PM Characteristics Research Articles

2412 標準PM生成装置により生成されるPMの性状に及ぼす燃料中硫黄分の影響(G07-1 エンジンシステム(1),21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

Nanometer size particulate matter (Nano-PM) emitted from a flame of fossil fuel has been received attention due to their harmful potential for health. However, detailed knowledge about Nano-PM formation mechanism has not been clarified yet. The objective of this study is to investigate the relation between the PM characteristics and sulfur in fuel using standard Nano-PM generator. A pool flame was used for production of Nano-PM. Kerosene and Thiophen added Kerosene were used as fuels. It was clear that the flame form changed from closed flame to open flame, when fuel flow rate M_f was over 0.4mg/s in the both fuels. The flame tip of open flame was opened and visible soot was emitted from the tip. As for the size distribution of PM, the peak diameter was gradually increased with an increase of fuel flow rate in Kerosene flame, but it was suddenly increased when the fuel flow rate exceeded 0.4mg/s, in Thiophene added Kerosene flame.

Comparison of Oxidative Properties, Light Absorbance, and Total and Elemental Mass Concentration of Ambient PM 2.5 Collected at 20 European Sites

ObjectiveIt has been proposed that the redox activity of particles may represent a major determinant of their toxicity. We measured the in vitro ability of ambient fine particles [particulate matter with aerodynamic diameters ≤2.5 μm (PM2.5)] to form hydroxyl radicals (•OH) in an oxidant environment, as well as to deplete physiologic antioxidants (ascorbic acid, glutathione) in the naturally reducing environment of the respiratory tract lining fluid (RTLF). The objective was to examine how these toxicologically relevant measures were related to other PM characteristics, such as total and elemental mass concentration and light absorbance.DesignGravimetric PM2.5 samples (n = 716) collected over 1 year from 20 centers participating in the European Community Respiratory Health Survey were available. Light absorbance of these filters was measured with reflectometry. PM suspensions were recovered from filters by vortexing and sonication before dilution to a standard concentration. The oxidative activity of these particle suspensions was then assessed by measuring their ability to generate •OH in the presence of hydrogen peroxide, using electron spin resonance and 5,5-dimethyl-1-pyrroline-N-oxide as spin trap, or by establishing their capacity to deplete antioxidants from a synthetic model of the RTLF.Results and ConclusionPM oxidative activity varied significantly among European sampling sites. Correlations between oxidative activity and all other characteristics of PM were low, both within centers (temporal correlation) and across communities (annual mean). Thus, no single surrogate measure of PM redox activity could be identified. Because these novel measures are suggested to reflect crucial biologic mechanisms of PM, their use may be pertinent in epidemiologic studies. Therefore, it is important to define the appropriate methods to determine oxidative activity of PM.

Diurnal and seasonal characteristics of particle volatility and chemical composition in the vicinity of a light-duty vehicle freeway

During the winter of 2005, physicochemical properties of size-fractionated PM 10 particles were analyzed next to State Route 110 (Pasadena freeway in Los Angeles, CA, USA), a light-duty vehicle freeway, closed to heavy-duty traffic. We report volatility of ultrafine particles and chemical characteristics in the coarse, accumulation, and ultrafine modes very close to the freeway and at an urban background site. For measurement of mass and chemical composition, the study employed in each location a Micro-Orifice Uniform Deposit Impactor (MOUDI) and a modified high-volume sampler. Both instruments sampled with the same size cutpoints. A tandem differential mobility analyzer (TDMA) was used at the two sampling sites to analyze the semivolatile fraction of the aerosols. Size distributions of the ambient aerosol were measured using a DMA and total number concentration using a condensation particle counter (CPC). In this study, which was a continuation of a campaign during summer 2004, we compared the seasonal, i.e. winter versus summer, and diurnal, i.e. daytime versus evening, variation in PM characteristics in the vicinity of this freeway. Conditions in winter differed most from those in summer during the evening rush-hour traffic, with much lower temperatures in the winter campaign. Diurnal variations in particle volatility were observed, with higher content of volatile material in aerosols sampled in the evenings. Particle number concentrations were also much higher during the evening hours, increasing from 67,000 to 110,000 cm −3. The average total number concentration next to the freeway was 80,000 cm −3 during the sampling period, which was higher than in summer, when the average was 46,000 cm −3. External mixing was observed with increasing nonvolatile fractions for 40, 80, and 120 nm particles (39% of particles). In general the volatility increased in the evenings, while the nonvolatile fraction decreased.

