Benzene ; analysis ; chemistry ; Benzene Derivatives ; blood ; urine ; Humans

The major purpose of this study is to construct a retrospective exposure assessment for benzene through a review of literature on Korea. Airborne benzene measurements reported in 34 articles were reviewed. A total of 15,729 individual measurements were compiled. Weighted arithmetic means [AM(w)] and their variance calculated across studies were summarized according to 5-year period intervals (prior to the 1970s through the 2010s) and industry type. Industries were classified according to Korea Standard Industrial Classification (KSIC) using information provided in the literature. We estimated quantitative retrospective exposure to benzene for each cell in the matrix through a combination of time and KSIC. Analysis of the AM(w) indicated reductions in exposure levels over time, regardless of industry, with mean levels prior to the 1980e1984 period of 50.4 ppm (n = 2,289), which dropped to 2.8 ppm (n = 305) in the 1990e1994 period, and to 0.1 ppm (n = 294) in the 1995e1999 period. There has been no improvement since the 2000s, when the AM(w) of 4.3 ppm (n = 6,211) for the 2005e2009 period and 4.5 ppm (n = 3,358) for the 2010e2013 period were estimated. A comparison by industry found no consistent patterns in the measurement results. Our estimated benzene measurements can be used to determine not only the possibility of retrospective exposure to benzene, but also to estimate the level of quantitative or semiquantitative retrospective exposure to benzene.
Benzene* ; Classification ; Korea* ; Retrospective Studies

Benzene ; DNA Damage ; Humans ; Research

Benzene ; toxicity ; Epigenesis, Genetic ; Humans

Benzene ; poisoning ; Female ; Humans ; Male ; Occupational Diseases

Benzene ; poisoning ; Chronic Disease ; Humans ; Poisoning ; diagnosis

Benzene ; poisoning ; Humans ; Leukemia ; chemically induced

This study utilized the Community Multiscale Air Quality model to simulate the spatial distribution of benzene, toluene, and xylene (BTX) concentrations from large national industrial complexes (IC) located in the Ulsan metropolitan region (UMR). Through controlling pollutant emissions from major IC, this study performed a quantitative analysis of the influence of pollutant emissions on BTX concentrations in surrounding urban areas. The results showed that approximately 40% of the annual average BTX concentrations in nearby urban grids were directly influenced by pollutant emissions from the IC. Seasonal modeling results indicated that average BTX concentrations were high around petrochemical complexes, with higher concentrations in the surrounding urban areas during the summer (July). All three of the BTX pollutants showed similar seasonal differences. Daily contributions differed significantly throughout the modeling period, with some values reaching a maximum of 80% during July. Overall, when urban areas were located downwind of the IC, contributions rose. Moreover, this study compared the differences in BTX contributions at each measurement point within the IC and urban areas, which showed that the influence of the IC emissions decreased significantly with distance. The spatial distribution and direct influence of the IC on BTX concentrations in the UMR identified through this study could be used to provide input data in environmental epidemiological studies.
Benzene ; Epidemiologic Studies ; Seasons ; Toluene ; Ulsan ; Xylenes

OBJECTIVE: To systematically investigate the changes rule of volatile oil and its main components released from moxa sticks under different headspace temperatures and combustion conditions, so as to guide the clinical rational selection of the temperature for moxa sticks. METHODS: Using the headspace gas chromatography-mass spectrometry (HS-GCMS) technique, the released gas from moxa sticks was collected at the headspace temperature (from room temperature [25 ℃] to 190 ℃) and during combustion. One mL of the gas was injected into 6890/5973N gas chromatography-mass spectrometry (GCMS). The release rates of volatile components of moxa sticks were calculated by total ion chromatography (TIC) and butanone internal standard method. The volatile components of moxa sticks were qualitatively analyzed by analyzing the mass spectra of each volatile component and matching the Nist 14 standard mass spectrometry library. By comparing and analyzing the peak intensity changes rule of 1,8-cineole and its main harmful components (benzene, toluene and phenol) under different headspace temperatures and combustion conditions, the optimal temperature for clinical use of moxa sticks was found. RESULTS: At room temperature and 50 ℃, the release rate of volatile components from moxa sticks was very low, and it showed a significant increase trend with the increase of temperature. When the headspace temperature was 190 ℃, the release rate of volatile components from moxa sticks reached 0.864 2%, which was 2 161 times as same as that at room temperature. After combustion, it dropped sharply to 0.027 9%, which was 96.8% lower than that at the headspace temperature of 190 ℃. When the headspace temperature was 125 ℃ and 150 ℃, the content of 1,8-cineole, a typical beneficial component in the volatile components of moxa sticks, was the highest. When the headspace temperature was higher than 150 ℃, its content showed a significant downward trend. Under combustion conditions, a large number of harmful substances, such as benzene, toluene and phenol, were detected. CONCLUSION The combustion condition is not conducive to the efficient utilization of the volatile oil of moxa sticks. Temperature of 125-150 ℃ is the best for releasing the volatile components of moxa sticks, which is not only conducive to the release of the beneficial volatile components of moxa sticks, but also can greatly inhibit the production of harmful components.
Benzene ; Eucalyptol ; Oils, Volatile ; Phenols ; Temperature ; Toluene

Objective: To understand the volatile organic components in the organic solvents used by enterprises in Baoan District, Shenzhen. Methods: From January to December 2020, a total of 541 organic solvent samples used by 86 companies were collected for volatile organic component analysis, and the main volatile components and high-risk occupational hazards in organic solvents used in different industries were analyzed. Results: A total of 201 volatile organic components were detected in 541 organic solvents. The top 5 components detected include xylene (29.76%, 116/541), toluene (21.81%, 118/541), methanol (20.70%, 112/541), n-hexane (14.79%, 80/541) and ethylbenzene (14.23%, 77/541). The detection rates of benzene, trichloroethylene, n-hexane, and 1, 2-dichloroethane, which were high-risk occupational hazards, were 2.40% (13/541), 3.70% (20/541), 14.79% (80/541), and 1.66% (9/541), respectively. The volatile components in organic solvents used in different industries was different. Benzene is more frequently detected in organic solvents used in the printing industry, trichloroethylene was more frequently detected in organic solvents used in the electronics industry, and n-hexane was more commonly found in organic solvents used in the electronics industry, printing and other industries, and 1, 2-dichloroethane has been more frequently detected in organic solvents used in the machinery industry. Conclusion: There are many types of organic solvents used by enterprises in Bao'an District, with complex components and differences in different industries.
Benzene/analysis* ; Hexanes ; Solvents ; Industry ; Trichloroethylene