Y’all know I have lived in the DC Metropolitan area for almost 3 decades. Over that time, the Potomac River has been cleaned up. (No, it’s not clean. But, coming from where it was in the 70’s and 80’s, there has been an amazing improvement.) And, over the past 3 decades, those EPA regulations that a certain party bitches about have made an amazing difference in local air quality. (That’s true even though DC has a slew of bus traffic- more tourist buses than almost every other place in the US.)