A leading respiratory consultant at University Hospital Southampton (UHS) is urging the public to adopt four simple steps into their daily routine to protect themselves against harmful air pollution.

Dr Thom Daniels, consultant respiratory physician at UHS, said poor air quality is “one of the major public health challenges of our time” but it is often “out of sight and out of mind”.

He spoke out ahead of Clean Air Day today (Thursday), an annual event which aims to raise awareness of the importance of clean air for health and the environment.

“Poor air quality is one of the major public health challenges of our time,” he explained.

“As well as a huge contributor to the climate emergency, it also contributes to the shortened lives, poor health and deaths of thousands of people in the UK and globally, many of whom are among the worst off in society.

“It is also important to emphasise that air pollution is associated with more deaths from heart disease and dementia than from lung disease every year, highlighting the significance of the issue at hand for everyone's health.”

Air pollution is contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere.

A key contributor to poor air quality is particulate matter (PM), a collection of solid and/or liquid materials of various sizes that range from a few nanometres in diameter (about the size of a virus) to around 100 micrometres (about the thickness of a human hair).

Particulate matter comes from human-made and natural sources and consists of both primary components, which are released directly from the source into the atmosphere, and secondary components, which are formed in the atmosphere by chemical reactions.

Despite the challenges air pollution presents, Dr Daniels, who is also the clinical lead for environmental sustainability at UHS, has outlined four simple steps everyone can take daily to reduce their own personal exposure:

Walk a different route. Air pollution is very localised in time and space and just by walking along quieter roads, or even a few metres further from a busy road, people can reduce their exposure.
Be outside at a different time. Air pollution is primarily from petrol and diesel vehicles and shows large peaks during rush hour between 7am and 9am and 4pm and 6pm. If possible, change the time of a walk to the shops, or a run to times with better air quality.
If you live near a road, try keeping the windows facing the road shut, particularly during rush hour.
During the COVID-19 pandemic everyone became used to wearing masks and wearing masks outside can also reduce exposure to harmful air pollution. Simple face masks probably reduce exposure by about 50 per cent and a tight-fitting “n95” mask will reduce exposure even more.

“Air pollution can be very nebulous, out of sight and out of mind, but one way that everyone might be able to recognise its prominence is by thinking about the ‘bits’ you might see when the sunlight streams though a window,” said Dr Daniels.

“What you can see is particulate matter, mainly household dust probably in the range of around a hundred micrometres, but the particulate matter we're talking about – the most important for human health – is about a tenth of that size and smaller.

“The reason the size is important is that the smaller the particle, the more arrow like, more needle like it is in its ability to penetrate through the lining of your cells into your blood vessels and to get around your body. The science that's coming out around this particulate matter is shocking, yet its invisibility is enabling it to wreak havoc.

“That is why I am urging people to take the four very simple steps I have outlined to reduce their own exposure that can be incorporated easily into daily life.”

Dr Daniels is also calling on the public to be aware of the difference between ‘outdoor’ air quality and ‘indoor’ air quality, having recently researched the effects on his own life.

He has been measuring his own exposure to air pollution by wearing a small clip-on device that measures particulate matter.

“Most research to-date has been about the effects of poor outdoor air quality, because this is the data that researchers have had access to,” he explained. “However, there is evidence to suggest that indoor air quality may be worse than outdoor air quality – and we spend more than 90% of our lives indoors,” he said.

“I’ve been conducting my own personal research to measure the air pollution or particulate matter of my own daily routines and the results were most revealing. It has really opened my eyes to indoor pollution.

“What I didn’t expect was to find that my exposure to indoor air pollution registered very highly on the device and took me in to the red zones – the points where I am most at risk of being exposed to harmful pollution.

“More often than not, the pollution was worse inside than it was outside – and that was not what I was expecting at all.

“There was one occasion where I burnt some toast which filled the kitchen with smoke – the readings were just off the scale.

“I threw open the windows and turned the cooker fan on and the smoke dissipated quickly, suggesting it was gone. In fact, the recording device suggested that the air quality was poor even two hours afterwards.”

He added: “This is not just the problem of people with known lung conditions such as asthma or COPD, everyone’s health is at risk from air pollution.

“Particulate matter has been found in pretty much every organ you care to name. It's probably in our brains, in our blood vessels and recent studies even found microplastics in testicles, possibly contributing to male infertility – air pollution gets everywhere.

“By adopting these four simple steps we can all reduce our risk.”

Lung expert offers four simple steps people can take to protect against air pollution