Modeling COVID-19 Impact on Consumption and Mobility in Europe: A Legacy Toward Sustainable Business Performance

This article has explored the impact of coronavirus disease 2019 (COVID-19)-induced decline in consumer durables and mobility on nitrogen dioxide (NO2) emission in Europe by providing empirical and graphical justifications based on consumer price index (CPI) and gross domestic product (GDP) deflator indexes. The empirical estimations show that carbon dioxide (CO2) and NOx emission along with other greenhouse gases drastically decreased in the wake of COVID-19-induced lockdowns and decrease in the demand of consumer goods in Europe. This means that COVID-19 improved environment in the European region. However, high cost (e.g., unemployment, loss of life, and social segregation) makes COVID-19 an unstable solution to environmental woes where positive impact of COVID-19 on environment achieved in short run cannot be guaranteed in the long run. Besides environment, COVID-19 drastically curtailed economic activities and exposed them to the risk of economic crisis particularly in case of Europe.


INTRODUCTION
Coronavirus disease 2019  was detected in December 2019 in Wuhan city, which is located in Hubei province of People's Republic of China (Birtus and Lǎzǎroiu, 2021;Irfan et al., 2021d,e;Mitchell, 2021;Ahmad et al., 2022). COVID-19 is an existential threat on many fronts (Stevens, 2020;Smith and Machova, 2021;Irfan et al., 2022b). It halted economic activities, increased unemployment, declined cross-border trade, reduced mobility, and weakened social fabrics (Hopkins and Potcovaru, 2021;Irfan et al., 2021f;Rydell and Kucera, 2021). However, despite all its disadvantages, COVID-19 has positively contributed to environment in different countries and regions since its outbreak in Wuhan (Chakraborty and Maity, 2020;Wang and Su, 2020;Irfan et al., 2021a). As per latest reports of the WHO, there were 89,048,345 reported cases of COVID-19 and total number of 1,930,265 confirmed deaths due to coronavirus disease 2019 until 10th January 2021 (WHO, 2021). Coronavirus disease 2019  reached at the peak across the globe and touched the climax in many of the countries (Iqbal et al., 2021). In some countries of Europe and Africa, such as UK, Italy, Spain, and Greece, transmuted forms of COVID-19 caused widespread disaster in form of huge loss of human lives, but the severity of coronavirus disease 2019 is not confirmed yet Tanveer et al., 2021;Shi et al., 2022). Henceforth, COVID-19 has direly affected economic activities and human lives; particularly, it extremely affected consumption and mobility at the larger extent (Razzaq et al., 2020;Wu et al., 2021;Xiang et al., 2022).
Coronavirus disease 2019 has changed our way of life and world busiest airports have suspended their operations due to severe wave of coronavirus disease 2019 (Irfan et al., 2021b;Wen et al., 2022). Railway transport suspended their operations and train station gives a deserted look without masses after the spread of COVID-19. Strict lockdown imposed by the government officials due to the spread of COVID-19 (Hao et al., 2021). Due to these lockdowns, supermarkets were closed and industrial units stopped production (Kumar et al., 2020;WEF, 2020). Eventually, due to strict lockdowns, masses are forced to stay isolated at homes and there is high probability for uncertain future along with rising unemployment after COVID-19, which has seriously decreased the demand for consumer and durable goods in addition to human mobility (WEF, 2020;Irfan et al., 2022c). Huge financial losses incurred in various sectors such as transportation, tourism, and aviation (Irfan et al., 2021a(Irfan et al., , 2022a. Such a disciplinary measures, such as strict lockdowns, are taken by the governments across the world in order to control widespread coronavirus disease 2019 (Kim, 2020;Irfan et al., 2021c;Islam et al., 2022) and these strict official measures seriously affected social and economic activities globally Nuvvula et al., 2022). Harmful and unhealthy effects of COVID-19 also risked global recession and unemployment Abbasi et al., 2022). In sum, normal way of life is changed and socioeconomic activities are significantly reduced due to COVID-19 (Rauf et al., 2021;Razzaq et al., 2021).
Despite the detrimental effects of COVID-19, scholars look at COVID-19 from different perspectives (Chandio et al., 2021;Rydell and Suler, 2021;Watson and Popescu, 2021). They claim that due to the suspension of socioeconomic activities and strict lockdowns along with decrease in consumption have significantly reduced nitrogen dioxide (NO 2 ) and emission of other harmful gases (He et al., 2020b;Elavarasan et al., 2021). NO 2 is closed associated with economic and human activities (Tan et al., 2009). NO 2 pollutes the atmosphere in the urban and industrial areas. NO 2 is composed of primary and secondary pollutants and it is severely harmful for the climate, atmosphere, and human lives as well (Atkinson et al., 2018;Kovacova et al., 2019;Kliestik et al., 2020). As per statistical reports of the WHO, NO 2 emission from fuel combustion causes approximately over 3.8 million mortalities per year all over the world. Additionally, exposure to ambient (outdoor) NO 2 emission is cause of total number of deaths over 4.2 million per year globally (Ogen, 2020a). Recently, NO 2 emission significantly decreased after COVID-19 strict lockdowns. Accordingly, as per point of view of environmental experts, they believe that COVID-19 is a "blessing in disguise" (Muhammad et al., 2020;Durana et al., 2021). Thus, decrease in CO 2 and NO x emission after COVID-19 was a blessing in disguise for over stressed environment (Manuel and Nuno, 2020;Muhammad et al., 2020). The National Aeronautics and Space Administration (NASA) published statistical reports about NO 2 emission, which claims that NO 2 emission significantly decreased by 50% in some areas such as Wuhan, London, and New Delhi (NASA, 2020).
