Maandelijkse archieven: november 2016

Ongemakkelijke waarheid over uw houtkachel: Slecht voor milieu en uw GEZONDHEID!!

BRON MailOnline

Inconvenient truth about your wood-burning stove: They can be bad for the environment AND your health

  • More than million homes now have one with thousands installed each year
  • Their increasing use has shifted the way electricity is being generated 
  • But now experts are concerned stoves are bad for environment and health 

Wintry nights are drawing in and across suburbia the middle classes are enjoying a cosy evening ritual. They’re throwing another log in the wood-burner and sitting back to bask in the glow of a real fire — and of their own good fortune.

Not since the Aga has there been a more must-have status symbol for aspirational families. More than a million homes now have one, with 175,000 new ones being installed every year.

The rise of the trendy domestic stove, used to heat a room or an entire house, has coincided with a revolutionary shift in the way electricity is being generated in Britain, from coal to wood — and has led to us burning the most wood since the Industrial Revolution.

Health risk: Basking in an innocent home comfort, or adding to a dangerous environmental pollution?

Health risk: Basking in an innocent home comfort, or adding to a dangerous environmental pollution?

Costing anything up to £6,000 to buy and install, wood-burning stoves and boilers have joined Apple Mac computers, Smeg fridges, Nespresso coffee machines and Dyson vacuum cleaners as a badge of honour among the successful and the environmentally conscious.

There are even government subsidies designed to tempt householders away from ‘dirty’ carbon fuels to heat their homes and on to ‘clean’ logs and wood pellets.

But the cold truth is that — at odds with its perceived green credentials — the wood-burning craze is posing a real danger to the environment, and to our health.

Air quality experts say the stoves contribute to an ever-thickening cloud of smog engulfing our towns and cities, which is increasing the risk of cancer, lung disease, heart attack, stroke and even dementia.

Exacerbating the problem is the seemingly innocent habit people have of throwing open the doors of the stove to recreate the effects of an open fire or to warm up a room more quickly — thereby flooding the air with a deadly cocktail of noxious gases and toxic wood smoke particles.

Wood smoke is a cocktail of gases and dangerous microscopic particles. Some of these blobs of soot, called PM2.5s, are 100 times smaller than the diameter of a human hair and can get deep into our lungs. They’re so tiny that experts think they may even be able to get through the lungs and into other organs.

Worryingly, domestic wood-burning is now the UK’s single largest source of PM2.5 emissions.

Smoke also contains harmful pollutants such as benzene, formaldehyde, acrolein, nitrogen oxides and a class of nasty chemicals called PAHs.

Plus, any burning of fuel produces carbon monoxide, the potentially deadly, colourless gas.

But are wood-burners really as bad as all that? Can something as ancient and natural as throwing a log on the embers on a winter’s night really be dragging us back to the bad old days of ‘pea soupers’ and respiratory disease?

Stoves add to an ever-thickening cloud of smog 

Apparently so. UK air quality is now so bad that many cities and towns routinely fail to meet international standards. This year, a study by the respected Royal College of Physicians warned that outdoor air pollution is contributing to 40,000 deaths a year.

More worrying still, researchers revealed that more than nine out of ten Britons live in areas with pollution levels above World Health Organisation air quality limits.

While much of this pollution comes from dirty diesel engines, which, ironically, were encouraged by successive governments as a greener alternative to petrol, around one-tenth of our air pollution is blamed on our renewed appetite for ‘real’ wood fires.

Part of the appeal lies in their supposed green credentials. Unlike coal fires, wood fuel is ‘carbon neutral’. That’s because trees absorb the greenhouse gas carbon dioxide from the atmosphere as they grow. Burning wood simply releases this CO2 back into the air — meaning it makes little contribution to global warming.

Air quality experts say the stoves contribute to an ever-thickening cloud of smog engulfing our towns and cities, which is increasing the risk of cancer, lung disease, heart attack, stroke and even dementia

Air quality experts say the stoves contribute to an ever-thickening cloud of smog engulfing our towns and cities, which is increasing the risk of cancer, lung disease, heart attack, stroke and even dementia

Despite this, domestic stoves, logs and wood pellets don’t get any direct green subsidy from the Government. But other wood- burners do. Under one scheme, called the Renewable Heat Incentive, anyone fitting a wood-burning hot water boiler gets quarterly cash payments over seven years.

The scheme is designed to help people living in remote areas that are off the gas grid and who are having to rely on oil. Since 2009, around 12,000 homes have been given subsidies — typically between £2,000 and £3,500 over seven years — for biomass boilers.

Yet these are nothing compared with the £817 million given to energy companies switching from coal to wood to help meet emissions targets set in the 2008 Climate Change Act. Moreover, some environmentalists argue that the switch to wood-burning is entirely skewed — and that it doesn’t take into account the destruction of natural habitat caused when trees are felled.

Last year, it was revealed how some wood pellets destined for UK power stations are actually imported from the U.S. — giving them a black mark over the carbon footprint created by the airmiles spent transporting the product thousands of miles to Britain.

Yet advocates of wood-burners argue that when used properly — that is, with the door closed — they are cleaner and safer than conventional open fireplaces. Fumes are carried up the chimney, and there’s no chance of a log rolling out of the grate and on to a carpet, creating a potential fire hazard.

Even so, with all that smoke being emitted into the air, there is a serious cost to our health, says Dr Gary Fuller, an expert in air quality at King’s College London. He has gone as far as comparing the toxic, dirty air in today’s cities to that of the Fifties and Sixties, when open coal fires were often the only source of heat in most homes.