802 軽油の層流火炎から発生するPMの計測(G06-1 燃焼,G06 熱工学)

Size distributions of nano-PM in diffusion flame of diesel fuel were experimentally investigated using a scanning mobility particle sizer (SMPS). Effect of lubricating oil content on PM characteristics was discussed. Concentrations of dry soot, SOF and sulfate in nano-PM were measured by a PM analyzer. Furthermore, to investigate the mechanism of PM formation in a combustion process, the distributions of polycyclic aromatic hydrocarbons (PAHs) in the flame were measured by a laser induced fluorescence (LIF) method. Also, soot distributions were measured by a laser induced incandescence (LII) method. It was found that soot and PAHs concentrations increased with increasing the lubricating oil content.

Speciation and origin of PM10 and PM2.5 in selected European cities

Abstract PM characteristics of seven selected regions within the European Union (EU) were analysed and compared. Results of levels and speciation studies of PM10 and PM2.5 (with at least one year of data coverage from 1998 to 2002) at regional, urban background and kerbside sites were assessed. Based on the examples selected, PM10 levels (annual mean) ranged from 19 to 24 μg m −3 at regional background sites, from 28 to 42 μg m −3 at urban background, and from 37 to 53 μg m −3 at kerbside sites. PM2.5 levels varied from 8 to 20 μg m −3 at regional background sites, 20 to 30 μg m −3 at urban background and 25 to 40 μg m −3 at kerbside sites. The ratio PM2.5/PM10 is highly dependent on the type of site and varied widely between different EU regions. Source apportionment results showed that, on an annual average, the natural contribution (mineral and marine) at EU regional sites was in the range of 4–8 μg m −3 in PM10 decreasing in PM2.5, but contributions up to 19 μg m −3 were reported for specific locations. At urban sites, carbonaceous aerosols and secondary inorganic compounds accounted for a major fraction of PM10, and especially of the PM2.5 mass. Quantitative data on the contributions of the regional background, city background and local traffic to the mean annual levels of PM10, PM2.5 and major components were supplied. Climatic differences, long-range transport processes and winter traffic peculiarities (the latter in northern countries) contributed to the increase of PM10 and PM2.5 masses. At kerbside sites, an important dust contribution to PM2.5 is highlighted.

PM processing and characteristics of discontinuously reinforced aluminium : C.A.Smith, A.Rapaport. (Aerospatiale, France.)

PM processing and characteristics of discontinuously reinforced aluminium : C.A.Smith, A.Rapaport. (Aerospatiale, France.)

Room B, 10/16/2000 2: 00 PM - 4: 00 PM (PS) Characteristics of Extraterritorial Allodynia in Rats with Peripheral Mononeuropathy

<b>Room B, 10/16/2000 2: 00 PM - 4: 00 PM (PS) Characteristics of Extraterritorial Allodynia in Rats with Peripheral Mononeuropathy</b>

The wavelength dependence of the response of a pulse fluorometer using the single photoelectron counting method

We study the apparatus response function g (t) which must be known in order to deconvolute the fluorescence decay experiments obtained by the single photon counting method. Due to the flash and the PM characteristics, g (t) depends on the excitation and emission wavelengths. The PM contribution is analyzed qualitatively and found to be in agreement with the properties of the photoelectric effect. Therefore, the accurate determination of the ``true fluorescence decay'' cannot be obtained by the process commonly used, which consists in replacing g (t) by the apparatus response obtained with the PM receiving the light of the exciting pulse. The function g (t) may be obtained in using a reference fluorescent solution with a known fluorescence decay-time.