Vertical variation of source-apportioned PM2.5 and selected volatile organic compounds near an elevated expressway in an urban area.

Fine particulate matter (PM2.5) and volatile organic compounds (VOCs) are associated with adverse health effects and show spatial variation in three dimensions. The present study attempted to evaluate source contributions of PM2.5 and toxic VOCs in a metropolitan area focusing on the associated vertical variations. A special emphasis is put on the effects of the elevated expressway on the vertical variability of contribution estimates of the identified sources. Nine source factors, i.e., soil dust, sea salt/oil combustion, secondary nitrate, industrial emission, aged VOCs/secondary aerosol, traffic-related I, solvent use/industrial process, secondary sulfate, and traffic-related II, were identified using positive matrix factorization (PMF). The main contributors to PM2.5 were secondary sulfate (19.1%) and traffic-related emissions (traffic-related I and II, 16.1%), whereas the largest contributors to VOCs were traffic-related emissions (37.6%). The influence of the elevated expressway is suggested to be particularly critical on vertical variations of traffic-related emissions, including aging and secondary formation of locally accumulated air pollutants near roads. Increasing the building porosity under the viaduct could reduce the accumulation of air pollutants caused by the shelter effect. Additionally, in-street barriers would be beneficial in reducing population exposure to traffic-related emissions by altering the airflows near roads.

Molecular Chirality Detection with Periodic Arrays of Three-Dimensional Twisted Metamaterials.

Rapid detection of the handiness of chiral molecules is an important topic for pharmaceutical industries because chiral drugs with opposing handiness sometimes exhibit unwanted side effects. In this research, a rapid optical method is proposed to determine the handiness of the chiral drug "Thalidomide". The platform is a large array of three-dimensional (3D) twisted metamaterials fabricated with a novel method by combining nanospherical-lens lithography (NLL) and hole-mask lithography (HML). The fabrication is high-throughput and the twisted metamaterials cover a large area. Strong circular dichroism (CD) response is observed in the near-infrared (NIR) region, which enables the chiral detection to be performed by a low-cost and portable spectroscope system. The proposed nanofabrication method significantly improves the capabilities of NLL and HML, which can be quickly adapted to fabricate various periodic 3D metamaterials. In addition, the results of this research pave the road for the rapid penetration of nanophotonics into the pharmaceutical industries.

Optimization of Protoplast Preparation and Regeneration of a Medicinal Fungus Antrodia cinnamomea.

Antrodia cinnamomea is a unique medicinal fungus in Taiwan. It has been found rich in some pharmacologically active compounds for anti-cancer, hangover, and immune regulation etc. With the in-depth study of these components, it would be interesting and important to establish a molecular system for basic studies of A. cinnamomea. Thus, we would like to set up a foundation for this purpose by studying the A. cinnamomea protoplast preparation and regeneration. Firstly, we studied the optimization method of protoplast preparation of A. cinnamomea, and found various factors that may affect the yield during protoplast preparation, such as mycelial ages, pH values, and osmotic stabilizers. Secondly, in the regeneration of protoplasts, we explored the effects of various conditions on the regeneration of protoplasts, including different media and osmotic pressure. In addition, we found that citrate buffer with pH value around 3 dramatically increased the regeneration of protoplasts of A. cinnamomea, and provided a set of regeneration methodology for A. cinnamomea.

Comparison between Thermal Desorption Tubes and Stainless Steel Canisters Used for Measuring Volatile Organic Compounds in Petrochemical Factories.

