Exposure to particles, elemental carbon and nitrogen dioxide in workers exposed to motor exhaust

Abstract

Objectives: The main aim of this study was to investigate the personal exposure to diesel and petrol exhaust fumes in occupations when exposure is prevalent and/or high. We also investigated the correlation between the five particle fractions [particles with an aerodynamic diameter <1 μm (PM 1), particles with an aerodynamic diameter <2.5 μm (PM 2.5), particles in size 0.1-10 μm, elemental carbon (EC) and total carbon (TC)] and nitrogen dioxide (NO2), in the various occupational environments. Methods: Seventy-one workers were included in the study. They were subdivided into seven groups depending on working area, working indoors, out of doors or in vehicles and type of exposure (diesel or petrol exhaust). Personal measurements were performed during 3 days per worker. We used five indicators of the particle fraction: PM1, PM2.5, particle measured with a real-time monitoring instrument for particles in sizes 0.1 and 10 μm (DataRAM), EC and TC. We used NO2 as an indicator of the gas phase. Results: Tunnel construction workers showed the highest levels of exposure for all indicators, followed by diesel-exposed garage workers. For the other five groups, the levels were statistically significantly lower, and the differences between the groups were small. The full-shift geometric average of PM1 varied between 119 μg m-3 (tunnel construction workers) and 11 μg m-3 (taxi drivers). For PM2.5, the levels varied between 231 μg m-3 (tunnel construction workers) and 16 μg m-3 (bus and lorry drivers). For the measurements with the real-time monitoring instrument DataRAM, the levels varied between 398 μg m-3 (tunnel construction workers) and 14 μg m-3 (taxi drivers). For EC, the levels varied between 87 μg m-3 (tunnel construction workers) and 4 μg m-3 (other outdoor workers exposed to diesel exhaust), and for TC, the levels varied between 191 μg m -3 (tunnel construction workers) and 10 μg m-3 (taxi drivers). Finally, for NO2, the levels varied between 350 μg m-3 (tunnel construction workers) and 32 μg m-3 (other outdoor workers exposed to diesel exhaust). For the indoor workers exposed to diesel exhaust fumes only, all the indicators correlated comparatively well and statistically significantly to each other (r2 = 0.44-0.89). For the other groups, correlations were lower and showed no consistent pattern. Conclusions: The tunnel construction workers had exposure levels for all indicator substances that were considerably and significantly higher than for the other groups. The NO2 levels were higher for indoor workers exposed to diesel exhaust than for all other groups (except tunnel construction workers). All particle fractions, as well as NO2 correlated well in occupations with indoor exposure to diesel exhaust. © The Author 2007. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.