Consumer Reports' tests found high levels of potentially dangerous nitrogen oxide gases
Gas ranges have been the gold standard in cooking for decades. People love how responsive they are, that you can use them with different kinds of cookware, and, of course, the look of the real flame.
But that beloved flame also poses growing concerns, for both the health of users and of the planet.
One particular, and new, issue: nitrogen oxides, or NOx. These are gases that, outdoors, come primarily from vehicles and power plants and that can cause some of the haze associated with smog. But growing research suggests that gas ranges can also emit NOx, possibly at levels more than double the standard for outdoor air set by the Environmental Protection Agency.
That’s worrisome: The gases can worsen asthma and other lung diseases, and may increase the risk of asthma in children.
To investigate the problem further, and to see whether ventilation reduces those levels, Consumer Reports recently measured emissions of NOx and other gases from two typical gas ranges, in a controlled setting designed to mimic people cooking at home in a typical kitchen.
“Our tests found NO₂ at levels above those recommended by some public health organizations for indoors, particularly when the ranges were used without ventilation and when a burner was set on high,” says Ashita Kapoor, CR’s associate director of product safety. “That’s alarming.”
To test the ranges, CR built an insulated chamber with a range hood and ventilation fan, as your home kitchen might have. We then performed 24 tests, for each of the two ranges, to measure levels of not only NOx but also carbon monoxide, carbon dioxide, and particulate matter. We also measured oxygen levels to see whether they dropped dangerously low.
We put some monitors close to the ranges and some further away, to capture approximate gas levels for people cooking at the range as well as those standing nearby.
The two ranges were tested separately, first with a single burner on low and then with the same burner on high. We tested with and without ventilation, recording data for 90 minutes.
While the risks of asthma and other lung disorders are clear, to date the EPA has set legal limits only for outdoor air. So CR used guidelines set by Health Canada and the World Health Organization.
None of our testing revealed dangerous levels of carbon monoxide or particulate matter, nor did oxygen drop to unsafe levels.
But in several tests we recorded elevated levels of carbon dioxide and, even more concerning to Kapoor, nitrogen dioxide, one of the NOx gasses CR measured. Those gases are “more potent with respect to acute toxicity,” she says, making them more likely to cause problems even in the short time frame that people typically take while preparing a meal.
In two instances, we recorded elevated levels of nitrogen dioxide with a single burner set to low. And while using a range hood helped lower levels, in a few tests we still recorded levels that exceeded 1-hour guidelines set by the World Health Organization. And this was the case with both ranges.
In follow-up tests, CR plans to measure emissions from a larger sample of ranges.
While range hoods didn’t eliminate the problem in our tests, they did help. So if you cook on a gas range or cooktop, use the range hood or, if you don’t have one, take other steps to ensure adequate ventilation.
“You would never drag your gas grill into your kitchen to make dinner,” says James Dickerson, PhD, CR’s chief scientific officer, “but in effect, cooking with a gas stove comes with some of those same risks.”
So think of ventilating as a crucial part of your cooking routine. Take these steps:
- Use your range hood every time you cook, even if you’re just boiling an egg.
- If you don’t have a range hood, buy one and have it installed, preferably right above your range. That was more effective than vents or fans placed elsewhere, Kapoor says.
- Open windows and doors if you can, and use a fan. It’s best if the fan vents outside, but any fan that circulates the air can help the gases dissipate.
All those steps are extra important if anyone in your home, particularly a child or older person, suffers from asthma or other respiratory illness.
If you’re getting a new range, consider electric. They not only don’t emit potentially harmful gases but, contrary to popular opinion, they can cook more quickly. New induction ranges, which use electromagnetic pulses to heat, offer about three times the efficiency of gas. Many electric and induction ranges get top scores in CR’s ratings.
Induction ranges do require using magnetic cookware, but that’s not as limiting as it might sound. Magnetic stainless steel, cast iron, and pretty much all cookware made from multiple layers of metal are magnetic, while stamped aluminum fry pans and anodized aluminum cookware are not.
Finally, if you’re concerned about the costs of converting from gas to electric, you might qualify for rebates, depending on where you live and how much you make. The recently passed Inflation Reduction Act provides credits of up to $840 for the purchase of a new electric range, cooktop, or wall oven, as well as additional credits for installation costs, for those meeting the eligibility requirements.