Journal of Spatial Analysis Environmental Hazards

fa ارتباط بین کووید-19 و تغییرات آلاینده‌های هوا با استفاده از تصاویر ماهواره‌ای (مطالعه موردی: کلان‌شهرهای تهران، اصفهان و مشهد) "Relationship between Covid-19 and changes in air pollutants using satellite imagery (Case study: Tehran, Isfahan and Mashhad metropolises)" تخصصي Special پژوهشي Research با مشاهده اولین مورد تائید شده کووید-19 در شهر قم در 30 بهمن 1398 محدودیت‌هایی توسط دولت و دستگاه‌های اجرایی جهت جلوگیری از شیوع ویروس کووید-19 در تمام شهرهای ایران اعمال شد. بنابراین این مطالعه با هدف بررسی تغیر در تولید و انتشار آلاینده‌های دی‌اکسید گوگرد، دی‌اکسید نیتروژن، مونوکسید کربن و ازن در قبل و بعد از شیوع ویروس کووید-19 در سه کلان‌شهر تهران، اصفهان و مشهد با استفاده از داده‌های ماهواره‌ای سنتینل-5 انجام گرفت. برای این منظور با استفاده از سامانه گوگل ارث انجین مقادیر غلظت این آلاینده‌ها به‌صورت میانگین ماهانه در دو بازه 1 اسفند 1397 تا 1 اسفند 1398 برای دوره پیش از شیوع کووید-19 و بازه 1 اسفند 1398 تا 1 اسفند 1399 برای دوران شیوع کووید-19 در نظر گرفته شد. سپس برای ارزیابی معنی‌دار بودن تغیر در غلظت این آلاینده‌ها در قبل و بعد شیوع ویروس کووید-19 از آماره T-test (t وابسته) در سطح معنی‌داری 05/0 >p-value استفاده شد. نتایج آزمون T-test نشان داد که برای آلاینده‌های دی‌اکسید گوگرد، دی‌اکسید نیتروژن، مونوکسید کربن در هر سه شهر هیچ تغیر معناداری در میانگین غلظت داده‌ها رخ نداده است؛ اما ازن برای هر سه شهر تهران، اصفهان و مشهد دارای روند کاهشی و سطح معنی‌داری 05/0 >p-value بوده است. بیشترین مقدار تغیر در کاهش غلظت ازن برای کلانشهر تهران در خرداد ماه و آبان تا بهمن، برای اصفهان بین مهرماه تا اواسط دی و برای مشهد در اردیبهشت تا خرداد ماه و آبان تا بهمن مشاهده شد. همچنین، تغییرات مکانی ازن در شهر تهران در قبل و بعد شیوع اپیدمی قابل توجه بوده است. نتایج این مطالعه نشان داد که اعمال محدودیت‌ها نتیجه‌ای در کاهش انتشار آلاینده‌های اولیه از منابع انسانی نداشته است و فقط ممکن است در طی یک بازه کوتاه غلظت آلایندهها کاهش یابد اما بعد از رفع محدودیتها مجدد روند افزایشی داشته باشند. Study the Effects of Covid-19 on Air Pollutants by Using Sentinel-5 Satellite Images (Case Study: Metropolises of Tehran, Isfahan, and Mashhad) Zeinab shogrkhodaei, PHD. Student of Climatology, Faculty of Literature and Humanities, Department of Geography, Razi University Amanollah Fathnia*, Assistant Professor of Climatology, Faculty of Literature and Humanities, Department of Geography, Razi University Vahid Razavi Termeh, PHD. Student of GIS, Faculty of Geodesy and Geomantic, K. N. Toosi University. Introduction One of the challenges facing the international community right now is Covid-19. This pandemic has caused a comprehensive change in behavior contrary to the usual routine, which can lead to changes in people's lifestyles (Briz-Redón et al., 2021). The prevalence of this disease has not only affected the economy and health, but also the environment (Sohrabi et al., 2020). Among the effects of Covid-19 on the environment are the effects on beaches, noise, surface and groundwater, municipal solid waste, and air quality (Zambrano-Monserrate et al., 2020). The restrictions applied during the Covid-19 era were accompanied by a reduction in greenhouse gas emissions by transport and industry, which affected air quality (Rybarczyk and Zalakeviciute, 2020). Air is a vital element for the survival of all living things, but human activities have caused the release of many harmful pollutants into the atmosphere and endangered human health (Ghorani-Azam et al., 2016). Among the causes of death, air pollution is the fourth leading cause of death in the world after tobacco (WHO, 2020a). Sulfur dioxide, nitrogen oxide, carbon monoxide, and ozone are some of the pollutants that cause short-term or long-term exposure to heart and lung disease (Briz-Redón et al., 2021). Human activities are one of the main sources of air pollutants, so their concentration is expected to decrease during the Covid-19 period (Ghahremanloo et al., 2021). Materials and methods