KARACHI: A study recently conducted by Karachi University’s Institute of Environmental Studies (IES) has found that the city’s air remains heavily laden with hazardous pollutants throughout the year, posing serious threat to public health.

The research team comprised Dr Aamir Alamgir, Principal Investigator and assistant professor at IES, Dr Noor Fatima, Effah Malik, Shahzaib Shamim and Abdul Basit.

It studied levels of PM2.5 and PM10 — both inhalable microscopic particles suspended in the air that can induce adverse health effects — at 22 locations in the seven districts daily for 10 hours for 12 months last year.

The areas selected for monitoring were: New Karachi, F.B Area, Nazimabad, Liaquatabad, Hyderi Market, Hasan Square, Nursery, Sohrab Goth, Jackson market, Naurus Chowrangi, Model Colony, Landhi, Shan Chowrangi, Shama market, Jinnah Square, Quaidabad, Port Qasim, Kala Pul (DHA), Tibet Centre, Surjani Town and Orangi Town.

Particulate matter poses greatest environmental risks to human health, says expert

“Karachi suffers from serious particulate matter pollution that has been proved to be one of the greatest environmental risks to health,” shared Dr Alamgir.

He added that the concentration of hazardous air pollutants in Karachi has reached a point where seasonal, or monsoon changes don’t bring about any positive impact on the city’s ambient air quality.

He regretted lack of action on the part of government as the city had been constantly ranked among the most polluted cities in the world.

Citing the WHO data, he said ambient (outdoor) air pollution was estimated to have caused 4.2 million premature deaths worldwide in 2019 and that some 89% of those premature deaths occurred in low-and middle-income countries.

Sources of pollution

Dr Alamgir explained that the major source of pollution in case of Karachi was vehicular emissions followed by construction work, unpaved road networks, fossil fuel combustion, industrial emissions and open waste burning.

The study found that most locations not only exceeded the WHO daily concentration limits for PM2.5 (15ug/m3) and PM10 (45ug/m3), but also drastically breached the 24 hour-average limits set by the Sindh Environmental Protection Agency.

The study points out that the concentration limits under the Sindh Environmental Quality Standards (SEQS) (75ug/m3 for PM2.5 and 150ug/m3 for PM10) are multiple times higher than the WHO standards.

The daily mean concentrations of both pollutants — PM2.5 ranged between 71ug/m3 and 160ug/m3 whereas PM10 ranged between 180ug/m3 and 410ug/m3 — at most locations remained constantly higher than the WHO guidelines and the SEQS.

The concentrations of particulate matter reach alarming levels during peak working hours at Hasan Square, Quaidabad, Nursery, Naurus Chowrangi, Sohrab Goth, and Tibet Centre, mainly due to heavy traffic load in these localities.

The team found that district East was the most polluted region where levels of both PM2.5 and PM10 remained higher during the whole study period. The area had an annual mean concentration of 126.51ug/m3 for PM2.5 and 326.81ug/m3 for PM10.

District Central was found to be least polluted with the annual mean concentration of PM2.5 reported to be 86.98ug/m3 and 228.21ug/m3 for PM10.

Poor air quality index

The study also used the air quality index (AQI) tool and found the AQI values at most locations ranged from 201 to 300, categorising it as “very unhealthy”.

(The AQI values within 0 – 50 is categorised as Good, 51 – 100 is moderate, 101 – 150 is unhealthy for sensitive groups, 151 – 200 is unhealthy, 201 – 300 is very unhealthy and 301 or higher is hazardous.)

“Inaction has brought us to this shocking stage. We must act now and take corrective measures,” regretted Dr Alamgir, emphasising the need for urgent action.

According to him, several studies have assessed the impact of air pollution on health and linked prolonged exposure to PM2.5 and PM10 with illnesses such as stroke, heart disease, lung cancer, and both chronic and acute respiratory diseases, including asthma.

“Some past studies also found Karachi’s air quality poor during pre-monsoon season in all industrial zones,” he said.

He criticised Sepa for making a significant deviation from the WHO standards on air quality.

“We need to bring our standards in line with the international standards, incentivise industries to follow air quality standards and enforce the law,” Dr Alarmgir said, adding that policies and investments supporting cleaner transport, power generation, better municipal waste management and energy efficient homes would reduce key sources of outdoor air pollution.

Published in Dawn, July 28th, 2024