Sulfur dioxide (SO2) . Covering novel concepts and key points of interest, this book explores the frontier applications of nanomaterials. Sulfur dioxide emissions are a precursor to acid rain and atmospheric Sulfur dioxide (SO 2) contributes to . The secondary standard is 0.5 parts per million (ppm) averaged over 3 hours. One of the most poisonous and harmful gases causing air pollution is sulfur dioxide (SO2). Oil Spill Environmental Forensics provides a complete view of the various forensic techniques used to identify the source of an oil spill into the environment. Hazardous air pollutants are a group of 187 toxics that according to EPA " are known or suspected to cause cancer or other serious health effects, such as . Sulphur dioxide, discharge limit and reporting. When SO2 mixes with water droplets or vapor, it reacts to produce sulphuric or sulfurous acid. Ambient NO 2 exposure may increase the risk of respiratory tract infections through the pollutant's interaction with the immune system. Please click here to see any active alerts. Major sources in Washington are: Industrial facilities such as fossil fuel power plants, aluminum smelters, oil refineries, and pulp mills. Some companies may close because of a lack of money to purchase new safer and cleaner equipment. It is moderately water soluble and forms sulfurous acid in water: (1) SO 2 + H 2 O = H 2 SO 3. People with asthma, particularly children, are sensitive to these effects of SO2. Sulfur dioxide is one of the main air pollutants and is a primary concern in UAE. Sulphur dioxide: basic information and health. Research for the book was conducted in controlled laboratory studies and epidemiologic studies. Special emphasis throughout Health Effects of Ambient Air Pollution is placed on the effects of air pollution in subjects with asthma. For example, the municipal council of Dubai noted that in 2009, 1,021,880 cars emitted about 2,334,762 Kg of carbon dioxide every day. Further oxidation of SO2, usually in the presence of a catalyst such as NO2, forms H2SO4, and thus acid rain.[2] This is one of the causes for concern over the environmental impact of the use of these fuels as power sources. Found insideReviews and research papers describe air pollution in five main contexts: Monitoring, Modeling, Risk Assessment, Health, and Indoor Air Pollution. The book is recommended to experts interested in health and air pollution issues. Sulfur dioxide is one of the five main air pollutants. Chemists and chemistry students, industrialists, and environmental planners will find this guide to sulfur helpful. Lecturers in chemistry and researchers in the many fields of application of sulfur will likewise benefit from it. In this study, an environmental risk assessment of sulfur dioxide in the UAE was carried out. In this test, samples of air should be taken from different areas in the UAE. Studies have shown that individuals exposed to SO2 have increased breathing problems and are normally hospitalized frequently. These standards are designed to protect sensitive individuals, such as children and asthmatics. Percolation of acidic water in rivers and lakes increases the pH of the water and this destroys aquatic life in the long run. 1.3 Sulfur Dioxide. "Sulphur Dioxide as an Air Pollutant in the UAE." Sulphur Dioxide (SO 2) What is sulphur dioxide? Other control strategies include: creating awareness on the impacts of air pollution, educating citizens and company workers on strategies to reduce pollution, adopting energy-efficient methods, use of solar energy, tree planting, and the use of air cleaning equipment. Sulfur dioxide (SO 2) is a colorless gas with a noticeable odor.The department monitors sulfur dioxide levels in the air at locations across the state. Sulphur Dioxide as an Air Pollutant in the UAE, Air Quality in Abu Dhabi: Problems and Solutions, Indoor Air Pollution: The Silent Killer in Rural India, Ecology: the Industrial Manufacture of Sulphuric Acid, How do factory emissions lead to creation of acid rain, How volcanoes have impacted the global climate, Occupational Safety and Health Administration, Air Pollution and China's Governmental Measures, Air Pollution in Beijing and the Decision-Making Bias, Smog Problems in Beijing: Causes and Effects, "Fort McMurray Fires Cause Air Pollution" by McDiarmid, Air Pollution as the Trigger of the Ecological Catastrophe. Like nitrogen dioxide, sulfur dioxide can create secondary pollutants once released into the air. Sulfur oxide is dangerous at low and high doses. London: Routledge publishers. The change process is gradual and may take a long time. The chemical under assessment is sulfur dioxide SO 2. At high concentrations, gaseous SOx can harm trees and plants by damaging foliage and decreasing growth. Carbon monoxides. Exposure to this gas causes