Document 445LEygqxL2y4eENbMnyaZ35N

mi filiation The total weight of brake linings in use is 1001 000,00.P.-X ,,,i _ 200.000 Tons. 2000 The quantity worn off these linings per year follows from the assumptions made in c. 1 50 200.000 _ as 200.000 x q3- x V10n0n =- ------6------ Tons/yr. This wear dust contains 1% asbestos, hence emission is 200.000 6 ~ 100 2000 Tons/yr. 6 Allowing for the fact .that 20X is not emitted, the total emission is .thus 2000 80 6 x 100 1600 . = 270 Tons/yr. Effect on the Atmosphere There are no facts relating directly to asbestos on which one may judge the effect of these emissions on urban air. However, there has been a considerable amount of study done on the diffusion of other materials from automobiles, particularly lead and carbon monoxide. At a recent ACS Symposium in Minneapolis^ evidence was presented which placed the level for lead emission at 0.01 pg/m3 in Thule, Alaska and 2.5 pg/m3 in. New York City. Next to busy highways a level in excess of 50 pg/m may well be possible. In the light of this data the value of 2 I'.g/m^ for average urban air conditions, suggested by .Cm , seems -eminently treasonable. . f.nngi^ar< ng that 1.25 x 10 tons of lead are emitted in total from automobiles then the following factor is'used. Avg. Cone, asbestos in city air from automobiles - Ouantity of 2 itg/m3 city air asbestos emitted x 1.25 x 105 tons Pb from cars Applying this figure to the present case and assuming that 200 tons are emitted in city areas, then we get that: MT RESEARCH INSTITUTE 68