OBJECTIVE: The purpose of this study was to compare thermal desorption tubes and stainless steel canisters for measuring volatile organic compounds (VOCs) emitted from petrochemical factories. METHODS: Twelve petrochemical factories in the Mailiao Industrial Complex were recruited for conducting the measurements of VOCs. Thermal desorption tubes and 6-l specially prepared stainless steel canisters were used to simultaneously perform active sampling of environmental air samples. The sampling time of the environmental air samples was set up on 6 h close to a full work shift of the workers. A total of 94 pairwise air samples were collected by using the thermal adsorption tubes and stainless steel canisters in these 12 factories in the petrochemical industrial complex. To maximize the number of comparative data points, all the measurements from all the factories in different sampling times were lumped together to perform a linear regression analysis for each selected VOC. Pearson product-moment correlation coefficient was used to examine the correlation between the pairwise measurements of these two sampling methods. A paired t-test was also performed to examine whether the difference in the concentrations of each selected VOC measured by the two methods was statistically significant. RESULTS: The correlation coefficients of seven compounds, including acetone, n-hexane, benzene, toluene, 1,2-dichloroethane, 1,3-butadiene, and styrene were >0.80 indicating the two sampling methods for these VOCs' measurements had high consistency. The paired t-tests for the measurements of n-hexane, benzene, m/p-xylene, o-xylene, 1,2-dichloroethane, and 1,3-butadiene showed statistically significant difference (P-value < 0.05). This indicated that the two sampling methods had various degrees of systematic errors. Looking at the results of six chemicals and these systematic errors probably resulted from the differences of the detection limits in the two sampling methods for these VOCs. CONCLUSIONS: The comparison between the concentrations of each of the 10 selected VOCs measured by the two sampling methods indicted that the thermal desorption tubes provided high accuracy and precision measurements for acetone, benzene, and 1,3-butadiene. The accuracy and precision of using the thermal desorption tubes for measuring the VOCs can be improved due to new developments in sorbent materials, multi-sorbent designs, and thermal desorption instrumentation. More applications of thermal desorption tubes for measuring occupational and environmental hazardous agents can be anticipated.

Chromium-induced skin damage among Taiwanese cement workers.

Little research has been done on the relationships between chromium exposure, skin barrier function, and other hygienic habits in cement workers. Our purpose was to investigate chromium-induced skin barrier disruption due to cement exposure among cement workers. One hundred and eight cement workers were recruited in this study. Urinary chromium concentration was used to characterize exposure levels. The biological exposure index was used to separate high and low chromium exposure. Transepidermal water loss (TEWL) was used to assess the skin barrier function. TEWL was significantly increased in workers with high chromium exposure levels than those with low chromium exposure levels (p = 0.048). A positive correlation was also found between urinary chromium concentration and TEWL (R = 0.28, p = 0.004). After adjusting for smoking status and glove use, a significant correlation between urinary chromium concentrations and TEWL remained. Moreover, workers who smoked and had a high chromium exposure had significantly increased TEWL compared to nonsmokers with low chromium exposure (p = 0.01). Skin barrier function of cement workers may have been disrupted by chromium in cement, and smoking might significantly enhance such skin barrier perturbation with chromium exposure. Decreased chromium skin exposure and smoking cessation should be encouraged at work.

Risks of musculoskeletal disorders among betel quid preparers in Taiwan.

BACKGROUND: Betel quid chewing is common in Taiwan. The work of betel quid preparers is characterized by long hours of static work, awkward working posture and highly repetitive hand/wrist motion. However, the musculoskeletal health of betel quid preparers receives very little attention. METHODS: The Chinese version of the Standardized Nordic Musculoskeletal Questionnaire (NMQ) was administered, and electrogoniometers and electromyography were used in this cross-sectional study to characterize the hand/wrist motion of the subjects. Physical examinations on the thumbs and wrists of the subjects were conducted by means of Phalen's test and Finkelstein's test, respectively. RESULTS: Among the 225 participants, more than 95% attributed their musculoskeletal complaints to their work, and shoulder, neck, hand/wrist, and lower back discomfort were most frequently reported. More than 70% of the preparers did not seek medical treatment for their musculoskeletal problems. Based on the physical examination, 24% of the participants had suspected symptom of either carpal tunnel syndrome (CTS) or DeQuervain's tenosynovitis. The instrumental measurements indicated that betel quid preparation is characterized by extreme angle ranges and moderate repetition of wrist motion as well as low forceful exertion. CONCLUSIONS: This study concludes that betel quid preparers are a high risk group of developing musculoskeletal disorders (MSDs). Future studies by electrogoniometers and detailed physical examination on betel quid preparers are needed to determine the predisposing factors for CTS. Some intervention measures to prevent MSDs and to lessen psychological stress for this group of workers are strongly suggested.

