Metro-North tests air filtration system that could kill COVID, other viruses

Metro-North is testing a new three-stage air filtration and purification system for its rail cars that could kill not only the coronavirus, but nearly all airborne viruses, bacteria and particulates, officials said Thursday.

Initial laboratory tests found that 99.9 percent of airborne viruses and bacteria were killed, Metro-North claimed.

The new system passes 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, Metro-North officials said. The air is then safely exposed within a self-contained unit, to ultraviolet radiation that has been proven to kill bacteria, mold, and viruses, they said. Third, the air is exposed to a wave of ionized particles that attack pollutants, chemically decomposing them, they said.

Earlier this month, the technology was installed on one M7 rail car on the Harlem and Hudson lines.

Testing will continue through the end of the year. If the tests are successful, Metro-North will install the new system on other lines next year, including the 471 M8 rail cars on the New Haven Line.

Both the MTA and researchers with the U.S. Environmental Protection Agency will test the technology to determine its effectiveness on public transit.

If approved, Metro-North would become the first railroad in North America to have this type air purification system installed on its fleet. The total cost to install the system in all cars is $13 million.

“We are testing a new revolutionary air purification system that can kill COVID-19 and virtually all viruses,” Metro-North Railroad President Catherine Rinaldi said at New York’s Grand Central Terminal on Thursday. “It brings our existing air filtration system to a new enhanced level.”

“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,” Rinaldi said. “The benefits provided by this new system would last well after the pandemic has ended.”

James Heimbuecher, the railroad’s chief mechanical officer, said the system begins with a magnetic field that captures particles and then finishes with ionization technology.

“The ions can attach to not only viruses, which would then kill them, but also attach to any other particulate in the vehicle (rail car),” he said.

About one-third of the air traveling through the 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, Metro-North said.

The air filtration and purification system, which was developed by Maryland-based Knorr Brake Company and its Merak North America division, is incorporated into the railroad’s existing ventilation systems. It enhances in-car air filtration, which already filters air 30 times an hour or once every 120 seconds, Metro-North said.

Rinaldi stressed the importance of rail riders wearing face masks. “It is the single most important thing that we all can do to keep each other safe.”

Rinaldi said ridership has increased on MTA trains. During the peak of the pandemic in the spring, ridership was down 95 percent.

“Now, we’re 77 percent down” during the week and 50 percent down on the weekend, she said.

“That’s a significant improvement,” she said.