The U.S. Environmental Protection Agency is quietly allowing big polluter states to blow more ozone onto their neighbors. This past August, the agency sent a technical memo to its regional offices regarding the Clean Air Act’s “good neighbor requirements,” which limit air pollution that travels across state lines. The memo suggests that states can adopt a higher ozone limit—which would allow a whopping 43 percent more cross-state pollution than under President Obama. Most concerning: The EPA did so without conducting any analysis into the rollback’s potential health impacts—a particular concern for ozone, which can cause respiratory illnesses like asthma attacks (particularly in children) and increase risks for heart attacks and premature death. The “good neighbor requirements” have been pushed to the side under this administration, as states like Maryland and others have fought (unsuccessfully) for stricter federal oversight and relief from upwind polluters. According to the Maryland EPA’s own estimates, 70 percent of Baltimore’s smog drifts in from out-of-state cars, trucks, power plants, and other industries.