2.Relationship between dust mass concentration and fiber number concentration of refractory ceramic fibers.
Xiaojun ZHU ; Tao LI ; Hongfei WANG
Chinese Journal of Industrial Hygiene and Occupational Diseases 2015;33(4):309-312
OBJECTIVETo explore the quantitative relationship between the dust mass concentration and fiber number concentration of refractory ceramic fibres.
METHODSA typical refractory ceramic fiber plant was selected as the study site. Fifty-three paired samples of total dust mass concentration and fiber number concentration were collected using the long-time fixed site mode. The total dust mass concentration was measured according to the GBZ/T 192.1-2007 (Measurement of dust in the air of workplace, part 1: Total dust concentration). Membrane filter method/phase-contrast optical microscopy was used to determine the fiber number concentration. Univariate analysis was used to describe the distribution of the two concentrations and their ratio. Spearman rank correlation, as well as linear regression, logarithmic curve, polynomial, power function, and exponential curve model, were used to explore the relationship between the two concentrations. Results The range of the total dust mass concentration (x) was 0.45-13.82 mg/m3. The range of the fiber number concentration (y) was 0.01-1.04 f/ml. The range of the ratio (x/y) was 4-158. All of the three parameters did not follow normal distribution (P<0.000 1). The two concentrations showed a positive correlation (r,=0.705 22, P< 0.000 1). All the coefficients of determination (R2) of linear regression, logarithmic curve, polynomial, power function, and exponential curve model were relatively low. The trinomial curve model had the highest R2 (0.6848) and the fitted equation was y=-0.001, 1x+0.010 4x2+0.101 4x-0.055 1.
CONCLUSIONThere is a positive correlation between the total dust mass concentration and fiber number concentration of refractory ceramic fibers. However, there is no fixed regression relationship between the two concentrations, and neither is a definite coefficient which can be used to convert each other. The two concentrations cannot be replaced by each other.
Air Pollutants, Occupational ; analysis ; Ceramics ; Dust ; analysis ; Occupational Exposure
7.Improvement on flame atomic absorption spectrometry for determining Tin concentration in air of workplaces.
Xun-ping YAO ; Li WANG ; Lan-yun FANG ; Peng-bo LENG
Chinese Journal of Industrial Hygiene and Occupational Diseases 2011;29(11):864-866
OBJECTIVETo explore the influence factors on determining Tin concentration in air of workplaces with flame atomic absorption spectrometry and to establish an accurate, sensitive and high-efficient method.
METHODSThe different reagents were used to digest the sampling filter membranes and the determining conditions of flame atomic absorption spectrometry were adjusted, then the determining results were compared.
RESULTSWhen 3 ml hydrochloric acid and 0.5 ml nitric acid served as the digesting reagents and the determining conditions of flame atomic absorption spectrometry were adjusted to the best conditions, there was the good linearity in the tested concentration range of Tin, the correlation coefficient was larger than 0.9990. The limit of quantification was 1.0 p.g/ml. The extraction recovery was between 99.6%-102.6%, and the RSD were all less than 5.0%.
CONCLUSIONThe proper kinds and quantity of digestive reagents in pretreatment of the samples should be chosen for the accuracy and precision of the determination according to the influence factors of determination.
Air Pollutants, Occupational ; analysis ; Spectrophotometry, Atomic ; methods ; Tin ; analysis ; Workplace
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