Nairobi
County experiences rapid industrialization and urbanization that contributes to
the deteriorating state of air quality, posing a potential health risk to its
growing population. Currently, in Nairobi County, most air quality monitoring
stations use low-cost, inaccurate monitors prone to defects. The study’s objective was to map
Nairobi County’s air
quality using freely available remotely sensed imagery. The Air Pollution Index
(API) formula was used to characterize the
air quality from cloud-free Landsat satellite images i.e., Landsat 5 TM, Landsat 7 ETM+, and Landsat 8 OLI from Google
Earth Engine. The API values were computed based on vegetation indices namely
NDVI, TVI, DVI, and the SWIR1 and NIR bands on the QGIS platform.
Qualitative accuracy assessment was done
using sample points drawn from residential, industrial, green spaces, and
traffic hotspot categories, based on a passive-random sampling
technique. In this study, Landsat 5 API imagery for 2010 provided a reliable
representation of local conditions but indicated significant pollution in green
spaces, with recorded values ranging from -143 to 334. The study found that
Landsat 7 API imagery in 2002 showed expected results with the range of values
being -55 to 287, while Landsat 8 indicated high pollution levels in Nairobi.
The results emphasized the importance of air quality factors in API calibration
and the unmatched spatial coverage of satellite observations over ground-based
monitoring techniques. The study recommends the recalibration of the API
formula for characteristic regions, exploring newer satellite sensors like
those onboard Landsat 9 and Sentinel 2, and involving key stakeholders in a
discourse to develop a suitable Kenyan air quality index.
References
[1]
Balakrishnan, K., et al. (2019) The Impact of Air Pollution on Deaths, Disease Burden, and Life Expectancy across the States of India: The Global Burden of Disease Study 2017. The Lancet Planetary Health, 3, E26-E39.
[2]
Tibuakuu, M., Michos, E.D., Navas-Acien, A. and Jones, M.R. (2018) Air Pollution and Cardiovascular Disease: A Focus on Vulnerable Populations Worldwide. Current Epidemiology Reports, 5, 370-378. https://doi.org/10.1007/s40471-018-0166-8
[3]
Kinney, P.L. (2018) Interactions of Climate Change, Air Pollution, and Human Health. Current Environmental Health Reports, 5, 179-186. https://doi.org/10.1007/s40572-018-0188-x
[4]
WHO (2023) Air Pollution. https://www.who.int/health-topics/air-pollution#tab=tab_1
[5]
Ghorani-Azam, A., Riahi-Zanjani, B. and Balali-Mood, M. (2016) Effects of Air Pollution on Human Health and Practical Measures for Prevention in Iran. Journal of Research in Medical Sciences, 21, 65. https://doi.org/10.4103/1735-1995.189646
[6]
(Tony) Cox, L.A. (2017) Socioeconomic and Air Pollution Correlates of Adult Asthma, Heart Attack, and Stroke Risks in the United States, 2010-2013. Environmental Research, 155, 92-107. https://doi.org/10.1016/j.envres.2017.01.003
[7]
Phung, D., et al. (2016) Air Pollution and Risk of Respiratory and Cardiovascular Hospitalizations in the Most Populous City in Vietnam. Science of the Total Environment, 557-558, 322-330. https://doi.org/10.1016/j.scitotenv.2016.03.070
[8]
Mokoena, K.K., Ethan, C.J., Yu, Y., Shale, K. and Liu, F. (2019) Ambient Air Pollution and Respiratory Mortality in Xi’an, China: A Time-Series Analysis. Respiratory Research, 20, Article No. 139. https://doi.org/10.1186/s12931-019-1117-8
[9]
WHO (2021) WHO Global Air Quality Guidelines: Particulate Matter (PM2.5 and PM10), Ozone, Nitrogen Dioxide, Sulfur Dioxide and Carbon Monoxide: Executive Summary. https://www.who.int/publications/i/item/9789240034433
[10]
Kim, Y.P. and Lee, G. (2018) Trend of Air Quality in Seoul: Policy and Science. Aerosol and Air Quality Research, 18, 2141-2156. https://doi.org/10.4209/aaqr.2018.03.0081
[11]
Orru, H., Ebi, K.L. and Forsberg, B. (2017) The Interplay of Climate Change and Air Pollution on Health. Current Environmental Health Reports, 4, 504-513. https://doi.org/10.1007/s40572-017-0168-6
[12]
