Metro-North Pilots Air Purification System In Train Cars

Metro-North is piloting a new technology to filter and purify the air inside train cars, in hope of helping people feel comfortable riding the commuter railroad again.

Ridership had dropped 91 percent in March when New York state closed down during the coronavirus outbreak. It hasn't recovered: on Wednesday, Metro-North reported 66,700 riders, down 77 percent from the 2019 average.

The technology creates an electrical field to generate a wave of ionized particles that destroy airborne viruses, bacteria and particulate matter — including the coronavirus that causes COVID-19.

"As more and more customers return to Metro-North trains, they want to be confident that we are doing everything that we can to keep them safe and healthy," Metro-North Railroad President Catherine Rinaldi said in an announcement. "If the pilot proves successful, not only does this new air purification technology kill COVID-19, it kills any virus including the standard flu or bacteria that cause the common cold, and even particulate matter like diesel fumes.

"The benefits provided by this new system would last well after the pandemic has ended."

The technology was installed in two HVAC units of a Metro-North car on Oct. 7 and is being installed by the end of the month on a Long Island Rail Road car. The railroads will evaluate its effectiveness and its ability to scale up for installation throughout their fleets of more than 1,100 rail cars each.

It is completely invisible to the customers, said Metro-North Chief Mechanical Officer James Heimbuecher. “We like that it can be incorporated into our existing ventilation systems with minimal intrusion. If this pilot proves successful, our crews are ready to begin adding this system across our entire fleet.”

Introduction of the technology has emerged through the MTA’s “COVID Response Technology” that was announced in July to engage the private tech industry and rapidly evaluate and deploy innovative technologies that make public transit safer, healthier and more responsive to customer and workforce needs in light of the global pandemic.

The MTA is the first transit agency in North America to test this process.

“I am excited that Metro-North and the Long Island Rail Road are taking the lead by piloting this cutting-edge technology that could have a significant role in fighting this pandemic,” said MTA Chief Innovation Officer Mark Dowd.

About one-third of the air traveling through a Metro-North train car's ventilation system is fresh air pulled from above the roof of the cars. The system totally replaces the air inside a car 12 times an hour, or about once every five minutes.

The new system passes the air through three stages. The first stage applies an electrostatic discharge to actively target viruses, and then uses physical filtration to remove the charged particles. The air is then safely exposed within a self-contained unit, to ultraviolet radiation that has long been proven to kill bacteria, mold, and viruses. Third, the air is exposed to a wave of ionized particles that attack pollutants, chemically decomposing them.

The ions further travel deeply through the air distribution ducts of the car and into the vehicle interior to enhance the railroads’ existing disinfection of surfaces inside the cars.

The purification system is part of the MTA’s multi-faceted approach to minimizing health risk to customers and employees during the pandemic by high tech means and old-fashioned elbow grease.

Developed by Westminster, Md.-based Knorr Brake Company and its Merak North America division, it is now incorporated into the railroads’ existing ventilation systems in the pilot program. It enhances in-car air filtration – which already filters air 30 times an hour or once every 120 seconds, exceeding CDC standards for certain medical facilities and far surpassing standards for classrooms and restaurants.

"The combination of filtration, purification, and disinfection provides an engineered solution superior to any one of the technologies acting alone,” said Rich Bowie, Knorr Brake Company Vice President, Marketing, Sales & Systems.

In partnership with the MTA, researchers with the U.S. Environmental Protection Agency will test the technology to determine effectiveness in meeting the needs for public transit.

In addition to launching its COVID Response Challenge, the MTA has been exploring the use of ultraviolet light for disinfecting subway surfaces, with possible expansion to commuter rail. The MTA has heightened cleaning and disinfecting of cars and stations to new levels, installed hand sanitizer dispensers at stations along with vending machines selling personal protective equipment, and applied floor decals to assist customers with social distancing.

Underscoring the inherent safety of public transportation, a recent study conducted for the American Public Transportation Association found no link between public transportation usage anywhere in the world and clusters of COVID-19.