The size of the non-sampling error is directly related to the accuracy and reliability of the sampling survey result. This paper studied the non-sampling errors generated during the sampling process of the China National Human Biomonitoring Program(CNBP), mainly including the sampling frame error, non-response error and measurement error. The program reduced the influence of the non-sampling error on the quality of the survey effectively by scientifically designing the sampling scheme and questionnaire, strengthening investigator trainings and standardizing the data review, which could be used to provide reference for the control of non-sampling errors in public health monitoring projects in China.

Objective: To investigate the urine methyl tert-butyl ether (MTBE) level of a primary school students in Changping District, Beijing, and analysis the effect factors, give the advice if the MTBE is eligibility as an exposure biomarker of automobile exhaust. Methods: Using the panel study, randomly selected 20 sixthgrade students (10 male and 10 female) from Zhixing School in Changping district, Beijing, from June 7th to 13th, 2018. All participants completed a questionnaire for collecting demographic and geographic information and daily activities. All participants were given guidance to repeatedly collected urine samples 3 times (8:00, 11:00 and 16:00 instant urien) a day for 7 days, totally 420 urine samples were collected. Urine MTBE were measured and the statistic significant of the Urine MTBE at different groups were evaluated. Results: MTBE were detected in all 420 urine samples of primary school students, the geometric mean of creatinine-corrected MTBE exposure level in 8:00, 11:00 and 16:00 instant urine were 0.12, 0.12 and 0.12 mg/g creatinine, respectively. Urine MTBE concentration was statistical significant in different daily outdoor activity time, the distance of home address to the main road, and daily use time of air purification equipment in class(P=0.00, 0.04, 0.00). Conclusion There was a universal MTBE exposure among students in a primary school in Beijing, and the impact factors to exposure level were daily outdoor activity time, distance from home address to the closest main road, and daily use time of air purification equipment in class. This result indicate MTBE may be a valuable candidate for exposure biomarker of automobile exhaust, and more research should be done.

Objective To explore the genomic structure of 8 exons in D gene of RhD(-) Chinese Han population.Methods Polymerase chain reaction-sequence specific primers(PCR-SSP) were used to study genomic DNA from 50 samples of RhD(-) Chinese Han donors. Exons 2,3,4,5,6,7,9,10 of RHD gene and exons 1,2,4,5 of RHCE gene were specifically amplified, also intron 4 of them was amplified. Results Phenotypes of the 50 RhD(-) donors were:22 ccdee, 22 Ccdee, 3 CcdEe, 3 CcdEe. The 8 exons of RHD gene were completely absent in 25 donors with ccdee or ccdEe phenotype, while polymorphisms of D gene exons were found in 25 donors with Ccdee or CcdEe phenotype:the presence of all 8 exons of D gene in 9 donors, the absence of the 8 exons in 7 donors, the presence of exon 2 in 5 donors, the presence of exon 6 in 3 donors and the presence of exons 2,6,10 in 1 donor were demonstrated. Conclusion Polymorphisms of RHD gene exons were present among RhD(-) Chinese Han blood donors. The 8 exons of RHD gene were completely absent in donors with Rhesus cc phenotype, while 5 polymorphisms of RHD gene exons were found in donors with Rhesus Cc phenotype. The discrepancy of the RHD gene in RhD(-) individuals between Chinese Hans and Caucasians indicates that care should be exercised by clinicians in the use of the RhD genotyping results.