Living near busy roads could put men at higher risk of premature death – even when air pollution levels are rated as ‘safe’, claim researchers.

A major study found exposure to traffic pollutants can push up the risk of dying by seven per cent, compared with living in quieter neighbourhoods.

There is mounting evidence of the health dangers of pollution, which is already known to play a part in asthma attacks, heart attacks and strokes.

Microscopic particles largely generated by diesel exhausts have been shown to cause lung damage and harmful changes in blood vessels and clotting.

But the latest study adds to research showing problems occur at levels well below those stipulated in current European Union (EU) air-quality directives.

The new research examined two decades of data from 22 studies involving over 367,000 residents of large cities in 13 European countries.

Researchers looked at the impact of prolonged exposure to tiny particles of soot or dust found in traffic fumes and industrial emissions, fine-particle matter known as PM 2.5.

They estimate that for every increase of 5 micrograms per cubic metre (5 µg/m3) in annual exposure to PM 2.5, the risk of dying from rises by seven per cent.

The risk of death increased only in men, not in women.

Study leader Dr Rob Beelen from Utrecht University in the Netherlands, said ‘A difference of 5 µg/m3 can be found between a location at a busy urban road and at a location not influenced by traffic.

‘Our findings support health impact assessments of fine particles in Europe which were previously based almost entirely on North American studies.’

In the study air pollution concentrations of nitrogen oxides and particulate matter were estimated at home addresses of participants, along with traffic load on nearly major roads.

Traffic density on the nearest road and total traffic load on all major roads within 100m of the residence were also recorded.

Among the participants, 29,076 died from natural causes during the average 14 years of follow up, says a report in The Lancet medical journal (must credit).

The results showed that long-term exposure to fine particles with a diameter of less than 2.5 micrometres (PM2.5) posed the greatest threat to health even within concentration ranges well below the limits in current European legislation.

The link between prolonged exposure to PM2.5 and premature death was significant even after taking into account factors such as smoking, obesity and activity levels.

Dr Beelen said ‘Our findings suggest that significant adverse health effects occur even at PM2.5 concentrations well below the EU annual average air-quality limit value of 25 µg/m3.

‘The WHO air-quality guideline is 10 µg/m3 and our findings support the idea that significant health benefits can be achieved by moving towards this target.’

Previous research found pregnant women exposed to ‘safe’ levels of air pollution have a higher risk of giving birth to small babies.

Jeremy Langrish and Nicholas Mills from the University of Edinburgh, writing a commentary in the journal, said ‘Despite major improvements in air quality in the past 50 years, the data from Beelen and colleagues’ report draw attention to the continuing effects of air pollution on health.

‘These data, along with the findings from other large cohort studies, suggest that further public and environmental health policy interventions are necessary and have the potential to reduce morbidity and mortality across Europe.

‘Movement towards more stringent guidelines, as recommended by WHO, should be an urgent priority.’

Prof Frank Kelly, Professor of Environmental Health at King’s College London, said ‘This study enhances an increasing scientific evidence base that PM2.5 poses a danger to health at concentrations below current EU limit values and supports the ongoing WHO review of European air quality policies.

‘Results such as these, plus recently published data claiming combustion emissions in the US account for 200,000 premature deaths per year, show that policy measures have enormous potential to create a cleaner and healthier environment.

‘Such action is particularly urgent in cities where concentrations of pollutants routinely breach current EU limit values, let alone the more stringent and health-based WHO guidelines - such as London.’