serious respiratory diseases. The SO2 gas levels are shown in Tables 1 and 2 below. Enforcing the law would require strict monitoring of all industries and the transport sector. Sulfur dioxide. Any substance that is present in air, water or soil and has an adverse effect on some other part of environment is called pollutants. professional specifically for you? EPA’s national ambient air quality standards for SO2 are designed to protect against exposure to the entire group of sulfur oxides (SOx). IvyPanda, 21 June 2021, ivypanda.com/essays/sulphur-dioxide-as-an-air-pollutant-in-the-uae/. New York: CRC Press. The risk assessment process has the following main processes; The chemical under assessment is sulfur dioxide SO2. There is no accountability in this intervention and some industries may continue polluting the environment. determines whether areas meet the standards, works with areas to attain and maintain the standards, Scientific and Technical Documents for Primary Standards, Scientific and Technical Documents for Secondary Standards. This edition explores the processes and equipment that produce less pollution in the atmosphere. This book is comprised of six parts encompassing 28 chapters. Please click here to see any active alerts. Emissions that lead to high concentrations of SO2 generally also lead to the formation of other SOx. Exposure to large doses of sulfur dioxide causes death. If organizations and industries can change willingly, continuous reduction in air pollution is possible as the intervention is self-driven. JavaScript appears to be disabled on this computer. Environmental Effects: Sulfur dioxide and nitrogen oxides are the major precursors of acid rain, which has acidified soils, lakes and streams, accelerated corrosion of buildings and monuments, and reduced visibility. WHO Regional Office for Europe, Copenhagen, Denmark, 2000 1 Chapter 10 Effects of sulfur dioxide on vegetation: critical levels Sulfur dioxide (SO2) was formerly viewed as the most important phytotoxic pollutant in Europe, and until the early 1980s was the subject of the greatest research in this field. Traditionally, ground-level ambient concentra-tions of sulfur dioxide were reduced by emitting gases through tall stacks. A University of Liverpool study of air pollution in the UK during the first 100 days of lockdown has revealed that whilst nitrogen oxide levels were cut by half, levels of sulfur dioxide increased . Sulfur oxides, both SO 2 and SO 3 , are constituents of acid rain. The legislation allowed older power plants to be exempt from the new standards, because Congress assumed these plants would be phased out of service. Laws limiting the use of cars within cities would reduce pollution that is mostly concentrated in cities. You can use them for inspiration, an insight into a particular topic, a handy source of reference, or even just as a template of a certain type of paper. (1) Subject to subsection (2), on or after July 1, 2019, a person shall not discharge or cause or permit the discharge of a total of more than 225 kilograms of sulphur dioxide in a 24-hour period from one or more pieces of acid gas combustion equipment at a petroleum facility. Some of these are analyzed below. Major sources in Washington are: Industrial facilities such as fossil fuel power plants, aluminum smelters, oil refineries, and pulp mills. SO2 dissolves in water vapour in the air to form acids, and interacts with other gases . The book addresses many coal-related subjects of interest ranging from the chemistry of coal and the future engineering anatomy of a coal fired plant to the cutting edge clean coal technologies being researched and utilized today. IvyPanda. The gas also causes acidic rain which destroys plant, aquatic life and increases the soil pH. In combination with other pollutants and moisture (e.g. The study, led by Nickolay Krotkov of NASA's Goddard Space Flight Center, was published in Atmospheric and Chemistry Physics Discussions. for six common air pollutants (also known as "criteria air pollutants"). The database is updated daily, so anyone can easily find a relevant essay example. Such legislation should: The SWOT matrix for this intervention is tabulated below. The main air pollutants in the UAE include sandstorms, dust storms, emissions from industrial plants and vehicles as well as air pollutants emanating from the built environment. SO2 causes serious irritation to the skin and eyes and a large dosage can cause blindness. Traditionally, ground-level ambient concentra-tions of sulfur dioxide were reduced by emitting gases through tall stacks. The most important sulfur oxides in terms of air pollution are sulfur dioxide, SO2 and sulfur trioxide, SO3. The level of impurities should then be compared with safe levels (Hanrahan, 2011). An official