An integrated approach was developed to assess exposure and health-risk from polycyclic aromatic hydrocarbons (PAHs) contained in oil mists in a fastener manufacturing industry. One previously developed model and one new model were adopted for predicting oil mist exposure concentrations emitted from metal work fluid (MWF) and PAHs contained in MWF by using the fastener production rate (Pr) and cumulative fastener production rate (CPr) as predictors, respectively. By applying the annual Pr and CPr records to the above two models, long-term workplace PAH exposure concentrations were predicted. In addition, true exposure data was also collected from the field. The predicted and measured concentrations respectively served as the prior and likelihood distributions in the Bayesian decision analysis (BDA), and the resultant posterior distributions were used to determine the long-term exposure and health-risks posed on workers. Results show that long term exposures to PAHs would result in a 3.1%, 96.7%, and 73.4% chance of exceeding the PEL-TWA (0.2 mg/m³), action level (0.1 mg/m³), and acceptable health risk (10⁻³), respectively. In conclusion, preventive measures should be taken immediately to reduce workers’ PAH exposures.

Wind tunnel experiments were performed to explore how leaf size and leaf microroughness impact the collection efficiency of ultrafine particles (UFP) at the branch scale. A porous media model previously used to characterize UFP deposition onto conifers (Pinus taeda and Juniperus chinensis) was employed to interpret these wind tunnel measurements for four different broadleaf species (Ilex cornuta, Quercus alba, Magnolia grandiflora, and Lonicera fragrantissima) and three wind speed (0.3–0.9 ms⁻¹) conditions. Among the four broadleaf species considered, Ilex cornuta with its partially folded shape and sharp edges was the most efficient at collecting UFP followed by the other three flat‐shaped broadleaf species. The findings here suggest that a connection must exist between UFP collection and leaf dimension and roughness. This connection is shown to be primarily due to the thickness of a quasi‐laminar boundary layer pinned to the leaf surface assuming the flow over a leaf resembles that of a flat plate. A scaling analysis that utilizes a three‐sublayer depositional model for a flat plate of finite size and roughness embedded within the quasi‐laminar boundary layer illustrates these connections. The analysis shows that a longer leaf dimension allows for thicker quasi‐laminar boundary layers to develop. A thicker quasi‐laminar boundary layer depth in turn increases the overall resistance to UFP deposition due to an increase in the diffusional path length thereby reducing the leaf‐scale UFP collection efficiency. It is suggested that the effects of leaf microroughness are less relevant to the UFP collection efficiency than are the leaf dimensions for the four broadleaf species explored here.

People living or working near roadways have experienced an increase in cardiovascular or respiratory diseases due to vehicle emissions. Very few studies have focused on the PM exposure of highway police officers, particularly for the number concentration and size distribution of ultrafine particles (UFP). This study evaluated exposure concentrations of particulate matter (PM) in the Sinying police station near a highway located in Tainan, Taiwan, under different traffic volumes, traffic types, and shift times. We focused on periods when the wind blew from the highway toward the police station and when the wind speed was greater than or equal to 0.5 m/s. PM2.5, UFP, and PM-PAHs concentrations in the police station and an upwind reference station were measured. Results indicate that PM2.5, UFP, and PM-PAHs concentrations in the police station can be on average 1.13, 2.17, and 5.81 times more than the upwind reference station concentrations, respectively. The highest exposure level for PM2.5 and UFP was observed during the 12:00 PM–4:00 PM shift while the highest PAHs concentration was found in the 4:00 AM–8:00 AM shift. Thus, special attention needs to be given to protect police officers from exposure to high PM concentration.