Prevalence of musculoskeletal disorders and ergonomic assessments of cleaners.

BACKGROUND: Professional cleaning has emerged as a new industry in Taiwan in the past few years. However, information about the workload and prevalence of musculoskeletal disorders (MSDs) among these workers is still limited. This study investigated the prevalence of musculoskeletal discomforts and the characteristics of musculoskeletal activities of cleaning workers in Taiwan. METHODS: Face-to-face interviews to collect basic information and to administer the Chinese version of the Standardized Nordic Musculoskeletal Questionnaire were conducted on 180 cleaners. Biaxial electrogoniometers and electromyography were used to characterize the motion and forceful exertion of 56 cleaners during work. RESULTS: Nearly 90% of the participants reported musculoskeletal discomfort in at least one body part due to work. Of the nine body parts examined, hand/wrist (41.7%), shoulder (41.1%), low back (37.8%), and elbow (33.3%) were most frequently reported to exhibit discomfort. Additionally, time pressure as a psychosocial risk factor was found to be associated with discomfort in several body parts. Measurements of electrogoniometry showed that wrists of many cleaners were frequently held in extreme angles of ulnar/radial deviation, leading to an increased risk of developing carpal tunnel syndrome. Motion repetitiveness and force output during mopping and sweeping tasks were considered less influential in developing hand/wrist discomfort. CONCLUSIONS: Cleaners in Taiwan are a high-risk group for developing MSDs, and solutions are needed to avoid extreme motion angles of the wrists when performing cleaning tasks. Moreover, both psychosocial stress and the welfare of this group of workers deserve immediate attention from management and the government.

Oxidative DNA damage estimated by urinary 8-hydroxy-2'-deoxyguanosine and arsenic in glass production workers.

A total of 130 male glass workers, including 33 administrative workers, 18 batch house workers, 42 craftsmen, and 37 melting process workers, were recruited to investigate the potential DNA damage resulting from toxic element exposure. The occupational exposure to trace elements, including arsenic (As), cadmium (Cd), manganese (Mn), nickel (Ni), lead (Pb), and selenium (Se), was estimated by their urinary levels as internal doses. In addition, all participants filled a self-filled questionnaire indicating their individual information. The average levels of urinary As, Cd, Mn, Ni, Pb, Se, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were 282.3 ± 464.6, 3.07 ± 5.39, 3.81 ± 11.43, 81.48 ± 138.9, 18.23 ± 49.61, 165.2 ± 224.9, and 17.21 ± 26.34 µg/g creatinine, respectively. The urinary levels of 8-OHdG and toxic elements were strongly associated with the work nature of the worker, with an exception of Mn and Pb. In contrast, the levels of toxic element were not influenced by age, smoking behavior, and alcohol consumption. The urinary 8-OHdG was found significantly higher in higher internal exposure groups of As, Cd, Ni, and Se. However, the stepwise multiple regression models showed that urinary 8-OHdG was only associated with urinary As and heat stress but inversely with age.

Prevalence of musculoskeletal disorders and job exposure in Taiwan oyster shuckers.

BACKGROUND: Oyster shucking is characterized by long hours of static work, awkward working posture, and highly repetitive hand/wrist motion. The objectives of this study were to investigate the prevalence of musculoskeletal discomfort and kyphosis in oyster shuckers in Taiwan as well as the biomechanical features of oyster shucking. METHODS: The Chinese version of the Standardized Nordic Musculoskeletal Questionnaire was successfully collected from 234 oyster shuckers. The characteristics of workstation, hand/wrist motion angles, and muscular exertion in shucking oysters were recorded. Measurements to identify kyphosis were also taken from the subjects and a control group. RESULTS: Among the participated oyster shuckers, low back (75.2%), hand/wrist (60.3%), shoulder (44.0%), and elbow (27.8%) discomfort were reported most frequently. The prevalence of low back discomfort in oyster shuckers was higher than various groups of workers who need long hours of seated position. Those who worked on tables had fewer musculoskeletal complaints in shoulder and elbow (P < 0.05) than those not. Additionally, oyster shuckers were more prone to kyphosis than the general population (P < 0.001). CONCLUSIONS: Oyster shuckers are observed to have high prevalence of musculoskeletal discomfort and kyphosis. Introduction of ergonomic design to oyster shucking workshops is strongly suggested.

