Document jm6NR8abao3ZJMjQj2Odmq529

peculation The total weight of brake linings in use is 100, 000, QOQ, X _4 __ 200,000 Tons. 2000 The quantity worn off these linings per year follows from the' assumptions made in c. as 200.000 x | x = 200^000 Tons/yr. This wear dust contains 1% asbestos, hence emission is -2--0---06.000 * 100 " 2000 6 Tons/yr. Allowing for the fact .that 20* is not emitted, the total 'emission is .thus 2000 80 100 s 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/m in Thule, Alaska and 2.5 |ig/m in New York City. Next to busy highways a level in excess of 50 ng/m3 may- well be possible. In the light of this data the value of 2 p.g/m3 for average urban air conditions, suggested -by.CM , seems -eminently .reasonable. ng that 1.25 x 105 tons of lead are emitted in total from automobiles then the following factor is'used. Avg. Cone, asbestos in city air from automobiles - Quantity of 2 uo/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: HT RESEARCH INSTITUTE 68