The article doesn’t mention air supply issue. But it says the women had no health problem.
The truck was just 6 degrees Celsius (43 degrees Fahrenheit) inside, said Francart, Villefranche-sur-Saône’s prosecutor. The women were all wearing thick coats and had no health problems, she said.
It sounds like they called for help because they realized the truck was going in the wrong direction, not so much because of health concerns.