Occupational hand dermatitis among cement workers in Taiwan.

BACKGROUND/PURPOSE: Occupational dermatitis among cement workers is a major occupational health concern. The two most important occupational hazards for cement workers are irritant and allergic cement contact dermatitis. The objective of this study was to investigate the severity of occupational cement contact dermatitis and the common allergens among cement workers in Taiwan. METHODS: A total of 97 cement workers from the Cement Workers' Association of Tainan City and County participated in this study. A structured questionnaire was used to evaluate the demographic data and work-related activities of these cement workers. A complete skin examination was conducted, and skin manifestations were assessed by a dermatologist. Allergens from European Standard Tray (Chemotechnique Diagnostic AB, Sweden) with a total of 25 substances were used for patch testing. RESULTS: Our results showed that 65 out of 97 cement workers were suffering from occupational cement hand contact dermatitis. The most affected skin area was the hand. Thickening of the dorsal surface of the hand, especially around the metacarpophalangeal joint area, and hyperkeratosis of the palm were the major skin manifestations. The results of the patch test showed that 24 out of 97 were allergic to potassium dichromate, nine were allergic to thiuram mix, nine were allergic to fragrance mix and seven were allergic to cobalt chloride. The final diagnosis, based on the results of the skin examination and the patch test, showed that 43 of 97 cement workers had irritant cement contact dermatitis and 22 had allergic cement contact dermatitis. CONCLUSION: We conclude that occupational cement hand dermatitis among cement workers is an important and severe issue in Taiwan, and the most common allergens among cement workers are potassium dichromate, thiuram mix, fragrance mix and cobalt chloride. The high positive rate of chromium hypersensitivity among cement workers reflects the urgency to regulate the addition of ferrous sulfate to cement in Taiwan.

Effect of hand dermatitis on the total body burden of chromium after ferrous sulfate application in cement among cement workers.

BACKGROUND: Ferrous sulfate (FeSO(4)) added to cement has been used to reduce the prevalence of dermatitis in workers. However, the effect of dermatitis on the total uptake of chromium in cement with or without FeSO(4) has not been previously explored. OBJECTIVE: The objective of this study was to compare the urinary chromium levels before and after FeSO(4) addition among cement workers with or without hand dermatitis. METHODS: Thirty-five male workers were recruited in this study for two consecutive years: 2003 without using FeSO(4) and 2004 after adding FeSO(4). Urinary chromium was used as a biomarker to estimate the total body burden of chromium. RESULTS: Urinary chromium concentration showed significant decreases after FeSO(4) was used, and a larger decrease of urinary chromium was observed in workers with hand dermatitis than for those without hand dermatitis. Moreover, a significant decrease of urinary chromium was observed in workers with hand dermatitis in both 2003 and 2004. CONCLUSION: FeSO(4) decreases the total body burden of chromium, especially in workers with severe and continuous hand dermatitis.

The total body burden of chromium associated with skin disease and smoking among cement workers.

BACKGROUND: Hand eczema and other skin diseases have been associated with the exposure of chromium among cement workers. Studies on skin disease and other factors associated with the body burden of chromium are limited. OBJECTIVE: The present study investigated the role of skin disease and smoking in the association with body burden of chromium among cement workers. METHODS: Forty-five workers (38 men and 7 women) were recruited for this study and interviewed to obtain information on demographic status, lifestyle, employment history, and affecting factors. Urine samples were collected to measure the urinary chromium concentration to represent the body burden of chromium. RESULTS: The average urinary chromium concentration was approximately 6 times higher in non-smoking workers with hand eczema than in non-smoking workers with no skin disease (45.5 vs. 7.6 microg/L). The average chromium level increase to 87.0 microg/L for smokers with the disease. Compared with workers with no hand eczema, the odds ratio of having urinary chromium concentration exceeding the biological exposure index level significantly increased to 11.6 (95% CI=1.3-102.2) for non-smoking workers with skin disease, and to 48.0 (95% CI=4.5-510.8) for smoking workers with skin disease. The multiple regression analysis showed that the use of gloves may reduce significantly the chromium exposure. CONCLUSIONS: Inadequate protection and personal behavior increase the internal dose of chromium in cement workers. Total body burden of chromium are higher among cement workers with skin disease and smoking habit. These workers deserve intervention education on personal hygiene to reduce the exposure of chromium.