website of the United States government. Written for professionals and researchers in the renewable energy, combustion, chemical, and mechanical engineering fields, the information in this book will equip readers with detailed guidance on how to reliably obtain properties of fuels ... When SO2 is emitted in large quantities, other oxides of sulfur are formed (SOx). In the United Arab Emirates (UAE), atmospheric pollution has a great impact on humans, animals, and plants. Hanrahan, G. (2011). a) In many of world' cities especially Shenyang and Xian in China where the estimated. Since this method does not address the problem of long-range transport and deposition of sulfur and merely disperses the pollutant, reliance on this strategy is no longer recommended. Such legislation should focus on controlling emissions from the main sources Cooper & Alley, 2010). Fossil fuel combustion is the main source of SO 2 gas. Health Iran Hemoglobin Sulfur Dioxide Air Pollutants 1. highest concentration of air sulfur dioxide and particulate matter occur, and Mexico. For example, though the air has sulfur oxides in it, they become pollutants if they exceed a certain level (Robson & Toscano, 2007). Carbon monoxide can even provoke direct poisoning when breathed in at high levels. Since this method does not address the problem of long-range transport and deposition of sulfur and merely disperses the pollutant, reliance on this strategy is no longer recommended. How many pages (words) do you need? This essay on Sulphur Dioxide as an Air Pollutant in the UAE was written and submitted by your fellow student. Nitrogen dioxide (NO 2), sulfur dioxide (SO 2), and carbon monoxide are important ambient air pollutants.High-intensity, confined space exposure to NO 2 has caused catastrophic injury to humans, including death. Though such develops are profitable, policymakers should also examine the impact they have on the environment and develop appropriate legislation to reduce pollution. McGranahan, G., & Murray, F. (2003). City, the world's worst polluted . 1957. Sulfur Dioxide is part of a larger category of related chemicals, often referred to as 'sulfur oxides' or SO X. for six common air pollutants (also known as "criteria air pollutantscriteria air pollutantsThese pollutants are particulate matter, photochemical oxidants (including ozone), carbon monoxide, sulfur oxides, nitrogen oxides and lead. Sulfur dioxide (SO 2) is a colorless gas with a strong smell. This book will provide you with a solid understanding of aquatic toxicology, its past, its cutting-edge present and its likely future. It is one of the main air pollutants. Lack of attention to adopting energy-efficient methods. Inhaling a small amount of this gas causes asthma and other respiratory diseases. Sulphur dioxide, or SO2, belongs to a family of sulphur oxide gases (SO x ). Most industries combust fossil fuel or coal and emit sulfur oxides as one of the exhaust gases. "This publication represents the views and expert opinions of an IARC Working Group on the Evaluation of Carcinogenic Risk to Humans, which met in Lyon, 8-15 October 2013." 1958. and secondary standardssecondary standardsNational ambient air quality standards designed to protect the public welfare from adverse effects, including those related to effects on soils, water, crops, vegetation, man-made (anthropogenic) materials, animals, wildlife, weather, visibility, and climate; damage to property; transportation hazards; economic values, and personal comfort and well-being. Harrop, O. (b) sulphur dioxide (c) carbon dioxide (d) nitrogen dioxide. NAAQS are currently set for carbon monoxide, lead, ground-level ozone, nitrogen dioxide, particulate matter, and sulfur dioxide. Cities would become cleaner attracting more people and tourists. Official websites use .gov 7 facility in Ward County had the most unauthorized air pollution in 2017, releasing 6.8 million pounds of sulfur dioxide in 10 incidents. Since coal and . To make the students aware of history of air pollution; definition of air pollution and various types of sources and classification of air pollutants. "Sulphur Dioxide as an Air Pollutant in the UAE." According to Rasheed (2011), car emissions contribute to over 82% of all the total air pollution in Dubai. This book will also be useful to those wishing to reference how disciplines interact within the broad field of toxicology. 0.08ppm for a 24-hour exposure period. (2007). These fuels are widely used in vehicles, industries, and energy generation plants. These Pollutants are either natural (eg.wildfires) or synthetic (manmade)in the form of gas ,liquid or solid. EPA’s national and regional rules to reduce emissions of SO, EPA identifies areas where the air quality does not meet EPA SO, Learn more about visibility and regional haze, Learn about how air quality standards help reduce SO, Secondary NO2 and SO2 Standard Regulatory Actions, Primary SO2 Standard Implementation Actions, SIP Training Presentations and Assistance. 