In this study, the required data were the average monthly pollutants of sulfur dioxide, nitrogen dioxide, carbon monoxide and ozone before (20 February 2019 to 20 February 2020) and after (20 February 2020 to 20 February 2021) the prevalence of Covid-19 virus. For this purpose, Sentinel-5P satellite images were used to prepare the required data set. The case study included three metropolises of Tehran, Mashhad, and Isfahan. Google Earth Engine was used to access Sentinel-5P satellite images. The final output of the images for each pollutant was interpolated for better display and exposure in GIS software using the kriging method. Then, a T-test was used to compare the differences between the concentrations of contaminants before and after the outbreak of the Covid-19 virus and to evaluate the mean correlation. Based on this test, values that were p-value <0.05 were considered significant. This was considered as a change in the concentration of the contaminant before and after the Covid-19 virus (decreasing or increasing). Those pollutants with a p-value <0.05 were considered unchanged. Results and Discussion Analysis of the T-test showed that for pollutants such as sulfur dioxide, nitrogen dioxide, and carbon monoxide in all three metropolises, there was no significant change in their concentration before and after the outbreak of the Covid-19 virus. However, significant changes were observed for ozone pollutants. Also, its concentration trend in all three metropolises has been a decreasing trend. The main sources of emissions of nitrogen dioxide, carbon monoxide, sulfur dioxide, and ozone are related to human activities, including transportation and industry (Ghahremanloo et al., 2021; Cárcel-Carras et al., 2021). Pollutants such as carbon monoxide, nitrogen dioxide and sulfur dioxide are the primary pollutants; It means that they are emitted directly from sources, while ozone is a secondary pollutant and depends on complex and nonlinear atmospheric chemistry (Bekbulat et al., 2021). Given that the concentration of ozone surface decreases significantly with increasing concentration of nitrogen dioxide. When nitric oxide (NO) emissions are high enough, the NO released into the atmosphere converts a large portion of ozone to nitrogen dioxide (Hashim et al., 2021). In addition, in all three cities, when the concentration of nitrogen dioxide increased, we saw a decrease in the amount of ozone concentration. In addition, during the Covid-19 era, many industries that produced primary pollutants, including carbon monoxide, nitrogen dioxide, and sulfur dioxide, were not on the closure list or were telecommuted. Despite the decline in the performance of some activities, important sectors such as manufacturing plants, industrial and mining centers, agriculture, and public transportation have continued to operate even during severe restrictions. The mean difference between the concentrations of nitrogen dioxide before and after the outbreak of Covid-19 was positive. However, this average difference is small. However, the concentration of nitrogen dioxide is slightly increased, especially in cold seasons; Therefore, it can be said that ozone concentration has decreased. Keywords: Covid-19, Air Pollutants, Remote Sensing, Sentinel-5.   آلودگی هوا, محدودیت رفت و آمد, سیستم اطلاعات جغرافیایی, تغییرات مکانی. Covid-19, Air Pollutants, Remote Sensing, Sentinel-5, GIS. 21 40 http://jsaeh.khu.ac.ir/browse.php?a_code=A-10-66-1&slc_lang=fa&sid=1 zeinab shogrkhodaei سیده زینب شکرخدایی zeinab.shogrkhodaei@yahoo.com 100319475328460010636 100319475328460010636 No Razi university دانشگاه رازی amanollah Fathnia امان اله فتح نیا a_fathnia@razi.ac.ir 100319475328460010637 100319475328460010637 Yes Razi university دانشگاه رازی Vahid Razavi Termeh سید وحید رضوی ترمه Vrazavi70@gmail.com 100319475328460010638 100319475328460010638 No K. N. Toosi University دانشگاه خواجه نصیرالدین طوسی