Occupational Health Risks Associated with Exposure to Particulate Matter; PM2.5, PM10, Formaldehyde (HCHO) and other Gases in Wastewater Treatment Plants

Purpose: This research assessed the occupational exposure associated with particulate matter (PM2.5 and PM10), formaldehyde vapors (HCHO) and carbon dioxide (CO2) in a wastewater treatment plant in Nairobi, Kenya. The determined airborne pollutants levels were analyzed to identify potential health risks on the Plant's workers. Materials and Methods: Air quality measurements were conducted across six locations for a period of three months using a hand-held air quality monitoring device, Temptop M2000 which has high precision formaldehyde, laser particle and carbon dioxide sensors. Three samples were collected at each location and this data analyzed using Statistical software. Observations were also made on the prevalent activities in each location and used in data interpretation. Findings: PM2.5 and PM10 levels exceeded WHO guidelines, with the highest concentrations recorded at the pond (11.60±1.57 µg/m³) and inlet works (17.41±1.55 µg/m³), respectively. CO2 was highest in office areas (571.33±207.1 ppm), while HCHO peaked at the inlet (0.81±0.18 mg/m³), surpassing the 0.08 mg/m³ WHO guideline. Elevated temperatures (mean 27.98±2.36°C) were linked to increase PM2.5, while higher relative humidity (mean 44.13±5.75%) correlated with greater concentrations of PM10, HCHO, and CO2. A one-sample t-test confirmed significantly elevated PM2.5 and HCHO levels. The levels for all contaminants were highest during the morning and dropped as the water volumes reduced from in the evening. Hazard quotients indicated substantial health risks, particularly for HCHO at HQ=5.125, suggesting potential respiratory, cardiovascular, and carcinogenic effects. Although the cancer risk from HCHO exposure was found to be minimal, chronic exposure may pose long-term health effects. Unique Contribution to Theory, Practice and Policy: This study recommended enhanced worker protection through PPE provision, routine medical check-ups, and adherence to national air quality regulations to mitigate risks. Effective hazard management strategies are also crucial for safeguarding health within wastewater treatment environments.