AIRBORNE MEASUREMENTS OF SAVANNA FIRE EMISSIONS AND THE REGIONAL DISTRIBUTION OF PYROGENIC POLLUTANTS OVER WESTERN AFRICA

We measured CO2, CO, CH4, H-2, and NO2 in air masses polluted by savan na fires over Cote d'Ivoire, western Africa. Elevated concentrations o f these trace gases were found in fire plumes and also in extensive ha ze layers. Trace gas mixing ratios ranged as high as 605 ppmv for Co-2 , 14.8 ppmv for CO, 2.7 ppmv for Ch(4), 4.2 ppmv for H-2, and 25 ppbv for No-w. We compare our emission ratios to those obtained in previous field and laboratory studies. The emission ratios, expressed as an av erage and as a range or as an average only, were: dCo/dCo(2) 5.3 x 10( -2) (3-18x10(-2)); dCh(4)/dCo 5.3x10(-2); dH(2)/dCo 2.4x10(-1) and dNO (2)/dCO(2) 1.8x10(-4) (1.5-2.2x10(-4)). The values found match those f ound during similar measurements, though our results point to rather v igorous burning in the savanna western Africa.