Carbon monoxide is often called the silent killer: invisible and odourless, it is responsible for 40 deaths a year in the UK. But there is a much more prolific killer seeping through homes: radon, a natural radioactive gas, is responsible for 1,100 UK deaths every year from lung cancer, yet its threat is largely unknown or ignored. This week, the UK Radon Association, in collaboration with Public Health England (PHE), has launched a campaign to alert the public to the danger.
Radon gas escapes from the Earth’s surface constantly and is considered harmless in open air, accounting for half of an average Briton’s exposure to radiation. A byproduct of naturally occurring radium and uranium breaking down, radon is problematic only if it gets trapped in poorly ventilated homes, which can happen in areas where geological conditions produce it in higher concentrations. The largest affected areas in the UK are the south-west of England, the Yorkshire Dales and Wales, but there are many other affected swaths, taking in Milton Keynes, Nottingham, Lincoln, the Peak District, much of Northern Ireland, the southern border of Scotland and Aberdeenshire.
Radon produces radioactive dust in the air, which can damage lung tissue. Like carbon monoxide, we can’t see, smell or taste it – but that’s where the similarities end. Radon’s ill effects are cumulative, taking decades of high exposure, so the threat is easier to ignore.
Another factor, says Neil McColl, of the PHE’s Centre for Radiation, Chemical and Environmental Hazards, is that radon “just comes from the house, but not anything in particular in the house, such as a boiler. People say: ‘Oh well, I’ve lived here for years, my gran lived here for years, it hasn’t affected me.’” As a result, even when local authorities offer free radon testing (it usually costs £49.80 via the PHE website), they have struggled to raise the uptake from 30 to 50%.
So how do you know if you could be affected? The first many people hear of a potential problem is during conveyancing searches when buying a home. But if you are concerned, the initial port of call is the PHE website, ukradon.org. Together with the British Geological Survey, PHE has produced maps showing the likelihood of high radon levels in your home.
Living in a high-risk area does not necessarily mean you will have a problem, and testing will, in most cases, provide reassurance. The maps indicate the percentage of houses affected in an area, from a 0-1% chance of a high reading, to above 30%. PHE’s advice, says McColl, is that if you have a greater than 1% chance of a high radon level, you should test your home.
The amount of radon in a house will be a result of a combination of the geology under it, the style of building, what is covering the ground around it, how people live in it, and what ventilation exists. For instance, says Martin Freeman, chair of the Radon Association UK: “Wood-burning stoves that do not have a dedicated air intake directly from an external source can cause an increase in the draw of radon from the ground.”
Radon’s presence is measured in becquerels (units of radioactivity) per cubic metre (Bq/m3) of air. “Over a long period of years,” says McColl, every extra 100Bq/m3 of exposure, “increases your lung cancer risk by about 16%, above what your baseline would be.” Air crew or workers at nuclear fuel plants get significantly less radiation exposure than someone living in a house with 200Bq/m3 of radon – the level at which PHE advises taking action. “You should be looking to make big cuts to below 100,” says McColl. For smokers, whose baseline risk is far higher, he recommends taking action if concentrations are more than 100.
Levels can be reduced dramatically through remedial work to increase ventilation, either under the house or within it, and this ranges in cost from about £200 to £3,000. Jo Watkins, who lives in the Forest of Dean area, got a high radon reading after being offered a free test by the council. “It was the first we’d heard about it,” she says. “We didn’t know whether to have the test or not because we’d lived here for 30 years already.”
Testing is carried out with two small plastic units; one placed upstairs and one downstairs for three months. Watkins’s reading came back at 820Bq/ m3. “Our neighbour’s was 1,200, and yet my son, who lives about three miles away, got a reading below 100,” she says. Contractors surveyed her traditional stone cottage, and quoted £3,000 to install two underground ventilation tunnels with fans. “Our house has a big footprint and they came with enormous drills and drilled under the house. It only took a day.” Following the work, radon levels at the house dropped to 64Bq/m3. The fans, she says, are outside and very quiet, although you can hear them if you listen hard.
But if radon is so harmful, and the problem is relatively easy to fix, why is word getting around so slowly? McColl says: “It may be the single biggest cause of radiation exposure, but it’s still not as big as some of the other major public health issues.” Smoking, which causes 28,000 deaths from lung cancer a year, and diet, for instance. “It would be unreasonable for me to expect the same level of investment as things that affect tens or hundreds of thousands of people every year. We’ve got to put it into perspective.”
• UK Radon Awareness Week runs from 7-13 November. For more information, visit radonweek.co.uk
