[Show abstract][Hide abstract] ABSTRACT: Objective:
Workplace aerosol sampling is challenged by its influencing factors and methodological limitations. Some factors, including blank setting, electrostatic effect, sample mass gain, and limit of detection (LOD), were studied to characterize them further and thereby to improve the sampling method.
Through a field sampling in two shipyards and by an analysis of a large amount of dust data from different industries, the influencing factors were comparatively studied with emphasis on their effect on the final result.
After calibration with field blanks, the concentrations of most sample types in the shipyards decreased significantly, varying by as much as -24.3% of the final measurements. After laboratory blank calibration, dust concentrations increased or decreased without a definite change trend. With a variation of -1.8%, only the measurements of Chinese "total dust" sampled with polypropylene filters were significantly influenced by the electrostatic effect. The LOD coincidence rate was only 17.3% for American respirable dust in different industries and 12.2% for respirable particles collected by normal flow rate samplers (FSP2) in the shipyards. The latter increased to 73.9% when high flow samplers (FSP10) were used.
It was suggested that field blank calibration was the predominant influencing factor in comparison with electrostatic effect and laboratory blank adjustment. The LOD coincidence rate was too low for reliable sampling, and this might be improved by use of high flow samplers.
Full-text · Article · Jul 2014 · Journal of Occupational Health
[Show abstract][Hide abstract] ABSTRACT: In China, dust samplers were originally designed to collect 'total dust' for a short term during production, which is different from the widely adopted sampling strategy for dust. With the aim to provide the conversion factor from Chinese total dust to US and German respirable dust and to look at the influences on conversion factors from environment, production, and instruments, a comparative field study on the dust concentration measurements by different sampling methods was carried out in the same Chinese industries as in the 1989-1990 study and in some other factories. A supplemental experiment was also conducted in a wind tunnel. Dust concentration was measured with a parallel sampling strategy by using the following samplers: 10-mm nylon cyclone for US respirable dust (AR), FSP-Berufsgenossenschaftliches Institut für Arbeitssicherheit (BIA) cyclone for German respirable dust (GR), and samplers for Chinese total dust (CT). Totally, 1434 samples were collected (269 AR, 198 GR, and 967 CT), from which 429 matched sample pairs (249 pairs of AR/CT, 180 GR/CT) were available to calculate conversion ratios. Industry- and job-based conversion factors are presented in this study. The conversion factor of AR/CT was 0.38 for tungsten mines, 0.19 for copper/iron mines, 0.65 for tin mines, and 0.20 for pottery industry, while the factor of GR/CT was 0.69 for tungsten, 0.37 for copper/iron, and 0.52 for pottery. In the job category, AR/CT factors varied from 0.16 to 0.96 and GR/CT from 0.12 to 0.72. For the industries studied in 1988-1989, the AR/CT and GR/CT factors were 0.29 and 0.45, respectively. Both factors were definitely influenced by production, CT dust concentration, sample gain, and variation of dust concentration. Moreover, the respirable dust concentration by FSP-BIA was significantly higher than that by 10-mm cyclones, 63.27-73.10% more as showed also by the wind tunnel experiment. Meanwhile, the GR/CT ratio was significantly larger than the AR/CT in every industry or job with only few exceptions. The GR/CT estimates should be considered as independent ones. Following these results, there is a need to use 'ideal samplers' (consistent with the internationally accepted respirable fraction) in practice and to assess the existent samplers in order to homogenize the exposure data situation.