Hence, we want to examine relationship empirically whether COVID-19-induced decline in consumer goods and mobility in particular case of Europe has any impact on NO 2 emission or not? A study of Castellanos and Boersma (2012) confirmed that decrease in consumption significantly reduced NO 2 emission in a region. Even though, there are numerous factors, which contributed to NO 2 emission, but production and consumption are principal as well as significant causes of NO 2 emission (Tukker et al., 2006;EEA, 2015;Majeed et al., 2021). Altogether, Europe is not only hardly hit by COVID-19, but it also imposed strict lockdowns, which significantly reduced the human mobility (Hasanat Shah et al., 2021). Accordingly, Europe is an ideal region to be focused to explore the post-COVID-19-induced decline impact of consumption and mobility on environmental degradation (NO 2 emission). Accordingly, it is highly expected that post-COVID-19-induced decline in consumption patterns and restrictive mobility due to lockdowns will significantly reduce NO 2 emission in Europe.
There are lot of studies, such as Rahaman et al. (2020), Mumtaz et al. (2021), Mumtaz et al. (2021), Xu et al. (2021), Lin et al. (2021), and Rehman et al. (2021), have evaluated the post-COVID-19 impact on the different sectors of the economy with particularly focused on the health sector. Additionally, there is also bunch of studies, such as Birtus and Lǎzǎroiu (2021), Watson and Popescu (2021), Rydell and Suler (2021), Smith and Machova (2021), Rydell and Kucera (2021), Hopkins and Potcovaru (2021), Mitchell (2021), and Stevens (2020), provided invaluable insight while exploring the postpandemic COVID-19 impact on consumer behaviors, choices, purchasing habits, and human psychology. No doubts, these studies are quite invaluable in context of analyzing the postpandemic COVID-19 impact on the whole economy globally and human consumption patterns especially, but policy implications of these studies are not based on empirical justifications. To the best of our knowledge, this is the first study, particularly for European countries, which has empirically and graphically analyzed the impact of post-COVID-19-induced decline in consumption patterns and restrictive mobility on NO 2 emission. Although, the study of Hasanat Shah et al. (2021) provide valuable insight to understand the impact of post-COVID-19-induced decline in consumption patterns and restrictive mobility on NO 2 emission for particularly in case of Europe, but this study also suffers from significant shortcomings. This study has explored the impact of post-COVID-19-induced decline in consumption patterns and restrictive mobility on environmental degradation (NO 2 emission) by using satellite images and qualitative analysis. Accordingly, this study shed light on this topic on general perspectives, but it does not provide discussion and policy analysis based on empirical estimations.
Thus, this study extends the study of Hasanat Shah et al. (2021) with significant differences. First, we analyzed the impact of post-COVID-19-induced decline in consumption patterns and restrictive mobility on NO 2 emission on empirical basis through the methods of consumer price index (CPI) and inflation, gross domestic product (GDP) deflator indexes. Second, we have formulated variable for death rate as per confirmed COVID-19 cases (% annually) from empirical dataset. Additionally, we have formulated variables to understand the marginal percentage change of consumer price index [% ( CPI)] after COVID-19 and the marginal percentage change of mobility index [% ( mobility)] after COVID-19 in Europe to provide more rigorous empirical analysis and also provide interesting policy implications based on empirical results. We notice that death rate as per confirmed COVID cases (% annually) is quite high and demand of consumer goods significantly declines after COVID-19 in Europe. To the best of our knowledge, this is the first study based on Europe, which provided rigorous analysis empirically and graphically to explore the impact of post-COVID-19induced decline in consumption patterns and restrictive mobility on NO 2 emission. Rest of the article is organized as: Section Theoretical Framework discusses theoretical framework. Section Empirical analysis and framework provides insight about dataset, descriptive statistics, and empirical analysis. Section Conclusion discusses the policy implication.

