ORIGINS OF PO-210 IN THE ATMOSPHERE AT LAMTO, IVORY-COAST - BIOMASS BURNING AND SAHARAN DUSTS

Measurements of Po-210 and Pb-210 activities in surface air at Lamto ( Ivory Coast) during 18 months are presented and discussed in relation to the regional sources of Po-210. High seasonal variation is observed with maximum in winter, reaching an activity of Po-210 as high as 1 B q per 10(3) m(3). Our estimation shows that the high Po-210 activity i n winter is not closely related to the local biomass burning emissions but rather due to the particular atmospheric circulation patterns and geographical location of this region: in winter, surface winds having continental origin bring soil dusts, enriched in Po-210 and Pb-210, f rom Sahara desert. However, biomass burning and the growth from Rn-222 within the atmosphere appear to be the major sources of unsupported P o-210 in the other seasons. Copyright (C) 1996 Elsevier Science Ltd