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1.
Environ Sci Technol. 2014;48(3):1499-507. doi: 10.1021/es4048472. Epub 2014 Jan 23.

Inhalable microorganisms in Beijing's PM2.5 and PM10 pollutants during a severe smog event.

Author information

1
PTN (Peking University-Tsinghua University-National Institute of Biological Sciences) Joint Graduate Program, Center for Synthetic and Systems Biology, TNLIST, MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University , Beijing 100084, People's Republic of China.

Abstract

Particulate matter (PM) air pollution poses a formidable public health threat to the city of Beijing. Among the various hazards of PM pollutants, microorganisms in PM2.5 and PM10 are thought to be responsible for various allergies and for the spread of respiratory diseases. While the physical and chemical properties of PM pollutants have been extensively studied, much less is known about the inhalable microorganisms. Most existing data on airborne microbial communities using 16S or 18S rRNA gene sequencing to categorize bacteria or fungi into the family or genus levels do not provide information on their allergenic and pathogenic potentials. Here we employed metagenomic methods to analyze the microbial composition of Beijing's PM pollutants during a severe January smog event. We show that with sufficient sequencing depth, airborne microbes including bacteria, archaea, fungi, and dsDNA viruses can be identified at the species level. Our results suggested that the majority of the inhalable microorganisms were soil-associated and nonpathogenic to human. Nevertheless, the sequences of several respiratory microbial allergens and pathogens were identified and their relative abundance appeared to have increased with increased concentrations of PM pollution. Our findings may serve as an important reference for environmental scientists, health workers, and city planners.

PMID:
24456276
PMCID:
PMC3963435
DOI:
10.1021/es4048472
[Indexed for MEDLINE]
Free PMC Article
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2.
Environ Sci Technol. 2014;48(1):599-606. doi: 10.1021/es403884e. Epub 2013 Dec 20.

Decomposition of potent greenhouse gas sulfur hexafluoride (SF6) by Kirschsteinite-dominant stainless steel slag.

Author information

1
School of Environmental and Chemical Engineering, Shanghai University , No. 333 Nanchen Rd., Shanghai 200444, P. R. China.

Abstract

In this investigation, kirschsteinite-dominant stainless steel slag (SSS) has been found to decompose sulfur hexafluoride (SF6) with the activity higher than pure metal oxides, such as Fe2O3 and CaO. SSS is mainly made up of CaO·FeO·SiO2(CFS)/MgO·FeO·MnO(RO) phase conglomeration. The SF6 decomposition reaction with SSS at 500-700 °C generated solid MF2/MF3 and gaseous SiF4, SO2/SO3 as well as HF. When 10 wt % of SSS was replaced by Fe2O3 or CaO, the SF6 decomposition amount decreased from 21.0 to 15.2 or 15.0 mg/g at 600 °C. The advantage of SSS over Fe2O3 or CaO in the SF6 decomposition is related to its own special microstructure and composition. The dispersion of each oxide component in SSS reduces the sintering of freshly formed MF2/MF3, which is severe in the case of pure metal oxides and inhibits the continuous reaction of inner components. Moreover, SiO2 in SSS reacts with SF6 and evolves as gaseous SiF4, which leaves SSS with voids and consequently exposes inner oxides for further reactions. In addition, we have found that oxygen significantly inhibited the SF6 decomposition with SSS while H2O did not, which could be explained in terms of reaction pathways. This research thus demonstrates that waste material SSS could be potentially an effective removal reagent of greenhouse gas SF6.

PMID:
24328286
DOI:
10.1021/es403884e
[Indexed for MEDLINE]
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