Mayor Bloomberg, who has criticized this year’s presidential primary debates as uninformative, said he would make senators Obama and McCain give straightforward explanations of their policies if he were to moderate a debate between the two candidates.

“I know exactly what I would do: I would drill each candidate in front of the other, and have follow-up after follow-up after follow-up until you get real concrete answers,” Mr. Bloomberg said at a press conference yesterday in the Bronx. The mayor’s preferred debate format probably would not go over well with the candidates, he acknowledged, putting the likelihood of such an event at “probably less than zero.”

Mr. Bloomberg said he is not sure why the Obama and McCain campaigns turned down his offer this week to host a town hall meeting with ABC at Federal Hall in Lower Manhattan, which he called a “perfect venue” for the two candidates. He added that if Messrs. McCain and Obama accept a debate in New York at some point, they will be free to negotiate the rules themselves.

“We don’t benefit from it other than as good citizens, but the public has a right to know where these candidates stand, and I think the best place to start would be in New York City,” Mr. Bloomberg said.

The mayor’s remarks came at a press conference in which he announced the creation of a new Office of Environmental Remediation, to be headed by Daniel Walsh, that will help facilitate the cleanup of contaminated “brownfields” throughout the city. Mr. Bloomberg called on Albany to change state laws and procedures governing the cleanup of the polluted sites, such as allowing developers to clean contaminated areas voluntarily and then giving them a liability release encouraging them to build on the site.