Wood smoke is a cocktail of gases and dangerous microscopic particles but is worse when you open the door to heat the room quicker

Wood smoke is a cocktail of gases and dangerous microscopic particles but is worse when you open the door to heat the room quicker

‘We know from those smogs that solid fuel burning causes urban air pollution problems,’ he says.

‘A return to wood-burning is being seen in cities throughout western Europe, while in London, wood-burning can be responsible for 10 per cent of air pollution in winter.

‘There is evidence that good wood-burning stoves produce less air pollution than open fires, because they burn wood more efficiently, but any home burning wood will be creating more air pollution than heating by gas, oil or electricity.

And if you don’t have a wood-burner yourself, well, you’re still not safe — not even with your doors and windows shut.

Much of the smoke and its component particles returns to ground level, where it seeps through gaps under doors and around windows to get back into our homes. In parts of America, indoor concentrations of fine particles from wood smoke can be 70 per cent of outdoor levels, even in homes that don’t have a wood fire. Dr Fuller has found similar results here.

There’s no question that modern wood-burning stoves are far less polluting in the home than traditional fires, producing 90 per cent less pollution and 14 per cent less carbon dioxide.

Even if you don’t have one, you’re not safe 

Meanwhile, the wood burning industry body, the Stove Industry Alliance, insists new European regulations are making stoves even more efficient and clean. Its spokesman was insistent the real benefits came from using them as intended — i.e. with the door firmly shut.

‘The door should only be opened for refuelling,’ he said. ‘Independent tests have shown that emissions introduced into the room during refuelling are low.’

Studies are now under way in New Zealand to look at the health risks from stoves in real homes rather than laboratories.

Risk of fire is another concern. Wood-burning stoves should be safer than an open fire because the flames and spitting logs are behind glass. But installing wood-burning stoves in homes, and particularly ones with thatched roofs, can send insurance bills soaring.

So how can you reduce the pollution from a wood-burning stove both inside and outside your home? Scientists in New Zealand have shown that smoke emissions from a wood fire very much depend on how the fire is lit and refuelled, and the quality of the wood.

Fires are most polluting in their first hour of use because the fuel is not burning efficiently. There are also bursts of pollution when doors are opened and the stoves reloaded.

Older stoves are likely to be more polluting — and potentially more leaky — than newer models. And dirty stoves will be less efficient than clean ones. Using well seasoned, properly dried wood cuts down on smoke. Owners should avoid overloading their stoves and robbing the fire of air.

There’s an irony to all this, of course. Just as the drive towards dirty diesel in the name of battling climate change turns out to have been an environmental disaster for air quality, so does the move towards wood burning.

And it seems that only time will tell exactly how serious a toll it takes on our health. 

GGD onderzoekt instrumenten voor het meten van houtrook

Onderzoek naar instrumenten om houtrook te meten (foto: archief RTV Drenthe)Onderzoek naar instrumenten om houtrook te meten (foto: archief RTV Drenthe)
GRONINGEN/DRACHTEN – De GGD’s in Noord-Nederland willen opnieuw kijken naar de nauwkeurigheid van instrumenten om houtrook te meten. Daarbij test de GGD goedkope en minder geavanceerde meetapparaten, omdat daarmee de handhaving door gemeenten betaalbaar blijft.

Reden voor het onderzoek is de toename van het aantal mensen dat last zegt te hebben van houtkachels in de buurt. De fijnstof in houtrook kan kankerverwekkend zijn. Mensen kunnen er stress door ervaren of problemen met de luchtwegen krijgen.

Duidelijke overschrijding norm
Vorig jaar deed de GGD al een eerste onderzoek. Frans Greven: “We hebben bij verschillende mensen gemeten die zeggen last te hebben. We zagen op de toen geteste apparaten soms een duidelijke overschrijding van de normen. Maar de nauwkeurigheid van die metingen is het probleem.”

In het nieuwe onderzoek wil de GGD ook andere apparaten testen. Greven: “Die hele houtrookproblematiek is een witte vlek. We moesten vorig jaar ergens beginnen. Nu lijkt het erop dat we wat kunnen vinden.”

Meldpunt rookoverlast
Roland van der Hoek van het landelijke meldpunt Rookoverlast in Drachten vindt dat gemeenten met dit onderzoek een verkeerde keuze maken. “Een duur meetinstrument kost ongeveer 20.000 euro. Als gemeenten samen zo’n apparaat aanschaffen vallen de kosten wel mee.”

Van der Hoek vindt verder dat gemeenten in Nederland de regelgeving in Duitsland zouden moeten overnemen. De bewijsvoering is hier omgedraaid. Daar moet de stoker aantonen dat hij het goed doet.

Roland van der Hoek: “Gezondheidsschade door houtrook is moeilijk aan te tonen. In Duitsland zijn mensen met een houtkachel daarom verplicht twee keer per jaar roetmonsters uit de afvoerpijp te laten nemen. Zo kunnen zij aantonen dat goed hout op een goede manier is verstookt.”

Volgens Van der Hoek voorkom je met de Duitse regelgeving ook burenruzies. “Controle is beter dan dat je moet bewijzen dat je last hebt.”

Rook bij gevel meten
Frans Greven erkent dat er een juridisch verschil is tussen de Duitse en Nederlandse aanpak. “Maar daar gaan wij niet over. Wat mij betreft is het probleem met de Duitse aanpak dat de rook die uit de pijp komt nog niet de hoeveelheid rook is bij de gevel van degene die er last van heeft. Dat is wat wij willen meten.”

De GGD heeft voor een vervolgonderzoek financiën toegezegd gekregen door de Academische Werkplaats Milieu en Gezondheid. Het hoopt nog op een bijdrage van het Rijk.
Door: Hielke Meijer