Chernobyl at home

A report published this week has suggested that air pollution in big cities ould be as damaging to our health as the radiation Chernobyl survivors were exposed to. But short of moving to the countryside, what can city dwellers do? Quite a lot, actually. Leo Hickman offers in The Guardian 10 tips on how to breathe more easily

"Take a deep breath. If you live in an urban environment, which four out of five of us now do, then you are exposing yourself to a cocktail of airborne pollutants that could be seriously damaging your health". And all becasue the air pollution you suck into your lungs each day could be shortening your life expectancy even more than the radiation exposure suffered by survivors of the Chernobyl disaster in 1986.

Meanwhile the World Health Organisation reports that transport-related air pollution — which now causes the vast majority of urban air pollution — causes a wide range of health problems including "cancer, adverse pregnancy and birth outcomes, and lowering of male fertility". In 2004, a report said that a pedestrian walking down Marylebone Road in London would draw in the equivalent pollution of one cigarette in just 48 minutes. But other than moving to the countryside, what practical steps can city dwellers take to reduce their exposure to urban air pollution? Quite a lot, it turns out.

1 Watch where you walk

One of the best ways to reduce your exposure to air pollution, says Dr Roy Colvile, a senior lecturer in air-quality management at Imperial College London, is to avoid walking along busy streets and thoroughfares, instead choosing side streets and parks. Carefully choosing your route has a "dramatic" effect, he says, because pollution levels can fall by a factor of 10 just by moving a few metres away from the main source of the pollution — exhaust fumes. "Just by being one block away makes a massive difference as the high pollution levels are generally restricted to fairly small areas within a city," he says. Also, try to avoid walking down "street can yons" (where tall buildings hug tightly to the sides of streets, creating valleys in which pollutants build up), don't walk behind smokers, and walk on the windward side of the street where exposure to pollutants can be 50% less than on the leeward side.

2 Pavement sense

When you're crossing a road, stand well back from the kerb while you wait for the lights to change or for a gap in the traffic. Every metre really does count when you are in close proximity to traffic, according to Colvile. "Do all you can to avoid getting stuck for too long on a central reservation," he adds. As the traffic moves off from a standstill, the fumes can dissipate in just a few seconds, particularly if the wind is up, which means holding your breath during this momentary period can make a difference, silly as that might sound. Also, don't dawdle: cross the road as quickly as possible. And once you're over, continue along the pavement as far away from the kerb as possible.

3 Avoid pollution spikes

Predictably, there are large spikes in pollution during times of high traffic congestion — ie, the morning and late-afternoon rush hours. Pollution levels generally fall during the night-time. The time of year can also make a big difference. Pollution levels tend to be at their lowest during the spring and autumn when winds are at their "freshest"; the trapping effect of extreme cold and hot spells tend to exacerbate the build-up of pollutants.

Venturing outside when there is less pollution obviously makes sense, but of course that's not always realistic. In fact, the hottest part of a summer's day — the time when most office workers go outside during their lunchbreak — is a particularly bad time to head out, according to Noel Nelson, one of the authors of the Royal Commission report. Walking in the rain, conversely, is a good way of avoiding the worse excesses of air pollution, he adds, as the rain "cleans" the air both by washing out the pollutants and bringing with it fresher air.

4 Wear a mask

Masks can be a good thing, but they only make a difference if they fit tightly and are cleaned regularly. Even the slightest gap to allow you to breathe more easily will cancel out any benefits. Worse, if you fail to clean or change the mask regularly there is a danger of allowing oily organic compounds to build up on the filter. Build-up can make the air you breathe dirtier rather than cleaner. As for looking like Michael Jackson while you go about your daily business . . . only you can decide how high a price you're willing to pay for clean lungs.

5 Pushchairs

According to the Royal Commission report, several recent studies indicate that "children living close to busy roads have an approximate 50% increased risk of experiencing respiratory illness, including asthma". Children are smaller than adults and therefore that much closer to the source of pollution when walking besides roads. They also have a faster metabolic rate and breathe more rapidly, and tend to inhale more pollution, proportionate to their size, than adults. One small step that can be taken is not to push them along in a buggy too close to traffic. Colvile advises positioning the buggy alongside you, instead of in front of you, when waiting to cross the road.