Huang, X., et al. (2021) Enhanced Secondary Pollution Offset Reduction of Primary Emissions during COVID-19 Lockdown in China. National Science Review, 8, nwaa137. https://doi.org/10.1093/nsr/nwaa137
[13]
Rafee, S.A.A., et al. (2017) Contributions of Mobile, Stationary and Biogenic Sources to Air Pollution in the Amazon Rainforest: A Numerical Study with the WRF-Chem Model. Atmospheric Chemistry and Physics, 17, 7977-7995. https://doi.org/10.5194/acp-17-7977-2017
[14]
Sevimoglu, O. (1997) Assessment of Major Air Pollution Sources in Efforts of Long Term Air Quality Improvement in Istanbul. Sakarya University Journal of Science, 24, 389-405. https://doi.org/10.16984/saufenbilder.586655
[15]
NPS.Gov. Where Does Air Pollution Come from? Air (U.S. National Park Service). https://www.nps.gov/subjects/air/sources.htm
[16]
Air Pollution Hurts the Poorest Most. https://www.unep.org/news-and-stories/story/air-pollution-hurts-poorest-most
[17]
Burroughs Pena, M.S. and Rollins, A. (2017) Environmental Exposures and Cardiovascular Disease: A Challenge for Health and Development in Low- and Middle-Income Countries. Cardiology Clinics, 35, 71-86. https://doi.org/10.1016/j.ccl.2016.09.001
[18]
Mannucci, P.M. and Franchini, M. (2017) Health Effects of Ambient Air Pollution in Developing Countries. International Journal of Environmental Research and Public Health, 14, 1048. https://doi.org/10.3390/ijerph14091048
[19]
De Souza, P. (2020) Air Pollution in Kenya: A Review. Air Quality, Atmosphere & Health, 13, 1487-1495. https://doi.org/10.1007/s11869-020-00902-x
[20]
Kenya National Bureau of Statistics—Humanitarian Data Exchange. https://data.humdata.org/organization/kenya-national-bureau-of-statistics
[21]
Kinney, P.L., et al. (2011) Traffic Impacts on PM2.5 Air Quality in Nairobi, Kenya. Environmental Science & Policy, 14, 369-378. https://doi.org/10.1016/j.envsci.2011.02.005
[22]
Enoh, N. and Kipruto, J. (2015) Urban Air Quality in the City of Nairobi, Kenya: Application of Energy Dispersive X-Ray Fluorescence and Principal Component Analysis. http://erepository.uonbi.ac.ke/handle/11295/90202
[23]
Egondi, T., Ettarh, R., Kyobutungi, C., Ng, N. and Rocklov, J. (2018) Exposure to Outdoor Particles (PM2.5) and Associated Child Morbidity and Mortality in Socially Deprived Neighborhoods of Nairobi, Kenya. Atmosphere, 9, Article No. 351. https://doi.org/10.3390/atmos9090351
[24]
Egondi, T., Muindi, K., Kyobutungi, C., Gatari, M. and Rocklov, J. (2016) Measuring Exposure Levels of Inhalable Airborne Particles (PM2.5) in Two Socially Deprived Areas of Nairobi, Kenya. Environmental Research, 148, 500-506. https://doi.org/10.1016/j.envres.2016.03.018
[25]
Machiyama, K., Mumah, J.N., Mutua, M. and Cleland, J. (2019) Childbearing Desires and Behaviour: A Prospective Assessment in Nairobi Slums. BMC Pregnancy Childbirth, 19, Article No. 100. https://doi.org/10.1186/s12884-019-2245-3
[26]
Rastogi, M. (2021) A Review Paper on Traffic Pollution. Asian Journal of Research in Business Economics and Management, 11, 118-123. https://doi.org/10.5958/2249-7307.2021.00050.5
[27]
Ngo, N.S., Gatari, M., Yan, B., Chillrud, S.N., Bouhamam, K. and Kinney, P.L. (2015) Occupational Exposure to Roadway Emissions and inside Informal Settlements in Sub-Saharan Africa: A Pilot Study in Nairobi, Kenya. Atmospheric Environment, 111, 179-184. https://doi.org/10.1016/j.atmosenv.2015.04.008
[28]
Mukaria, S.M. (2017) Traffic Police Knowledge, Attitude and Practices Concerning Motor Vehicle Air Pollution at Key Nairobi Road Junctions. http://erepository.uonbi.ac.ke/handle/11295/102027
[29]
Mulaku, G.C. and Kariuki, L.W. (2001) Mapping and Analysis of Air Pollution in Nairobi, Kenya. http://erepository.uonbi.ac.ke/handle/11295/55771
[30]
Gatari, M.J., Boman, J. and Wagner, A. (2009) Characterization of Aerosol Particles at an Industrial Background Site in Nairobi, Kenya. X-Ray Spectrometry, 38, 37-44. https://doi.org/10.1002/xrs.1097
[31]
Faith Ndunge Mutua, C.K.D.M.N. (2021) Determination of PM10 and PM2.5 Concentration in Ambient Air Samples in Nairobi City, Kenya (2016).
