground level ozone, which is the main component of smog. While the ozone at the upper regions of Earth’s atmosphere protect us from the sun’s harmful rays, ground level ozone can create health effects such as chest pain, coughing, throat irritation and congestion.
“Ozone is a major problem here on the Front Range. Almost every city on the Front Range is going to be deemed noncompliant for EPA’s ozone standard,” says Volckens. “Believe it or not, barbequing can contribute enough pollution to affect ozone pollution.”
The Environmental Protection Agency released a draft document early in February saying that the agency should reform the current ozone standard to a level as low as 60 parts per billion, down from 75 parts per billion.
Grilled foods can even have deleterious effects on your health. A Swedish study found that when meat fat drips on the hot coals of a charcoal grill, the smoke that arises actually contains a carcinogenic compound known as polycyclic aromatic hydrocarbons. PAH and another carcinogenic compound called HCAs (heterocyclic amines, if you’re into the science of it all) will also form in meats cooked using high-temperature methods. According to the National Cancer Institute, ongoing studies are investigating the association between meat intake, meat cooking methods and cancer risk.
“Cooking with charcoal is highly culturally accepted,” says Volckens. “We think foods coming from a charcoal grill taste better, but the byproducts of charcoal production are significantly more harmful.”
“For PAHs, when you get char on the food or when food is cooked under smoky conditions, those PAHS will be present in the smoke and the char and they go into your body.
There’s a lot of research that shows people who eat more of those charred foods are getting more diseases than people who [eat less charred foods].”
But J. Scott Smith, a professor of food chemistry at the Kansas State University, spent some time a few years back figuring out how to provide some protection against carcinogens found in grilled meats. Turns out it’s as easy as marinating meats with the right blend of herbs and spices.
Smith’s group measured HCAs in grilled round steaks before and after grilling and found that marinating them in a product containing rosemary and thyme reduced levels of HCAs by 87 percent, which the team found was correlated to the amount of antioxidants present in the marinade.
An even better way to sate your need to grill without the risk of cancer is to toss some veggies on the Barbie, as fruits and vegetables don’t contain the protein and amino acids that create HCAs in grilled meat.
After all this work to green your grill, don’t let safety fall to the wayside. Here in the West, wildfire is a serious matter. Kim Scott, the life safety educator and spokesperson for Boulder Fire Rescue, says it’s easy to let a fun afternoon of grilling turn into a dangerous situation. No charcoal or woodfire grills are allowed in Boulder city limits, so when you’re firing up your propane grill for the first time after winter, check the hose.
“Cold temperatures and high altitude can cause cracks in the gas line,” says Scott.
She adds that grills should be attended at all times, placed well away from homes, and grills should be cleaned either right before or directly after use.