Coronavirus Disease 2019 Cases in Europe
A number of pandemic diseases spread out in the advent of 21st century. COVID-19 is officially acknowledged as the sixth pandemic disease of this century. These universal pandemic diseases, which resulted in the large number of fatalities and costed huge budget in terms of billions of dollars (Allocati et al., 2016;Fan et al., 2019;Kovacova and Lewis, 2021). COVID-19 postured serious human, economic, and social challenges to the entire human being across the world and it damaged the human health system at the large extent. Nowadays, COVID-19 is a serious health concern in Europe (Hasanat Shah et al., 2021). COVID-19 broke out from Hubei province of mainland of China in the month of December, but soon it became super-spreader in every knock and corner across the world. On 24th January 2020, the first case of COVID-19 was reported in Europe in France and in the month of March, COVID-19 spread across all the major countries of Europe. On 8th November 2020, the number of new cases reached the climax when Europe reported 341,150 new cases on a single day. On 20th December 2020, the total accumulative cases of COVID-19 in Europe were 236,734,046 (WHO, 2021). There is no break and recession in the decline of COVID-19 cases and thus, COVID-19 cases will further intensify and accelerate, unless it is not properly curbed by usage of authentic vaccines such as "The Netherlands" and "Sentinel-5 Precursor."

Nitrogen Dioxide Emission in Europe
Nitrogen dioxide is the amalgamation of oxygen and nitrogen. NO 2 is not only a primary, but also a secondary pollutant and it is a serious cause of respiratory problems. NO 2 not only directly degrades human health issues, but also damages health indirectly by significantly contributing to global warming (Webb and Hunter, 1998). Nitrogen gases do not react with oxygen at normal temperature, but these gases react with oxygen at higher temperature and resultantly, the reaction of nitrogen gases with oxygen produces NO 2 . Fuel combustion is non-natural sources of NO 2 , but forest fires and lightening are natural sources of nitrogen dioxide (NO 2 ). Non-natural sources of NO 2 can further be classified into mobile and stationary sources. For instance, the combustion of gasoline in automobiles is a mobile source of NO 2 , while NO 2 emissions coming from coal-fired and electric power  plants are non-natural stationary sources of NO 2 (Duncan et al., 2016). As per statistical figures of Table 1, we notice that road transport and industrial production units are principal cause of NO 2 emission, particularly in case of Europe. Figure 1 uses data from the Copernicus-5P satellite to show the average nitrogen dioxide concentrations from 13 March to 13 April 2020, compared with the same period of time from 2019. Figure 1 reports that COVID-19-induced lockdown and decline in consumption significantly decreased NO 2 . Equally demand for electricity in Europe after COVID-19 decreased by more than 25%. Less demand for electricity means that Europe is consuming less fuel energy and accordingly less NO 2 will be released in the air. Beside stationary sources, mobile source of NO 2 in Europe also reported a sharp decline after COVID-19 (Hasanat Shah et al., 2021). Please see Figure 1, the impact of decline in mobility and industrial production significantly reduced amount of nitrogen oxide emission in March to April 2020.

