[Characteristics and Reactivity of VOCs in a Typical Industrial City in Summer].

To investigate the ambient pollution caused by volatile organic compounds (VOCs) in a typical industrial city in summer, the characteristics and chemical reactivity from VOCs and the causes of ozone (O3) pollution were analyzed using online VOCs measurements during polluted and non-polluted periods in Zibo city in July 2020. The results showed that the average hourly concentration of total volatile organic compounds (TVOC) during the polluted period[(50.6±28.3)] µg·m-3 was 32.5% higher than that during the non-polluted period[(38.2±24.9) µg·m-3]. The contribution of all VOCs categories were as follows:alkanes>aromatics>alkenes>alkynes, and the diurnal averages of TVOC and O3 concentrations were opposite during the polluted and non-polluted period. Ozone formation potential (OFP),·OH radical loss rate (L·OH), and secondary organic aerosol formation potential (SOAp) during the polluted period were higher than those during the non-polluted period. Alkenes contributed most to OFP and L·OH, whereas aromatics contributed most to SOAp. The tendency of the diurnal average of OFP and SOAp was overall consistent with that of TVOC. The priority species of OFP, L·OH, and SOAp were alkenes and aromatics. The VOCs/NOx method was applied to identify the O3-VOC-NOx sensitivity during the polluted and non-polluted periods, and the results showed that the photochemical regimes were VOCs-limited and transition regions. In addition, the smog production model (SPM) was employed to identify the O3 formation regime, and the results showed that those during the polluted period were identified as VOCs-limited and transition regions from 08:00 to 16:00, whereas the non-polluted period was mainly considered to be VOCs-limited. To mitigate the O3 pollution in summertime, the synergistic control of VOCs (especially alkenes and aromatics) and NOx emissions should be enforced.

[Comparison of VOCs Pollution Characteristics Between an Urban Site and a Background Site in Summer in Zibo].

To study the differences in volatile organic compound (VOCs) pollution characteristics between an urban site and a background site in summer, ambient VOCs were monitored using an online gas chromatograph (GC) at an urban site and a background site (Mt. Lu) in Zibo in July 2020. The VOCs pollution characteristics and chemical reactivity were analyzed, and the sources of VOCs were identified using the positive matrix factorization model(PMF). The results showed that ρ(TVOC) and ρ(NOx) were higher at the urban site, but ρ(O3) was higher at the background site. Diurnal average characteristics of ρ(TVOC) and ρ(NOx) were high at night and low during the day at the urban site, and there were no obvious variation characteristics at the background site. The diurnal average characteristics of ρ(O3) were consistent at the urban and background sites, showing low level at night and high level during the day; however, the peak in the background site was later than that at the urban site. The average ρ(TVOC) at the urban site and background site were (44.9±27.5) µg·m-3 and (17.3±9.1) µg·m-3, respectively, and the mass fraction of each component was ordered as alkanes>aromatics>alkenes>alkynes in both sites. The average ozone formation potentials(OFP)were (115.5±63.1) µg·m-3 and (38.0±20.2) µg·m-3, and the contribution of each component was ordered as alkenes>aromatics>alkanes>alkynes. The respective average values of·OH radical loss rate(L·OH) were (3.9±2.3) s-1 and (1.0±0.6) s-1, with the highest contribution of alkenes and the lowest contribution of alkynes in both sites. The average values of secondary organic aerosol formation potential(SOAp) were (0.5±0.3) µg·m-3 and (0.2±0.06) µg·m-3, respectively, with aromatic being the most abundant group. According to the source appointment by the PMF model, the main source of VOCs in the urban site was traffic sources (52.4%), followed by petroleum evaporation (19.2%), solvent evaporation (17.3%), and oil and biological sources (11.1%). The source of VOCs in the background site mainly came from traffic sources (40.2%), followed by solvent evaporation (31.3%), combustion sources (19.3%), and biological sources (9.2%). Zibo City should strengthen the management and control of motor vehicle emissions, petroleum evaporation, and the use of industrial solvents.

[Source and Health Risk Assessment of PM2.5-Bound Metallic Elements in Road Dust in Zibo City].

