What is Sulfur dioxide?
- A colourless, pungent gas
- Harmful pollutant (top 6 air pollutants)
- chemical formula of SO2
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| Representation of a sulfur dioxide molecule credits: earthtimes.org |
Sources of sulfur dioxide
- Natural
- Release from oceans
- forest fires
- biological decay
- Volcanic activity
- Industrial
- Emissions from industrial facilities
- fossil fuel combustion
- Generating electricity supply
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| Chart of the main contributions towards emissions of sulfur dioxide credits: www.environment.gov.au |
Effects of sulfur dioxide
- reacts with water vapour or other chemicals in the atmosphere to form sulfur based particles which reflect the sun's rays and cools the earth for periods of time (not necessarily a positive effect)
- sulfur dioxide forms haze which reduces visibility
- irritates eyes and cause breathing difficulties as it irritates lungs too
- Forms into acid rain (rain with pH value of 4 or less)
- dissolves in rainwater to form sulfurous acid (SO2 (g) +H2O (l)---> H2SO3 (aq) )
- sulfurous acid is oxidised in air to form sulfuric acid (2 H2SO3 (aq)+ O2 (g) ---> 2 H2SO4 (aq) )
- Acid rain leaches important nutrients from soil and destroys plants
- reduce pH value of natural water bodies and kill aquatic life
- reacts with metals and carbonates, thus corroding and destroying monuments, statues, buildings and bridges
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| Haze in Kuala Lumpur source: en.wikipedia.org |
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| How acid rain is formed source: ecopolproject.blogspot.com |
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| Graphic illustration of acid rain source: initzs.deviantart.com |
Link to youtube video:
Watch our short youtube video to find out more! :) Group 1's youtube video :-)
Hopefully you enjoyed the video and learnt valuable knowledge from the short 2 min video!
Sources for info:
- Chemistry matters 'O' Level textbook by Marshall Cavendish
- http://www.epa.gov/airquality/sulfurdioxide/
- http://en.wikipedia.org/wiki/Sulfur_dioxide
Now that you know about the effects of sulfur dioxide on the environment, how is sulfur dioxide used in our daily lives and how does it affect us be it positively or negatively?
Open ended question:
Now that you know about the effects of sulfur dioxide on the environment, how is sulfur dioxide used in our daily lives and how does it affect us be it positively or negatively?
Sulfur dioxide is used in our daily lives, especially as a food preservative. For example, the orange apricots that we buy in wholesale markets have actually been bleached in sulfur dioxide to increase its shelf life and to also kill potentially harmful bacteria on the apricot. Also, sulfur dioxide is actually harmless to a normal healthy person when taken in low concentrations.
ReplyDeleteAnother use of sulfur dioxide is that it is used in wine making. In order to keep the wine fresh till it is opened and to prevent it from reacting with substances in the air such as oxygen, sulfur dioxide is added to the wine. Sulfur dioxide prevents the wine from being oxidised as it acts as an antioxidant. This means that sulfur dioxide present in wine actually binds to dissolved oxygen and prevents the wine from being oxidised, thus keeping the wine fresh till it is opened.
Although sulfur dioxide has many benefits, the main concern of its usage for such purposes is that it largely affects the group of people with asthma or asthma history. When inhaled or ingested at high dilution by this group of people, it could potentially induce an asthma attack due to breathing difficulties caused by the acidity and pungent smell of the gas. According to a research recorded by the US National Library of Medicine, one in nine asthmatics gives a history of asthma worsened by the ingestion or inhalation of sulfur dioxide.
Thus, although there are good uses of sulfur dioxide, the disadvantages of it could push society to scale down on the usage of sulfur dioxide and may consider switching to another alternative.
By: Group 4 (Duncan, Zhi Yuan, Joe, Ngai Chun)
Sulphur dioxide is a reducing agent and is used for bleaching and as a fumigant and food preservative.Large quantities of sulphur dioxide are used in the contact process for the manufacture of sulphuric acid.
ReplyDeleteSulphur dioxide is used in bleaching wool or straw, and as a disinfectant.
Liquid sulphur dioxide has been used in purifying petroleum products.
Sulphur dioxide in foods and beverages: its use as a preservative and its effect on asthma.Sulphur dioxide is widely used in the food and drinks industries for its properties as a preservative and antioxidant. Whilst harmless to healthy persons when used in recommended concentrations, it can induce asthma when inhaled or ingested by sensitive subjects, even in high dilution. About one in nine asthmatics gives a history of asthma worsened by drinking 'soft drinks' containing sulphur dioxide. They are comparatively young and their asthma is predominantly extrinsic. The amount of sulphur dioxide in foods is limited by regulation in the UK, by directive in the EEC, and by recommendations to 'good manufacturing practice' in the USA. A list is given of foods and beverages commonly containing sulphur dioxide. These are predominantly dried fruits and vegetables, soft drinks and alcoholic beverages. Maximal permitted concentrations are quoted. Exposure to sulphur dioxide may also occur during the manufacture and preparation of foods and drinks in the factory, restaurant and home.
By Group 8 (Jing Jing, Ya Ling, Sarah, Bonnie)
Sulfur dioxide is used as a preservative, in wine making, as a reducing bleach and for dechlorination. It is also used in bleaching wool or straw, and as a disinfectant.
ReplyDeleteLarge amount of sulfur dioxide in the environment poses a serious threat to our body and the ecosystem. Besides causing acid rain which can damage crops and kill marine life, the exposure to sulphates and the exposure to acids derived from SO2 is extremely risky for people's health because these compounds enter the circulatory system directly through the airways. Sulfur dioxide can cause breathing difficulties, airways inflammation, eye irritation, heart failure and mortality in infants and elderly.
-group 6 (Jessica, Jie Ying, Shi Qi, Tania)
DeleteSulfur dioxide is sometimes used as a preservative or used in wine making.
ReplyDeleteSulfur dioxide is commonly added to dried fruit, fruit juices, fruit, breakfast cereals, and many processed snacks including cookies, soft drinks, meat, cereal bars, muesli bars, yogurt, ice cream, candy, frozen french fries, bread, margarine, and gluten-free flours. The process of preserving food with sulfur dioxide is intended to provide a longer shelf life, kill harmful bacteria that might grow on vegetation and foods, and help food products maintain a certain visual appearance. Additionally, they can soften dough or bleach foods. Sulfur dioxide is used as a preservative because it works as an antimicrobial preventing the growth of bacteria, mold, and fungus; an antioxidant preventing rancidity; and as a chemical that attacks enzymes that cause discoloration, ripening, and rotting, usually in fruits after harvest. Through the process of plasmolysis plant and food cells are altered by contraction and separation through the loss of water.
Sulfur dioxide is still being used as a food preservative in many common snack foods despite being one of the top two air pollutants in urban areas, a corrosive gas, a primary cause of haze and acid rain, and a cause of respiration problems, lung disease, early death (due to a thiamine deficiency), documented water and plant damage, cardiovascular disease, blood toxication, developmetal toxication, gastro-intestinal and liver disease, neurological disturbances, irritable bowel syndrom, behavior disturbances, skin rashes, asthma, folic acid deficiency, as well as a nose and ear irritant.
Sulfur dioxide plays two important roles in wine making. Firstly, it is an anti-microbial agent, and as such is used to help curtail the growth of undesirable fault producing yeasts and bacteria. Secondly, it acts as an antioxidant, safeguarding the wine's fruit integrity and protecting it against browning. When dissolved in wine, SO2 can also exist in what is called an ionised form. This form has the greatest antioxidant effect.
By: Group 5 (Htoo, Jieling, Qianhong, Wang Yu)
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ReplyDelete