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Ozone (O3) is a pollutant of concern in urban areas because of its effects on health, crops, ecosystems, and materials. Despite efforts to meet the Japanese air quality standard for O3 in the Kanto region, the attainment percentage is close to zero. Considering that O3 formation is sensitive to emissions of volatile organic compounds (VOC) and nitrogen oxides (NOx), this study evaluated a range of reductions in the emissions of both precursors using a regional air quality model (ADMER-PRO) and estimated their benefits measured as the economic change due to O3 concentration differences between scenarios. The simulation period was set during the 2016 O3 season. The results showed that O3 concentrations could be reduced using two approaches: significant reduction in VOC levels combined with minor NOx level changes or significant NOx emission reduction. Significant reduction in NOx levels was the most effective strategy for a generalized decrease in the O3 levels in the Kanto region, and the benefit analysis revealed that the most significant economic impacts could be achieved by adopting the latter approach. [ABSTRACT FROM AUTHOR]

Abstract: We have developed a compact, laser-based, single photon ionization time-of-flight mass spectrometer (SPI-TOF-MS) for on-line monitoring of trace organic species. To obtain the mass spectrum, we use a nearly fragmentation-free SPI technique with 10.5eV (118nm) vacuum ultraviolet laser pulses generated by frequency tripling of the third harmonic of an Nd:YAG laser. The instrument can be operated in a linear TOF-MS mode or a reflectron TOF-MS mode in the coaxial design. We designed ion optics to optimize detection sensitivity and mass resolution. For data acquisition, the instrument is controlled using LabVIEW control software. The total power requirement for the vacuum unit, control electronics unit, ion optics, and detection system is approximately 100W. We achieve a detection limit of parts per billion by volume (ppbv) for on-line trace analysis of several organic compounds. A mass resolution of 800 at about 100amu is obtained for reflectron TOF-MS mode in a 0.35m long instrument. The application of on-line monitoring of diesel engine exhaust was demonstrated. [Copyright &y& Elsevier]

This study evaluated gasoline evaporative emissions from fuel-cap removal during the refueling process (or "puff loss") for one gasoline vehicle in the Japanese market. Specifically, the puff loss emissions were measured after a real-world driving event in urban Tokyo, Japan for different seasons and gasoline types. The experimental results indicated higher puff loss emissions during summer than in winter and spring despite using low vapor pressure gasoline during summer. These higher puff loss emissions accounted maximally for more than 4 g of the emissions from the tested vehicle. The irregular emission trends could be attributed to the complex relationships between physical parameters such as fuel-tank filling, ambient temperature, ambient pressure, and gasoline vapor pressure. Furthermore, an estimation model was developed based on the theory of thermodynamics to determine puff loss emissions under arbitrary environmental conditions. The estimation model included no fitting parameter and was in good agreement with the measured puff loss emissions. Finally, a sensitivity analysis was conducted to elucidate the effects of three physical parameters, i.e., fuel tank-filling, ambient pressure, and gasoline type, on puff loss emissions. The results indicated that fuel tank-filling was the most important parameter affecting the quantity of puff loss emissions. Further, the proposed puff loss estimation model is likely to aid the evaluation of future volatile organic compound emission inventories. [ABSTRACT FROM AUTHOR]

Abstract: A silicone membrane sample introduction system combined with a vacuum ultraviolet single photon ionization time-of-flight mass spectrometer (VUV-SPI-TOFMS) has been developed to detect trace volatile organic compounds in environmental air. The maximum enrichment factors of benzene, toluene, and chlorobenzene using the membrane introduction system relative to a direct introduction system were found to be 15.3, 11.0, and 12.1, respectively. The gas permeability of toluene through the silicone membrane was consistent with that of the manufacturer''s reported value. The gas permeabilities of the silicone membrane used in the present study were estimated for benzene and chlorobenzene by theoretical calculations using the enrichment factors. The enrichment factors of benzene, toluene, and chlorobenzene were independent of their mixing ratios at <34ppmv. The detection limits of benzene and chlorobenzene with the membrane introduction system were improved by one order of magnitude relative to direct introduction. Detection of almost sub-ppbv level of benzene and chlorobenzene was achieved in the membrane introduction VUV-SPI-TOFMS. [Copyright &y& Elsevier]