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151.
J. Jacobson A. Kuja D. Shriner S. Perrigan P. Irving J. Lee 《Journal of the Air & Waste Management Association (1995)》2013,63(6):777-783
Radish plants were exposed three times per week to simulated acidic rain at pH values of 2.6 to 5.4 over the course of four weeks in trials performed at Argonne, Illinois; Ithaca and Upton, New York; Corvallis, Oregon; Oak Ridge, Tennessee; and Toronto, Canada. Uniform genotype, soil media and planting techniques, treatment procedures, biological measurements, and experimental design were employed. Growth of plants differed among trials as a result of variation in greenhouse environmental conditions according to location and facilities. Larger plants underwent greater absolute but lower relative reductions in biomass after exposure to the higher levels of acidity. A generalized Mitscherlich function was used to model the effects of acidity of simulated rain or dry mass of hypocotyls using data from three laboratories that performed duplicate trials. The remaining data, from three other laboratories that performed only one trial each, were used to test the model. When the laboratory by trial effect was removed (influence of different growth. conditions), lack of fit to the Mitscherlich function was insignificant. Thus, a single mathematical model satisfactorily characterized the relationship between acidity and mean plant response. The pH value associated with a 10 percent reduction in mass was 3.3 ± 0.3 for hypocotyls. No value was estimated for shoots because effects oh shoots were not significant. The results of this study demonstrate that a generalized exposure-response model can be developed in the presence of large variations in environmental conditions when plant culture and exposure to simulated rain are standardized among laboratories. 相似文献
152.
S. Win Lee 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1568-1578
ABSTRACT Recent awareness of suspected adverse health effects from ambient particulate matter (PM) emission has prompted publication of new standards for fine PM with aerodynamic diameter less than 2.5 μm (PM2.5). However, scientific data on fine PM emissions from various point sources and their characteristics are very limited. Source apportionment methods are applied to identify contributions of individual regional sources to tropospheric particulate concentrations. The existing industrial database developed using traditional source measurement techniques provides total emission rates only, with no details on chemical nature or size characteristics of particulates. This database is inadequate, in current form, to address source-receptor relationships. A source dilution system was developed for sampling and characterization of total PM, PM2.5, and PM10 (i.e., PM with aerodynamic diameter less than 10 μm) from residual oil and coal combustion. This new system has automatic control capabilities for key parameters, such as relative humidity (RH), temperature, and sample dilution. During optimization of the prototype equipment, three North American coal blends were burned using a 0.7-megawatt thermal (MWt) pulverized coal-fired, pilot-scale boiler. Characteristic emission profiles, including PM2.5 and total PM soluble acids, and elemental and carbon concentrations for three coal blends are presented. 相似文献
153.
Minliang Shih Wen-Jhy Lee Cheng-Hsien Tsai Perng-Jy Tsai Chuh-Yung Chen 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1274-1280
Abstract Sulfur hexafluoride (SF6)-contained gas is a common pollutant emitted during the etching process used in the semiconductor industry. This study demonstrated the application of radio-frequency (RF) plasma in the decomposition of SF6. The decomposition fraction of SF6 [ηSF6 (Cin–Cout)/Cin x 100%] and the mole fraction profile of the products were investigated as functions of input power and feed O2/SF6 ratio in an SiO2 reactor. The species detected in both SF6/Ar and SF6/O2/Ar RF plasmas were SiF4, SO2, F2, SO2F2, SOF2, SOF4, S2F10, S2OF10, S2O2F10, and SF4. The results revealed that at 40 W, ηSF6 exceeded 99%, and the reaction products were almost all converted into stable compounds such as SiF4, SO2, and F2 with or without the addition of oxygen. Sulfur oxyfluorides such as SO2F2, SOF2, SOF4, S2OF10, and S2O2F10 were produced only below 40 W. The results of this work can be used to design a plasma/chemical system for online use in a series of a manufacturing process to treat SF6-containing exhaust gases. 相似文献
154.
Wing-tat Hung Ka-man Tam Chi-pang Lee Chi-pang Lee Lo-yin Chan Chun-shun Cheung 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1420-1430
Abstract Zhuhai, a relatively less developed city on the western coast of the Pearl River Delta (PRD) of China, is planning to undergo major development in coming years. A Hong Kong-Zhuhai-Macao Bridge project has been approved by the Central Government of China. The project will have great impact on the driving pattern and vehicular emissions to the city. This baseline study collected speed-time data of two instrumented private cars in morning and evening periods, as well as a daytime nonpeak period of >10 consecutive days in the spring and winter of 2003. The authors used the microwave speed sensor and global positioning system installed in the instrumented cars and used car-chasing technique to perform the data collection. They used the statistical package SPSS to assess the consistency, as well as to evaluate the variability of the data. Nine parameters, namely, average speed, average running speed, average acceleration rate, average deceleration rate, mean length of a driving period, time proportions of driving modes, average number of acceleration-deceleration changes, root mean square acceleration, and positive acceleration kinetic energy are calculated to represent the driving characteristics. A driving cycle for private cars was developed. If emission tests were conducted using the Zhuhai driving cycle, the level of vehicle emissions measured is likely to be in between that of the Federal Test Procedure (FTP) cycle and the Melbourne Peak cycle. 相似文献
155.
