Plans to extend Edinburgh’s city centre air pollution zone by 3.5 km to the south and west of the city have been announced by the council.
It designates an area where air pollution has broken the Scottish air quality safety standard.
Edinburgh has five pollution zones, with the city centre pollution zone first designated in 2000.
Campaigners said long-term exposure to air pollution can increase the risk of heart attacks and strokes.
Lesley Hinds, Edinburgh city council’s transport and environment convener, said: “We recognise that improving air quality in Edinburgh can be a challenge and we are making every effort to address this.
“We monitor air quality continuously across the city and extending the air quality management area enables us to direct actions more effectively at those locations.
“We are already working closely with bus and road freight operators to reduce vehicle emissions on some of our busiest traffic routes and recent monitoring suggests that air quality is improving in many places, including the South Bridge/Nicolson Street corridor.”
Emilia Hanna, of Friends of the Earth Scotland, said: “Toxic traffic fumes right here on Nicolson Street are harming the public’s health.
“Long-term exposure to this sort of air pollution can increase the risk of having a heart attack or stroke and has been linked with babies being born with low birthweights.
“Air pollution causes 200 early deaths in Edinburgh alone every year.
“Road traffic is the main cause of air pollution, so the council needs to work together with the Scottish government to get more people walking and cycling and using public transport.”