Text of my ‘When Worlds Collide’ column published in Ceylon Today Sunday newspaper on 27 January 2013
The new Global Burden of Disease (GBD) report, released in December 2012, says air pollution has become one of the top 10 killers in the world.
GBD, a global initiative involving hundreds of experts and the World Health Organisation (WHO), studied deaths and illnesses from all causes across the world. Its latest analysis shows that in South Asia, outdoor air pollution has become the sixth most dangerous killer.
Even more alarmingly, indoor air pollution (IAP) – right inside our homes and offices — is the second highest killer in our region.
IAP rarely gets much attention from environmental activists. Maybe because it affects mostly women and children, especially those in poorer households. But no one is immune from its health impacts.
This isn’t just about cigarettes. Second hand tobacco smoke is certainly cancer-causing, but not the only air pollutant indoors. There are other, seemingly innocuous gases and emissions that also make people ill. This is particularly so when prolonged exposure happens inside small, confined spaces – such as kitchens.
Cooking with biomass (wood, animal dung, crop waste) inside poorly ventilated kitchens turns them into de facto gas chambers without anyone realising it.
Globally, an estimated 3 billion people still cook and heat their homes using solid fuels in open fires and leaky stoves, according to WHO. About 2.7 billion burn biomass and a further 0.4 billion use coal. Most such users are poor, and live in developing countries.
As WHO notes: “Cooking and heating produces high levels of indoor air pollution with a range of health-damaging pollutants, including small soot particles that penetrate deep into the lungs. In poorly ventilated dwellings, indoor smoke can be 100 times higher than acceptable levels for small particles. Exposure is particularly high among women and young children, who spend the most time near the domestic hearth.”
In 2004, WHO estimated that IAP in homes was responsible for at least 4,300 premature deaths in Sri Lanka. The actual numbers can be higher.
Poor woman’s pollution
Dr Oliver Ileperuma, senior professor of chemistry at the University of Peradeniya, has been raising the alarm about IAP for many years.
“Indoor air pollution is an equally important aspect of air pollution that has received practically no attention in Sri Lanka,” he wrote in the Journal of the National Science Foundation back in 2000. “The air in enclosed spaces such as offices, classrooms and even homes can be significantly more polluted than outdoor air.”
Cooking fuel is the main source of indoor air pollution in most homes. Other sources include tobacco smoke and pollution coming in from outdoors.
“At least 70 compounds have been identified in the wood smoke…some of these are carcinogenic and some cause respiratory illnesses such as acute bronchitis,” says Prof Ileperuma.
Health and medical professionals have been studying and highlighting IAP’s impacts for sometime. In 2010, three researchers — Yatagama Nandasena, Ananda R Wickremasinghe and Nalini Sathiakumar – did a review of epidemiologic studies on air pollution and health in Sri Lanka. Their paper, published in BMC Public Health underlines why this aspect of air pollution – both indoor and outdoor — should receive more and urgent attention.
“Most of the traditional local stoves using firewood have incomplete combustion resulting in high pollutant emissions. This, coupled with poor ventilation can produce very high levels of indoor pollution,” the researchers say, citing development activist Raja Amerasekera who heads the Kandy-based organization Integrated Development Association (IDEA).
A few years ago, Amerasekera assessed exposure in kitchens using firewood with traditional stoves. He found that the average PM2.5 concentrations exceeding 1,200 micrograms per cubic metre. These tiniest and deadliest suspended particles in smoke can penetrate into the alveoli in our lungs.
IAP results from complex interactions between building types, level of ventilation, type of emissions as well as people’s behaviour patterns, the researchers say. Even relatively low concentrations of smoke, for example, can cause high levels of pollution inside small kitchens when they become trapped.
Although Sri Lanka as a tropical country is expected to have good indoor ventilation, some studies indicate that indoor air is more polluted than outdoor air – because home designers and builders have paid scant attention to ventilation.
Sometimes even large, modern houses are built this way. Even LP gas cookers, when used without adequate ventilation, can build up pollutants inside kitchens and homes.
But the worst combination is firewood and poor ventilation. Women and young children who usually stay around their mothers while cooking may be the most vulnerable.
According to the Household Income and Expenditure Survey 2009/10, conducted by the Department of Census and Statistics, 80% of Lankan households still use firewood (other fuel sources being LP gas, 16%, kerosene, 2.5%). Firewood use is less in urban areas, but even there, nearly 40% reported using it.
As people move up the “energy ladder”, they opt for fuel types that are cleaner, more convenient, efficient but also more costly. But “it is unlikely that a higher proportion of Sri Lankans will shift to cleaner fuels in the near future,” the three researchers note.The solution is to promote improved wood stoves that generate less smoke, and are also more fuel efficient. Several such stoves have been on the Lankan market, at reasonable prices, since the 1970s. Yet, their uptake has been slow – indicating a failure in social marketing and acceptance.
Changing this requires raising awareness and working with families, one household at a time. IDEA has been doing this for years: they work with selected rural communities, helping families to improve kitchen design and fuel use (see: http://www.ideasrilanka.org)
It entails replacing the traditional hearth with a better designed wood stove (they promote ‘Anagi’ stoves; other designs are also available), setting up chimney hoods and rearranging kitchens for the best use of available space.
The benefits are many. An improved stove burns fuel more efficient and requires a lesser quantity firewood; the chimney evacuates the smoke; while the ergonomically efficient kitchen means less time and drudgery for women.
In Aranayaka in Kegalle district, for example, families with improved kitchens found significant improvements in the air they breathe indoors (which IDEA measures) and in the general cleanliness of the household. The time they saved on cooking may be used in helping children with homework, tending to home gardens or livelihood activities.
Other factors besides cooking also affects air quality inside homes. Our increasing use of personal care and household chemicals – such as solvents, sprays, formaldehyde (from adhesives in furniture) – adds to low levels of air pollution. Opening windows and letting in fresh air can help flush out many of these.
A bigger concern is smoke from mosquito coils used in a growing number of urban and rural households. The health impacts have not been fully assessed in Sri Lanka, but a 2003 study of common brands of mosquito coils from China and Malaysia found many volatile organic compounds — including carcinogens and suspected carcinogens — in the coil smoke.
They noted how burning one mosquito coil would release the same amount of PM 2.5 pollutants as burning 75 to 137 cigarettes. The emission of formaldehyde from one coil can be as high as that released from burning 51 cigarettes.
So is our short term protection from dengue mosquitoes endangering our long term health? We need more studies and healthier alternatives.