The impact of COVID-19 lockdowns on surface urban heat island changes and air-quality improvements across 21 major cities in the Middle East.
Type
ArticleAuthors
El Kenawy, Ahmed MLopez-Moreno, Juan I
McCabe, Matthew

Domínguez-Castro, Fernando
Peña-Angulo, Dhais
Gaber, Islam M
Alqasemi, Abduldaem S
Al Kindi, Khalifa M
Al-Awadhi, Talal
Hereher, Mohammed E
Robaa, Sayed M
Al Nasiri, Noura
Vicente-Serrano, Sergio M
KAUST Department
Biological and Environmental Science and Engineering (BESE) DivisionEarth System Observation and Modelling
Environmental Science and Engineering Program
Water Desalination and Reuse Research Center (WDRC)
Date
2021-07-16Online Publication Date
2021-07-16Print Publication Date
2021-11Embargo End Date
2022-07-20Submitted Date
2021-06-11Permanent link to this record
http://hdl.handle.net/10754/670285
Metadata
Show full item recordAbstract
This study investigates changes in air quality conditions during the restricted COVID-19 lockdown period in 2020 across 21 metropolitan areas in the Middle East and how these relate to surface urban heat island (SUHI) characteristics. Based on satellite observations of atmospheric gases from Sentinel-5, results indicate significant reductions in the levels of atmospheric pollutants, particularly nitrogen dioxide (NO2), sulfur dioxide (SO2), and carbon monoxide (CO). Air quality improved significantly during the middle phases of the lockdown (April and May), especially in small metropolitan cities like Amman, Beirut, and Jeddah, while it was less significant in “mega” cities like Cairo, Tehran, and Istanbul. For example, the concentrations of NO2 in Amman, Beirut, and Jeddah decreased by −56.6%, −43.4%, and −32.3%, respectively, during April 2020, compared to April 2019. Rather, there was a small decrease in NO2 levels in megacities like Tehran (−0.9%) and Cairo (−3.1%). Notably, during the lockdown period, there was a decrease in the mean intensity of nighttime SUHI, while the mean intensity of daytime SUHI experienced either an increase or a slight decrease across these locations. Together with the Gulf metropolitans (e.g. Kuwait, Dubai, and Muscat), the megacities (e.g. Tehran, Ankara, and Istanbul) exhibited anomalous increases in the intensity of daytime SUHI, which may exceed 2 °C. Statistical relationships were established to explore the association between changes in the mean intensity and the hotspot area in each metropolitan location during the lockdown. The findings indicate that the mean intensity of SUHI and the spatial extension of hotspot areas within each metropolitan had a statistically significant negative relationship, with Pearson's r values generally exceeding - 0.55, especially for daytime SUHI. This negative dependency was evident for both daytime and nighttime SUHI during all months of the lockdown. Our findings demonstrate that the decrease in primary pollutant levels during the lockdown contributed to the decrease in the intensity of nighttime SUHIs in the Middle East, especially in April and May. Changes in the characteristics of SUHIs during the lockdown period should be interpreted in the context of long-term climate change, rather than just the consequence of restrictive measures. This is simply because short-term air quality improvements were insufficient to generate meaningful changes in the region's urban climate.Citation
El Kenawy, A. M., Lopez-Moreno, J. I., McCabe, M. F., Domínguez-Castro, F., Peña-Angulo, D., Gaber, I. M., … Vicente-Serrano, S. M. (2021). The impact of COVID-19 lockdowns on surface urban heat island changes and air-quality improvements across 21 major cities in the Middle East. Environmental Pollution, 288, 117802. doi:10.1016/j.envpol.2021.117802Sponsors
Research reported in this publication was supported financially by the Ministry of Higher Education, Research, and Innovation, Oman (TRC/CRP/SQU/COVID-19/20/20) and administratively by Sultan Qaboos University, Oman. The authors are grateful to the ORNL DAAC for providing MODIS/VIIRS Land data employed in this study.Publisher
Elsevier BVJournal
Environmental PollutionPubMed ID
34284210Additional Links
https://linkinghub.elsevier.com/retrieve/pii/S0269749121013841ae974a485f413a2113503eed53cd6c53
10.1016/j.envpol.2021.117802
Scopus Count
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