Human Health Risk Assessment of Inhalable Air Borne Wood Dust in Timber Milling Industry in Imo State, Nigeria

Abstract

Health risk assessment in timber milling industry was conducted using PM_2.5 as air quality indicator in Umuoayali timber market in Mbaitoli Local Government Area of Imo State to evaluate its impact on timber workers. Determination of ambient air quality was by application of hand-held Multi Gas Analyzer to sample PM_2.5. The mean result of the (PM_2.5) in the six workshops ranks viz: WS₄>WS₂>WS₃>WS₅>WS₆>WS₁ due to the effect of temperature, relative humidity and wind speed in the area that shown significant relationship with PM_2.5 (p<0.05), and the mean results compared to FMENV STD for good air quality. Health Risk Index (HRI) Air Quality Index (AQHI) was used to assess the level of risk and health implication of exposure to PM_2.5 respectively. The result of PM2.5 when compared to FMENV STD indicated that, the 20 sampled locations for wood dust ranged between 0.33-4.95 μg/m³ above the 0.25 μg/m³ FMENV STD. Health risk assessment result indicated that WS₁, WS₅ and WS6 (0.22-0.64 μg/m₃) were within the risk scale of 0- signifying timber workers within this range are bound to experience low risk ,and WS₂, WS₃ and WS4 (95.4-118.5 μg/m₃) were within the risk scale of >10 indicating very high risk (VHR) , and health implication showing poor in the selected workshops: (WS₁,WS₅, WS₆) to very poor : (WS₂,WS₃,WS₄) workshops showing tendency for respiratory disease for exposed sensitive population in and around timber market. This then calls for application of best management practices like local exhaust ventilation (LEV), respiratory protective device (RPD), and enforcement of rules and regulations to mitigate wood dust generation.

Keywords: Health risk, wood dust, timber, air borne, particulate matter