Effect of occupational exposure to rayon manufacturing chemicals on skin barrier to evaporative water loss.

To evaluate the effects of the occupational exposure to rayon manufacturing chemicals (RMC, containing predominantly carbon disulfide (CS(2)) and minor sulfuric acid) in a rayon factory on the basal transepidermal water loss (TEWL), barrier integrity (BI), and sequential increasing TEWL profiles. Six Thais and five Chinese workers in the spinning department of a rayon manufacturing plant and five healthy unexposed controls were recruited as the test subjects. An area of 4.5 x 5.5 cm on the mid-side of the volar forearm on the right hand was stripped by means of moderate pressure with commercially available adhesive tape by the same technician throughout the experiment. The skin was progressively stripped until glistening. TEWL was measured at every three and five tape strips on the right hand. The corresponding site on the left hand was measured parallel as the self-control. We found significant differences in basal TEWL and in BI between Chinese workers and Chinese controls, and between Thai workers and Chinese workers, respectively. Two-stage patterns of progressive TEWL profiles were found in such a chronic and repeated occupational exposure to RMC containing CS(2). The occupational exposure to RMC could result in the perturbation of the skin barrier function. Basal TEWL might be more sensitive to chronic skin irritant exposure. The TEWL profile achieved to the glistening stage might be necessary to avoid erroneous pattern estimation. Due to the lack of Thais control in this study, the racial difference in response to the RMC warrants further study.

Combined exposure to carbon disulfide and sulfuric acid simultaneously increases the risk of hand dermatitis in rayon industry.

OBJECTIVE: To evaluate the association between hand dermatitis (HD) and occupational exposure to CS(2) and to determine whether combined exposure to CS(2) and H(2)SO(4) exhibits a higher risk of HD. METHODS: In all, 110 subjects from a rayon factory were recruited and their exposure was classified into CS(2) exclusively, H(2)SO(4) exclusively, combined exposure, and nonexposure control based on workers' job characteristics. A dermatologist was designated in the diagnosis of HD on palm and dorsal sites for each subject. Other confounding factors including detergent, glove wearing, and participation in wet work were determined using a person-to-person questionnaire interview from 37 randomly selected subjects. RESULTS: Significant elevated odds ratios (ORs) for HD were found in CS(2) exclusively (44.8, P < 0.01) and combined exposure (49.0, P < 0.001) compared with control. Dose-response trends of ORs for HD were found across control, single exposure, and combined exposure for both CS(2) and H(2)SO(4). CONCLUSIONS: HD could occur resulting from occupational exposure to CS(2) alone. This study was unable to affirm that the exposure to H(2)SO(4) alone is associated with HD due to limited H(2)SO(4) exposure subjects. The combined exposure to both CS(2) and H(2)SO(4) simultaneously could increase the risk of HD. The control remedy in preventing dermal contact with either CS(2) or H(2)SO(4) among the rayon workers should be performed immediately.

Identification of agricultural tasks important to cumulative exposures to inhalable and respirable dust in California.

Little data exists on the determinants of agricultural dust exposure, particularly in dry climates. Annual exposure indices to inhalable and respirable dust were constructed by exposure estimates for specific tasks, task duration, and task frequency. The estimates of exposure levels were based on actual field measurements and subjective dust exposure ranking. The task duration and frequency data were obtained by questionnaire from 546 farm operators in California. Annual exposure indices were analyzed to determine which tasks were major contributors to chronic dust exposure. The important tasks were identified by comparisons of the cumulative distribution of exposures for all tasks and the cumulative distribution of exposures with one task deleted. Thirteen and 11 tasks were identified to be important to both inhalable and respirable dust exposures, respectively. Tasks identified to be important to agricultural exposure may be ascribed to exposure duration more than to exposure intensity. Information on task-specific exposure is important for developing control strategies in the agricultural workplace.