Jae Hwan Lee Chunrong Jia Sergei Chernyak 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1503-1517
Abstract Four popular thermally desorbable adsorbents used for air sampling (Tenax TA, Tenax GR, Carbopack B, and Carbopack X) are examined for the potential to form artifacts with ozone (O3) at environmental concentrations. The performance of these adsorbents for the ketone and alde-hyde species identified as O3-adsorbent artifacts was also characterized, including recovery, linearity, and method detection limits (MDLs). Using gas chromatography/mass spectrometry, 13 different artifacts were identified and confirmed for both Tenax TA and Tenax GR, 9 for Carbopack B, but none for Carbopack X. Several O3 artifacts not reported previously were identified, including: pentanal, 3-hexanone, 2-hexanone, hexanal, 3-heptanone, and heptanal with Tenax TA; pentanal, 3-hexanone, 2-hexanone, hexanal, and 3-heptanone on Tenax GR; and 1-octene and 1-nonene with Carbopack B. Levels of straight-chain aldehyde artifacts rapidly diminished after a few cycles of adsorbent conditioning/O3 exposure, and concentrations could be predicted using a first-order model. Phenyl-substituted carbonyl artifacts (benzalde-hyde and acetophenone) persisted on Tenax TA and GR even after 10 O3 exposure-conditioning cycles. O3 breakthrough through the adsorbent bed was most rapid in adsorbents that yielded the highest levels of artifacts. Overall, artifact composition and concentration are shown to depend on O3 concentration and dose, conditioning method, and adsorbent type and age. Calibrations showed good linearity, and most compounds had reasonable recoveries, for example, 90 ±15% for Tenax TA, 97 ±23% for Tenax GR, 101 ±24% for Carbopack B, and 79 ±25% (91 ±9% for n-aldehydes) for Carbopack X. Benzeneacetaldehyde recovery was notably poorer (22–63% across the four adsorbents). MDLs for several compounds were relatively high, up to 5 ng. By accounting for both artifact formation and method performance, this work helps to identify which carbonyl compounds can be measured using thermally desorbable adsorbents and which may be prone to bias because of the formation of O3- adsorbent artifacts. 相似文献
156.
Young Sung Ghim Kil-Choo Moon Sihye Lee Yong Pyo Kim 《Journal of the Air & Waste Management Association (1995)》2013,63(1):73-82
Abstract Temporal trends and spatial distributions of visibility measured by the human eye over 60 stations in Korea between 1980 and 2000 are analyzed and discussed. Generally, visibility is lowest on winter mornings and highest on summer afternoons throughout Korea. Visibility in Seoul is now in an increasing trend while it has decreased nationwide, especially in clean coastal areas. Spatial distribution of visibility in the 1990s was related negatively to that of relative humidity (RH). However, visibility generally decreased despite an overall decrease in RH throughout the country. Air pollutants should have played a role in this dissonant variation, particularly in relatively clean areas and on summer afternoons. It was interpreted that the visibility increase in major metropolitan areas, including the greater Seoul area, in the 1990s was caused mainly by the reduction in pollutant emissions by rigorous government policy. But the effect of the emission reduction was manifested with decreasing RH. 相似文献
157.
Chien-Li Lee Chitsan Lin 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1443-1448
Microwave (MW) is applied to enhance perchloroethylene (PCE) or pentachlorophenol (PCP) removal using zero-valent iron (ZVI; Fe0) as the dielectric medium. ZVI has a much higher dielectric loss factor (39.5) than other media; it is capable of absorbing MW radiation rapidly to speed up the release of electrons, leading to rises of the ZVI particle surface temperature. If the MW power is continued, excessive electricity will accumulated inside ZVI particles, resulting in sparks. The results show that during the initial 5 sec (700 W), the linear aliphatic PCE has a faster decomposing rate than the ringed PCP (82.0% vs. 4.8%) because less energy is required for decomposing the linear-chlorine bond (90 kcal mol?1) than ring-chlorine bonds (95 kcal mol?1). Later, the removal rate for either PCE or PCP remains the same when the exposure time is between 5 and 60 sec. Without MW irradiation, linear PCE molecules have larger surface area to contact ZVI, and hence they have better removal efficiencies than PCP molecules. Using Fe0 as a microwave dielectric medium to treat PCE or PCP is a new and worthwhile treatment technology; it is environmentally friendly, and its use will eliminate the secondary pollution.
Implications Nanoscale iron particles are characterized by high surface-area-to-volume ratios, high specific surface area, and high surface reactivity. With a much higher dielectric loss factor, it is capable of absorbing MW radiation rapidly to speed up the release of electrons, leading to rise in temperature. The time needed to achieve a satisfactory treatment is also reduced, leading to significant saving of energy consumption to make this method cost-effective and also environmentally friendly for the industry to pursuit sustainable development. 相似文献
158.
159.
Lee A. McBride III 《Journal of Agricultural and Environmental Ethics》2012,25(4):535-541
In The Agrarian Vision, Thompson argues that a better appreciation of agrarian ideals could lead to a more virtuous, more sustainable way of life. While I agree with Thompson in many respects, there are some aspects of the book that I question and others that I would like to hear Thompson explicate in greater detail. In this paper, I question Thompson’s claim that agrarian farmers and farming communities serve as ideal models of virtuous habits and good character. I challenge Thompson’s use of virtue theory, particularly the notion that farming virtues can be acquired without participating in farming practices. In the end, I make the point that Thompson seems to vacillate between being realistic and being idealistic, which may seriously complicate our notions of responsibility and obligation in practice. 相似文献
160.
Lee CS Lim YW Kim HH Yang JY Shin DC 《Environmental science and pollution research international》2012,19(5):1629-1639