Towns and cities across Ireland have been named and shamed by the World Health Organisation (WHO) for breaching safety levels for air pollution.

Poor air quality is a major cause of disease and death, WHO warned.

One way the global health body assesses air quality is by examining the levels of a type of pollution known as particulate matter (PMs).

WHO's latest data shows that Longford breached the safe limit set for PM10, at 22 micrograms per cubic metre (µg/m3). Bray was found to have PM10 levels of 20µg/m3.

Longford, Bray, Galway and Dublin breached the safe levels for another measure known as PM2.5, with Longford the worst offender at 15µg/m3.

In the North, Derry and Belfast were also found to have safe levels for PM2.5,

WHO said that across the world 80% of cities that measure outdoor air pollution are failing to meet its guidance for safe levels of air quality.

As air quality declines, the risk of stroke, heart disease, lung cancer, and chronic and acute respiratory diseases, including asthma, increases for the people who live in these areas, the health body said.

It said that ambient air pollution, made of high concentrations of small and fine particulate matter, is the greatest environmental risk to health - causing more than 3 million premature deaths around the world every year.

Dr Flavia Bustreo, WHO's assistant director general for family, women and children's health, said: "When dirty air blankets our cities, the most vulnerable urban populations - the youngest, oldest and poorest - are the most impacted."

Dr Maria Neira, director of the Department of Public Health, Environmental and Social Determinants of Health at WHO, added: "Urban air pollution continues to rise at an alarming rate, wreaking havoc on human health.

"At the same time, awareness is rising and more cities are monitoring their air quality. When air quality improves, global respiratory and cardiovascular-related illnesses decrease."