Isopleth diagram

Fig. 3. Typical isopleth diagram showing the three chemical regimes HC = hydrocarbons (22).

Fig. 8. isopleth diagram showing the response of concentrations to changes in initial NO and nonmethane hydrocarbon concentrations expressed as parts per million of carbon atoms (ppm C). The response to NO reductions is dependent on the particular initial concentrations. At point A, the graph indicates that decreasing NO would increase formation, and at point C, a decrease in the NO concentration results in a much larger decrease in... 

Fig. 15-S. Concentration isopleth diagram of ambient particulate matter calculated by a computer model. Source Zimmer, C. E., "Air Pollution," 3rd ed., Vol. Ill (A. C. Stem, ed.). Academic Press, New York, 1976.

A simple explanation of why the trends are more pronounced for the stations with the highest initial episodic peak levels would be that these stations show the highest ozone responses to VOC and NOx emission reductions. Whilst this is certainly feasible, it is not a common finding in photochemical ozone modelling. Ozone responses to changing VOC and NOx emissions in photochemical models are usually illustrated as isopleth plots. Ozone isopleths are commonly seen as a set of parallel curves, see Fig. 5 for one such isopleths diagram constructed from a European photochemical trajectory model [23]. It is not at all common for the isopleths to become closer together as would be implied by the ozone responses to... 

Fig. 5 Ozone isopleth diagram for 18th July 2006 at the EMEP GB0036R Harwell station plotted from the results of VOC and NOx emission sensitivity experiments performed with a Photochemical Trajectory Model [23]...

With the involvement of volatile organic compounds (VOCs) in the oxidation chemistry. Figure 11 represents a slice through an n-dimen-sional surface where there should be a third axis to represent the concentration of VOCs. The peak initial concentrations of ozone generated from various initial concentrations of NO , and VOCs are usually represented as an O3 isopleth diagram , an example of which is shown... 

The dependence of 03 production on the initial amounts of VOC and NOx is frequently represented by means of an ozone isopleth diagram. Such a diagram is a contour plot of maximum 03 concentrations achieved as a function of initial VOC and NOx concentrations. The diagram is generated by contour plotting the predicted ozone maxima obtained from a large number of simulations with an atmospheric VOC/NOx chemical mechanism with varying initial concentrations of VOC and NOx while all other variables are constant. 

For solutions of polydisperse polymers, such a procedure cannot be used because the critical concentration must be known in advance to measure its corresponding coexistence curve. Additionally, the critical point is not the maximum in this case but a point at the right-hand side shoulder of the cloud-point curve. T wo different methods were developed to solve this problem, the phase-volume-ratio method, e.g., Koningsveld, where one uses the fact that this ratio is exactly equal to one only at the critical point, and the coexistence concentration plot, e.g. Wolf, where an isoplethal diagram of values of tp 2 and tp 2 vs. (p 2 gives the critical point as the intersection point of cloud-point and shadow curves. 

Figure 17.4.1. Ozone isopleth diagram showing the dependencies of ozone on varying levels of initial VOCs and NO,. Concentrations are given in ppb. [Adapted from M.S. Bergin et at, Enc. ofEnv. Analysis and Remediation, 29, 3029,(1998)]...

The dependence of O3 produetion on the initial amounts of VOC and NO is frequently represented by means of an ozone isopleth diagram. An example of such a dia-... 

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