The City of Laval is offering bus riders a reduced fare the after a smog alert is issued in the region.

The public transit authority (STL) said Thursday that until Sept. 4, it will cost riders a buck (payable in cash, credit or debit) for a single fare that is valid for the entire bus and shared taxi network.

The STL has run this program for the past 15 years, and it's unique in the country.

"Emissions generated by transport contribute to the formation of smog. With this reduced fare, the STL is making a concrete contribution to improving air quality by encouraging as many people as possible to leave their cars behind and take public transit," says STL board of directors chair Jocelyne Frédéric-Gauthier.

The STL said smog alerts have triggered 23 fare reductions since the program was started.

During that time, more than 75,000 people hopped on a bus in the city.

The STL will broadcast any Environment Canada smog alert on its website and social media accounts.