Shifting Winds

EPA had begun its Chemical Assessment and Management Program (ChAMP) in 2007 to implement broader international commitments to ensure the safety of existing chemicals. Over the last several years, EPA expanded the horizon of ChAMP to potentially include voluntary challenge programs for wider categories of chemicals and chemicals present in the 

Nanoscale Materials Stewardship Program Interim Report, 3 (Jan., 2009) [hereinafter NMSP Interim Report] available through http //www.epa.gov/oppt/nano/. 

Nanoscale Materials Stewardship Program available through http //www.epa.gov/ oppt/nano/. 

United States in lower quantities. While these programs had not yet reached any critical mass, the underlying assumption was that much of this work might be done in a cooperative way with industry, mirroring the HPV and VCCEP initiatives. ChAMP has now been superseded by a new enhanced chemical management program currently being rolled out by the EPA.  

EPA has announced that while its priority is the passage of a more effective chemical management statute, it will work more actively with the tools available to it under TSCA ( 4, 5, 6, and 8) to require information needed to understand the risks posed by chemicals, to develop chemical action plans for high risk chemicals, and to regulate those risks. It is likely that this new emphasis on a more regulatory and less voluntary approach will be accompanied by a greater emphasis on enforcement. 

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The use of chemical land mines is now very limited and one of the reasons for this is the possibility of shifting winds blowing chem agents into positions of friendly troops (This section was reviewed by A.B.Schilling of PicArsn)... 

Baker T. C. and Haynes K. F. (1987) Maneuvers used by flying male oriental fruit moths to relocate a sex pheromone plume in an experimentally shifted wind-field. Physiol. Entomol. 12, 263-279. 

Lateral Spread.—When a gas i.s released in the open air, it immediately ex miub and diffuses into the atmosphere. This. cau.st>s the eloud spread laterally and vertically. Shifting wind and air currents also increase lateral spread as the cloud moves downwind. Coder average conditiims, the lateral spread is about 20 per cent of the distance tra eled, while for favorable. conditions it is about 15 per cent, and for unfavorable conditions it will amount to as much as 50 H r cent. 

Early next morning the infantry tried again, and one B Company platoon concealed the advance to the attack position with a 1,000-yard screen. The mortars maintained this screen for almost fourteen hours despite difficulties caused by shifting winds. Once the screen was established it was kept up by two WP rounds a minute, although for a short period around noon weather conditions made it necessary to raise this number to five. The mortar crews lifted the screen several... 

The initial direction of transport of pollutants from their source is determined by the wind direction at the source. Air pollutant concentrations from point sources are probably more sensitive to wind direction than any other parameter. If the wind is blowing directly toward a receptor (a location receiving transported pollutants), a shift in direction of as little as 5° (the approximate accuracy of a wind direction measurement) causes concentrations at the receptor to drop about 10% under unstable conditions, about 50% under neutral conditions, and about 90% under stable conditions. The direction of plume transport is very important in source impact assessment where there are sensitive receptors or two or more sources and in trying to assess the performance of a model through comparison of measured air quality with model estimates. 

There is normally considerable wind direcHon shear (change of direction) with height, especially near the ground. Although surface friction causes the wind to shift clockwise (veer) with height near the ground, the hori-... 

In a situation under stable conditions with a wind speed of 4 m s and tr, = 0.12 radians, the wind is bloviring directly toward a receptor 1 km from the source. How much must the wind shift, in degrees, to reduce the concentration to 10% of its previous value (At 2.15o- from the peak, the Gaussian distribution is 0.1 of the value at the peak.)... 

What cannot be obtained through local bifurcation analysis however, is that both sides of the one-dimensional unstable manifold of a saddle-type unstable bimodal standing wave connect with the 7C-shift of the standing wave vice versa. This explains the pulsating wave it winds around a homoclinic loop consisting of the bimodal unstable standing waves and their one-dimensional unstable manifolds that connect them with each other. It is remarkable that this connection is a persistent homoclinic loop i.e. it exists for an entire interval in parameter space (131. It is possible to show that such a loop exists, based on the... 

Another consideration when planning field fortification levels for the matrices is the lowest level for fortification. The low-level fortification samples should be set high enough above the limit of quantitation (LOQ) of the analyte so as to ensure that inadvertent field contamination does not add to and does not drive up the field recovery of the low-fortification samples. Setting the low field fortification level too low will lead to unacceptably high levels of the analyte in low field spike matrix samples if inadvertent aerial drift or pesticide transport occurs in and around where the field fortification samples are located. Such inadvertent aerial drift or transport is extremely hard to avoid since wind shifts and temperature inversions commonly occur during mixer-loader/re-entry exposure studies. 

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