Soils and plant fires naturally produce ammonia, but people contribute most to the atmosphere via agricultural operations such as fertilizer usage and animal grazing. Ammonia, when present in high concentrations in an environment, may cause soils to become acidic and impede plant development. As an air contaminant, it may cause heart and lung disease.
The period of study
According to new NASA research data, ammonia concentrations in the air grew significantly between 2008-2018 across West Africa and the Lake Victoria area. In addition to biomass burning, agricultural growth and intensification were associated with the surge.
The researchers utilized satellite data from 2008 to 2018 to track variations in ammonia vertical column densities, a direct measurement of gas distribution and concentration throughout the continent and their potential sources.
Africa’s ammonia emissions are less investigated than those in the US, EU, and China. NASA claims this is the first study to establish long-term changes in atmospheric ammonia concentrations in Africa.
The peak period of emission
Most of the rise in ammonia vertical column densities in West Africa occurred in February and March, when widespread farmland fires occurred. The research indicated that the majority of the rise happened before planting season.
Small agricultural fires may contribute significantly to atmospheric NH3. The research discovered a link between increasing biomass burning and elevated CO levels.
During February and March, ammonia levels rose 6% yearly across Nigeria. During the same period, the amount of carbon monoxide in the atmosphere increased, according to satellite data from 2008-2018.
Agricultural growth and fertilizer usage increased ammonia concentrations in the Lake Victoria basin. The results showed that increased fertilizer use on new and existing agricultural land polluted the area with ammonia.
The region with a decline in Ammonia emission
The 30,000 square-kilometre Sudd wetland fed by the Nile River demonstrated a 1.5 per cent yearly decline in ammonia during the study period.
During dry years, as more of the marsh dried up, ammonia concentrations climbed. Dry soil naturally emits ammonia. Less rain meant less ammonia.
Ammonia Hotspot in Africa
The research identified West Africa as an ammonia hotspot. Africa’s agricultural activities will increase and it is necessary to feed a rising population so that ammonia concentrations will rise.
The most significant mean annual amounts of atmospheric ammonia were discovered in North Equatorial Africa, notably West Africa, throughout the decade 2008–2018.
La Victoria Basin, South Sudanese wetlands, Nile Delta and river, were identified as regional hotspots.
Image credit : NASA
Sources of Ammonia
While ammonia is released from natural soils, agriculture is by far the primary source worldwide. Biomass burning is the second-largest source worldwide, with 60%- 70% coming from Africa. However, agricultural and biomass burning is the primary sources of ammonia in Africa.
Governments in several African nations are encouraging the use of fertilizer to enhance food production. In Africa, it is usual to burn both live and dead trees and plants.
The research concluded that higher agricultural inputs might be related to elevated ammonia concentrations in the Nile basin.
Requirement of policy changes
Adopting policies restricting ammonia emissions during the early phases of agricultural intensification in Africa may help prevent possible climate consequences. NASA also recommended improving atmospheric monitoring in Sub-Saharan Africa. It is critical to understand how ammonia emission sources change to ensure policies and technology that encourage sustainable agricultural growth.
Hickman, J. E., Andela, N., Dammers, E., Clarisse, L., Coheur, P., Damme, M. V., Di Vittorio, C. A., Ossohou, M., Galy-Lacaux, C., Tsigaridis, K., & Bauer, S. E. (2021, November 16). Changes In Biomass Burning, Wetland Extent, Or Agriculture Drive Atmospheric NH3 Trends In Select African Regions. ACP – changes in biomass burning, wetland extent, or agriculture drive atmospheric NH3 trends in select African regions. https://acp.copernicus.org/articles/21/16277/2021/.