“…Such results can seem strange especially that the NO 2 which is the precursor of O 3 has decreased over Cairo and Alexandria by 13% and 9%, respectively in April and decreased by higher values in March. However, such inconsistent relation between the NO 2 and O 3 concentrations has been previously observed in a lot of previous research work” ( Qin et al, 2004 ; Lin et al, 2005 ; Jiménez et al, 2005 ; Blanchard et al, 2008 ; Schipa et al, 2009 ; Castell et al, 2010 ; Wolff et al, 2013 ; Adame et al, 2014 ; Shen et al, 2014 ; Diéguez et al, 2014 ; Xie et al, 2016 ; Silva et al, 2018 ; Zou et al, 2019 ; Ezimand and Kakroodi, 2019 ; Tang et al, 2020 ; Soares et al, 2020 ; Liao et al, 2020 ; Mozaffar et al, 2020 ; Fang et al, 2020 ; Barcelo, 2020 ). In addition, several researchers have recently reported that O 3 levels increased in some cities during COVID-19 lockdown in complete contrast to the NO 2 concentrations ( Sicard et al, 2020 ; Siciliano et al, 2020 ; Tobías et al, 2020 ).…”
The outbreak of coronavirus disease (COVID-19) not only affected health and economics, but also its effect extended to include other aspects, such as the environment. Using Egypt as a case study, this paper presents the impact of COVID-19 pandemic on air pollution levels by studying nitrogen dioxide (NO
2
), ozone (O
3
), particulate matter represented in absorbing aerosol index (AAI), carbon monoxide (CO), and greenhouse gas (GHG) emissions. The paper also highlights the impact of COVID-19 pandemic on other environmental indicators including environmental noise, medical and municipal solid wastes. The paper presents the Egyptian COVID-19 story from its different angles including the development of confirmed COVID-19 cases, containment measures from the government, the impact on the country’s economy and the national energy consumption so as to effectively evaluate the effect on both the air pollution levels and the other studied environmental indicators. For the other environmental indicators, a strong link was observed between COVID-19 lockdown and the reduction in environmental noise, beaches, surface and groundwater pollution. For environmental noise, this has been confirmed by officially governmental announcements which reported that the level of environmental noise in Egypt was reduced by about 75% during the lockdown period. On the other hand, there are some negative effects, including an increase in medical solid waste (from 70 to 300 ton/day), municipal solid waste, as well as a less efficient solid waste recycling process. For air pollution levels, the data were obtained from National Aeronautics and Space Administration (NASA) and European Space Agency satellite data sets. The data for the lockdown period in 2020 have been extracted and compared to the corresponding months in the selected baseline period (2015-2019) to identify the effect that the lockdown period had on the air pollution levels in Egypt with focus on Cairo and Alexandria governorates. It was found that the AAI decreased by about 30%, the NO
2
decreased by 15 and 33% over Cairo and Alexandria governorates, respectively, and that the CO decreased by about 5% over both governorates. In addition, the GHG emissions in Egypt were reduced by at least 4% during the pandemic. In contrast, ozone levels increased by about 2% over Cairo and Alexandria governorates. It can be concluded that the implemented containment measures during COVID-19 pandemic had resulted in both positive and negative environmental impacts. The positive environmental impacts are not sustainable and deterioration on them is expected to occur after the lockdown as it was before the pandemic. Therefore, stricter laws must be enacted to protect the environment in Egypt.
“…Such results can seem strange especially that the NO 2 which is the precursor of O 3 has decreased over Cairo and Alexandria by 13% and 9%, respectively in April and decreased by higher values in March. However, such inconsistent relation between the NO 2 and O 3 concentrations has been previously observed in a lot of previous research work” ( Qin et al, 2004 ; Lin et al, 2005 ; Jiménez et al, 2005 ; Blanchard et al, 2008 ; Schipa et al, 2009 ; Castell et al, 2010 ; Wolff et al, 2013 ; Adame et al, 2014 ; Shen et al, 2014 ; Diéguez et al, 2014 ; Xie et al, 2016 ; Silva et al, 2018 ; Zou et al, 2019 ; Ezimand and Kakroodi, 2019 ; Tang et al, 2020 ; Soares et al, 2020 ; Liao et al, 2020 ; Mozaffar et al, 2020 ; Fang et al, 2020 ; Barcelo, 2020 ). In addition, several researchers have recently reported that O 3 levels increased in some cities during COVID-19 lockdown in complete contrast to the NO 2 concentrations ( Sicard et al, 2020 ; Siciliano et al, 2020 ; Tobías et al, 2020 ).…”
The outbreak of coronavirus disease (COVID-19) not only affected health and economics, but also its effect extended to include other aspects, such as the environment. Using Egypt as a case study, this paper presents the impact of COVID-19 pandemic on air pollution levels by studying nitrogen dioxide (NO
2
), ozone (O
3
), particulate matter represented in absorbing aerosol index (AAI), carbon monoxide (CO), and greenhouse gas (GHG) emissions. The paper also highlights the impact of COVID-19 pandemic on other environmental indicators including environmental noise, medical and municipal solid wastes. The paper presents the Egyptian COVID-19 story from its different angles including the development of confirmed COVID-19 cases, containment measures from the government, the impact on the country’s economy and the national energy consumption so as to effectively evaluate the effect on both the air pollution levels and the other studied environmental indicators. For the other environmental indicators, a strong link was observed between COVID-19 lockdown and the reduction in environmental noise, beaches, surface and groundwater pollution. For environmental noise, this has been confirmed by officially governmental announcements which reported that the level of environmental noise in Egypt was reduced by about 75% during the lockdown period. On the other hand, there are some negative effects, including an increase in medical solid waste (from 70 to 300 ton/day), municipal solid waste, as well as a less efficient solid waste recycling process. For air pollution levels, the data were obtained from National Aeronautics and Space Administration (NASA) and European Space Agency satellite data sets. The data for the lockdown period in 2020 have been extracted and compared to the corresponding months in the selected baseline period (2015-2019) to identify the effect that the lockdown period had on the air pollution levels in Egypt with focus on Cairo and Alexandria governorates. It was found that the AAI decreased by about 30%, the NO
2
decreased by 15 and 33% over Cairo and Alexandria governorates, respectively, and that the CO decreased by about 5% over both governorates. In addition, the GHG emissions in Egypt were reduced by at least 4% during the pandemic. In contrast, ozone levels increased by about 2% over Cairo and Alexandria governorates. It can be concluded that the implemented containment measures during COVID-19 pandemic had resulted in both positive and negative environmental impacts. The positive environmental impacts are not sustainable and deterioration on them is expected to occur after the lockdown as it was before the pandemic. Therefore, stricter laws must be enacted to protect the environment in Egypt.