Preview · Article · Jan 2012 · Annals of Occupational Hygiene
[Show abstract][Hide abstract] ABSTRACT: Respirator fit test panels provide an objective tool for selecting representative human test subjects based upon their facial characteristics for use in research, product development, testing and certification. Fit test panels were typically based upon anthropometric data such as the 1967-1968 survey of American military personnel. In this study, the objectives were to: (i) evaluate the applicability of the recently developed National Institute for Occupational Safety and Health (NIOSH) respirator fit test panels for Chinese workers and (ii) develop new respirator fit test panels using the Chinese survey data. Overall, 95% of the workers in the Chinese survey fall within the NIOSH bivariate and principal component analysis (PCA) panels, suggesting that these panels would also be appropriate for the Chinese population. However, distribution of the subject across the panels was not uniform; only 6.3% of survey participants fell into five cells of the bivariate panel and only 7.2% were found within three cells of the PCA panel. Therefore, new respirator fit test panels with subject dimensions and distributions specific to Chinese workers may be beneficial for certain applications. Two new respirator fit test panels were developed with the same techniques used to create the NIOSH panels. All measurements were weighted to match age and gender distributions of the Chinese population from the 2005 census. The bivariate approach used face length and face width measurements, and the PCA panel was developed using the first two principal components obtained from a set of 10 facial dimensions. Respirators designed to fit these Chinese worker-specific panels are also likely to accommodate >95% of Chinese workers.
Preview · Article · Feb 2009 · Annals of Occupational Hygiene
[Show abstract][Hide abstract] ABSTRACT: Millions of workers in China rely on respirators and other personal protective equipment to reduce the risk of injury and occupational diseases. However, it has been >25 years since the first survey of facial dimensions for Chinese adults was published, and it has never been completely updated. Thus, an anthropometric survey of Chinese civilian workers was conducted in 2006. A total of 3000 subjects (2026 males and 974 females) between the ages of 18 and 66 years old was measured using traditional techniques. Nineteen facial dimensions, height, weight, neck circumference, waist circumference and hip circumference were measured. A stratified sampling plan of three age strata and two gender strata was implemented. Linear regression analysis was used to evaluate the possible effects of gender, age, occupation and body size on facial dimensions. The regression coefficients for gender indicated that for all anthropometric dimensions, males had significantly larger measurements than females. As body mass index increased, dimensions measured increased significantly. Construction workers and miners had significantly smaller measurements than individuals employed in healthcare or manufacturing for a majority of dimensions. Five representative indexes of facial dimension (face length, face width, nose protrusion, bigonial breadth and nasal root breadth) were selected based on correlation and cluster analysis of all dimensions. Through comparison with the facial dimensions of American subjects, this study indicated that Chinese civilian workers have shorter face length, smaller nose protrusion, larger face width and longer lip length.
[Show abstract][Hide abstract] ABSTRACT: To investigate the health impacts of crystalline silica mixed dust and other potential occupational hazards on workers in ceramic factories, a cohort study of 4851 workers registered in the employment records in 3 ceramic factories in Jingdezhen city of China between 1972 and 1974 was identified. The cohort mortality was traced throughout 2003 with an accumulation of 128970.2 person-years, revealed 1542 deaths. Standardized mortality ratios (SMRs) were calculated for the main causes of death by using Chinese national mortality rates as reference. The mortality from all causes in three ceramic factories was 12.0 per thousand and the cumulative mortality was 31.8%. Malignant neoplasm, cardiovascular diseases, respiratory diseases, infectious diseases were the first four illnesses that threaten workers' life, and they accounted for 73.2% of all deaths. The results of this study showed that the standardized mortality ratio for all subjects was 1.02, which is very close to that expected on the basis of the China national mortality rates. Statistically significant mortality excesses for respiratory disease (SMR=1.36), pneumoconiosis (SMR=37.34), infectious disease (SMR=5.70) and pulmonary tuberculosis (SMR=3.88) were observed. The mortality of 2938 dust-exposed workers was higher than that of 1913 non dust-exposed workers. Except for pneumoconiosis, the mortality from lung cancer, non-malignant respiratory diseases and pulmonary tuberculosis in dust-exposed workers were significantly increased as compared with that in non-exposed workers, and the relative risks (RRs) were 1.86 (1.16-2.99), 2.50 (1.84-3.40), 1.81 (1.34-2.45). The exposure-response relationships between cumulative dust exposure level and mortality from all causes, colorectal cancer, lung cancer, respiratory diseases, and pulmonary tuberculosis were also identified. The findings indicated that silica mixed dust in ceramic factories has harmful impact on the workers' health and life span in ceramic factory.
Full-text · Article · Sep 2008 · Journal of Huazhong University of Science and Technology