Consumer Durables in Europe
Industrial activities and change in lifestyle both in the developed and developing countries exploited environment in order to grow rapidly (Castro, 2004;Adams, 2009;Ahmad, 2021, 2022). Some scholars justified the degradation of environment (using Kuznets' inverted-U hypothesis) and suggested that environment heals itself after a certain level of development (Allen and Webber, 2010). But, environment never recovered from the shocking emission of carbon dioxide (CO 2 ), NO 2 , and other greenhouse gases. Therefore, some sane voices raised the issue of environmental pollution on international forums and tried to find balance in economic activities and environment (e.g., Sustainable Development Goal 13). But, addiction to consumerism and heavy reliance on consumption for rapid development, both in the developed and developing countries, failed them to bring effective changes (Calvin et al., 2015). Consumption contributes roughly 75% of share to the GDP of the European Union (EU) countries and it contributes roughly 70% to the share of US GDP. Developed capitalist economies heavily depend on consumption for rapid economic development (EEA, 2015). Even though, consumer products significantly contribute toward economic development of the country, but heavily dependence on the consumption might be cause of environmental pollution and degradation (EEA, 2015;Panayiotis, 2019;Hazuchova et al., 2020;Lazaroiu et al., 2021). Consumption contributed 70% to the GDP in developed countries in 2019, while the contribution of consumption to GDP in developing countries was 75%. 2 Irresponsible consumer behavior caused environmental pollution and global warming (Adams, 2009). Table 2 shows that consumption of utilities and fossil fuel jointly contribute 60% to global emission in 2018. Table 3 reports the main variables used in the study.

Mobility
The process of globalization intensified local as well as crossborder mobility. Generally, people in developed countries were more mobile, but recently economic activities in developing countries intensified mobility there. International travel increased by leaps and bounds in the last three decades. Only 228 million people crossed international border on airplane in 1980. This number reached to 1 billion in 2012 and crossed the figure of 1.5 billion by the end of 2019. The UN body forecasted that international traveling could plunge by 60-80% in 2020 3 and most of this decline will come from the developing countries. This means that almost a billion people will skip international air traveling after COVID-19 in order to avoid infection and inconvenience. Similarly, road transport in the first half of 2020 was 50% down compared to average road transport in 2019. Transport is responsible for energy-related global carbon emission. Figure 2 shows that cars and trucks are the main contributor to greenhouse gases. Recently, sharp decline in mobility due to COVID-19 has significantly reduced demand for oil and, therefore, less carbon (and other greenhouse gasses) was released into air. Residents of congested and populous cities in the developed countries such as London, Paris, Beijing, and New York are enjoying noise-free environment because of low mobility. Transport mobility also causes inconvenience to wildlife, e.g., road transport in Canada alone kills more than 1 billion bees annually, while cars killed 1,600 billion different  insects in Holland in 2011. 4 Similarly, air transport disrupts the navigation system of migratory birds. Today, the economic development of developed and developing countries heavily depends on trade across the international borders, especially in energy, goods, and services. However, such exchanges severely spoiled the environment. In the last four decades, transportation facilitated a lot in terms of cost-efficiency, but its environmental effects did not heal-up. Transport burns fossil fuels, which release hazardous gases such as NO 2 and empirical evidence suggests that road transport significantly contributes to global warming (He et al., 2020a,b). Road transport is a main cause of nitrogen oxide emission in Europe (see Table 1).

Dataset, Variables, and Source
Nitrogen dioxide (NO 2 ) is the dependent variable, while consumer price index (CPI), confirmed COVID-19 cases, COVID-19-induced deaths, and other control variables are explanatory variables of this empirical study. We are analyzing the impact of COVID-19-induced decline in consumer durables and mobility on NO 2 emission in Europe by empirically and graphically analyzing through consumer price indexes and inflation, GDP deflator indexes for particularly focused on European region.