[32]
Okafor, N.U., Alghorani, Y. and Delaney, D.T. (2020) Improving Data Quality of Low-Cost IoT Sensors in Environmental Monitoring Networks Using Data Fusion and Machine Learning Approach. ICT Express, 6, 220-228. https://doi.org/10.1016/j.icte.2020.06.004
[33]
Becker, R. and Henderson, V. (2015) Effects of Air Quality Regulations on Polluting Industries. Journal of Political Economy, 108, 379-421. https://doi.org/10.1086/262123
[34]
Concas, F., et al. (2021) Low-Cost Outdoor Air Quality Monitoring and Sensor Calibration. ACM Transactions on Sensor Networks, 17, Article No. 2. https://doi.org/10.1145/3446005
[35]
Doc, P. (2010) Gazzetted Laboratories. Molecular Imaging, No. 2, 1-4.
[36]
Sifakis, N.I. and Soulakellis, N.A. (2000) Satellite Image Processing for Haze and Aerosol Mapping (SIPHA): Code Description and Presentation of Results. The International Geoscience and Remote Sensing Symposium, 1, 222-224.
[37]
Hadjimitsis, D.G., Retalis, A. and Clayton, C.R.I. (2002) The Assessment of Atmospheric Pollution Using Satellite Remote Sensing Technology in Large Cities in the Vicinity of Airports. Water, Air and Soil Pollution: Focus, 2, 631-640.
[38]
Nairobi City County (2019) Nairobi City County Air Quality Action Plan (2019-2023). https://www.eci-africa.org/wp-content/uploads/2019/05/Nairobi-Air-Quality-Action-Plan_Final_ECI_31.12.2018.pdf
[39]
Nguyen, H.-H., Thi Thuy An, T., Tien Lam, L., Hai Hoa, N., Thai Son, L. and Van Hung, N. (2018) Using Landsat Imageries for Particle Pollution Mapping in Hanoi City. Journal of Forestry Science and Technology, No. 5, 53-61. https://earthexplorer.usgs.gov
[40]
A Systems Approach to Air Pollution (ASAP)—African Centre for Technology Studies (ACTS). https://www.acts-net.org/research/projects/a-systems-approach-to-air-pollution-asap
[41]
Marsh, J.G., et al. (1988) A New Gravitational Model for the Earth from Satellite Tracking Data: GEM-T1. Journal of Geophysical Research: Solid Earth, 93, 6169-6215. https://doi.org/10.1029/JB093iB06p06169
[42]
Fishman, J., Minnis, P. and Reichle, H.G. (1986) Use of Satellite Data to Study Tropospheric Ozone in the Tropics. Journal of Geophysical Research: Atmospheres, 91, 14451-14465. https://doi.org/10.1029/JD091iD13p14451
[43]
Lelieveld, J., et al. (2002) Global Air Pollution Crossroads over the Mediterranean. Science (80-.), 298, 794-799.
