Natural gas and indoor air pollution: a comparison with coal gas and liquefied petroleum gas / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>The study was designed to compare the combustion products of coal gas, liquefied petroleum gas and natural gas in relation to indoor air pollution.</p><p><b>METHODS</b>Regular pollutants including B(a)P were monitored and 1-hydroxy pyrene were tested in urine of the enrolled subjects. Radon concentrations and their changes in four seasons were also monitored in the city natural gas from its source plant and transfer stations to final users. To analyze organic components of coal gas, liquefied petroleum gas and natural gas, a high-flow sampling device specially designed was used to collect their combustion products, and semi-volatile organic compounds contained in the particles were detected by gas chromatograph-mass spectrograph (GC/MS).</p><p><b>RESULTS</b>Findings in the study showed that the regular indoor air pollutants particles and CO were all above the standard in winter when heating facilities were operated in the city, but they were lowest in kitchens using natural gas; furthermore, although NO2 and CO2 were slightly higher in natural gas, B(a)P concentration was lower in this group and 1-hydroxy pyrene was lowest in urine of the subjects exposed to natural gas. Organic compounds were more complicated in coal gas and liquefied petroleum gas than in natural gas. The concentration of radon in natural gas accounted for less than 1% of its effective dose contributing to indoor air pollution in Beijing households.</p><p><b>CONCLUSION</b>Compared to traditional fuels, gases are deemed as clean ones, and natural gas is shown to be cleaner than the other two gases.</p>

The TD-PCR and Phylogenetic Analysis of Bacillus licheniformis 16S rDNA / 微生物学通报

16S rDNA sequences of 30 Bacillus strains originally identified as Bacillus licheniformis from China Center of Industrial Culture Collection (CICC) were determined and analyzed. The results indicated that 24 strains are affiliated to Bacillus licheniformis;3 strains are affiliated to Bacillus cereus and 1 strain is affiliated to Bacillus subitilis;the similarity levels of 16S rDNA among the rest of 2 strains and other strains of Bacillus licheniformis,range from 96.4% to 97.4%,further tests are needed to clarify their position. Also we testified that 5' terminal 500bp of 16S rDNA is available to differentiate the strains of Bacillus licheniformis、Bacillus subtilis and Bacillus cereus.