Descriptive Statistics
The results for descriptive statistics are given in Table 4. For European countries, the mean value of COVID-19-confirmed cases is 12.5 and its maximum and minimum values fall within the range of 24 and 1, respectively. The mean value of death rate of COVID-19-infected cases (annual%) is 2.01 and these values fall within the range of 3.52 and 0.82, respectively. Additionally, the mean value of CPI (2020) is 1.41, while an average range of CPI (2020) assumes values within 1.24-12.27. Additionally, the mean value of CPI (2019) is 2.21, while an average range of CPI (2019) assumes values within 0.25-15.17.
If we make comparative analysis of the values of descriptive statistics of CPI (2020) with those of CPI (2019), we noticed that the mean value of CPI (2020) significantly decreased by 0.80 index points compared to those of CPI (2019). Additionally, the minimum values of CPI (2020) turned to negative digits (−1.24), which imply that the demand of consumer goods significantly reduced after COVID-19 compared to consumption patterns before COVID-19. The mean value of inflation, GDP deflator index (2020) and inflation, GDP deflator index (2019) is 3.36    (2020) with those of GDP deflator index (2019), we noticed that the mean value of CPI (2020) significantly increased by 0.46 index points compared to those of GDP deflator index (2020). As per our descriptive statistics results, which are shown in Table 4, we noticed that demand of consumer goods significantly decreased after COVID-19 because mean value of CPI significantly decreased by 0.80 index points in 2020 (CPI is aggregate composite of all the average indexes of all the consumer goods). The correlation matrix results are given in Table 5. We noticed that there exists a negative association between COVID-19 cases and consumer price indexes. Additionally, there is also negative relationship exists between death rate of COVID-19infected cases (% annually) and consumer price indexes, which strongly support our theoretical and empirical estimations for European region.

Statistical and Graphical Analysis
Our statistical and numerical figures are given in Table 6. We noticed that there are 327,680 confirmed total number of cases in Austria until 16th December 2020 and there are 4,648 confirmed deaths until 16 December 2020 in Austria.
Additionally, in Austria, CPI significantly decreased in 2020 compared to that of 2019. In case of other European countries, i.e., Belgium, Bulgaria, Croatia, Denmark, Finland, France, Germany, Greece, Hungary, Italy, Lithuania, Malta, Netherlands, Norway, Poland, Portugal, Romania, Spain, Sweden, Switzerland, Turkey, and UK, CPI also significantly decreased in 2020 relative to CPI of 2019 due to large number of COVID-19 cases and high number of COVID-19-induced deaths, but GDP deflator index did not affect significantly due to post-COVID-19 pandemic.
All the numerical and statistical summary reports are given in Table 4.
From the graphical trend in Figure 3, we noticed that consumer price index in 2020 decreased significantly relative to CPI of 2010. We infer your graphical analysis that decrease in the values of CPI significantly decreases the demands of consumer goods in European countries.
From the graphical trend in Figure 4, we noticed that CPI of 2020 significantly decreased compared to inflation GDP deflator index of 2020, which implies from your graphical analysis that decrease in the index values of GDP deflator index in 2020 after COVID-19 is quite minimal compared with the marginal difference of CPI of 2020. Henceforth, we conclude that demands of consumer goods significantly reduced in European countries.
From the graphical trend in Figure 5, we noticed that there is a positive correlation between confirmed cases of COVID-19 vs. COVID-19-induced deaths. The trend behavior in Figure 3 shows that as far as confirmed number of cases of COVID-19 is increasing in European region, COVID-19-induced deaths are also multiplying significantly. Thus, there is positive proportional relationship between confirmed number of cases of COVID-19 and COVID-19-induced deaths as per clearly depicted in the graphical presentation in Figure 3.

Empirical Results and Analysis
For empirical analysis, we have generated variable for death rate as per confirmed COVID-19 cases (% annually) from empirical dataset. Additionally, we have formulated variable for % ( CPI) after COVID-19 and % ( mobility) after COVID-19 in Europe. Our empirical result estimations are given in Table 7. We noticed that death rate as per confirmed COVID-19 cases (% annually) is quite high in the European countries.
Due to high death rate of COVID-19 cases, the marginal percentage change of consumer price index [% ( CPI)] after COVID-19 is significantly decreased in the whole European region. Additionally, the marginal percentage change of mobility index [% ( mobility)] after COVID-19 also significantly reduced in Europe. We conclude from our empirical estimation that COVID-19 affected economic and consumption activities in European region. On the contrary, environmental experts claim that COVID-19 is blessing in disguise. It healed the environment due to decrease in the demand of consumer goods. Consumer goods emit huge amount of NO 2 gases. Due to less demand of consumer goods, NO 2 emission will significantly decreased in the atmosphere. Accordingly, less emission of NO 2 will heal the environment due to less use of consumer goods in Europe.

