More than one in every 24 deaths in Belfast is linked to long-term exposure to air pollution, a new study has found.
The Centre for Cities' annual study of the UK's major urban areas, Cities Outlook 2020, found that the deadly toxin PM2.5 was linked to 178 deaths in just one year, or 4.1% of all adult deaths in the city.
While the number of deaths is lower than in some other UK capitals, Belfast is the second biggest emitter of PM2.5 per head in the UK, after Swansea.
PM2.5 is a pollutant that is a concern for people's health when levels are high. It consists of tiny particles in the air that reduce visibility and cause the air to appear hazy when levels are elevated.
The charity said the deadly levels of PM2.5 are currently legal in Northern Ireland, England and Wales, despite breaking the World Health Organisation's air pollution guidelines.
It said that cities such as Belfast should introduce ultra low emission zones in order to charge car and van drivers in city centres, and ban the use of wood burning stoves and coal fires in areas where air pollution exceeds guidelines
Malachai O'Hara, deputy leader of the Green Party in Northern Ireland, said this "must be a public health priority".
"This important piece of research by the Centre for Cities starkly articulates the scale of the issue," said the councillor for the Castle area in Belfast.
"We know that people with pre-existing conditions, the elderly and children are particularly afflicted by poor air quality.
"UK-wide studies also demonstrate that poor air quality afflicts inner city and working class communities in a disproportionate way.
"I led green groups across the city in measuring Nitrogen Dioxide (NO2). We identified 28 breaches of the EU legal limits.
"Since being elected last May, my first motion was to address air pollution.
"It calls for adoption of World Health Organisation limits, enhanced monitoring including PM2.5 and the creation of clean air zones.
"Belfast City Council has committed to a detailed assessment of air pollution including PM2.5 and this year will be developing a new ambitious air quality action plan, led by sustainable transport groups, public health organisations and environmental groups. Now we need the returned Assembly to develop the enabling legislation for clean air zones so we can provide clean air for everyone."
John Barry, Professor of Green Political Economy at Queen's University, co-chairs the newly formed Belfast Climate Commission.
He said the statistics were a "shocking reminder of the health impacts of air pollution, much of it from our reliance on petrol and diesel vehicles, especially cars".
"A shift towards greater public transportation, cycling and walking would improve air quality, reduce deaths and the ill health impacts of air pollution in respiratory conditions, which have an economic cost in terms of the impact on the NHS, lost economic activity and above all the quality of citizens' lives," he added.
"Reducing our dependence on cars would have multiple benefits, not least reduce the city's greenhouse gas emissions causing climate breakdown, but also improve the quality of life of citizens."