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91.
John R. Reisel Tracy A. Kellner Kenneth F. Neusen 《Journal of the Air & Waste Management Association (1995)》2013,63(4):522-528
ABSTRACT Partially speciated hydrocarbon (HC) emissions data from several small utility engines, as measured by a Fourier Transform Infrared analyzer, are presented. The engines considered have nominal horsepower ratings between 3.7 and 9.3 kW. Both side-valve and overhead-valve engines are studied, and four different fuels are used in the engines. The results indicate that the small HCs present in the exhaust tend to be in the form of either methane or unsatur-ated HCs. Other small alkanes, such as ethane and propane, are present in only relatively small concentrations. In terms of ozone formation potential, the HCs in the form of methane will lead to little ozone, but the distribution of the C2 and C3 species is not ideal from an ozone reduction standpoint. It is also found that the presence of oxygen in the fuels appears to lead to somewhat more complete combustion, although the effects are not large. Finally, the overhead-valve engines appear to have lower HC emissions than side-valve engines, which is primarily due to higher operating A/F ratios and the engine geometry. 相似文献
92.
Alvin C.K. Lai Tracy L. Thatcher William W. Nazaroff 《Journal of the Air & Waste Management Association (1995)》2013,63(9):1688-1699
ABSTRACT To facilitate routine health risk assessments, we develop the concept of an inhalation transfer factor (ITF). The ITF is defined as the pollutant mass inhaled by an exposed individual per unit pollutant mass emitted from an air pollution source. A cumulative population inhalation transfer factor (PITF) is also defined to describe the total fraction of an emitted pollutant inhaled by all members of the exposed population. In this paper, ITFs and PITFs are calculated for outdoor releases from area, point, and line sources, indoor releases in single zone and multizone indoor environments, and releases within motor vehicles. Typical PITFs for an urban area from emissions outdoors are ~10-6–10-3. PITFs associated with emissions in buildings or in moving vehicles are typically much higher, ~10-3–10-1. 相似文献
93.
Modeling the Effects of Tile Drain Placement on the Hydrologic Function of Farmed Prairie Wetlands 下载免费PDF全文
Brett Werner John Tracy W. Carter Johnson Richard A. Voldseth Glenn R. Guntenspergen Bruce Millett 《Journal of the American Water Resources Association》2016,52(6):1482-1492
The early 2000s saw large increases in agricultural tile drainage in the eastern Dakotas of North America. Agricultural practices that drain wetlands directly are sometimes limited by wetland protection programs. Little is known about the impacts of tile drainage beyond the delineated boundaries of wetlands in upland catchments that may be in agricultural production. A series of experiments were conducted using the well‐published model WETLANDSCAPE that revealed the potential for wetlands to have significantly shortened surface water inundation periods and lower mean depths when tile is placed in certain locations beyond the wetland boundary. Under the soil conditions found in agricultural areas of South Dakota in North America, wetland hydroperiod was found to be more sensitive to the depth that drain tile is installed relative to the bottom of the wetland basin than to distance‐based setbacks. Because tile drainage can change the hydrologic conditions of wetlands, even when deployed in upland catchments, tile drainage plans should be evaluated more closely for the potential impacts they might have on the ecological services that these wetlands currently provide. Future research should investigate further how drainage impacts are affected by climate variability and change. 相似文献
94.
Problem
States with laws regarding ATV use and safety have lower mortality and injury rates than states with few or no restrictions. Our objective was to assess the attitudes of registered Ohio voters concerning potential legislation regarding ATV use and safety to determine the feasibility of its enactment.Method
A statewide telephone survey of 838 registered Ohio voters was conducted and results were weighted by region to accurately represent all Ohio voters.Results
Registered voters were in favor of restricting the use of ATVs by children < 16 years (81%), prohibiting passengers on ATVs (81%), requiring helmets (78%), and requiring all ATV owners and users to take a safety class (77%). ATV riders indicated that a mandatory helmet law would increase helmet use.Impact on Industry
Assessing public opinion regarding public health and safety laws is a critical first step when considering legislation to improve ATV safety. 相似文献95.
96.
Johnson LL Ylitalo GM Arkoosh MR Kagley AN Stafford C Bolton JL Buzitis J Anulacion BF Collier TK 《Environmental monitoring and assessment》2007,124(1-3):167-194
To better understand the dynamics of contaminant uptake in outmigrant juvenile salmon in the Pacific Northwest, concentrations
of polychlorinated biphenyls (PCBs), DDTs, polycylic aromatic hydrocarbons (PAHs) and organochlorine pesticides were measured
in tissues and prey of juvenile chinook and coho salmon from several estuaries and hatcheries in the US Pacific Northwest.
PCBs, DDTs, and PAHs were found in tissues (whole bodies or bile) and stomach contents of chinook and coho salmon sampled
from all estuaries, as well as in chinook salmon from hatcheries. Organochlorine pesticides were detected less frequently.
Of the two species sampled, chinook salmon had the highest whole body contaminant concentrations, typically 2--5 times higher
than coho salmon from the same sites. In comparison to estuarine chinook salmon, body burdens of PCBs and DDTs in hatchery
chinook were relatively high, in part because of the high lipid content of the hatchery fish. Concentrations of PCBs were
highest in chinook salmon from the Duwamish Estuary, the Columbia River and Yaquina Bay, exceeding the NOAA Fisheries' estimated
threshold for adverse health effects of 2400 ng/g lipid. Concentrations of DDTs were especially high in juvenile chinook salmon
from the Columbia River and Nisqually Estuary; concentrations of PAH metabolites in bile were highest in chinook salmon from
the Duwamish Estuary and Grays Harbor. Juvenile chinook salmon are likely absorbing some contaminants during estuarine residence
through their prey, as PCBs, PAHs, and DDTs were consistently present in stomach contents, at concentrations significantly
correlated with contaminant body burdens in fish from the same sites. 相似文献