The problem with improved cooking stoves

Improved cookstoves such as rocket and gasifier cookstoves could be more harmful to humans than conventional cookstoves, according to a new study.
| Photo Credit: AP

Improved cookstoves such as rocket and gasifier cookstoves have been shown to be more harmful to humans than conventional cookstoves due to the excessive presence of ultrafine air pollution particles, a new study has found.

In 2015, 85.6 million years of life were lost due to impairment due to indoor air pollution and resulted in more than 2 million early deaths worldwide. A big contributor to indoor pollution is domestic solid fuel burning used for cooking and heating. 

Why is burning domestic solid fuel toxic?

The burning of domestic solid fuels such as wood, coal, peat and animal dung releases a number of toxic pollutants in the form of particle matter (PM). It can range from ultrafine fine particles (0.1 μm or less), fine particles (2.5 μm or less) and coarse particles (10 μm or smaller). It also produces polluting gasses such as carbon monoxide, sulphur dioxide and nitrogen dioxide.

Published in Science of the Total Environment, the new study states that improved cookstoves can reduce fine particles (PM2.5) by 35% to 65%, but the emission of ultrafine particles (PM0.1) increases by twice as much.

Also Read | Health as the focus of air pollution policy 

The team involved in the study found that the large surface area of ultrafine particles allows them to absorb a significant amount of hazardous metals and chemicals such as arsenic, lead, nitrate, sulphate, and polycyclic aromatic hydrocarbons. 

“The global cost-of-living crisis has led to many turning to wood, coal, peat and other biomass fuels for domestic fuel combustion to cook or heat their homes. Unfortunately, our research suggests that there may be an even higher health cost to pay in the near future,“ said Prashant Kumar, a co-author of the study and professor at the University of Surrey, in an email to The Hindu.

How are ultrafine particles causing harm?

Due to their smaller size, ultrafine particles can travel to the innermost portion of the lung (alveoli) and steer clear of the body’s defence mechanism.

“The tiny particles can easily infiltrate the nasal passages, leading to potential health risks, and our most vulnerable will pick up that bill,” Dr Kumar said.

While improved stoves have been designed to reduce fuel consumption, smoke and harmful emissions than traditional stoves, their ability to burn the fuel more thoroughly produces more harmful ultrafine particles. 

Using solid fuel in improved stoves is especially common in rural regions of developing countries such as India, China and Sub-Saharan African countries. 

Also Read | Cooking with gas, not wood

Even in developed countries, improved stoves are used to heat homes in cold weather. The U.S. Environment Protection Agency estimated that 12.7 million Americans primarily utilise wood as a source of heat in 2015. In Ireland, 20% of houses use wood as fuel.

Is there a solution?

“This is clearly a global issue impacting developing countries and superpowers alike, and so we all need to come together to ensure that clean air is available to all of society and not just the fortunate few,” said Dr Kumar. 

He also suggested solutions such as using eco-fuel pellets that emit fewer toxic fumes. “The development of heat stoves approved by the UK Department of Environment, Food and Rural Affairs that are designed to improve combustion efficiency and reduce pollutant emission also needs to be investigated,” he added.