A nearby school bus lot dumps plenty of pollution in the Ivy City air, residents say. (Jared Soares for The Washington Post)

Last week, D.C. Council member Kenyan McDuffie (D-Ward 5) made the unsurprising request of Mayor Vincent C. Gray that his administration scrap plans to park charter tour buses on the grounds of the historic-but-crumbling Crummell School in Ivy City.

Now McDuffie, who represents Ivy City, has a council colleague joining him. Mary M. Cheh (D-Ward 3), chair of the council’s committee handling environmental matters, posted a letter Monday asking Gray to ditch the bus plans on ecological grounds.

The letter notes that Howard University researchers have found that the neighborhood is a “high-background area for fine aerosols” — that is, airborne particulate matter like diesel exhaust — and those aerosols disperse more slowly than in other areas. Cheh also notes that a Superior Court judge found that a requirement for a more complete environmental impact assessment of the bus lot was illegally circumvented.

The upshot, Cheh writes: “Under the circumstances, it is unwise and dismissive of the community’s serious and valid health concerns to continue litigation or to attempt to move forward with this project.” Instead, she’d prefer the city pursue “alternative, less deleterious venues for the buses.”

Last week, a Gray administration spokesman declined to comment on McDuffie’s request. The city on Friday asked the judge handling the court challenge to the bus lot to stay her decision stopping the bus parking plans while it appeals, Washington City Paper reported.