Rail:
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Our trains use Merv 13 air filters, and the HVAC brings in fresh air and mixes it with the air inside. Air is also circulated when doors open at stations.
- Cars beginning with the digit "4" also have CO2 sensors which instruct the system to bring more outside air if needed.
Metrolinx.com Article:
Metrolinx - Airflow on the GO: How Metrolinx keeps things fresh on trains
The transit agency explains how GO Transit keeps the air as freshly circulated as possible.
Aug 26, 2020
Here’s how the air circulation system works.
Each bi-level train coach has two units – a heating ventilation and an air conditioning unit, also referred to as an HVAC unit.
The HVAC unit has two fresh air intake ducts and grilles, one return air grille and the main air supply duct.
Fresh air enters the HVAC system through grilles located on each side of the coach’s exterior.
The fresh air intake represents about 20 per cent of the air being continuously circulated at any given time in the interior of the car.
The remaining 80 per cent of the air is recycled, in fact, it’s impossible to have 100% fresh air as it would make for a very uncomfortable train ride.
The recycled air is needed to keep a moderate temperature in the car – otherwise the system would be trying to cool hot air or heat cold air – It simply wouldn’t make for a pleasant commute.
As for the filters, they are specifically designed to make sure the air is safe to breathe.
The fresh air from the outside goes through a MERV 13 filter, and then that air is recirculated inside the coach through a MERV 8 filter.
“The fresh air filters found in the HVAC units are the MERV 13 filters, typically used in hospitals and surgical rooms,” says Robert Fuller, Metrolinx director of rail services.
“We want our customers to take comfort in knowing the air they breathe in our coaches is filtered to the highest level possible, given the design of our current HVAC system.”
The effectiveness of the ventilation system depends on how well it moves air. This can be calculated based on how frequently the air changes per hour (AC/h). In other words, calculating how many times the entire coach is supplied with air in an hour.
The air inside a GO train coach is replaced 10 times per hour with fresh air and 50 times per hour when mixing in recirculated air, a frequency that meets or exceeds public health guidelines.
GO Transit’s maintenance crews perform daily checks on HVAC systems inside the coaches to ensure they’re providing customers with the safest air possible.
Maintaining the highest air quality on trains is just one of the ways Metrolinx has been fighting the spread of COVID-19. Other measures include staff and customers wearing face coverings, the roll out of unique dividers between train and bus seats, and hand sanitizer dispensers in stations and onboard vehicles, as well as frequent vehicle and station cleaning that has staff constantly wiping down touch-points.
But safety doesn’t stop there.
The transit agency is continuing to monitor its air purification system closely, conducting feasibility studies to find out if there are any additional solutions that could add another level of air purification.
“We are continuing to determine if there are other technologies or systems that can further improve the ventilation system,” says Fuller.
“We want to give our customers as safe of a place to be as possible. ”So the next time you take a GO train, tap your PRESTO card, wear a face covering and just breathe – GO transit is doing everything to make sure your air is clean and safe.”