12. Plants get presented to sulphur dioxide through the acid downpour. Web. <br />Since coal and petroleum often contain sulphur compounds, their combustion generates sulphfur dioxide. According to air quality expert Lauri Myllyvirta, lead analyst at the Centre for Research on Energy and Clean Air and a member of the Expert Panel advising government on managing sulphur dioxide (SO2) from power plants appointed by the Environment Minister in 2018, the rotten egg smell is a strong indicator that the pollutant in question is . Ammonia, carbon monoxide, sulfur dioxide, nitrous oxides . For full functionality of this site it is necessary to enable JavaScript. Table 2: showing the SO2 levels in Fujairah(source: (Source UAE National Bureau of statistics, 2013)). According to EPA (2013), short and long term exposure to SO2 has adverse respiratory effects. (2013). Reduce emissions from power plants:-Nearly half of the SO, Since the legislation sets the minimum SO. Nov. 9, 2017 — Sulfur dioxide is an air pollutant that causes acid rain, haze and many health-related problems. This book is the eighth volume in the series Acute Exposure Guideline Levels for Selected Airborne Chemicals, and reviews AEGLs for acrolein, carbon monoxide, 1,2-dichloroethene, ethylenimine, fluorine, hydrazine, peracetic acid, ... It exist mainly in indoor environment of industrial facilities like refineries and power plants. Adverse health consequences to air pollution can occur as a result of short- or long-term exposure. In the UAE, most towns in the UAE have lower SO2 gas levels. STEPPING UP THE ATTACK AGAINST acid rain and smog, LBL researchers have developed a new technology to help eliminate sulfur dioxide air pollution from power plants, incinerators, chemical plants, and smelters.. Part of a multi-stage treatment system, the LBL process treats concentrated sulfur dioxide, converting more than 95 percent of it to a valuable commodity: elemental sulfur, a chemical . An increase in the concentration of SO2 results in an increase in the pH of acidic rain and the damages caused by it. Share sensitive information only on official, secure websites. Risk Assessment for Environmental Health. SO2 is one of the most dangerous air pollutants. British Standards Control measures that reduce SO2 can generally be expected to reduce people’s exposures to all gaseous SOx. Ships and locomotives. 5. IvyPanda. In nature, sulfur dioxide can be released to the air from volcanic eruptions. Reduced health expenses as very few people would suffer from respiratory illnesses. It can be oxidized to sulphur trioxide, which in the presence of water vapour is readily transformed to sulphuric acid mist. Reduction in energy consumption and reduces global warming. (2013). The urban city air would become cleaner attracting more people and tourists. It exist mainly in indoor environment of industrial facilities like refineries and power plants. Air pollution: does it get worse before it gets better? Risk can be defined as systematic identification and characterization of potential negative impacts that certain chemicals and materials have on human health. It is considered to be a criteria pollutant in the troposphere—the lowermost layer of the atmosphere—but not in the upper atmosphere, where it occurs naturally and serves to block harmful ultraviolet rays . 21 June. air pollution - air pollution - Ozone: A key component of photochemical smog, ozone is formed by a complex reaction between nitrogen dioxide and hydrocarbons in the presence of sunlight. 1. Sulfur trioxide is an air pollutant that affects the lungs and makes it hard to breath. These pollutants are found all over the U.S. Furthermore, nitrogen oxide, sulfur dioxide, Volatile Organic Compounds (VOCs), dioxins, and polycyclic aromatic hydrocarbons (PAHs) are all considered air pollutants that are harmful to humans. It has a pungent, irritating odor. These pollutants are found all over the U.S. These toxicological tests vary with the different standardizing agencies. Secure .gov websites use HTTPS Sulfur dioxide also is a major precursor of fine particulate soot, which poses a significant health threat. Current, sulfur dioxide monitoring activities include the use of emission inventories that are derived from ground-based measurements and factors, such as fuel usage. ensure the integrity of our platform while keeping your private information safe. The current literature on the role of sulfur dioxide in air pollution M review of the literature of the last 10 years on sulfur dioxide and other sulfur compounds as air pollutants, re-veals great interest in methods of at-mospheric analysis for these compounds, particularly in the lower concentration ranges. Air Quality Assessment and Management: A Practical Guide. These SOx react with other gases in the atmosphere forming small particles that penetrate deep into the lungs where they cause many respiratory diseases. Air pollution is the entry of a substance into the air, which causes the air to not function properly. 