The Labour-controlled council recently approved plans for a £5m replacement multi-storey car park on Victoria Street in the city centre, but Green Party candidate Cllr Tom Crone said this would involve the loss of valuable trees.
Declaring the protection of green space and tackling environmental problems as among his campaign priorities, Crone said: "Air pollution causes an estimated 239 deaths per year in Liverpool but next to nothing is being done to reduce it."
He said the car park proposal "will see valuable trees lost from the city centre, and will encourage yet more traffic, making congestion and air pollution both worse".
The Greens currently form the official opposition to the city's majority Labour group.
- Crone was one of seven candidates for the post of mayor. Since publication of this article, Labour incumbant Jo Anderson was relected to the post on 6/5/2016.