[44]
Kaufman, Y.J., Tanré, D. and Boucher, O. (2002) A Satellite View of Aerosols in the Climate System. Nature, 419, 215-223. https://doi.org/10.1038/nature01091
[45]
El-Askary, H. (2006) Air Pollution Impact on Aerosol Variability over Mega Cities Using Remote Sensing Technology: Case Study, Cairo, Egypt. Egyptian Journal of Remote Sensing and Space Science, 9, 31-40.
[46]
El-Nadry, M., Li, W., El-Askary, H., Awad, M.A. and Mostafa, A.R. (2019) Urban Health Related Air Quality Indicators over the Middle East and North Africa Countries Using Multiple Satellites and AERONET Data. Remote Sensing, 11, Article No. 2096. https://doi.org/10.3390/rs11182096
[47]
Semlali, B.-E.B., El Amrani, C. and Denys, S. (2019) Development of a Java-Based Application for Environmental Remote Sensing Data Processing. International Journal of Electrical and Computer Engineering, 9, 1978-1986. https://doi.org/10.11591/ijece.v9i3.pp1978-1986
[48]
Kalajdjieski, J., et al. (2020) Air Pollution Prediction with Multi-Modal Data and Deep Neural Networks. Remote Sensing, 12, Article No. 4142. https://doi.org/10.3390/rs12244142
[49]
Kenya National Bureau of Statistics (2019) Kenya Population and Housing Census Volume 1: Population by County and Sub-County. https://www.knbs.or.ke/?wpdmpro=2019-kenya-population-and-housing-census-volume-i-population-by-county-and-sub-county
[50]
Mundia, C. and Murayama, Y. (2013) Modeling Spatial Processes of Urban Growth in African Cities: A Case Study of Nairobi City. Urban Geography, 31, 259-272. https://doi.org/10.2747/0272-3638.31.2.259
[51]
Zhang, X., Chen, X. and Zhang, X. (2018) The Impact of Exposure to Air Pollution on Cognitive Performance. Proceedings of the National Academy of Sciences of the United States of America, 115, 9193-9197. https://doi.org/10.1073/pnas.1809474115
[52]
Odhiambo, G.O., Nairobi, K., Kinyua, A.M., Gatebe, C.K. and Awange, J. (2010) Motor Vehicles Air Pollution in Nairobi, Kenya. Research Journal of Environmental and Earth Sciences, 2, 178-187. http://maxwellsci.com/print/rjees/v2-178-187.pdf
[53]
Barsi, J.A., Lee, K., Kvaran, G., Markham, B.L. and Pedelty, J.A. (2014) The Spectral Response of the Landsat-8 Operational Land Imager. Remote Sensing, 6, 10232-10251. https://doi.org/10.3390/rs61010232
[54]
QGIS Version 3.28. https://www.qgis.org/en/site/
[55]
Carlson, T.N., Perry, E.M. and Schmugge, T.J. (1990) Remote Estimation of Soil Moisture Availability and Fractional Vegetation Cover for Agricultural Fields. Agricultural and Forest Meteorology, 52, 45-69. https://doi.org/10.1016/0168-1923(90)90100-K
[56]
Zevenbergen, A.W., Rango, A., Ritchie, J.C., Engman, E.T. and Hawkins, R.H. (1988) Rangeland Runoff Curve Numbers As Determined from Landsat MSS Data. International Journal of Remote Sensing, 9, 495-502.
[57]
Tucker, C.J. (1979) Red and Photographic Infrared Linear Combinations for Monitoring Vegetation. Remote Sensing of Environment, 8, 127-150. https://doi.org/10.1016/0034-4257(79)90013-0
[58]
Mozumder, C., Reddy, K.V. and Pratap, D. (2013) Air Pollution Modeling from Remotely Sensed Data Using Regression Techniques. Journal of the Indian Society of Remote Sensing, 41, 269-277. https://doi.org/10.1007/s12524-012-0235-2
[59]
Costa, L.G., Cole, T.B., Dao, K., Chang, Y.C., Coburn, J. and Garrick, J.M. (2020) Effects of Air Pollution on the Nervous System and Its Possible Role in Neurodevelopmental and Neurodegenerative Disorders. Pharmacology & Therapeutics, 210, Article ID: 107523. https://doi.org/10.1016/j.pharmthera.2020.107523
