“You’re going to start with the natural gas flame,” the teenage one-time Food Network Star Kids winner explained in a professionally produced video to her 6,700 Instagram followers, adding, “because the flames actually come up, you can heat and cook your tortilla.” Kelley’s not the only Instagram influencer praising the flames of her stove.It’s the result of a carefully orchestrated campaign dreamed up by marketers for representatives with the American Gas Association and American Public Gas Association, two trade groups that draw their funding from a mix of investor- and publicly owned utilities.What the polished posts don’t mention is that those perfectly charred tacos and fast weeknight meals come at a steep price: Gas stoves expose tens of millions of people in the United States to levels of pollution so high that they would be considered illegal outdoors.Every time you ignite a gas stove, you’re filling your home with many of the same pollutants in exhaust from cars—carbon monoxide, nitrogen oxides, particulate matter, and formaldehyde, which are all associated with a range of chronic health problems like respiratory problems and cardiovascular disease.Two studies out in May added to that research with a closer look at one gas in particular: nitrogen oxide, a building block for smog, that is harmful even in short spurts and at lower levels."