Comprehensive two-dimensional liquid chromatography (LC×LC) coupled with a diode array detector (DAD) has been used for the first time to investigate chemical heterogeneity and map the hydrophobicity versus molecular weight distribution of the most hydrophobic acid fractions in water-soluble organic matter (WSOM) from fine atmospheric aerosols collected over different seasons at a urban location. The use of LC×LC–DAD, combining the use of two independent separation mechanisms (per aqueous liquid chromatography [PALC] versus size-exclusion chromatography [SEC]), has shown a great potential for unraveling and resolving the heterogeneity of WSOM, further providing a deeper insight into how size-distinguished aerosol WSOM fractions differ in hydrophobicity during different seasonal events. The combination of PALC×SEC–DAD data with an already proposed data treatment procedure revealed that the WSOM samples collected during warm seasons are enriched in aliphatic structures, while those collected during colder seasons exhibit a higher degree of structures with conjugation of π-bonds (e.g., aromatics) alongside aliphatic structures

Particle-bound mercury (PBM) concentrations in particulate matter (PM), PM10 and PM2.5, were investigated during dust and non-dust events at urban and rural sites in Cabo Verde, Africa. During dust events, PBM averaged 35.2 pg m^-3 (PM10) and 16.1 pg m^-3 (PM2.5) compared to 15.9 pg m^-3 (PM10) and 1.21 pg m^-3 (PM2.5) during non-dust events representing 2.21- and 13.3-fold increases, respectively. The PM10/PM2.5 PBM ratio was 2.19 during dust and 13.1 in non-dust events, highlighting the role of coarse particles during non-dust periods. Air mass trajectories and elemental markers associate PBM sources to mineral dust, mining, oceanic emissions, and biomass burning. Health risk assessment indicates higher inhalation risk compared to dermal or ingestion pathways. By comparing the PBM concentrations during dust and non-dust events, for PM10, dust and long-range transport contributed about 63 % to the average PBM concentration in urban and 52 % in the rural areas and enriched PBM levels in PM2.5 by about 84 % (urban) and 94 % (rural). This result indicates that fine-mode PM is significantly enriched with PBM during dust events, elevating exposure risks and associated health impacts.

Sub‐Saharan Africa has been the last continent to experience a significant number of cases in the novel Coronavirus (COVID‐19). Studies suggest that air pollution is related to COVID‐19 mortality; poor air quality has been linked to cardiovascular, cerebrovascular, and respiratory diseases, which are considered co‐morbidities linked to COVID‐19 deaths. We examine potential connections between country‐wide COVID‐19 cases and environmental conditions in Senegal, Cabo Verde, Nigeria, Cote D'Ivorie, and Angola. We analyze PM_2.5 concentrations, temperatures from cost‐effective in situ measurements, aerosol optical depth (AOD), and fire count and NO₂ column values from space‐borne platforms from 1 January 2020 through 31 March 2021. Our results show that the first COVID‐19 wave in West Africa began during the wet season of 2020, followed by a second during the dry season of 2020. In Angola, the first wave starts during the biomass burning season but does not peak until November of 2020. Overall PM_2.5 concentrations are the highest in Ibadan, Nigeria, and coincided with the second wave of COVID‐19 in late 2021 and early 2022. The COVID‐19 waves in Cabo Verde are not in phase with those in Senegal, Nigeria, and Cote, lagging by several months in general. Overall, the highest correlations occurred between weekly new COVID‐19 cases meteorological and air quality variables occurred in the dry season.

SubSahara Africa has been the last continent to experience a significant number of cases in the novel Coronavirus (COVID-19). Several studies have suggested that air pollution is related to COVID-19 mortality; poor air quality has been linked to cardiovascular, cerebrovascular, and respiratory disease, which are considered co-morbidities linked to COVID-19 death. We examine potential connections between country-wide COVID-19 mortality and environmental conditions in Senegal, Cabo Verde, Nigeria, Cote D’Ivoire, and Angola. We analyze PM2.5 concentrations from cost-effective in situ measurements, aerosol optical depth (AOD), and fire count from space-borne platforms during the dry season when dust and biomass burning aerosols are present in Southern Africa. In addition, we examine the COVID-19 mortality during the wet season using space-borne rain measurements to determine potential linkages which might occur as a result of time spent indoors and concurrent cases of flu, waterborne and vector-borne diseases in West Africa. Results are presented from March through December of 2020.