Understanding the Trend of NO<sub>2</sub>, SO<sub>2</sub> and CO over East Africa from 2005 to 2020
The atmospheric chemistry constituents of nitrogen dioxide (NO<sub>2</sub>), sulphur dioxide (SO<sub>2</sub>) and carbon monoxide (CO) are associated with air pollution and climate change. In sub-Saharan Africa, a lack of sufficient ground-based and aircraft observations has,...
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MDPI AG
2021-10-01
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| Series: | Atmosphere |
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| Online Access: | https://www.mdpi.com/2073-4433/12/10/1283 |
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| author | Ronald Opio Isaac Mugume Joyce Nakatumba-Nabende |
| author_facet | Ronald Opio Isaac Mugume Joyce Nakatumba-Nabende |
| author_sort | Ronald Opio |
| collection | DOAJ |
| description | The atmospheric chemistry constituents of nitrogen dioxide (NO<sub>2</sub>), sulphur dioxide (SO<sub>2</sub>) and carbon monoxide (CO) are associated with air pollution and climate change. In sub-Saharan Africa, a lack of sufficient ground-based and aircraft observations has, for a long time, limited the study of these species. This study thus utilized satellite observations as an alternative source of data to study the abundance of these species over the East African region. The instruments used included the Ozone Monitoring Instrument (OMI), the Atmospheric InfraRed Sounder (AIRS), and the TROPOspheric Monitoring Instrument (TROPOMI). An investigation of trends in the data series from 2005 to 2020 was carried out using the sequential Mann-Kendall test while the Pearson correlation coefficient was used to compare the data records of the instruments. The analysis revealed no trend in NO<sub>2</sub> (<i>p</i> > 0.05), a decreasing trend in SO<sub>2</sub> (<i>p</i> < 0.05), a decreasing trend (<i>p</i> < 0.05) in CO closer to the surface (850 hPa to 500 hPa) and an increasing trend (<i>p</i> < 0.05) in CO higher up in the atmosphere (400 hPa to 1 hPa). There is likely a vertical ascent of CO. The correlation between the instrument records was 0.54 and 0.77 for NO<sub>2</sub> and CO, respectively. Furthermore, seasonal fires in the savanna woodlands were identified as the major source of NO<sub>2</sub> and CO over the region, while cities such as Kampala, Nairobi, and Bujumbura and towns such as Dar es Salaam and Mombasa were identified as important NO<sub>2</sub> hotspots. Similarly, the active volcano at Mt. Nyiragongo near Goma was identified as the most important SO<sub>2</sub> hotspot. |
| first_indexed | 2024-03-10T06:44:17Z |
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| issn | 2073-4433 |
| language | English |
| last_indexed | 2024-03-10T06:44:17Z |
| publishDate | 2021-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Atmosphere |
| spelling | doaj.art-58425f63339e4fc08315dd9ff78df7442023-11-22T17:25:08ZengMDPI AGAtmosphere2073-44332021-10-011210128310.3390/atmos12101283Understanding the Trend of NO<sub>2</sub>, SO<sub>2</sub> and CO over East Africa from 2005 to 2020Ronald Opio0Isaac Mugume1Joyce Nakatumba-Nabende2Department of Geography, Geo-informatics and Climatic Sciences, Makerere University, 7062 Kampala, UgandaDepartment of Geography, Geo-informatics and Climatic Sciences, Makerere University, 7062 Kampala, UgandaDepartment of Computer Science, Makerere University, 7062 Kampala, UgandaThe atmospheric chemistry constituents of nitrogen dioxide (NO<sub>2</sub>), sulphur dioxide (SO<sub>2</sub>) and carbon monoxide (CO) are associated with air pollution and climate change. In sub-Saharan Africa, a lack of sufficient ground-based and aircraft observations has, for a long time, limited the study of these species. This study thus utilized satellite observations as an alternative source of data to study the abundance of these species over the East African region. The instruments used included the Ozone Monitoring Instrument (OMI), the Atmospheric InfraRed Sounder (AIRS), and the TROPOspheric Monitoring Instrument (TROPOMI). An investigation of trends in the data series from 2005 to 2020 was carried out using the sequential Mann-Kendall test while the Pearson correlation coefficient was used to compare the data records of the instruments. The analysis revealed no trend in NO<sub>2</sub> (<i>p</i> > 0.05), a decreasing trend in SO<sub>2</sub> (<i>p</i> < 0.05), a decreasing trend (<i>p</i> < 0.05) in CO closer to the surface (850 hPa to 500 hPa) and an increasing trend (<i>p</i> < 0.05) in CO higher up in the atmosphere (400 hPa to 1 hPa). There is likely a vertical ascent of CO. The correlation between the instrument records was 0.54 and 0.77 for NO<sub>2</sub> and CO, respectively. Furthermore, seasonal fires in the savanna woodlands were identified as the major source of NO<sub>2</sub> and CO over the region, while cities such as Kampala, Nairobi, and Bujumbura and towns such as Dar es Salaam and Mombasa were identified as important NO<sub>2</sub> hotspots. Similarly, the active volcano at Mt. Nyiragongo near Goma was identified as the most important SO<sub>2</sub> hotspot.https://www.mdpi.com/2073-4433/12/10/1283nitrogen dioxidesulphur dioxidecarbon monoxideOMITROPOMI |
| spellingShingle | Ronald Opio Isaac Mugume Joyce Nakatumba-Nabende Understanding the Trend of NO<sub>2</sub>, SO<sub>2</sub> and CO over East Africa from 2005 to 2020 Atmosphere nitrogen dioxide sulphur dioxide carbon monoxide OMI TROPOMI |
| title | Understanding the Trend of NO<sub>2</sub>, SO<sub>2</sub> and CO over East Africa from 2005 to 2020 |
| title_full | Understanding the Trend of NO<sub>2</sub>, SO<sub>2</sub> and CO over East Africa from 2005 to 2020 |
| title_fullStr | Understanding the Trend of NO<sub>2</sub>, SO<sub>2</sub> and CO over East Africa from 2005 to 2020 |
| title_full_unstemmed | Understanding the Trend of NO<sub>2</sub>, SO<sub>2</sub> and CO over East Africa from 2005 to 2020 |
| title_short | Understanding the Trend of NO<sub>2</sub>, SO<sub>2</sub> and CO over East Africa from 2005 to 2020 |
| title_sort | understanding the trend of no sub 2 sub so sub 2 sub and co over east africa from 2005 to 2020 |
| topic | nitrogen dioxide sulphur dioxide carbon monoxide OMI TROPOMI |
| url | https://www.mdpi.com/2073-4433/12/10/1283 |
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