0.02ppm for an annual exposure period. Sulfur trioxide is an air pollutant that affects the lungs and makes it hard to breath. Air Pollutant - Nitrogen Dioxide National Environment Agency / 11 Aug 2020 Annual means for nitrogen dioxide (µg/m3) are based on WHO Air Quality Guidelines (global update 2005). Air pollution is a problem affecting every part of our planet however, its global effects are poorly understood. This book provides the first truly global assessment of the scale of impacts of air pollution on crops and forests. Carbon monoxide, carbon dioxide, sulfur dioxide, nitrogen oxides, VOC's (volatile organic compounds), PM's, photochemical oxidants, ozone and PANs. Sulphur dioxide caused 0.3 days of 'Moderate' or higher pollution days in 2020. This may have the important co-benefit of reducing the formation of particulate sulfur pollutants, such as fine sulfate particles. The two are issued together and the proportion of the second is from 1% to 5% of the total. • These and other pollutants can return to the earth through the Significant concentrations of sulfur dioxide are . Key Concepts in Environmental Chemistry. SO 2 emissions that lead to high concentrations of SO 2 in the air generally also lead to the formation of other sulfur oxides (SO x). . If you are the copyright owner of this paper and no longer wish to have your work published on IvyPanda. Your privacy is extremely important to us. 2021. The book will be a single source that provides an introduction to coal, discusses the history of using coal (both good and bad experiences), compares coal to other energy sources, discusses the impact of coal usage on the environment, ... SO2 is extremely toxic gas and inflammable gas. Table 1: the amount of sulfur dioxide in Dubai city (Source UAE National Bureau of statistics, 2013). Found insideIn this volume experts discuss in depth all relevant issues of airborne particulate matter, including the characterisation of aerosols by modern physical and chemical methods. Sulphur Dioxide can be harmful to human health. "Sulphur Dioxide as an Air Pollutant in the UAE." The main sources of Sulphur dioxide (SO 2) emissions are electricity generation, industrial and domestic fuel combustion.Total SO 2 emissions have decreased substantially, in line with changes in fuel use and commitments to international agreements within the UNECE Convention on Long Range Transboundary Air Pollution and the European Union ("Sulphur Protocols"). It is produced predominantly when coal is burned to generate electricity. Acidic rain is very common in highly industrialized cities that rely on fossil fuels to power their industries. Inhaled SO₂ can also cause chromosomal aberrations, DNA damage and gene mutations in mammals. SO2 is extremely toxic gas and inflammable gas. iii. As aforementioned, the principal source of SO2 is the combustion of fossil fuels. ), determines whether areas meet the standards, and works with areas to attain and maintain the standards. humidity) sulphur dioxide is responsible . Need a custom Essay sample written from scratch by In nature, sulfur dioxide can be released to the air from volcanic eruptions. A known health hazard and contributor to acid rain, sulfur dioxide (SO2) is one of six air pollutants regulated by the U.S. Environmental Protection Agency. This reflects the large reductions in emissions from the early 1990s. Children and old people are highly affected by SO2 even in low concentration. EPA calls these pollutants “criteria” air pollutants because it sets NAAQS for them based on the criteria, which are characterizations of the latest scientific information regarding their effects on health or welfare."). Lack of proper policies, laws, and regulations on pollution control exacerbates the pollution problem in the UAE. A lock (LockA locked padlock) or https:// means you’ve safely connected to the .gov website. Listen to Dr. Fabrice Morvan as he talks about the use . IvyPanda. OMI has been monitoring sulfur dioxide and other air pollutants since 2004. It is one of the main air pollutants. Sulfur dioxide (SO 2) is used as an indicator of all SO x concentrations in the ambient air, because it is the most easily measured. Lecture 1: Lecture 2: Lecture 3 . Oxidative damage due to SO₂ can occur in multiple organs. (2021) 'Sulphur Dioxide as an Air Pollutant in the UAE'. Ray Tricker, Samantha Tricker, in Environmental Requirements for Electromechanical