The rhythmic process of breathing is at the centre of our daily lives, controlling everything we say, do and feel.
But, despite watching our chests rise and fall every few seconds, how many times have you stopped to actually consider the impact of taking a breath?
In recent years, the case for the damaging effect of pollution has continued to grow, with numerous studies linking poor air quality to everything from cardiovascular disease and asthma to mental health issues and reduced fertility.
According to the World Health Organisation (WHO), 4.2million people die every year as a result of exposure to outdoor air pollution and 3.8 million due to household exposure, accounting for 43% of all deaths and disease from chronic obstructive pulmonary disease, 24% from stroke, and 29% from lung cancer.
Most recently, researchers at the University of Washington found the air in some cities could be as damaging to health as smoking.
The study revealed toxic fumes from traffic, planes, and factories is causing an increasing number of city dwellers to develop chronic lung disease, and living in such an environment can produce the same effect as inhaling 20 cigarettes a day for 29 years.
So, how and why is air pollution damaging our health?
In his book, Every Breath You Take: A User’s Guide To The Atmosphere, Dr Mark Broomfield explores what contributes to the quality of the air we breathe, connecting the dots between everything from environmental factors and house prices to fine particles and the hole in the ozone layer.
In his career as an air quality specialist, Dr Broomfield has seen dramatic change in attitudes towards air pollution and the importance of measuring emission levels, and he believes the last few years have been vital in terms of understanding the true dangers that can lurk in each breath.
“Air pollution has been getting better for quite a long time in the West, to the point where some places, such as Scotland, have some of highest standards for air quality in the world,” he explained.
“Steps have been taken to improve air quality by moving away from burning coal, switching to gas and renewable energy, and cutting down on vehicle emissions.
“However, it is only in the last two or three years that there has been a large uptake in people realising just how important air quality is. People are now more aware than they ever were of the health consequences of air pollution.”
The air we breathe is comprised of around 78% nitrogen and 21% oxygen, but it is within the remaining 1% that health-impacting gases and particles can be found.
Although more research is needed to understand what substances are damaging our health, scientists believe it’s mainly fine particles of PM2.5 and nitrogen dioxide, which are breathed into our lungs.
Even in areas with relatively clean air, pollution can still have an effect on adults and children.
Dr Broomfield explained: “In Scotland air pollution results in around 2,500 early deaths every year. In terms of external factors, it’s one of the most significant causes of early death – it’s more significant than obesity, road accidents and passive smoking combined.
“And this is within a relatively clean part of the world, with the advantages of favourable weather including strong winds, rain and shorter bursts of sunshine.
“Even if we achieve all the air quality standards, pollution still continues to affect us – even at low levels there is still an on-going health burden we don’t necessarily notice.”
Described as a “public health emergency” by WHO, known health complaints caused by air pollution are continuing to increase, and the next generation could be the most adversely affected if government and individuals don’t make clean air a priority.
“You can buy a bottle of water but you can’t buy a bottle of air – we have no choice but to breathe what’s in front of our nose,” said Dr Broomfield.
“It’s vitally important we start to consider the impact we’re having on our environment.”
Every Breath You Take: A User’s Guide To The Atmosphere, is out now, £9.99, Duckworth