High metal concentration in Delhi air putting residents at risk, says TERI study

Scientists who conducted the study said that some of these metals were extremely toxic for human health and regular exposure to it can lead to fatal health consequences

Delhi has a high concentration of heavy metals in its air, exposing the residents, especially children, to a range of respiratory and cardiovascular diseases, a study by The Energy and Resources Institute (TERI) has said.

According to experts, the primary sources of metals in Delhi’s air is vehicular exhaust, open fires and fumes from industrial operations in neighbouring states. (HT Archive)

The study showed that in October 2019, when Delhi’s pollution levels start getting worse, the concentration of zinc in the city’s PM 2.5 (particulate matter with diameter less than 2.5 micrometres) was 379 ng/m3 (nanogram per cubic metre of air), this increased to 615 ng/m3 in September 2020.

The study was carried out in six cities across India, with different air pollution ecologies—Delhi (megacity), Ludhiana (high industrial activities), Patiala (high agricultural and biomass burning), Panchkula (PM 2.5 attained city), Vishakapatnam (coastal region) and Jaisalmer (desert). The researchers analysed air quality levels in October 2019.

The study showed that in October 2019, when Delhi’s pollution levels start getting worse, the concentration of zinc in the city’s PM 2.5 (particulate matter with diameter less than 2.5 micrometres) was 379 ng/m3 (nanogram per cubic metre of air), this increased to 615 ng/m3 in September 2020. Similarly, the share of lead in Delhi’s air was 233ng/m3 in 2019, which increased to 406ng/m3 in 2020, the concentration of arsenic increased from 3ng/m3 to 11ng/m3 and cadmium increased from 8ng/m3 to 21ng/m3.

Scientists who conducted the study said that some of these metals were extremely toxic for human health and regular exposure to it can lead to fatal health consequences. For instance, increased concentration of cadmium and arsenic in the air can overtime result in higher risk of cancer, kidney issues and, hypertension, diabetes and cardiovascular diseases.

According to experts, the primary sources of metals in Delhi’s air is vehicular exhaust, open fires and fumes from industrial operations in neighbouring states. “Factors such as high traffic volume in Delhi and industrial activities in areas surrounding it, leads to increased share of heavy metals in the air... It is very important to understand the chemical make of the pollutants that you are being exposed to. For instance, the PM 2.5 levels in your city could be under 60ug/m3, which is considered an acceptable standard, but if the air has high concentration of toxic metals then your health is at a higher risk,” said Kanhaiya Lal, associate fellow (environment and health), TERI.

Children at higher risk

Scientists conducted a detailed health survey of 413 children -- aged 14-17 years -- in Delhi, and found that 75.4% complained of breathlessness, 24.2% felt itchiness in eyes, 22.3% reported regular sneezing or runny nose, 20.9% complained of cough in the morning. They also reported skin rash, asthma, and phlegm in the morning.