To study the pollution characteristics, sources, and ecological and health risk of PM2.5-bound metallic elements in road dust in Zibo City, a total of 97 dust samples were collected in eight districts between October 2016 and May 2017, and particles smaller than 2.5 µm were suspended filtered using a resuspension system. Inductively coupled plasma mass spectrometry (ICP-MS) and optical emission spectrometry (ICP-OES) were used to investigate 18 metal elements within the dust samples. The results showed that the mass fraction of Ca[ω(Ca)] was highest with an average of 120307.7 mg·kg-1, which was 7.2 times higher than the soil background values for Shandong Province. The mean values of ω(Zn), ω(Cu), ω(Sb), and ω(Cd) were 13.9, 11.7, 13.3, and 29.6 times higher than the background values, respectively. The geo-accumulation index (Igeo) indicated high levels of Cd, Zn, Cu, and Sb pollution, especially in winter. Enrichment factors (EFs) also indicated high concentrations of Cd, Zn, Sb, and Cu in the road dust, which were notably affected by human activities. Principal component analysis (PCA) showed that biomass combustion, coal burning, vehicle emissions, iron and steel smelting, and soil dust are the five main sources of metal elements in road dust in Zibo City. The potential ecological risk of Cd and the total potential risk were extremely high during three seasons and was highest in winter. Health risk assessment showed that As and Pb had a non-carcinogenic risk for children, while Cr presents a carcinogenic risk. In conclusion, pollution from PM2.5-bound metallic elements in road dust in Zibo City is derived from anthropogenic sources and is most severe during winter. Importantly, the levels of pollution detected represent potential ecological risk as well as some non-carcinogenic and carcinogenic risks for children. Therefore, the source control of road dust requires particular attention.

The effectiveness and safety of acupuncture for knee osteoarthritis: An overview of systematic reviews.

BACKGROUND: Knee osteoarthritis (KOA), known as severe degenerative arthritis, commonly occurs in middle-aged and elderly people all over the world. Acupuncture as traditional oriental intervention is getting widely used and several systematic reviews (SRs) have reported the effectiveness of acupuncture on pain relief and functional recovery in patients with KOA. OBJECTIVE: Conducting an overview of SRs to provide more reliable evidence-based medical references for clinical practitioners and researchers of the effectiveness and safety of acupuncture for KOA. DATA SOURCES: EMBASE, Medline, Web of science, the Cochrane library, China National Knowledge Infrastructure, the Chinese Science and Technology Periodical Database, China Biology Medicine, Wan Fang Digital Journals, and PROSPERO databases from inception to December 2018, magazines, websites, and unpublished sources. SELECTION CRITERIA: Potential SRs were independently selected by 2 reviewers following a predetermined protocol. DATA EXTRACTION: Data information of included SRs were independently extracted by 2 reviewers following a predetermined standardized data extraction form. REVIEW APPRAISAL: The risk of bias and reporting quality of included SRs were evaluated by the Risk of Bias in Systematic reviews (ROBIS) tool and the Preferred Reporting Item for Systematic Review and Meta-analysis (PRISMA) statement. The quality of evidence of outcomes was evaluated by the Grading of Recommendations Assessment, Development and Evaluation (GRADE). RESULTS: A total of 12 SRs were included. All the SRs were published in recent 12 years, ranging from 2006 to 2017. According to ROBIS, 4 SRs were in low risk in domain 1 and 7 in domain 3 of phase 2, and 2 SRs were low risk in phase 3. Among 27 items of PRISMA, 19 items were reported over 70% of compliance. Using GRADE assessment, of 34 outcomes, high quality of evidence was found in 5 outcomes, 17 outcomes were rated moderate quality, and 11 outcomes were low quality. According to high-quality outcomes, acupuncture had more total effective rate, short-term effective rate, and less adverse reactions than western medicine in treating KOA. In terms of Lequesne index and Lysholm knee score scale score, the effectiveness of electroacupuncture was better than that of western medicine. LIMITATIONS: There might be missing information. There may be duplicated clinical trials included by each SR that might have impact on the synthetic findings. CONCLUSIONS: According to the high-quality evidence, we concluded that acupuncture may have some advantages in treating KOA. However, there are some risk of bias and reporting deficiencies still needed to be improved.

