Inequalities in urban air pollution in sub-Saharan Africa: an empirical modeling of ambient NO and NO2 concentrations in Accra, Ghana
Road traffic has become the leading source of air pollution in fast-growing sub-Saharan African cities. Yet, there is a dearth of robust city-wide data for understanding space-time variations and inequalities in combustion related emissions and exposures. We combined nitrogen dioxide (NO _2 ) and ni...
| Main Authors: | , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/ad2892 |
| _version_ | 1827340590061191168 |
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| author | Jiayuan Wang Abosede S Alli Sierra N Clark Majid Ezzati Michael Brauer Allison F Hughes James Nimo Josephine Bedford Moses Solomon Baah Ricky Nathvani Vishwanath D Samuel Agyei-Mensah Jill Baumgartner James E Bennett Raphael E Arku |
| author_facet | Jiayuan Wang Abosede S Alli Sierra N Clark Majid Ezzati Michael Brauer Allison F Hughes James Nimo Josephine Bedford Moses Solomon Baah Ricky Nathvani Vishwanath D Samuel Agyei-Mensah Jill Baumgartner James E Bennett Raphael E Arku |
| author_sort | Jiayuan Wang |
| collection | DOAJ |
| description | Road traffic has become the leading source of air pollution in fast-growing sub-Saharan African cities. Yet, there is a dearth of robust city-wide data for understanding space-time variations and inequalities in combustion related emissions and exposures. We combined nitrogen dioxide (NO _2 ) and nitric oxide (NO) measurement data from 134 locations in the Greater Accra Metropolitan Area (GAMA), with geographical, meteorological, and population factors in spatio-temporal mixed effects models to predict NO _2 and NO concentrations at fine spatial (50 m) and temporal (weekly) resolution over the entire GAMA. Model performance was evaluated with 10-fold cross-validation (CV), and predictions were summarized as annual and seasonal (dusty [Harmattan] and rainy [non-Harmattan]) mean concentrations. The predictions were used to examine population distributions of, and socioeconomic inequalities in, exposure at the census enumeration area (EA) level. The models explained 88% and 79% of the spatiotemporal variability in NO _2 and NO concentrations, respectively. The mean predicted annual, non-Harmattan and Harmattan NO _2 levels were 37 (range: 1–189), 28 (range: 1–170) and 50 (range: 1–195) µ g m ^−3 , respectively. Unlike NO _2 , NO concentrations were highest in the non-Harmattan season (41 [range: 31–521] µ g m ^−3 ). Road traffic was the dominant factor for both pollutants, but NO _2 had higher spatial heterogeneity than NO. For both pollutants, the levels were substantially higher in the city core, where the entire population (100%) was exposed to annual NO _2 levels exceeding the World Health Organization (WHO) guideline of 10 µ g m ^−3 . Significant disparities in NO _2 concentrations existed across socioeconomic gradients, with residents in the poorest communities exposed to levels about 15 µ g m ^−3 higher compared with the wealthiest ( p < 0.001). The results showed the important role of road traffic emissions in air pollution concentrations in the GAMA, which has major implications for the health of the city’s poorest residents. These data could support climate and health impact assessments as well as policy evaluations in the city. |
| first_indexed | 2024-03-07T21:22:40Z |
| format | Article |
| id | doaj.art-229f385b899542d08b4ef772ae8a8dd3 |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-07T21:22:40Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-229f385b899542d08b4ef772ae8a8dd32024-02-27T07:42:20ZengIOP PublishingEnvironmental Research Letters1748-93262024-01-0119303403610.1088/1748-9326/ad2892Inequalities in urban air pollution in sub-Saharan Africa: an empirical modeling of ambient NO and NO2 concentrations in Accra, GhanaJiayuan Wang0Abosede S Alli1Sierra N Clark2https://orcid.org/0000-0002-8592-3466Majid Ezzati3Michael Brauer4Allison F Hughes5https://orcid.org/0000-0002-9912-6935James Nimo6Josephine Bedford Moses7Solomon Baah8Ricky Nathvani9https://orcid.org/0000-0002-4488-5862Vishwanath D10Samuel Agyei-Mensah11Jill Baumgartner12James E Bennett13Raphael E Arku14https://orcid.org/0000-0001-8914-8463Department of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts , Amherst, MA, United States of AmericaDepartment of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts , Amherst, MA, United States of AmericaDepartment of Epidemiology and Biostatistics, School of Public Health, Imperial College London , London, United Kingdom; MRC Centre for Environment and Health, School of Public Health, Imperial College London , London, United KingdomDepartment of Epidemiology and Biostatistics, School of Public Health, Imperial College London , London, United Kingdom; MRC Centre for Environment and Health, School of Public Health, Imperial College London , London, United Kingdom; Regional Institute for Population Studies, University of Ghana , Accra, Ghana; Abdul Latif Jameel Institute for Disease and Emergency Analytics, Imperial College London , London, United KingdomSchool of Population and Public Health, The University of British Columbia , Vancouver, CanadaDepartment of Physics, University of Ghana , Accra, GhanaDepartment of Physics, University of Ghana , Accra, GhanaDepartment of Physics, University of Ghana , Accra, GhanaDepartment of Physics, University of Ghana , Accra, GhanaDepartment of Epidemiology and Biostatistics, School of Public Health, Imperial College London , London, United Kingdom; MRC Centre for Environment and Health, School of Public Health, Imperial College London , London, United KingdomDepartment of Epidemiology and Biostatistics, School of Public Health, Imperial College London , London, United Kingdom; MRC Centre for Environment and Health, School of Public Health, Imperial College London , London, United KingdomDepartment of Geography and Resource Development, University of Ghana , Accra, Ghana; Department of Civil and Environmental Engineering, Imperial College London , London, United KingdomInstitute for Health and Social Policy, McGill University , Montreal, Canada; Department of Epidemiology, Biostatistics, and Occupational Health, McGill University , Montreal, CanadaDepartment of Epidemiology and Biostatistics, School of Public Health, Imperial College London , London, United Kingdom; MRC Centre for Environment and Health, School of Public Health, Imperial College London , London, United KingdomDepartment of Environmental Health Sciences, School of Public Health and Health Sciences, University of Massachusetts , Amherst, MA, United States of AmericaRoad traffic has become the leading source of air pollution in fast-growing sub-Saharan African cities. Yet, there is a dearth of robust city-wide data for understanding space-time variations and inequalities in combustion related emissions and exposures. We combined nitrogen dioxide (NO _2 ) and nitric oxide (NO) measurement data from 134 locations in the Greater Accra Metropolitan Area (GAMA), with geographical, meteorological, and population factors in spatio-temporal mixed effects models to predict NO _2 and NO concentrations at fine spatial (50 m) and temporal (weekly) resolution over the entire GAMA. Model performance was evaluated with 10-fold cross-validation (CV), and predictions were summarized as annual and seasonal (dusty [Harmattan] and rainy [non-Harmattan]) mean concentrations. The predictions were used to examine population distributions of, and socioeconomic inequalities in, exposure at the census enumeration area (EA) level. The models explained 88% and 79% of the spatiotemporal variability in NO _2 and NO concentrations, respectively. The mean predicted annual, non-Harmattan and Harmattan NO _2 levels were 37 (range: 1–189), 28 (range: 1–170) and 50 (range: 1–195) µ g m ^−3 , respectively. Unlike NO _2 , NO concentrations were highest in the non-Harmattan season (41 [range: 31–521] µ g m ^−3 ). Road traffic was the dominant factor for both pollutants, but NO _2 had higher spatial heterogeneity than NO. For both pollutants, the levels were substantially higher in the city core, where the entire population (100%) was exposed to annual NO _2 levels exceeding the World Health Organization (WHO) guideline of 10 µ g m ^−3 . Significant disparities in NO _2 concentrations existed across socioeconomic gradients, with residents in the poorest communities exposed to levels about 15 µ g m ^−3 higher compared with the wealthiest ( p < 0.001). The results showed the important role of road traffic emissions in air pollution concentrations in the GAMA, which has major implications for the health of the city’s poorest residents. These data could support climate and health impact assessments as well as policy evaluations in the city.https://doi.org/10.1088/1748-9326/ad2892air pollutionnitrogen dioxide (NO2)nitrogen oxides (NOx)sub-Saharan AfricaGhanaair pollution inequality |
| spellingShingle | Jiayuan Wang Abosede S Alli Sierra N Clark Majid Ezzati Michael Brauer Allison F Hughes James Nimo Josephine Bedford Moses Solomon Baah Ricky Nathvani Vishwanath D Samuel Agyei-Mensah Jill Baumgartner James E Bennett Raphael E Arku Inequalities in urban air pollution in sub-Saharan Africa: an empirical modeling of ambient NO and NO2 concentrations in Accra, Ghana Environmental Research Letters air pollution nitrogen dioxide (NO2) nitrogen oxides (NOx) sub-Saharan Africa Ghana air pollution inequality |
| title | Inequalities in urban air pollution in sub-Saharan Africa: an empirical modeling of ambient NO and NO2 concentrations in Accra, Ghana |
| title_full | Inequalities in urban air pollution in sub-Saharan Africa: an empirical modeling of ambient NO and NO2 concentrations in Accra, Ghana |
| title_fullStr | Inequalities in urban air pollution in sub-Saharan Africa: an empirical modeling of ambient NO and NO2 concentrations in Accra, Ghana |
| title_full_unstemmed | Inequalities in urban air pollution in sub-Saharan Africa: an empirical modeling of ambient NO and NO2 concentrations in Accra, Ghana |
| title_short | Inequalities in urban air pollution in sub-Saharan Africa: an empirical modeling of ambient NO and NO2 concentrations in Accra, Ghana |
| title_sort | inequalities in urban air pollution in sub saharan africa an empirical modeling of ambient no and no2 concentrations in accra ghana |
| topic | air pollution nitrogen dioxide (NO2) nitrogen oxides (NOx) sub-Saharan Africa Ghana air pollution inequality |
| url | https://doi.org/10.1088/1748-9326/ad2892 |
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