Indoor air pollution is 3.5 times worse than outdoor air pollution – Science Story


The air in our homes may be three times more polluted than outdoors, due to cooking fumes, candles and wood-burners.

A snapshot study measured tiny nanoparticles of pollution within houses in four British towns and cities, then compared them to the streets outside.

Indoor spaces were three-and-a-half times more polluted than the outdoors on average, and at one point, a family of four in Lancaster were exposed to pollution levels more than 560 times higher than outside.

Experts say this is because fumes from trains and traffic are trapped inside well-insulated homes, where they take longer to clear.

In Lancaster, the family are thought to have increased the indoor pollution in their home by using a fashionable wood-burner and cooking toast for breakfast.

Chris Large, from environmental charity Global Action Plan, which commissioned the study, said: ‘You can’t just close your door and shut out air pollution. 

The combination of indoor and outdoor air pollution sources is turning our homes into toxic boxes, with pollution trapped inside.’ 

Dr Mark Miller, an air quality expert at the University of Edinburgh, who was not involved, said: ‘We know that levels of particles can reach very high levels indoors, especially during cooking or from wood-burning heaters.

‘The particles measured in these investigations are ultra-fine particles which are the very smallest particles in the air. 

It is these particles that are inhaled right into the bottom of the lung and could even penetrate into the blood.’ 

Ultra-fine particles outdoors have been linked to heart disease, strokes and even suggested to be a potential cause for dementia.

However more research is needed on sources of indoor pollution, like cooking and stoves, to determine if these particles are as bad for human health as those from vehicle exhausts.

The problem is that indoor pollution combines with fumes from traffic and trains, which can hang around for hours inside with no rain or wind to clear them.

The study, conducted by National Air Quality Testing Services, compared indoor and outdoor pollution at four homes in London, Liverpool, Lancaster and Pontypridd.

In the south London home, indoor air pollution peaked at triple the level outdoors, at a time when a steak was being fried for dinner. 

In Pontypridd, the highest number of tiny pollution particles per cubic centimetre was 18 times the maximum number counted outside.

In Lancaster the most striking result was seen at 10.40 in the morning, when there was less traffic on the road. 

Indoor pollution in a family home was 563 times higher than outside, which experts believe was a result of diesel fumes from passing trains, a wood-burning stove, gas hob and cooked toast.

Paul Young, 40, who lives in that house with wife Joanna and daughters Flora, 9, and Tilda, 7, said: ‘Like lots of people we like to create a homely atmosphere, and yet I know that I am contributing to pollution in the rest of the city.

‘We could seriously think about using the wood-burner less frequently.’ Emma Prior, from Liverpool, whose house was 60 per cent more polluted than outside on average, saw her indoor pollution soar when her son burned eggy bread made for breakfast.

She said: ‘I’m really surprised to see the peaks inside my house.’ In London, Sara Bacon, who lives in a two-storey maisonette, saw her 10-year-old daughter Martha hospitalised with pneumonia last year and her six-year-old daughter Martha diagnosed with a severe chest infection as a baby.

She said: ‘I’ve become concerned that it’s down to air pollution.’ Global Action Plan commissioned the research to highlight Clean Air Day on June 20, which will focus on the effect of air pollution on pregnant women.

A separate survey suggests children may be more exposed to air pollution than in the past, with 55 per cent of parents saying their children spent more time indoors than they did at the same age.

The charity says people can reduce their exposure to indoor pollution by opening windows when cooking, trying not to burn toast and buying electric ovens.


Comments are closed.