TREES and plants in Dorset are helping the NHS to save millions of pounds by removing air pollution.

A study for the Office for National Statistics (ONS) reveals that in 2015 the NHS avoided £6.1 million in health costs thanks to air quality improvements by natural vegetation. That’s £14.55 for every resident.

Nationally, the ONS estimates there were 7,100 fewer lung and heart-related hospital admissions, 27,000 fewer life years lost and 1,900 fewer premature deaths thanks to the service provided by nature. The saving for the whole of the UK was £1 billion.

Woodlands, grasslands and shrubs in Dorset absorbed 17.7 tonnes of air pollutants - about 69 kg of contaminants per hectare.

Top of the ranking was Breckland and South Norfolk, with 75.2 kg filtered by every hectare of land. Lambeth ranked bottom, filtering just 5.1 kg for hectare.

The most harmful of these substances is PM2.5, small particles with a diameter of less than 2.5 micrometres - about 3% of the diameter of a human hair. These particles can trigger chronic disease such as asthma, heart disease, bronchitis, and cause other respiratory problems

The data also includes PM10, sulphur dioxide, nitrogen dioxide, ground-level ozone and ammonia.

In Dorset, ozone was the pollutant most absorbed by plants, making up about 80% of the total.

According to the ONS, trees account for the highest volume of air pollutants removed by vegetation.

Overall, the study shows that 1.4 billion kg of harmful substances were taken out by vegetation in the UK in 2015.

Professor Paul Cosford, of Public Health England, said:“Air pollution is a growing threat to the public’s health, evidence shows it has a strong causal association with coronary heart disease, stroke, lung cancer and childhood asthma.”

Karen Exley, Head of Public Health England’s air quality and public health group, added:

“Long-term exposure to particulate matter is known to be a contributory factor in early deaths, particularly for people with cardiovascular and respiratory disease, and is estimated to have an effect equivalent to 29,000 deaths a year in the UK.

“Long-term exposure to nitrogen dioxide is also thought to contribute to early deaths although its effects have yet to be quantified.”

A study published by the British Heart Foundation last week links levels of air pollution well below the UK’s current legal limits with serious changes in the heart structure.

Simon Gillespie, Chief Executive at the British Heart Foundation, said:

“Although the increase in heart chamber size is small in this study, it is an early warning sign, which may explain the increased risk of heart failure in individuals exposed to higher level of pollution.

“We urge the Government to adopt the more stringent World Health Organization air quality guidelines.”

The health and social care costs of air pollution in England could reach £18.6 billion by 2035 unless action is taken, according to Public Health England.

Last year, the cost was estimated to be £157 million.