Acid fogs

Aldehydes are important because they are temporary reservoirs of free radicals (see eqs. 11 and 12). HCHO is a known carcinogen. Nitric acid is formed by OH attack on NO2 and by a dark-phase series of reactions initiated by O3 + NO2. Nitric acid is important because it is the second most abundant acid in precipitation. In addition, in southern California it is the major cause of acid fog. 

Based on your hypotheses in question 4, what can you infer about the damage done to plants by acid fog as compared with acid rain ... 

The foam-scrubbing technique has been studied for a variety of gases, including ammonia, sulfur dioxide, hydrogen sulfide, formaldehyde, and nitrogen oxides. Liquid and solid streams that have been experimented with include sulfuric acid fog and mist, dust, fly ash, and methylene blue. 

Flux measurements to collector surfaces demonstrated that removal rates can be very rapid. In Table I, characteristic times have been calculated for deposition during dense fog. These values were determined from the total solute fluxes, mixing heights, and average pollutant concentrations measured during the individual events. The removal times were calculated to be 6 to 12 h for these periods with the exception of N(V) in non-acidic fogs. Between the occurrences of fog, aerosol deposition was substantially reduced ... 

Acid deposition, e.g., acid fog, acid rain, acid snow. 

Evidence was found for the major processes responsible for the acidification of fogwater (i) the scavenging of acidic precursor aerosol, (ii) the scavenging of gaseous nitric acid, and (iii) oxidation of reduced sulfur components to sulfate. Conversion of S02(g) to sulfate in fogwater does not appear to proceed faster than 10% hour" and therefore cannot account for the high acidities observed at the beginning of fog events however, sulfate production in the precursor air parcel can lead to sulfuric acid fog condensation nuclei. 

Acid deposition, sss Acid rsun Acid fog, lQd7-10d8 Acid nenti siiizuig csipacity, 10 5 Acid I Eiin ... 

Atmospheric corrosion of metals is differentiated from the other forms of corrosion due to exposure of metals to different atmospheres rather than immersion in electrolytes. The spontaneous atmospheric corrosion of materials is controlled by the temperature, the relative humidity, the time of wetness, the pH of the electrolyte, and the presence of contaminants such as chlorides, NH3, SO2, NO2, and acidic fogs. In most cases, the rate equations have hmited validity due to different local atmospheric conditions. Metals spontaneously form a solid metal oxide film when exposed to dry atmospheres. The barrier oxide film reaches a maximum thickness of 2-5 nm [1-6]. The corrosion rate of metals exposed to a wet atmosphere is similar to that observed during immenion in aerated water in the presence of dissolved oxygen. Atmospheric corrosion rates decrease in dry atmospheres with corrosion mechanisms that are different from those in wet atmospheres. 

C. Arroyave, F.A. Lopez, M. MorciUo, The early atmospheric corrosion stages of carhon steel in acidic fogs, Corros. Sci. 37 (1995) 1751—1761. 

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