Varför är luftföroreningar så farliga för dina lungor?

During the industrial revolution, there was little awareness of quite how much damage could be done to healthy people's lungs by pollution - largely because we'd never had it on such a huge scale before. But we have known for a long time that clean air is good for the lungs - after all, people with 'consumption' (tuberkulos) used to be sent to the mountains to breathe the fresh air.

Toxic gases

Long gone, fortunately, are the days of the old 'London Smog', where thousands of people died every year from complications of the blanket of pollution that covered the city. In the UK, we don't tend to see the same very high levels as major, severely polluted cities, such as Beijing, New Delhi, Santiago in Chile, and Mexico City.

The combination of sulfur dioxide - produced when fossil fuels are burned, and the major culprit in acid rain - and nitrogen dioxide from motor vehicles and generators, is a toxic mix.

Cities such as Los Angeles - surrounded on three sides by mountains - find their pollutants trapped under a layer of warm air and unable to escape. But low wind speeds in the UK can have a similar effect, with pollutants not being blown away.

Health hazards

We now have a much better understanding of how air pollution does its damage. As well as toxic gases, tiny particles, known as particulate matter (PM) can reach deep into your body. In addition to damaging your lungs, the smaller particles can actually get into your bloodstream, reaching your heart and even your brain.

But first and foremost, air pollution affects your lungs. We breathe in a new lungful of air 15-20 times a minute. Deep inside the lungs, this air meets a network of tiny blood vessels with very thin walls. Oxygen from the air is transferred into the blood across these walls, going on to supply all the organs of the body - and carbon dioxide produced by the body is passed from the blood and breathed out. Just as with tobacco smoke, pollution can clog and irritate the lining of the lungs.

Avoiding air pollution

Get into the habit of finding out what pollution levels are on a day-to-day basis. Levels can vary dramatically depending on where you are and what the weather's like.

It's time to use your tech to keep up to date. The Met Office has hundreds of weather stations all across the country which put out daily reports not just on the chance of rain but also on air pollution levels. You can find them online.

Once you know what pollution levels are on any given day, take them into account. When you do go out, plan your trip as much as possible to avoid busy roads.

If you have heart or lung issues, consider putting off any strenuous outdoor activity until levels are lower. As soon as you start exercising, you breathe harder and faster, usually through your mouth. This means you take in more air and don't filter pollution out through your nose in the same way.

Facemasks may be of use in reducing exposure to air pollution, especially in areas with high pollution levels. Their effectiveness depends on the type of mask, how well they fit, and the pollutants found in the air. Facemasks with a rating of N95 or higher - equivalent to PPP2 in Europe - and which filter out at least 95% of particles, are usually recommended.

With thanks to My Weekly magazine, where this article was originally published.