4 million people died prematurely! How can cooking at home still cause serious pollution?

A study recently published in International Environment shows that in 12 major cities around the world, the kitchens of three-quarters of low-income households are seriously polluted by cooking emissions.

The first-of-its-kind study, conducted by the University of Surrey in the UK and its global collaborators, found for the first time that poor ventilation and poor fuel choice are the biggest causes of poor air quality in kitchens.

The size of the kitchen and the way food is cooked also mattered, with levels of indoor air pollution being particularly high when deep-frying food was being prepared.

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"Wealth inequality clearly affects indoor air quality," said Prashant Kumar, founding director of the Global Centre for Clean Air Research (GCARE) at the University of Surrey and an author of the paper. "The impact of indoor air quality also differs along gender lines. Women are disproportionately affected by cooking pollution, especially in developing countries. This needs to be addressed to improve health and promote equality."

The highest average pollution level was found in Dhaka, Bangladesh, because kitchens there are usually small and food is mainly cooked by frying, which requires people to stay in the kitchen for a long time.

At the other end of the spectrum is Medellín, Colombia, where kitchens have the best air quality because they have larger spaces and use cleaner cooking fuels.

The cooking methods of different dishes will also affect the kitchen air quality. For example, frying is a cooking method that emits the most particulate pollutants.

The study found that residents in Dhaka, Dar es Salaam, Nairobi and other places spend more than 40% of their cooking time on frying; while residents in Cairo, Sulaymaniyah, Akure and other places spend 2/3 of their cooking time on stewing food, thereby reducing the emission of particulate pollutants.

In addition, cooking with charcoal caused the highest levels of kitchen pollution, producing more than three times the pollutants of liquefied petroleum gas (LPG). The pollution level caused by cooking with natural gas was only 30% lower than that of charcoal.

The study also found that kitchens that incorporate mechanical ventilation, such as range hoods, can cut pollution in half compared to kitchens with natural ventilation alone.

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"Improving air circulation, using cleaner fuels, increasing the filtration efficiency of range hoods, and reducing deep-frying are all ways to reduce pollution from cooking," Kumar said. "Around the world, kitchens are often places where people gather, but these findings suggest that cooks should discourage family and friends from staying away from the kitchen while cooking."

The World Health Organization estimates that around 4 million people die prematurely from indoor air pollution caused by the use of solid fuels and kerosene stoves in kitchens.

Exposure to high levels of particle pollution, including those from cooking, has been linked to the development of conditions such as heart disease, pneumonia, stroke, lung cancer and chronic obstructive pulmonary disease.

Next, the research team will further analyze their findings and develop guidelines for reducing kitchen contamination.

Related paper information:

https://doi.org/10.1016/j.envint.2022.107155

Source: China Science Daily

Author: Xu Rui

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