The workplace environment in factories producing ribbed smoked sheet rubber (RSS), the interiors which are heavily contaminated by wood burning smoke, was evaluated with a focus on the concentration of suspended particulates and particle-bound PAHs as well as workers' exposure in the breathing zone during the period January, -February, 2008 in Thailand. Seasonal changes in particulate and PAH concentrations are discussed in relation to the amount of RSS produced, wind direction, ventilation type and the geometry of the factory building. The concentration of particulate matter in the workplace was shown to increase nearly linearly with RSS production while being influenced by the wind direction to the open sides of the building and wind speed. Particulate concentrations in the workplace and in the worker's breathing zone were lower than those for other common occupational exposure limits. However, rather high PAH concentrations of 97.4 ± 129 ng/m 3 and 142 ± 184 ng/m 3 were found in the workplace and in the breathing zone, respectively. BaP TEQ concentrations in the workplace ranging from 21.4 to 91.0 ng/m 3 were similar to those in a sinter plant. The workers' exposure to PAHs was similar to that in a sinter plant, a metal recycling plant, a paving bitumen manufacturing plant and a carbon black manufacturing plant. The mass fraction of PAHs in particles in the RSS factory was as high as 0.30 BaP TEQ ng/μg, much higher than that in a carbon black plant (0.004-0.01 BaP TEQ ng/μg). The results reported herein suggest that the workers in the RSS factory have a somewhat high health risk from exposure to PAHs. Natural ventilation by the addition of roof turbines was insufficient in terms of reducing PAHs levels in the workplace although a roof ridge vent was functional and had a positive effect.

Evaluation of the exposure of humans to ultrafine, airborne particles is an important aspect of health in the workplace, especially in cases where nano-particles are present. However, portable sampling devices for efficiently collecting ultrafine particles in a worker's breathing zone are not readily available. The present study describes the design and development of a portable sampler for collecting particulates in the breathing zone, as a possible tool for this purpose. The design is based on the use of an "Inertial Filter" to separate various-sized nano-order particles. Inertial filters consisting of SUS fiber felt (fiber diameter 5.6-13.5 μm) placed in circular nozzles (3-6 mm diameter with 4.5 mm length) were used. To achieve the smallest dp50 under the allowable pressure drop of a portable pump, the influence of fiber loading on separation performance and pressure drop were investigated. The influence of particle loading was also examined in relation to pressure drop and separation performance. The smallest dp50 under the allowable pressure drop (5.7 kPa at 6 L/min) for the battery pump employed was ~140 and 200 nm respectively for SUS fibers of 5.6 and 9.8 μm diameter (particle volume fraction ~0.013). The change in separation performance due to particle loading was confirmed to be acceptable for use under the present conditions. Under these conditions, a sufficient amount of particles can be collected for chemical analyses, e.g., particle-bound PAHs after 6-8 hours of sampling. Hence, the developed sampler has the potential for use in evaluating exposure to ultrafine particles in the breathing zone in the workplace.

BackgroundUrinary 1-hydroxypyrene (1-OHP) was selected as a biomarker of polycyclic aromatic hydrocarbons (PAHs) to explore the accumulation level in the bodies of workers at rubber smoke sheet factories in southern Thailand.MethodsSpot urine samples were taken from four groups of workers from June 2006 to November 2007. The nonexposure or control groups included habitual cigarette smokers and nonsmokers. The other two groups were workers exposed to particle-bound PAHs from rubber wood smoke and they were nonsmokers. All spot urine samples were analyzed for 1-OHP and creatinine levels.ResultsThe mean ± standard deviation urinary 1-OHP in the control group of habitual smokers and the nonsmokers was 0.24 ± 0.16 μmol/mol creatinine and not-detected to 0.14 μmol/mol creatinine, respectively. In the workers, the 1-OHP levels on workdays had no significant difference from the 1-OHP levels on the days off. The yearly average 1-OHP level was 0.76 ± 0.41 μmol/mol creatinine whereas the average 1-OHP level during 10 consecutive workdays was 1.06 ± 0.29 μmol/mol creatinine (p > 0.05).ConclusionThe urinary 1-OHP levels of workers exposed to PAHs were high. The accumulation of 1-OHP in the body was not clear although the workers had long working hours with few days off during their working experience. Therefore, a regular day off schedule and rotation shift work during high productive RSS should be set for RSS workers.

Soft X-rays with a wave length of 1.3 × 10 -4 -4.1 × 10 -4 μm were tested for use in studying the decomposition of polycyclic aromatic hydrocarbons (PAHs), widespread hazardous and carcinogenic pollutants that are emitted during biomass burning. Both size-fractionated and -unfractionated smoke particles, after irradiation by the soft X-rays, were collected on quartz-fiber filters using two different residence times through the irradiating zone to determine the effect of the soft X-ray irradiation on particle-bound PAH concentration. Smoke particles produced by rubberwood burning had a single modal size distribution consisting of fine particles less than 2 m and a large mass fraction of PAHs in particles that were about 5 times higher than the urban ambient particles. The PAHs in the rubberwood smoke were decomposed by soft X-ray irradiation up to about 30%, essentially independent of the duration of the irradiation (0.022-0.067 sec) and with a slight dependence on the boiling temperature of each PAH composition. From the irradiation test for the size fractionated particles, PAHs in finer fraction particles were found to be decomposed more effectively. Soft X-rays have the potential for use as an effective device for pollution control.

Developing and encouraging a safety culture is an important factor to achieve a safe workplace with low injury rates. Safety climate can be an indicator of the status of an occupational health and safety management system in an organization. It can provide a snapshot of the safety culture. The Thai version of Nordic Occupational Safety Climate Questionnaire is used to evaluate the safety climate in the food manufacturing industry in Songkhla, Thailand. The results can also be used as a guideline in the development and safety management in the future. The response rate was great. The employees who participated were 14.7% male and 85.3% were female. Most subjects were 41-50 years-old and most had a 1-to 5-year working experience. The highest safety climate score of the workers was the dimension of "workers" trust in the efficacy of safety systems" (3.29) while the lowest score was the dimension of "workers' safety priority and risk non-acceptance" (2.89). For the leaders, the highest safety climate score was the dimension of "workers" safety commitment" (3.44) and the lowest score was the dimension of "management safety empowerment" (3.10). The factors related to accident occurrence were the differences in the organizations and the mean score of the safety climate dimension of "worker"s safety priority and risk non-acceptance".