The concurrent presence of high values of organic SOA precursors and reactive halogen species (RHS) at very low ozone concentrations allows the formation of halogen-induced organic aerosol, so-called XOA, in maritime areas where high concentrations of RHS are present, especially at sunrise. The present study combines aerosol smog-chamber and aerosol flow-reactor experiments for the characterization of XOA. XOA formation yields from alpha-pinene at low and high concentrations of chlorine as reactive halogen species (RHS) were determined using a 700 L aerosol smog-chamber with a solar simulator. The chemical transformation of the organic precursor during the aerosol formation process and chemical aging was studied using an aerosol flow-reactor coupled to an FTIR spectrometer. The FTIR dataset was analysed using 2D correlation spectroscopy. Chlorine induced homogeneous XOA formation takes place at even 2.5 ppb of molecular chlorine, which was photolysed by the solar simulator. The chemical pathway of XOA formation is characterized by the addition of chlorine and abstraction of hydrogen atoms, causing simultaneous carbon-chlorine bond formation. During further steps of the formation process, carboxylic acids are formed, which cause a SOA-like appearance of XOA. During the ozone-free formation of secondary organic aerosol with RHS a special kind of particulate matter (XOA) is formed, which is afterwards transformed to SOA by atmospheric aging or degradation pathways.
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http://dx.doi.org/10.1039/c3fd00093a | DOI Listing |
Food Chem Toxicol
December 2024
Departments of Otolaryngology-Head and Neck Surgery; Departments of Cell Biology, The University of Oklahoma Health Sciences Center, Oklahoma City OK 73104, USA; Departments of TSET Health Promotion Research Center, Stephenson Cancer Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA. Electronic address:
Electronic cigarettes (e-cigarettes) have emerged as a potential alternative to traditional smoking and may aid in tobacco harm reduction and smoking cessation. E-cigarette use has notably increased, especially among young non-tobacco users, raising concerns due to the unknown long-term health effects. The oral cavity is the first and one of the most crucial anatomical sites for the deposition of e-cigarette aerosols.
View Article and Find Full Text PDFJ Chromatogr A
December 2024
School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China. Electronic address:
The evolution of precursors to form secondary organic aerosol (SOA) is still a challenge in atmospheric chemistry. Chamber experiments were conducted to simulate the ambient OH oxidation of naphthalene and α-pinene, which are typical markers of anthropogenic and biogenic emissions. Particulate matters were sampled by quartz filters and were analyzed by comprehensive two-dimensional gas chromatography (GC×GC) coupled with a thermal desorption system (TD) and a mass spectrometer (MS).
View Article and Find Full Text PDFJ Phys Chem A
December 2024
Department of Chemistry, University of Zanjan, PO Box 38791-45371 Zanjan, Iran.
The high abundance of acetone ((CH)C═O), which makes it a good candidate for oxygenated molecules, and the high reactivity of oxygen atoms in the first excited state O(D) are two well-known facts in the chemistry of the atmosphere. In this research, we prove that the singlet oxygen and acetone system is capable of proceeding through multiwell multipath reactions, leading to the production of several organic aerosols. Hence, the nature of species released by the (CH)C═O + O(D) reaction to air can be clarified by profound attention to the possible routes.
View Article and Find Full Text PDFBiotechnol Lett
December 2024
Key Laboratory of Environmental Chemistry and Ecotoxicology of Organic Pollutants of Chongqing, Ecological and Environment Monitoring Center of Chongqing, 252 Qishan Road, Chongqing, 401132, China.
Rapid diagnostic tools for Porphyromonas gingivalis (Pg), the primary microorganism responsible for the development of periodontitis, particularly those designed for chair-side applications, could provide substantial health benefits to patients. To address this issue, we developed a CRISPR/Cas12a-based rapid Pg detection method. Dual-gRNA and hairpin reporter strategies were employed to enhance CRISPR/Cas12a reaction efficiency.
View Article and Find Full Text PDFChemosphere
December 2024
Foundation for the Promotion of Health and Biomedical Research in the Valencian Region, FISABIO-Public Health, 21, Av. Catalunya, 46020, Valencia, Spain.
This work aims to establish a strategy to comprehensively assess the indoor air quality in schools including the analysis of chemical pollutants, bio-aerosols like fungi, bacteria and respiratory viruses and the identification of volatile and semi-volatile organic compounds applying non-targeted approaches. For this, a pilot study was performed in four primary schools from Spain, located in different urban and rural areas during different seasons. Common indoor pollutants, like CO NO, O, CO, particulate matter (PM, PM), ultrafine particles (UFP), total volatile organic compounds (TVOCs), and formaldehyde (HCHO), were assessed in terms of maximum recommended levels, daily variations, seasonality, and school location.
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