Experimental Studies of Microwave Reflection and Attenuation by Plasmas Produced by Burning Chemicals in Atmosphere

A series of chemicals are designed and prepared. With the method of thermodynamics, the average electron densities of the plasmas generated by burning chemicals are calculated. The reflection and attenuation of the microwaves, in a frequency band of 2 GHz to 15 GHz, by the plasma are measured. The results of measurements indicate that the plasma can absorb the energies of the microwaves in a broad band and reflect them faintly. Moreover, theoretical discussion reveals that the electron-neutral collision is the major factor that results in the absorption in the wide band. By using Appleton equations, average collision frequencies and electron densities are calculated from the attenuations of microwaves.

Inventory of primary emissions of selected persistent organic pollutants to the atmosphere in the area of Great Mendoza

The setting up of a country or region-based inventory is considered a crucial step toward the elimination of worldwide persistent organic pollutants(POPs)contamination.Moreover,the need of comparable emission inventories at city or region level is widely recognized to develop evidence-based policies accounting for the relation between emissions and institutional,socio-economic and demographic characteristics at small scale level.Due to the low spatial and temporal resolution of the available measurements,highly variable air concentrations of several POPs have been observed in Latin American and Caribbean countries.This paper presents a high resolution spatially disaggregated atmospheric emission inventory for selected POPs in order to assess the environmental fate of some of these compounds in a finer resolution.As study case we estimated releases to air of POPs in a typical mid-size urban conglomeration in Argentina.Inventoried compounds were total polychlorinated biphenyls(PCBs),total polybrominated diphenyl ethers(PBDEs),total dichlorodiphenyltrichloroethane(DDT)on a sum basis,hexachlorobenzene(HCB)and dioxins and furans(PCDD/Fs),for which emissions were estimated in 0.92 kg/year,1.65 kg/year,4.2E-02 kg/year(total sum of congeners),0.86 kg/year and 4.4E-02 kg/year respectively,values that are in accordance with the geographic and economic context.Although emitting sources are quite varied,there are very clear trends,particularly in relation to open burning of municipal solid waste and agrochemical use as major contributors.Overall,the inventory provides valuable data for the analysis of the heterogeneity of POP emissions and the necessary inputs for air quality modeling.