Mcdowellschroeder4898

The relationships between modeled TVOC/NOx ratios and O3 reductions, as well as the titration effect, were also discussed. The model results provided useful references for the mitigation strategy of ozone reduction in Lanzhou and other major cities in northwest China with similar climate and topography conditions.The present study assessed the association between phthalate exposure and mitochondrial DNA (mtDNA) polymerase γ (POLG) methylation along with the potential effect on the characteristics of body fat in children. A total of 152 children were enrolled. The urinary concentrations of phthalate metabolites were measured using ultraperformance liquid chromatography-tandem mass spectrometry. Genomic DNA was extracted from the buffy coat, and bisulfite-treated DNA was subjected to a pyrosequencing assay. In total, 17 CpG sites in the exon 2 region of POLG were included in the analysis. A multivariable regression model was applied to determine whether characteristics of body fat were associated with phthalate exposure and methylation of POLG. After adjustment for covariates, male children with a ten-fold increase in mono-methyl phthalate (MMP) or mono-benzyl phthalate (MBzP) concentrations had significantly higher measurements for total body fat (MMP β = 6.47%; MBzP β = 3.54%), and trunk fat (MMP β = 6.67%; MBzP β = 3.90%). Male children who had hypermethylation at the 2nd CpG site in exon 2 of POLG also had high measurements for BMI (β = 1.66 kg/m2), waist (β = 4.49 cm) and hip (β = 4.81 cm) circumference, total body fat (β = 5.48%), and trunk fat (β = 6.21%). A dose-response relationship existed between methylation at the 2nd CpG site in exon 2 of POLG and characteristics of body fat (p for trend less then 0.01). This study suggested that male children who are exposed to phthalic acid esters have high body weight, BMI, and body and trunk fat percentages. click here Methylation of the exon 2 region of POLG is a possible mechanism behind the causal effect of endocrine-disrupting substances.Organic amines are one of the most important nitrogen-containing compounds in the atmosphere, and their reactions with tropospheric ozone contribute significantly to the formation of secondary organic aerosols (SOA). However, the chemical pathways of their reaction with atmospheric ozone are poorly understood. This study investigates the atmospheric ozonolysis mechanism of two typical organic amines-diethylamine and triethylamine using experimental and theoretical methods. Intermediate results from GC-MS and PTR-TOF-MS analysis confirm the formation of eight and eleven nitrogen- and oxygen-containing products during the ozonolysis of diethylamine and triethylamine, respectively. N-ethylethanimine (56.5% in average) or acetaldehyde (64.9% in average) is formed as the dominant product from the ozonolysis of each organic amine. Ozonolysis pathway results indicate that the conversion to N-ethylethanimine is the dominant pathway for diethylamine ozonolysis. At the same time, triethylamine prefers the initial transformation to diethylamine with the discharge of acetaldehyde and then converts to N-ethylethanimine. Higher SOA mass concentration is obtained from the ozonolysis of triethylamine than diethylamine, probably because the former releases a larger amount of intermediate products, especially acetaldehyde. Our results provide a deep insight into the atmospheric processing of organic amines via ozonolysis and the implications of this mechanism for SOA formation.A biomimetic Egeria-densa-like hybrid composite nanofiber membrane was fabricated to degrade organic pollutants in water, with PVDF nanofibers as stems to provide support, and ZnO nanowires as leaves to provide active sites. The Sm-doped ZnO nanowires@PVDF nanofiber membranes were characterized by FE-SEM, X-ray photoelectron spectroscopy, Fourier transform infrared, X-ray diffraction, and UV-vis diffuse reflectance spectrometer. Compared with the pure ZnO nanowires@PVDF nanofiber membrane, the Sm-doped membrane showed higher photocatalytic performance. The excellent photocatalytic activity was attributed to the increased specific surface area and the decreased bandgap of ZnO nanowires after Sm doping, which inhibited the recombination rate of electrons and holes and improved the absorption of visible light. We found that the superoxide free radicals (O2-) played a critical role in photocatalytic degradation. The Sm-doped ZnO nanowires@PVDF nanofiber membrane exhibited good stability after 5 cycles of RhB degradation. We believe such Sm-doped hybrid membrane can work as an effective photocatalyst for wastewater treatment.Perfluoroalkyl and polyfluoroalkyl substances (PFASs) have been manufactured and used for over 50 years, and now are worldwide distributed in the environment. The atmospheric environment is the main compartment for PFASs to be transported and transformed, and relevant research has highlighted the global occurrence and impacts of atmospheric PFASs in ecosystems and human health. With the phasing-out and restriction of eight‑carbon chain-length (C8) PFASs in developed countries, China has become the largest producer of C8 PFASs since 2004. Subsequently, a number of studies on PFASs in the Chinese atmospheric environment have been conducted in the recent decade. This review documented twenty-eight studies on PFASs in Chinese outdoor air published to date. Methods of sampling, extraction, cleanup, and instrumental analysis were summarized for both ionic and neutral PFASs. Levels, compositions, and spatial distribution of PFASs from different areas in China (i.e. source, urban, and remote regions, and north versus south China) were compared and discussed. Leaves and tree barks were proposed as effective bioindicators to reflect the contamination status of atmospheric PFASs. Special attention can be given to non-target screening for future research directions.The evaluation of the importance of having accurate and representative stations in a network for river water quality monitoring is always a matter of concern. The minimal budget and time demands of water quality monitoring programme may appear very attractive, especially when dealing with large-scale river watersheds. This article proposes an improved methodology for optimising water quality monitoring network for present and forthcoming monitoring of water quality under a case study of the Selangor River watershed in Malaysia, where different monitoring networks are being used by water management authorities. Knowing that the lack of financial resources in developing countries like Malaysia is one of the reasons for inadequate monitoring network density, to identify an optimised network for cost-efficiency benefits in this study, a geo-statistical technique coupled Kendall's W was first applied to analyse the performance of each monitoring station in the existing networks under the monitored water quality parameters.