Understanding the Trend of NO2, SO2 and CO over East Africa from 2005 to 2020

Abstract

The atmospheric chemistry constituents of nitrogen dioxide (NO2), sulphur dioxide (SO2) 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 NO2 (p > 0.05), a decreasing trend in SO2 (p < 0.05), a decreasing trend (p < 0.05) in CO closer to the surface (850 hPa to 500 hPa) and an increasing trend (p < 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 NO2 and CO, respectively. Furthermore, seasonal fires in the savanna woodlands were identified as the major source of NO2 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 NO2 hotspots. Similarly, the active volcano at Mt. Nyiragongo near Goma was identified as the most important SO2 hotspot.

Coal Dust Characteristics and Its Association with Air Quality in Palembang Coal Unloading Station

“…These compounds also have short atmospheric lifetimes, realistically, days to months. SO2 is in the atmosphere for two days, while for NO2, the time is longer at 1 to 10 days, and CO has a maximum residence time of thirty to ninety days [16]. Although at the three sampling points, it was found that CO exposure was still below the threshold (<10000 µg/Nm 3 ) because of its strong bond with the hemoglobin molecule, carboxyhemoglobin was formed.…”

Trends of Ground-Level Ozone in New York City Area during 2007–2017

“…It has been previously used to examine the effect of wildfires on O 3 , compliance with NAAQS, and to smooth the effects of local meteorology and short-term changes in local emissions [24,25]. The annual trend was computed using the de-seasonalized monthly 8-h max O 3 concentrations by applying the non-parametric sequential Mann-Kendall test at a confidence level of 95% [26,27].…”

Estimation of Biogas Generated in Two Landfills in South-Central Ecuador

“…Therefore, the model may not be valid since the concentrations are out of the given range. However, for future biogas estimates, we will compare with other models to develop our own model considering the climatic conditions, the characteristics of the waste and concentrations of the gases typical of the sector where the landfill is located [16,32,53,54]. Hence, in the results of works performed in 2011, the potential for electrical production of biogas, generated in the Pichacay landfill, calculated through theoretical models conducted by the (EPA), assuming a concentration of 50% CH 4 and 50% CO 2 starting in 2009, it has been estimated that it will reach a higher point of biogas generation in 2019, with 1152 m 3 /h with a maximum capacity of 1.90 MW.…”