6 Beware of exercising in traffic

Cycling or jogging disproportionately expose you to air pollution — you inhale three times as much as if you were walking, according to Colvile — for the simple reason that your lungs are gasping for more air than the people you're speeding past on the pavement. The best times of day to exercise, thus avoiding the worst excesses of air pollution, are early morning or in the evening. Alternatively, exercise indoors or in a park. Cyclists — for whom the exhaust of a car should be seen as being as much of a hazard as the front bumper — should stick to side-roads where possible.

7 Where to sit on the bus

Buses are cleaner in terms of their emissions than even just a decade ago, particularly London's fleet, but they still emit pollutants worth avoiding. Intriguingly, Colvile says that his own research shows that sitting on the driver's side of a bus can increase your exposure by 10% compared with sitting on the side nearest to the pavement. And sitting upstairs on a double-decker can reduce your exposure too. He says it's difficult to say whether travelling on an undergound train, if you have that option, is better or worse than taking the buses, but he does say that the air pollution on underground trains tends to be less toxic by weight than that found at street level because the pollution is principally made up of minute iron particles thrown up by the wheels travelling along the rails as opposed to the mixture of pollutants found in diesel and petrol fumes.

8 Protect yourself indoors too

We spend about 90% of our time indoors, on average, and two-thirds of that time is spent at home; more perhaps for some of the most vulnerable groups such as the elderly and children. And indoor pollution can actually be more of an issue than that found outdoors, it seems: studies by the US Environmental Protection Agency (EPA) suggests that pollution levels can be two to five times higher indoors than out — and this can rapidly rise depending on what activity you are doing at home. It tends to be a different soup of chemical pollutants from the ones we encounter outside, and if anything, less is known about how they affect us. Our centrally-heated, carpeted, airtight homes only act to aggravate the situation.

Ventilating your home is therefore an important step to take in reducing risk — hopefully with air that's not full of air pollutants from the outside — as is using a good doormat to help prevent outdoor pollutants from the pavement being walked into your home. (The EPA has raised doubts about the claims made by some "ozone generating" indoor air purifiers, by the way.)

Feeling smug about the fact that you live high up in a flat away from outside air pollution? Well, unless you live in a penthouse at the top of a very tall skyscraper, then height doesn't seem to offer significant sanctuary. A study by Hong Kong's City University used laser measurements to show that pollution levels in the city remain constant up to heights of 700m. Living in the suburbs, away from major roads, seems the best way to avoid the worse excesses of urban air pollution. But that then means you are statistically far more likely to be a car owner and are therefore only exacerbating the situation.

9 Don't drive

The best thing you can do, both for yourself and for your fellow citizens, is to get out of the car. Fuel choice is also important: diesel may produce less carbon dioxide compared with petrol, which is good news in terms of climate change, but it produces more ground-level pollutants. While urban air-pollution levels today, compared with the "pea-soupers" of the mid-20th century, could be said to be vastly improved — healthy young men don't tend to drop down dead in the street now from air pollution as they did then, says Colvile — we are now exposed to a form of pollution that can much more readily enter our bloodstream. A particle of pollution today tends to be 100 times smaller than a particle of coal soot and therefore it can pass into the blood stream via the lungs as opposed to being caught in the bronchial passage. The full health implications of this shift in pollution type have yet to become fully apparent.

10 Get out of town!

As long as you go by public transport so as not to create yet more pollution, lifting yourself up and out of the urban mire offers at least a temporary escape. But don't head to the south-east corner of England. Colvile speaks of a "sheet of pollution from Europe", thick with sulphates, nitrates and ozone, that now regularly reaches across the Channel and can affect the counties south of London. For example, the air over the idyllically rural South Downs is only two to three times cleaner compared with the air over central London. Better instead to head to the nation's extremities, preferably facing into the winds blowing off the Atlantic

So breath normaly and leave forever.