On Wednesday, the EPA released a new interactive map letting people check out the biggest stationary sources of global-warming emissions in their area. It’s a nifty tool. But could it actually lead to less pollution? Quite possibly, yes, if the past is any guide.

(Ross D. Franklin/AP)

One recent book, “Coming Clean: Information Disclosure and Environmental Performance” charts the impacts that the Toxics Release Inventory had on polluters. As Mark Stephan, a professor at Washington State University, Vancouver, explained to me, he and his co-authors conducted interviews with a variety of companies about their responses to the new public database. Many companies didn’t even realize they were spewing out so much pollution until forced to start keeping records. And that proved to be a big deal.

For instance, when the inventory was first disclosed in 1987, Monsanto executives realized that the company was one of the largest emitters in the country and pledged to reduce its toxic air releases 90 percent by 1992. This wasn’t in response to any new laws — Monsanto wasn’t legally required to do anything. The company was simply reacting to public information. Stephan adds that many other companies soon followed suit, in response to a fusillade of newspaper stories about toxic waste and pressure from community groups and local environmentalists.

It’s difficult to quantify the exact impact of the inventory, since there were a lot of other things going on at the same time, such as new Clean Air Act rules and technological change. But a 2009 Georgia Tech study (PDF) by economist Nicholas Powers found that the counties listed as among the most toxic under the TRI saw a marked decrease in “dirty” facilities and an even larger increase in new “clean” facilities — suggesting that the pollution wasn’t just getting shipped overseas. Firms really were mopping up.

Now, that doesn’t mean the new greenhouse-gas inventory will play out in exactly the same way. For one, information about toxic pollution like mercury, which affects the local community, is more likely to spark public outrage than information about greenhouse gases, whose climate impacts are more diffuse and global. Still, Stephan predicts that at least some companies won’t enjoy finding themselves on top-10 lists of greenhouse-gas polluters and will try to reduce their emissions as a response.

“What we saw happening internally is that some of these companies were really affected by being forced to collect data on just how much they were polluting,” Stephan says. “Sure, some companies just felt like they had to fill out the paperwork and turn it in. But we saw a significant number of them change their environmental practices.”

That’s hardly a substitute for hard regulations — or a price on carbon — that will actually require emissions cuts. But it’s a first step, and a potentially significant one.