CONCLUSION
The United Nations considers that environmental degradation is one of the serious and the challenging issues of the 21st century. Environmental pollution, including NO 2 emission, is quite detrimental to human health. NO 2 is not only harmful for degradation of human health, but also damages human health indirectly by contributing to the global warming (Hasanat Shah et al., 2021). In order to completely control COVID-19 pandemic, especially European countries and China, strictly imposed lockdown and forced the public to quarantine at homes and closed the public places. All the business and economic activities are suspended due to vast spread of COVID-19. Despite all of the tireless efforts to heal environment and reduce emission of hazardous gases, human efforts achieved little success in the context of achieving the goal of sustainable environmental development.
From our empirical estimations, which are given in Tables 4, 7, we can claim that COVID-19 is blessing in disguise and it healed the environment to the larger extent by reducing the demand of consumer goods and significantly decreased the mobility in Europe. Consequently, due to decline in demand of consumer goods and decline in mobility, it significantly decreased the environmental pollution (reduced NO 2 emission) in Europe. Our graphical Figures 3-5 strongly support the empirical estimations that COVID-19 provided a breathing space to the environment to heal and refurbish at least in the short run (see Table 7). However, in the couple of months, our empirical and graphical results confirm that COVID-19 extensively improved the environment in addition to strict lockdowns that significantly reduced NO 2 . COVID-19 is blessing to explore innovative ways to make environmental friendly development.
Our empirical and graphical result estimations agree with those of Hasanat Shah et al. (2021), which explored this relationship qualitatively by satellite images and proved that NO 2 emission is quite lower in countries with strict bans on mobility and also concluded that lower emission of NO 2 is associated with lower demand of consumer goods. Equally, our correlation matrix results strongly support (see Table 4) that decline in consumption is correlated in NO 2 emission. Additionally, due to strict official lockdowns, work online will definitely change our consumption behaviors and mobility patterns, which will significantly decrease NO 2 emission to large extent. Nevertheless, it is not quite sure whether human behaviors of COVID-19induced decline for demand of consumer goods and less mobility patterns will keep persistent in the long run? Anyway, we confirm that COVID-19 improved environment in the European region. However, high cost (e.g., unemployment, loss of life, and social segregation) makes COVID-19 an unstable solution to environmental woes where positive impact of COVID-19 on environment achieved in short run cannot be guaranteed in the long run. COVID-19 is a blessing in disguise for environment, at least in short run. We can claim from our empirical and graphical results that environmental experts and policymakers working on environmental healing can learn a lot from COVID-19 and can provide persistent environment friendly policy, which can bring real changes on environmental fronts in the long run. Our empirical analysis of this study is based on annual dataset. For further study, we can make our analysis and estimations more rigorous by collecting dataset based on daily or monthly basis and provide more unbiased result estimations due to more availability of sample observation; this will provide robust checks to our result estimations, if the dataset will be available on monthly or daily basis for the future study.
Actually, this empirical study is typically based on the analysis of post-COVID-19-induced decline in consumption and mobility on NO 2 emission in Europe and this empirical study is based on maximum 1 year and our dataset of the variables is available on annual basis and we cannot apply proper regression methods due to availability of dataset of only 1 year on annual basis. Conditionally, availability of our dataset of this empirical study is based on daily or monthly or quarterly basis and then we can further extend the idea of this study by applying rigorous panel regression methods for future study direction and more interestingly explain our results empirically and providing interesting policy implication by following result estimations of panel regression methods. Thus, we consider it as limitation of this study that we could not be able to apply rigorous panel regression methods due to availability of dataset of this proposed study on annual basis for only maximum 1 year.

DATA AVAILABILITY STATEMENT
The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.