Exposure to higher particulate matter pollution poses a significant threat to human health. Karachi, an industrial hub of Pakistan, has been facing poor air quality issues over the years, which also affect human health. This study was conducted for the first time in Karachi to identify the trends of PM2.5 and PM10 pollution among the districts of Karachi and evaluate associated non-carcinogenic health risks. To achieve this aim, 22 monitoring locations were selected from all 07 districts of Karachi, and daily ground PM levels were determined for the 12 months of the year 2023 using the Temptop Multi-Functional Air Quality Detector. The geospatial distribution of PM levels and associated AQI (Air Quality Index) were also assessed by using ArcGIS software version 10.3. Moreover, the health risk assessment through inhalation exposure was conducted using the US-EPA model for adults, children, and infants. The findings obtained from ground monitoring and satellite data revealed that the mean PM2.5 and PM10 levels have been found in the range of 86.99–126.51 µg/m3 and 228.21 – 326.81 µg/m3, drastically crossing the acceptable SEQs limits of 75 µg/m3 and 150 µg/m3 among all districts of Karachi. AQI levels were also found to be > 200, reaching unhealthy and very unhealthy levels for both monitored pollutants among the districts, further confirming that the citizens were at higher risk of experiencing air pollution-related health impacts. Furthermore, the HRA results showed that the mean non-carcinogenic HQ values for PM2.5 breached the threshold limit of 1 among all districts, and the risks were found in the order of East > South > Malir > West > Keemari > Korangi > Central. In contrast, HQ levels for PM10 were within the acceptable limit of 1 in all districts and population groups. However, the results of cumulative HI drastically crossed the safe limit of 1 among all districts, with the highest value observed in children of District Central (14.31) and the lowest observed in adults of District Keemari (3.53). Overall, the vulnerability of citizens in terms of non-carcinogenic risks calculated from mean HI were found to be children (8.84) > infants (8.67) > adults (5.41), indicating that exposed populations were at significant risk of experiencing non-carcinogenic health impacts and PM2.5 was the main culprit of deteriorating ambient air quality as well as increasing negative health implications. Overall, these findings provided baseline data for future studies and called for proactive mitigative strategies that must be immediately implemented to control source emissions of PM2.5 and PM10 pollution in Karachi.

Health Risk Assessment and Geospatial Variation of Particulate Matter Pollution in the Megacity of Karachi, Pakistan

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发表日期：

2025年6月16日

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Aamir Alamgir,
Noor Fatima,
Effah Malik,
Shahzaib Shamim,
Abdul Basit

摘要

Exposure to higher particulate matter pollution poses a significant threat to human health. Karachi, an industrial hub of Pakistan, has been facing poor air quality issues over the years, which also affect human health. This study was conducted for the first time in Karachi to identify the trends of PM_2.5 and PM₁₀ pollution among the districts of Karachi and evaluate associated non-carcinogenic health risks. To achieve this aim, 22 monitoring locations were selected from all 07 districts of Karachi, and daily ground PM levels were determined for the 12 months of the year 2023 using the Temptop Multi-Functional Air Quality Detector. The geospatial distribution of PM levels and associated AQI (Air Quality Index) were also assessed by using ArcGIS software version 10.3. Moreover, the health risk assessment through inhalation exposure was conducted using the US-EPA model for adults, children, and infants. The findings obtained from ground monitoring and satellite data revealed that the mean PM_2.5 and PM₁₀ levels have been found in the range of 86.99–126.51 µg/m³ and 228.21 – 326.81 µg/m³, drastically crossing the acceptable SEQs limits of 75 µg/m³ and 150 µg/m³ among all districts of Karachi. AQI levels were also found to be > 200, reaching unhealthy and very unhealthy levels for both monitored pollutants among the districts, further confirming that the citizens were at higher risk of experiencing air pollution-related health impacts. Furthermore, the HRA results showed that the mean non-carcinogenic HQ values for PM_2.5 breached the threshold limit of 1 among all districts, and the risks were found in the order of East > South > Malir > West > Keemari > Korangi > Central. In contrast, HQ levels for PM₁₀ were within the acceptable limit of 1 in all districts and population groups. However, the results of cumulative HI drastically crossed the safe limit of 1 among all districts, with the highest value observed in children of District Central (14.31) and the lowest observed in adults of District Keemari (3.53). Overall, the vulnerability of citizens in terms of non-carcinogenic risks calculated from mean HI were found to be children (8.84) > infants (8.67) > adults (5.41), indicating that exposed populations were at significant risk of experiencing non-carcinogenic health impacts and PM_2.5 was the main culprit of deteriorating ambient air quality as well as increasing negative health implications. Overall, these findings provided baseline data for future studies and called for proactive mitigative strategies that must be immediately implemented to control source emissions of PM_2.5 and PM₁₀ pollution in Karachi.