CO2, CH4, and CO Emission Sources and Their Characteristics in the Lamto Ecological Reserve (Côte d’Ivoire)

Abstract

CO2, CH4, and CO are the most critical atmospheric gases in terms of their impact on the radiative system, air quality, and health. This work provides information on the direction of source areas and potential sources of emissions and shows many aspects of these gases by a statistical analysis using bivariate polar diagrams and local weather conditions (e.g., temperature, wind speed, and wind direction), recorded at the Lamto station (LTO, 6°31′ N and 5°2′ W) in Côte d’Ivoire over the 2014–2018 period. The results show that the main regions contributing to the high concentrations of CH4 (>1925 ppb) and CO2 (>420 ppm) in the great dry season (GDS), great wet season (GWS), short dry season (SDS), and short wet season (SWS) are the north and north-west sectors of Lamto. In these directions, CH4 and CO2 concentrations are associated with wind speeds less than 6 m.s−1, due to the influences of local sources as emissions resulting from the degradation of organic matter submerged during the impoundment of the Taabo dam, and/or human activities linked to the practice of intensive agriculture. In addition, the high concentrations of CO (>350 ppb) are observed in GDS in the north, north-west, north-east, and east sectors for wind speeds less than or equal to 9 m.s−1, due to the influences of both local and distant sources. The correlation coefficients between CH4 and CO and between CH4 and CO2 are positive and significant in all sectors. However, those calculated between CO2 and CO have showed both low and high values in all seasons.