Metro officials believe that a batch of new air fresheners may be improving riders’ ratings of cleanliness on trains. (Photo by Matt McClain for The Washington Post)

Metro officials are hoping that Green Line riders will soon detect a subtle difference on their daily commute — a certain eau de cucumber melon, if you will.

As part of an effort to improve customer satisfaction with cleanliness on the trains, workers have been installing industrial-grade air fresheners on 6000-series trains that traverse the Green Line. The air fresheners are placed within the ventilation systems on the trains, and new ones are swapped in each month.

For now, the air fresheners come in two scents: cucumber melon and mango.

News of the newly-perfumed trains came at a Metro board meeting earlier this month, where Metro’s Chief Performance Officer Andrea Burnside said the decision to begin using air fresheners may have contributed to some heartening upward trends in the transit agency’s most recent “vital signs” progress report, at least when it comes to riders’ views on the cleanliness of the trains.

“We’ve been testing air fresheners on a limited number of railcars. At last measure there was about 6 percent of the fleet with air fresheners,” Burnside said.

“That did have a pretty nice impact quickly,” she added. “I guess if [the trains] smell good, people feel they’re clean.”

Metro spokeswoman Sherri Ly offered additional specifics on the statistics cited by Burnside. According to customer surveys, the percentage of riders satisfied with the level of cleanliness on railcars increased from 53 percent last December to 61 percent at the end of March.

“On the Green Line specifically, satisfaction on cleanliness improved to 73 percent, a 15 percent increase,” Ly said.

Of course, it’s difficult to know how much of that increase is directly a result of the air fresheners.

If other new Metro-related odors are any indication, riders’ opinions will likely be mixed as more of the trains are outfitted.