The Cellular Toxicity of PM2.5 Emitted from Coal Combustion in Human Umbilical Vein Endothelial Cells.

OBJECTIVE: To explore the relationship between different components of fine particulate matter (PM2.5) emitted from coal combustion and their cytotoxic effect in the vascular endothelial cells. METHODS: Coal-fired PM(2.5) was sampled using a fixed-source dilution channel and flow sampler. The sample components were analyzed by ion chromatography and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The PM(2.5) suspension was extracted using an ultrasonic water-bath method and then human umbilical vein endothelial cells (EA.hy926) were treated with various concentrations of the PM(2.5) suspension. Cell proliferation, oxidative DNA damage, and global DNA methylation levels were used to measure the cellular toxicity of PM(2.5) emitted from coal combustion. RESULTS: Compared to other types of coal-fired PM(2.5) preparations, the PM2.5 suspension from Yinchuan coal had the highest cytotoxicity. PM(2.5) suspension from Datong coal had the highest toxic effect while that from Yinchuan coal had the lowest. Exposure to coal-fired PM(2.5) from Jingxi coal resulted in lower 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels. At the same dose, PM(2.5) emitted from coal combustion could produce more severe DNA impairment compared to that produced by carbon black. Cell survival rate was negatively correlated with chloride and potassium ions content. The 5-methylcytosine (5-mC) level was positively correlated with Mn and negatively correlated with Zn levels. The 8 OHdG% level was positively correlated with both Mn and Fe. CONCLUSION: PM(2.5) emitted from coal combustion can decrease cell viability, increase global DNA methylation, and cause oxidative DNA damage in EA.hy926 cells. Metal components may be important factors that influence cellular toxicity.

Health risk assessment for vehicle inspection workers exposed to airborne polycyclic aromatic hydrocarbons (PAHs) in their work place.

Inhalatory and dermal exposures of on-duty vehicle inspection workers to polycyclic aromatic hydrocarbons (PAHs) in Beijing were investigated from April 18 to May 17, 2011. Exposure levels to particulate PAHs for the vehicle inspection workers at gasoline, bus and diesel lines were found to be 56.07 ng m(-3), 111.72 ng m(-3) and 199.80 ng m(-3), respectively. A probabilistic risk assessment framework was integrated with the toxic equivalence factors (TEFs) and the incremental lifetime cancer risk (ILCR) approaches to quantitatively estimate the exposure risk for vehicle inspection workers of the three work lines. The median values of inhalation risk were estimated to be 3.7 × 10(-7), 5.0 × 10(-7) and 1.37 × 10(-6), respectively, while the median dermal ILCR values were 7.05 × 10(-6), 6.98 × 10(-6) and 1.28 × 10(-5), respectively for gasoline, bus, and diesel inspection workers. Total ILCR was higher than the acceptable risk level of 10(-6), indicating unacceptable potential cancer risk.

The overall reaction process of ozone with methacrolein and isoprene in the condensed phase.

The reaction of isoprene and methacrolein with ozone was investigated at different stages in the condensed phase at temperatures from 15 to 265 K by IR spectroscopy. The results revealed the following overall reaction process: the generation of primary ozonide (POZ), then its decomposition, and finally conversion into secondary ozonide (SOZ), which supported the Criegee mechanism. In the POZ and SOZ of isoprene, ozone cyclo-added preferentially to the double-bond that is not substituted by the methyl group. For methacrolein, the mainly detected SOZ is claimed to be MACSII formed by recombination of the intermediate CH(2)OO radical with aldehyde carbonyl of methylglyoxal in stead of the ketone carbonyl group. Theoretical calculations were performed at the B3LYP//MP2/6-311++G (2d, 2p) level to analyze the resulting spectrum. The good agreement between the calculated infrared spectra of POZ and SOZ and the experimental spectra supports the above-described findings.