Scientists at the Indian Institute of Technology, Mandi (IIT Mandi), have obtained important insights into the health risks linked with indoor air pollution in rural homes of some northeastern states of India due to the use of traditional cooking practices. The study, which collected data from three northeastern states, found that more than 50 per cent of rural homes in Northeast India use traditional cooking fuels such as firewood and biomass, the emissions released on burning which are hazardous, and increase indoor aerosol exposure. Suspensions of fine solid or liquid particles in gas are called aerosols.
Some of the aerosols released in the kitchen air are particulate matter.
Which three states from Northeast India were studied?
The three states of Northeast India studied were: Assam, Arunachal Pradesh, and Meghalaya.
The findings were recently published in the form of three papers in two journals: Science of The Total Environment, and Environmental Pollution. The research was conducted in collaboration with the National Physical Laboratory, India, and the Institut National de Recherche et de Sécurité, France.
How was the study conducted?
As part of the study, the researchers compared the severity and disease burden linked with the use of biomass fuels for cooking to the use of Liquefied Petroleum Gas (LPG) for cooking.
For this, the scientists measured the concentrations of aerosols, toxic trace materials, and carcinogenic organic substances bound with them released when cooking using firewood, mixed biomass, and LPG. Toxic compounds include polycyclic aromatic hydrocarbons.
The scientists calculated the amount of aerosols inhaled by people in the kitchen while cooking.
Using models, the scientists estimated how the toxic particles and associated chemicals deposited in different parts of the human respiratory system.
This data was used to estimate the disease burden on the rural Northeast Indian population. The scientists focused on respiratory diseases such as chronic obstructive pulmonary disease (COPD), pneumonia, and cancers.
COPD is a group of diseases that results in airflow blockage due to damage to the airways or other parts of the lung, making it hard to breathe. COPD is primarily of two types: emphysema and chronic bronchitis. Emphysema involves damage to the lungs over time, while chronic bronchitis involves a long-term cough with mucus.
In order to understand the disease burden, the researchers used the ‘potential years of life lost’ metric, which is an estimate of the number of years a person lost from what would have been their lifespan had they not died prematurely due to poor health.
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Exposure to harmful aerosols, and disease burden in homes using biomass, firewood, and LPG
In homes which used firewood or biomass fuels, the exposure to harmful aerosols was two to 19 times higher than that in homes where LPG was used for cooking.
In kitchens where firewood is used, there is four to 10 times more enrichment of polycyclic aromatic hydrocarbons compared to LPG.
About 80 to 90 per cent of polyaromatic hydrocarbons were PM1 particles, which are less than one micron in size.
About 29 to 76 per cent of the total aerosol concentration in the kitchen air was found to be deposited in the respiratory system of those in the kitchen.
The kitchens using firewood had the highest concentration of aerosols and trace elements.
Meanwhile, in homes which used both firewood and mixed biomass, the disease burden was two to 57 times higher than that in homes which used LPG for cooking.
The aerosols produce free radicals in cells, which, in turn, increase oxidative stress. This damages cells, proteins, and DNA.
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For the people who used biomass fuels, the potential for oxidative stress and damage was four to five times higher than those who used LPG.
This is because when biomass is used to cook indoors, metals and organic chemicals are released, and these are inhaled by those in the kitchen.
In the kitchens which used biomass, there was about five times enrichment of total oxidative potential compared to LPG. The ability of particles to generate hydroxyl radicals in an aqueous solution is called oxidative potential.
In a statement released by IIT Mandi, Dr Sayantan Sarkar, who was involved in the research, said the study is the first to estimate disease burdens caused by exposure to indoor cooking emissions in India in terms of potential years of life lost. He also said that the study is the first to measure the potential for oxidative stress occurring as a result of exposure in the Indian context, and quantifies how much more risk biomass users face compared to LPG users.
Firewood and biomass using kitchens had the largest carcinogenic health risk and disease burden.
COPD was responsible for the highest number of potential years of life lost.
Significance of the study
The significance of the study is that it highlights the urgent need for rural families in Northeast India to transition to cleaner energy fuels for cooking. Therefore, LPG should be made more accessible, cook stove programmes improved, awareness spread in rural areas, local solutions funded, and health camps organised for rural women.
