Air-borne Pollutants

Dioxins, furans and heavy metals can be released as air borne pollutants in the ash, which needs to be landfilled with special care (i.e. mixed with cement) due to a danger of ground water contamination. 

Low-molecular, non-polar substances are relatively volatile. They therefore occur as air-borne pollutants, can be dispersed dilfusively and with movements of the air and may undergo oxidative, photolytic degradation. 

FIGURE 3.9. SEM micrographs showing the distribution of Degussa P25 particles for the 4.8-5.6-wl%) loading (Reprinted from Appl. Catal. B Environ., 1011, H. Ibrahim andH.I. de Lasa, Photocatalytic conversion of air borne pollutants Effect of catalyst type and catalyst loading on a novel Photo-CREC-Air unit, 1-13, Copyri t 2002, with pennission from Elsevier). 

Ibrahim H. and de Lasa H., 2002, Photo-catalytic conversion of air borne pollutants. Effect of catalyst type and ctalyst loading a a novel Phot-CREC-air unit. Applied Catalysis B Environmental 1011 1-13... 

The debate still remains regarding which configurations are the most adequate for the photocatalytic reactors to photoconvert air borne pollutants (Ollis and Al-Ekabi, 1993). Several options have been described (Chapter 11) fluidized bed (Brucato et al., 1992 Dibble and Raupp, 1992 Yue et al., 1983 ), annular packed bed (Raupp et al., 1997), coated honeycomb (Sauer and Ollis, 1994 Suzuki et al., 1991 Suzuki, 1993), fixed powder layer (Formenti et al., 1971 Peral and Ollis, 1992) and fiber optic reactor (Peill and Hoffmann, 1995). The Photo-CREC-Air reactor (Ibrahim and de Lasa, 2002) optimizes TiOa-mesh iiradiation and air contacting the supported TiOa. As reported in the upcoming section, this configuration yields model pollutant conversions with high apparent quantum efficiencies. 

THE EFFECT OF PROLONGED EXPOSURE TO AIR-BORNE POLLUTANTS ON THE PHOTOSYNTHESIS OF DOUGLAS FIR (Pseudotsuga menziesii) STUDIED WITH in vivo CHLOROPHYLL FLUORESCENCE... 

The Effect of Prolonged Exposure to Air-Borne Pollutants on the Photosynthesis of Douglas Fir (Pseudotsuga menziesii) Studied with in vivo Chlorophyll Fluorescence 611... 

Low-molecular mass aldehydes and phenols known to be hazardous and/or odorous substances may be emitted from incinerators, chemical plants, baking finish plants, and automobiles. They may be produced as secondary products of organic air-borne pollutants... 

The concentration of each chemical in the film appears in column 7 Equation 19.5 was used to obtain these estimates. Such large film loading ratios result because the air is assumed to be saturated with the chemical vapor the air concentrations appear in column 3. Nevertheless, the results indicate that impervious surface films do have the ability to be an effective medium for concentrating air-borne pollutants to high levels in urban setting where human exposure is sure to occur. 

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