“…In Tehran, major sources of criteria air pollutants, with the exception of O 3 as a secondary air pollutant, have previously been reported arising from road traffic-related emissions (the highest contribution for CO, PM 2.5 and NO X ), industrial activities (as the important emission sources of SO 2 , PM and NO X ), energy conversion sector (as another important contributor for NO X and PM emissions and the most notable contributor for SO 2 ), as well as household and commercial sectors (as the other contributors for NO X emissions) 10,11,55 . Therefore, based on the successful short-and long-term programs in other megacities of developed and developing countries 24,56,57 , we recommend a policy mix in order to improve the air quality situation in Tehran megacity: (1) the heavy-and light-duty vehicles (HDVs and LDVs) replacement program via providing financial incentives to owners of old vehicles to trade them with new/less polluting ones;…”
Section: Aqi and Responsible Ambient Air Pollutantmentioning
We investigated temporal variations of ambient air pollutants and the influences of meteorological parameters on their concentrations using a robust method; convergent cross mapping; in Tehran (2012-2017). Tehran citizens were consistently exposed to annual PM 2.5 , PM 10 and no 2 approximately 3.0-4.5, 3.5-4.5 and 1.5-2.5 times higher than the World Health Organization air quality guideline levels during the period. Except for O 3 , all air pollutants demonstrated the lowest and highest concentrations in summertime and wintertime, respectively. The highest O 3 concentrations were found on weekend (weekend effect), whereas other ambient air pollutants had statistically significant (P < 0.05) daily variations in which higher concentrations were observed on weekdays compared to weekend (holiday effect). Hourly O 3 concentration reached its peak at 3.00 p.m., though other air pollutants displayed two peaks; morning and late night. Approximately 45% to 65% of AQI values were in the subcategory of unhealthy for sensitive groups and PM 2.5 was the responsible air pollutant in Tehran. Amongst meteorological factors, temperature was the key influencing factor for PM 2.5 and PM 10 concentrations, while nebulosity and solar radiation exerted major influences on ambient SO 2 and o 3 concentrations. Additionally, there is a moderate coupling between wind speed and NO 2 and CO concentrations.
“…After the observed peaks at 7:00 and 8:00, the concentrations of NO 2 , and CO started to decrease and reached their lowest concentrations at 14:00 and 15:00 due to a combination of increasing boundary layer height, wind speed (WS), solar radiation (SR), and photochemical reactions in order to produce O 3 coupled with decreasing vehicle traffic emissions as evident by decreased ambient NO 2 . The night-time concentrations of NO 2 and CO were significantly lower than those observed during the daytime, mainly because of the above-mentioned reasons, as well as the lack of photochemical reactions for their destruction and consumption to produce ambient O 3 (Hu et al 2014 ; Heger and Sarraf 2018 ; Taghvaee et al 2018a , b ; Henschel et al 2015 ; Askariyeh and Arhami 2013 ; Song et al 2017 ; Ezimand and Kakroodi 2019 ; Zuberi et al 2015 ). Fig.…”
Many countries are concerned about how concentrations of outdoor air pollutants have decreased due to control measures aftermath of the COVID-19 outbreak. In Saudi Arabia, the measures started with suspending entry to Saudi Arabia on February 27, 2020, and ended with full prevention of Saudis for outdoor movement on April 2, 2020, until the back return to normal life by the start of September 2020. These measures are expected to impact air quality levels during this period by decreasing the concentrations of air pollutants. This paper investigates the major trends of ambient air pollution (SO 2 , NO 2 , CO, O 3 , and PM 10), and maps the spatiotemporal variability of air pollutants in Makkah city, using a continuous air quality monitoring network (6 sites) during the pre-pandemic period. Findings indicate the presence of a significant decrease of concentration rates during the lockdown period, compared with the pre-pandemic period, by 26.34% for SO 2 , 28.99% for NO 2 , 26.24% for CO, 11.62% for O 3 , and 30.03% for PM 10. Therefore, the vehicular traffic activities represent 25-30% of the total air pollution load in Makkah city. The COVID-19 lockdown conditions in Makkah provide a unique opportunity to evaluate the impact of the reduction of vehicular traffic activities on the air quality levels of Makkah city and similar mega-cities and introduce credible solutions to improve the conditions of the ambient environment and air quality in such settings.
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