image: Stanford PhD student Metta Nicholson observes a gas burner in a home where scientists measured air pollution as part of their data collection in California, Texas, Colorado, New York, and Washington, D.C.. view more Credit: Rob Jackson, Stanford Doerr School of Sustainability Households with gas or propane stoves regularly breathe unhealthy levels of nitrogen dioxide, a study of air pollution in U.S. homes found. “I didn’t expect to see pollutant concentrations breach health benchmarks in...