After a successful pilot of the program, BART began the installation of denser filters throughout its fleet as part of a multitiered plan aimed toward passenger safety during the COVID-19 pandemic.

Clean air plays an important role in mitigating the spread of COVID-19, especially in an enclosed space such as the BART train cars, according to BART spokesperson Chris Filippi. This notion contributed to the implementation of a systemwide filter installation in BART cars. Prior to launching the installation, however, filters were installed in five cars this past summer as part of a pilot program intended to work out any issues ahead of time, Filippi added.

While the existing air filtration system in BART cars was sufficient, BART has continued to look for even more ways to better improve air filters, Filippi said. He added that the new filters are capable of capturing much smaller particles.

“A key question that we had to answer through the pilot was to determine whether our legacy cars could still function properly with the installation of the newer filters. Because of the age of our legacy fleet, we must be careful to ensure that any equipment change does not disrupt other systems on the car,” Filippi said in an email. “The pilot program demonstrates that our legacy cars can operate safely with these more robust filters.”

Filippi added that the goal is to install denser filters in every BART train car. While there is no set deadline as of press time, Filippi said the process is gradual and will take place during each car’s scheduled maintenance so as not to disturb BART’s regular service.

According to Ben Holland, BART’s manager of vehicle system engineering, BART has been working closely with Bombardier Transportation, which is manufacturing new trains for them. He added that one of the remaining obstacles is finding suppliers for the particular filtration system they want to use in their existing trains.

BART engineers have also been in touch with scientists from the Lawrence Livermore National Laboratory to run experiments that can simulate a sneeze or cough, according to a BART press release. The goal is to better understand the flow and travel of particles that carry COVID-19.

“Ultimately, this effort is about being responsive to our riders. We are working diligently to enhance safety on BART and a big part of that is to ensure the best air circulation possible,” Filippi said in an email. “These new filters are an additional step to limit the spread of coronavirus and to bolster the confidence of the public in riding BART.”