Two new studies led by University of California, Berkeley, researchers spotlight the human health effects of exposure to smoke from open fires and dirty cookstoves, the primary source of cooking and heating for 43 percent, or some 3 billion members, of the world’s population. Women and young children in poverty are particularly vulnerable.
Pneumonia is the leading cause of death in children worldwide. Pneumonia kills an estimated 1.4 million children under the age of five years every year – more than AIDS, malaria and tuberculosis combined. Pneumonia can be caused by viruses, bacteria or fungi.
In the first study, the researchers found a dramatic one-third reduction in severe pneumonia diagnoses among children in homes with smoke-reducing chimneys on their cookstoves. The second study uncovered a surprising link between prenatal maternal exposure to woodsmoke and poorer performance in markers for IQ among school-aged children.
An estimated 3 billion people in the world still cook with open fires and dirty cookstoves, including this mother in Guatemala. (Photos by Nigel Bruce, University of Liverpool)
700 million black carbon free cookers would save over one million lives per year, reduce birth defects and reduce global warming.
Prior PNAS research – Association of selected persistent organic pollutants in the placenta with the risk of neural tube defects.
The findings on pneumonia, the chief cause of death for children five and under, will be published in the journal The Lancet on Thursday, Nov. 10, two days before World Pneumonia Day. While previous research has linked exposure to household cooking smoke to respiratory infections, the latest results come from the first-ever randomized controlled trial – the gold standard of scientific experiments – on air pollution.
“This study is critically important because it provides compelling evidence that reducing household woodsmoke exposure is a public health intervention that is likely on a par with vaccinations and nutrition supplements for reducing severe pneumonia”
The researchers found that using chimneys to vent cooking smoke outside homes led to a more striking decrease in cases of severe pneumonia compared with total pneumonia cases, possibly because the reduction in smoke with the chimney stoves was insufficient to significantly reduce all risk.
“The amount of smoke exposure babies were getting from the open woodfire stoves is comparable to having them smoke three to five cigarettes a day,” said Smith, whose research in this field began 30 years ago. “The chimney stoves reduced that smoke exposure by half, on average.”
IQ Impact Study
The results found, for the first time, a link between exposure to woodsmoke – as determined by carbon monoxide levels measured individually – during the third trimester of pregnancy and lower performance on neurodevelopmental tests when the children were ages 6 and 7. Specifically, the researchers found impairments in visuo-spatial perception and integration, visual-motor memory, and fine motor skills.
“I was surprised because woodsmoke was always considered a risk for respiratory health, but not IQ,” said study lead author Linda Dix-Cooper, who conducted the study for her master’s thesis in UC Berkeley’s Global Health and Environment graduate program. “The implications of our findings are highly worrisome. Neurodevelopmental impacts have societal costs, such as impacts on an individual’s future lifetime earnings and educational attainment.”
Dix-Cooper added that similar cognitive impacts among children have been noted in previous case reports of childhood acute carbon monoxide poisonings and in epidemiological investigations of other prenatal air pollutant exposures in developed countries’ urban centers. However, larger studies are needed to confirm the link with pollution from woodsmoke, she said.