Last year, Rafil Kroll-Zaidi submitted more than 2,000 complaints against idling trucks and buses in New York City. For this bit of civic-minded officiousness, he expects to earn more than $150,000 from the city’s government. “There is a symmetry that produces this peculiar form of self-interested activism,” he writes. “Those of us who wound up doing this because we are activist tattlers became enamored of the money our zeal incidentally produces, and those of us who joined solely for the money became legitimately passionate about the environmental stakes.” The story that Kroll-Zaidi writes about his work as a citizen enforcer — and the handful of misfits who are as devoted to the program as he is — is by turns hilarious and enraging, as the idling reporters’ do-gooderism bumps up against a city that, after first treating them as a mild annoyance, turns downright hostile to them.