Toxic heavy metals plentiful in Bengaluru’s air, finds 2019 study

When it came to PM 2.5, the eight-month long air quality study found levels of PM 2.5 in 20 of the 27 samples exceed permissible 24-hour average of 60 μg/m3.
Bangalore pollution
Bangalore pollution

News of high amounts of pollutants in a city’s air is never good news. While PM 2.5 and PM 10 are usually the indicators that reports go by, a city-based think tank has found that not only does Bengaluru’s air have high presence of PM 2.5 particles, but also higher than normal concentration of extremely toxic chemicals.

Data released on Monday in a report titled ‘Choking in the Garden City’ prepared by Sensing Local, non-governmental think tank, and Healthy Energy Initiative India showed that there were elevated levels of heavy metals in Bengaluru’s air in addition to the prime pollutant. The latter – PM 2.5 – refers to microscopic particulate matter that is less than 2.5 micrometres in size. Particulate matter can penetrate deep into the lung tissue, and affect health negatively.

The authors of the report also pointed to the emerging research which indicates higher vulnerability of populations to COVID-19 among those residing in regions with air pollution than those living in places with better air quality.

The air pollution data collected by the researchers found the presence of manganese, nickel, lead and crystalline silica in the samples.

“The results have demonstrated that the PM 2.5 levels in almost all sites tested exceed the statutory regulations. Presence of toxic chemicals like lead, manganese, nickel indicate that threat to air quality and health is not just from PM 2.5 but from toxic heavy metals that do not get accounted for,” said the report.

While manganese and lead are neurotoxins, crystalline silica is a respiratory irritant, and can cause silicosis, a lung disease generally known to only affect people exposed to silica at workplaces. Nickel is a carcinogen and it also affects the respiratory and immune systems in the body.

Other key findings of the study are: 

a. Levels of PM 2.5 in 20 of the 27 samples exceed the Indian National Ambient Air Quality Standards (NAAQS) of 60 μg/m3 for 24 hours.

b. Levels of manganese in 3 of the 27 samples exceed WHO annual average of 0.15 μg/m3. 

c. Levels of nickel in 20 out of 27 samples exceed the WHO’s annual average of 0.0025 μg/m3.

d. All 27 samples had elevated levels of crystalline silica, with eight of the 27 samples containing very high levels (above 10 μg/m3). There are no specific standards defined for concentration of silica in air in India or as per WHO.

e. For lead, no samples collected exceeded WHO’s annual average of 0.50 μg/m3. However, there is no known safe level of lead in the human body.

As part of the study, air quality was measured for April-November 2019 across 27 varied locations in the city (list given below). 

The 27 sample were collected from Avenue Road, Bannerghata Road, BBMP Head Office, Bellandur, Bowring Hospital, Haraluru, Hosur Road, two locations in IIM campus (within campus and outside), Indira Nagar 2nd Stage, Indira Nagar Defence Colony, Kalkere, Kengeri (near the railway station), 100ft Road Koramangala, Manyata Residency (inside Manyata tech park), Margosa Road (Malleshwaram), Mysore Road, Peenya, near Pheonix Market City (ITPL Road), Puttenahalli Lake, Residency Road & St Marks Road Junction, Silk Board (Fern Hill Apartments), Victoria Road, Madiwala Market Junction, Vikram Nagar (ISRO Layout), Wheeler Road and Junnasandra gate bus stop (Sarjapur Road).

The study was conducted as a collaboration between Sensing Local, Bengaluru, and Healthy Energy Initiative - India between April - November 2019 and was supported by Azim Premji Philanthropic Initiatives.

Ankit Bhargava of Sensing Local, said, “This study is unique because it brings together various stakeholders - the impacted communities, health experts, environmental experts and urban planners to collaboratively work towards identifying the problems of air pollution and finding solutions to it.” 

Ankit added, “Given that the data is local, the idea was that citizens would better relate to issues specific to their street/neighbourhood/ward while also recognizing common sources that require city wide action.”

You can access the report here.

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