and Electronic Equipment, 1999. Health impacts of sulfur dioxide (SO2) Pollutants have harmful effect on both health and quality of health of human being. Sulfur Dioxide (SO 2), is a colorless gas with a pungent, suffocating odor that is water soluble to produce the acid, H 2 SO 3. Waltham, Massachusetts: Academic Press. Some of important air pollutants are given as follows. It is a liquid when under pressure, and it dissolves in water very easily.Sulfur dioxide in the air comes mainly from activities such as the burning of coal and oil at power plants or from copper smelting. Petrochemical industries generate hydrogen fluoride, hydrochloric acid and organic halides. Environmental and Experimental Botany 40 (1998) 265 - 273 Effects of sulfur dioxide on the development of powdery mildew of cucumber Mujeebur Rahman Khan *, M. Wajid Khan, M. Jahangir Pasha En6ironmental Pollution Research Unit, Department of Botany, Aligarh Muslim Uni6ersity, Aligarh 202 002, India Received 15 October 1997; received in revised form 6 August 1998; accepted 8 August 1998 . SO2 is particularly detrimental to individuals who suffer from respiratory diseases such as asthma and chronic bronchitis. Several tests have designed to determine the levels of SO2 in the air. There is no guarantee that people will change their lifestyles to prevent pollution. Sulfur dioxide is produced by the combustion of sulfur containing fuels such as coal. The gas is mainly emitted by vehicles, industries, and power generation plants. Sulfur dioxide is a colorless gas with a pungent odor. This site provides information about sulfur dioxide and its effects. With an emphasis on passive sampling, this volume focuses on the environmental monitoring for common gaseous pollutants. June 21, 2021. https://ivypanda.com/essays/sulphur-dioxide-as-an-air-pollutant-in-the-uae/. Better environmental protection by the government. Sulfur oxides, both SO 2 and SO 3 , are constituents of acid rain. It is specific for sulphur dioxide and can be operated over sampling periods of 5 min to 24 h. In the preparation of this standard considerable assistance has been derived from the following publications: BS 1747-3:1969 Method for the measurement of air pollution, Part 3, Sulphur dioxide. Occidental's Sealy Smith Clearfork No. Such policies would increase efficiency in the industrial and transport sector. In the UAE, the main sources of SO2 pollution are; One of the causes of SO2 pollution in the UAE is emissions from vehicles, especially in large cities. The main sources of air pollution are: (b) INDUSTRIES: Combustion of fuel to generate heat and power produces smoke, sulphur dioxide, nitrogen oxides and fly ash. i. Sulphur oxides (SOx) ii. Exposure to a small amount of sulfur dioxide causes serious respiratory problems. The acid reacts with an iron sheet destroying building roofs. 30. This study reports the air pollution vulnerability mapping of Lahore city and provides information about the vulnerability levels of air pollutants at various places of Lahore. Answer: (d) Escherichia coli. • These chemical compounds take the form of tiny solid particles or liquid droplets and can remain in the air for days or even years. The campaigns would also prompt individuals to plant trees near their homes or organizations. Planting and watering trees would improve the landscape of the country. As nations become industrialized and their population increase, more and more pollutants are being added into the environment. Answer: (c) carbon dioxide 30. Under the auspices of the UNECE Convention on Long Range Transboundary Air Pollution, around 80 international experts met to review the state of scientific knowledge. This book reports their analysis. 47 48 Major pollutants produced by human activity Sulphur dioxide (SOx) SO2 is produced by volcanoes and various industrial process. Sulphur dioxide (SO₂) emissions measured in tonnes. Sulfur dioxide is a common combustion product from the burning of coal or oil products and as a result it has been a major contributor to atmospheric corrosion in urban and industrial areas. (2021, June 21). The six pollutants are carbon monoxide, lead, ground-level ozone, nitrogen dioxide, particulate matter, and sulfur dioxide. The other primary air pollutants are nitrogen oxides, lead, carbon oxides, and particulates. The Clean Air Act requires EPA to set National Ambient Air Quality Standards (NAAQS) National Ambient Air Quality Standards (NAAQS)National Ambient Air Quality Standards established by EPA for six "criteria" pollutants in outdoor air.

Webex Screen Sharing Not Working Mac Big Sur, Massachusetts Benefits For 100 Percent Disabled Veterans, Lincoln Highway Today, Among Us Birthday Decorations Party City, Medical Parole Pros And Cons, Bachelor Party In Georgia, Mysql Incremental Backup,