The working environment of the operators of heavy earth moving machineries (HEMMs) expose them to high airborne particulate matter (PM) concentration as a part of their occupation. Using a set of low-cost sensors, the present study investigated the in-cabin PM exposure of dumper, shovel and drill machine operators and compared it with the cabin outside PM concentration in a large opencast mine where a large number of HEMMs are deployed. The results revealed that the drill operators were exposed to the highest in-cabin PM concentration (PM1 = 190.98 ± 30.3 µg m−3, PM2.5 = 281 ± 52.85 µg m−3, PM10 = 1475.23 ± 915.42 µg m−3) followed by the exposures of shovel (PM1 = 45.62 ± 24.28 µg m−3, PM2.5 = 97.85 ± 51.10 µg m−3, PM10 = 354.38 ± 219.69 µg m−3) and dumper operators (PM1 = 42.08 ± 18.25 µg m−3, PM2.5 = 90.38 ± 44.55 µg m−3, PM10 = 331.05 ± 225.65 µg m−3). The exposure in the evening shift was 10% higher than exposure during the morning shift. The in-cabin PM concentrations while the dumper travelled on main haul road were ~ 2 times of the corresponding values when it travelled on the internal haul road. In addition to the outside concentration, the in-cabin PM levels are influenced by cabin ventilation (AC vs. non-AC), structural leakage, and door/window operation. AC cabins could reduce the PM exposure up to 40% (10% for non-AC cabins) than ambient mine environments. GLM explained 65–89% of PM concentration variability, with HEMM type and meteorological parameters as significant predictors. The health risk assessment indicates that all operators are exposed to non-carcinogenic health risks, as the Risk Quotient (RQ) values for each exceed the threshold of 1 (RQ > 1). Notably, the drill operator is subjected to the highest non-carcinogenic risk, with an RQ value of 8. While, the Excess Lifetime Cancer Risk (ELCR) assessment for PM2.5 exposure reveals potential carcinogenic risks among operators in two age groups. For the 18-year age group, the ELCR values range from 6.15 × 10⁻4 to 1.92 × 10⁻3, whereas for the 21 years and above age group, the values range from 5.13 × 10⁻4 to 1.60 × 10⁻3, indicating elevated cancer risk among 18 + age group of operators. This research highlights the occupational health risk of the HEMM operators working in opencast mines and important role of low-cost sensors in real-time PM exposure assessment in mining environments.

Estimation of real-time PM exposure and associated health risk of HEMM operators using low-cost sensors in a highly mechanised opencast coal mine

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发表日期：

2025年6月17日

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Dhruti Sundar Pradhan,
Aditya Kumar Patra,
Abhishek Penchala,
Samrat Santra

摘要

The working environment of the operators of heavy earth moving machineries (HEMMs) expose them to high airborne particulate matter (PM) concentration as a part of their occupation. Using a set of low-cost sensors, the present study investigated the in-cabin PM exposure of dumper, shovel and drill machine operators and compared it with the cabin outside PM concentration in a large opencast mine where a large number of HEMMs are deployed. The results revealed that the drill operators were exposed to the highest in-cabin PM concentration (PM₁ = 190.98 ± 30.3 µg m⁻³, PM_2.5 = 281 ± 52.85 µg m⁻³, PM₁₀ = 1475.23 ± 915.42 µg m⁻³) followed by the exposures of shovel (PM₁ = 45.62 ± 24.28 µg m⁻³, PM_2.5 = 97.85 ± 51.10 µg m⁻³, PM₁₀ = 354.38 ± 219.69 µg m⁻³) and dumper operators (PM₁ = 42.08 ± 18.25 µg m⁻³, PM_2.5 = 90.38 ± 44.55 µg m⁻³, PM₁₀ = 331.05 ± 225.65 µg m⁻³). The exposure in the evening shift was 10% higher than exposure during the morning shift. The in-cabin PM concentrations while the dumper travelled on main haul road were ~ 2 times of the corresponding values when it travelled on the internal haul road. In addition to the outside concentration, the in-cabin PM levels are influenced by cabin ventilation (AC vs. non-AC), structural leakage, and door/window operation. AC cabins could reduce the PM exposure up to 40% (10% for non-AC cabins) than ambient mine environments. GLM explained 65–89% of PM concentration variability, with HEMM type and meteorological parameters as significant predictors. The health risk assessment indicates that all operators are exposed to non-carcinogenic health risks, as the Risk Quotient (RQ) values for each exceed the threshold of 1 (RQ > 1). Notably, the drill operator is subjected to the highest non-carcinogenic risk, with an RQ value of 8. While, the Excess Lifetime Cancer Risk (ELCR) assessment for PM_2.5 exposure reveals potential carcinogenic risks among operators in two age groups. For the 18-year age group, the ELCR values range from 6.15 × 10⁻⁴ to 1.92 × 10⁻³, whereas for the 21 years and above age group, the values range from 5.13 × 10⁻⁴ to 1.60 × 10⁻³, indicating elevated cancer risk among 18 + age group of operators. This research highlights the occupational health risk of the HEMM operators working in opencast mines and important role of low-cost sensors in real-time PM exposure assessment in mining environments.