Ernest Welde says he’s been chased, swung at and even pushed by truck drivers, who disapprove of his side gig. From his phone, Welde records trucks that are parked for longer than three minutes with their engines still running, an offense in New York City.

“Every time I go out of my house, I am prepared for an assault,” Welde, an environmental attorney by day, told CNBC. “You have to go out expecting there’s going to be a confrontation.”

Welde’s hunt for idling trucks started because of an online citizen reporting program the NYC Department of Environmental Protection launched in 2019. It’s called the Citizens Air Complaint Program, and it allows ordinary New Yorkers to receive a monetary reward for their “enforcement efforts.”

Emissions from idling gasoline and diesel motor vehicle engines are known contributors to health problems, including asthma, respiratory issues and cardiovascular harm, according to the agency’s website.

To participate in the program, citizen reporters need to shoot a video showing a commercial vehicle idling for more than three minutes. They then log on to the city’s Idling Complaint System to file and track their complaint.

According to the DEP, the fine for a first-time offender is $350, and more for repeat offenders. A 25-percent cut — or $87.50 — is paid to the person who shot the video and filed the complaint.