Polycyclic aromatic hydrocarbons and nitro-polycyclic aromatic hydrocarbons in urban air particulate matter in Ho Chi Minh City, Viet Nam

Joint Research on Environmental Science and Technology for the Eart

SECONDARY GENERATION OF GASEOUS HONO AND ITS EFFECT ON OUR HEALTH

Joint Research on Environmental Science and Technology for the Eart

Proceeding of The International Seminar on Chemistry

Abstract Currently, most of the biodiesel is produced from vegetable oils and methanol in the presence of base catalysts using mechanical stirring method at temperature 50-65 o C. This method consumes much energy because oils and methanol must be heated up to desired temperature, and also requires rather long reaction time. Ultrasound-assisted reaction can reduce the reaction time much shorter than mechanical stirring and the reaction can be carried out at room temperature, so energy can be saved. In the pilot scale the trans-esterification was performed by circulation process under low frequency ultrasound (20 kHz) with the input capacity of 1 kW. Effect of various process parameters such as the amount of KOH, molar ratio of oil to methanol and also reaction time were investigated. The optimal conditions for the process were: oil/methanol molar ratio 1:5, the amount of KOH to oil 0.7 % w/w. Under these conditions, conversion of triglycerides to fatty acid methyl esters (FAMEs) was 96.3% within the reaction time 60 minutes . Glycerin, catalyst and excess methanol were separated easily from FAMEs phase. Crude biodiesel was purified by washing with tap water and drying at 65 o C under reduced pressure at 520torr

High Concentrations of Sulfur Dioxide and Sulfate Particles Observed in Suzu City, the Noto Peninsula in Late July 2012 : On the Influence of the Smoke of Sakurajima

Measurements of SO2 and sulfate aerosol concentrations in the atmosphere were performed in Suzu City, the Noto Peninsula, Ishikawa Prefecture in the summer of 2012. High concentrations of SO2 and sulfate aerosols in PM25 were observed in late July when CO and O3 concentrations did not increased. The high SO, and sulfate particles may not be due to anthropogenic air pollution. According to the atmospheric pressure pattern in summer and the results of trajectory analyses, the air mass over the Noto Peninsula was transported from the southern part of Kyushu. The large eruption of Sakurajima occurred on 24 July in 2012, and the fumes were transported to the Hokuriku district. Recently, the volcanic eruptions of Sakurajima have increased in activity and may highly affect the air environment, such as PM25, over Japan

Aerosol Liquid Water Promotes the Formation of Water-Soluble Organic Nitrogen in Submicrometer Aerosols in a Suburban Forest

Water-soluble organic nitrogen (WSON) affects the formation, chemical transformations, hygroscopicity, and acidity of organic aerosols as well as biogeochemical cycles of nitrogen. However, large uncertainties exist in the origins and formation processes of WSON. Submicrometer aerosol particles were collected at a suburban forest site in Tokyo in summer 2015 to investigate the relative impacts of anthropogenic and biogenic sources on WSON formations and their linkages with aerosol liquid water (ALW). The concentrations of WSON (ave. 225 +/- 100 ngN m(-3)) and ALW exhibited peaks during nighttime, which showed a significant positive correlation, suggesting that ALW significantly contributed to WSON formation. Further, the thermodynamic predictions by ISORROPIA-II suggest that ALW was primarily driven by anthropogenic sulfate. Our analysis, including positive matrix factorization, suggests that aqueous-phase reactions of ammonium and reactive nitrogen with biogenic volatile organic compounds (VOCs) play a key role in WSON formation in submicrometer particles, which is particularly significant in nighttime, at the suburban forest site. The formation of WSON associated with biogenic VOCs and ALW was partly supported by the molecular characterization of WSON. The overall result suggests that ALW is an important driver for the formation of aerosol WSON through a combination of anthropogenic and biogenic sources

Electrochemical Evaluation of the Number of Viable Bacteria Using Carbon Electrode Chip

To perform on-site bacterial testing at food and pharmaceutical manufacturing sites, it is desired to develop a new method that can quickly measure the number of viable bacterial cells. We have succeeded in measuring the number of viable bacteria using small and inexpensive disposable electrode chips focusing on electrochemical methods that realize quick detection and device miniaturization. The oxidized form of the tetrazolium salt, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), is soluble and highly permeable through cell membranes. MTT is a useful indicator for evaluating cell activity that not only turns color as a result of structural changes related to intracellular metabolism but also causes a clear current response. The carbon-screen-printed electrode chip provides a distinct current response related to the MTT redox reaction in a small volume of bacterial suspension (50 µL). Based on the fact that the current reaction of MTT was strongly dependent on intracellular metabolism, the number of viable cells in a bacterial suspension could be measured electrochemically. Current changes for live cells occurred within 10 min and increased with the incubation time. After only 60 min of incubation, we successfully estimated the number of viable cells in a bacterial suspension of 103 CFU mL−1. This technology eliminates the need for complicated testing, expensive equipment, and lengthy culture testing times, thereby enabling the confirmation of food safety before shipping to prevent food poisoning