Taking the SkyTrain is a daily routine for many Metro Vancouverites, but it turns out the commute can get really loud, so loud that some health experts suggest wearing earplugs.
A CBC News team rode the Expo and Millennium lines while carrying a sound meter to measure noise levels inside the trains.
Levels reached as high as 106 decibels while travelling over some sections of the track. Hearing damage can occur within five minutes at that level, according to WorkSafeBC. A TransLInk study says a construction site with a pneumatic hammer reaches noise levels of 90 decibels.
Occupational health rules allow for exposure to 85 decibels throughout an eight-hour workday.
University of British Columbia occupational and environmental health professor Hugh Davies says exposure while riding the train is much shorter, but he warns it still plays an important role in people's hearing health.
He says that's especially true if people go on to work in a loud environment or go to a concert later that day.
Davies also warns that the 85-decibel mark should also be taken with a grain of salt.
"The thinking among scientists now is that 75 decibels might be a more reliable lower limit," Davies added. "But that of course is an occupational exposure limit, it really is appropriate only for the working population which is quite different from the general population."
He says noise exposure can affect the elderly or children very differently.
Richard Neitzel, a professor at the University of Michigan's School of Public Health, looked at noise levels of all mass transit in New York City. Neitzel — together with a team of researchers — found levels were high enough to potentially increase the risk of noise-induced hearing loss.
But that is not the only concern, Neitzel explains, noting health impacts of noise go beyond possible hearing loss.
"If you're exposed to chronic levels of noise around what we're talking about, maybe the 70 to 80 decibel range, you're actually potentially going to be at an increased risk of having a heart attack, or a stroke, or hypertension," he added.
Neitzel says annoyance also plays a big factor, noting the psychological effect of noise exposure plays a role in overall health.
"So even if these levels are potentially not harmful to your hearing, or at least not directly harmful if we look at them alone, there may be other important impacts on your health that we really do need to pay attention to," he added.
While riding inside the trains, the CBC News team found older Mark I cars were noisier than newer Mark III cars.
"You're right," said Jillian Drews with TransLink. " [Newer cars] do have air conditioning so the windows don't need to be open. They also have better soundproofing and better door seals which prevent noise from getting in."
She says more than 200 cars are being ordered to replace the Mark I cars, but they won't be in service for five years.
Drews says work being done to reduce noise near the tracks will also push down sound levels inside the train. The work began after people who lived near the train tracks complained about excessive noise.
For those taking SkyTrain every day, Davies and Neitzel recommend wearing earplugs rather than listening to music through earbuds.