Introduction
In this case study I will be investigating whether traffic pollution causes asthma. There are many for's and against this statement. I will also be talking about how you can reduce air pollution. Asthma is a disease that affects your airways. Airways are the tubes that carry air in and out of your lungs. If you have asthma, the inside walls of your airways are swollen.
What is air pollution?
Air pollution is the presence of noxious substances in the air that we breathe. The air is filled with chemical substances and air pollutants which usually come from cars, industries and trucks. They pollute the air by refueling cars, manufacturing and oil refining.
There are two types of pollutions: Secondary and Primary.
Primary pollution is emitted straight into the air and secondary pollution comes from chemical reactions between pollutants in the atmosphere.
Five examples of pollutants are:
Sulphur Dioxide (SO2)
Carbon Monoxide (CO)
Nitrogen Dioxide(NO2)
Ozone (O3)
Hydrocarbons
Sulphur dioxide is a corrosive acid gas which combines with water vapour in the atmosphere to produce acid rain. SO2 in ambient air is also linked with asthma and chronic bronchitis.
The principal source of this gas is power stations burning fossil fuels which contain sulphur. Major SO2 problems now only tend to occur in cities in which coal is still widely used for domestic heating, in industry and in power stations.
Carbon monoxide (CO) is a colourless, practically odorless and tasteless toxic gas which is emitted into the atmosphere as a result of combustion processes, and is also formed by the oxidation of hydrocarbons and other organic compounds. CO at levels found in ambient air may reduce the oxygen-carrying capacity of the blood. It survives in the atmosphere for a period of approximately 1 month but is eventually oxidised to carbon dioxide (CO2).
Nitrogen oxides are formed during high temperature combustion processes from the oxidation of nitrogen in the air or fuel. The principal source of nitrogen oxides - nitric oxide (NO) and nitrogen dioxide (NO2), collectively known as NO2 - is road traffic, which is responsible for approximately half the emissions in Europe.
Nitrogen oxides are released into the atmosphere mainly in the form of NO, which is then readily oxidised to NO2 by reaction with ozone.
Nitrogen dioxide has a variety of environmental and health impacts. It is a respiratory irritant, may make asthma worse and possibly increase weakness to infections. In the presence of sunlight, it reacts with hydrocarbons to produce photochemical pollutants such as ozone. In addition, nitrogen oxides have a lifetime of approximately 1 day with respect to conversion to nitric acid. This nitric acid is in turn removed from the atmosphere by direct deposition to the ground, or transfer to aqueous droplets, thereby contributing to acid deposition.
Ground-level ozone (O3), unlike other primary pollutants mentioned above, is not emitted directly into the atmosphere, but is a secondary pollutant produced by reaction between nitrogen dioxide (NO2), hydrocarbons and sunlight. Ozone can irritate the eyes and air passages causing breathing difficulties and may increase susceptibility to infection. It is a highly reactive chemical, capable of attacking surfaces, fabrics and rubber materials. Ozone is also toxic to some crops, vegetation and trees.
A hydrocarbon is a chemical compound that consists only of the elements carbon (C) and hydrogen (H). Hydrocarbons contain a backbone consisting of carbon ...
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Ground-level ozone (O3), unlike other primary pollutants mentioned above, is not emitted directly into the atmosphere, but is a secondary pollutant produced by reaction between nitrogen dioxide (NO2), hydrocarbons and sunlight. Ozone can irritate the eyes and air passages causing breathing difficulties and may increase susceptibility to infection. It is a highly reactive chemical, capable of attacking surfaces, fabrics and rubber materials. Ozone is also toxic to some crops, vegetation and trees.
A hydrocarbon is a chemical compound that consists only of the elements carbon (C) and hydrogen (H). Hydrocarbons contain a backbone consisting of carbon atoms, called a carbon skeleton with hydrogen atoms attached to that backbone. Hydrocarbons, which are combustible, are the main components of fossil fuels, which include petroleum, coal, and natural gas.
What is Asthma?
Asthma is a constant disease that affects your airways. Airways are the tubes that carry air in and out of your lungs. Asthma closes up the inside walls of your airways causing it to become swollen. The tenderness makes the airways very sensitive, and they tend to react strongly to things that you are allergic to or find irritating. When the airways react, they get narrower, and less air flows through to your lung tissue. This therefore causes symptoms like wheezing, coughing, chest tightness, and trouble breathing
When your asthma symptoms become worse than usual, it is called an asthma episode or attack. During an asthma attack, muscles around the airways tighten up, making the airways narrower so less air flows through. Inflammation increases, and the airways become more swollen and even narrower. Cells in the airways may also make more mucus than usual. This extra mucus also narrows the airways. These changes make it harder to breathe.
What Causes Asthma?
It is not clear what causes Asthma however, there are many suspicions. We know that if other people in your family have asthma, you are more likely to develop it. New research suggests that being exposed to things like tobacco smoke, infections, and some allergens early in your life may increase your chances of developing asthma.
What Causes Asthma Symptoms and Attacks?
There are things in the environment that bring on your asthma symptoms and lead to asthma attacks. Some of the more common things include exercise, allergens, irritants, and viral infections. Some people have asthma only when they exercise or have a viral infection.
The list below gives some examples of things that can bring on asthma symptoms.
Allergens
* Animal dander (from the skin, hair, or feathers of animals)
* Dust mites (contained in house dust)
* Cockroaches
* Pollen from trees and grass
* Mold (indoor and outdoor)
Irritants
* Air pollution
* Cigarette smoke
* Cold air or changes in weather
* Strong odors from painting or cooking
* Scented products
* Strong emotional expression (including crying or laughing hard) and stress
What Are the Signs and Symptoms of Asthma?
The main signs and symptoms for asthma are:
* Coughing. Coughing from asthma is often worse at night or early in the morning, making it hard to sleep.
* Wheezing. Wheezing is a whistling or squeaky sound when you breathe.
* Chest tightness. This can feel like something is squeezing or sitting on your chest.
* Shortness of breath. Some people say they can't catch their breath, or they feel breathless or out of breath. You may feel like you can't get enough air in or out of your lungs.
* Faster breathing or noisy breathing.
There are many questions whether air pollution harms people and people with asthma.
Can air pollution harm people?
There is no question that air pollution could kill people. In one week following the infamous 'peasouper' fog in December 1952, 4,700 people died in London. Most of these people were elderly and already had heart or lung diseases. Astma isn't a concagous diseage and thereofere cannot be catched. Asthma is something you are born with and cannot get rid of.
Fortunately the effect of smog on the lungs is not so dramatic. Scientists have now conducted a number of laboratory experiments in which volunteers are exposed to ozone inside a steel chamber for a few hours. Even at quite low concentrations there is a reversible fall in lung function, an increase in the irritability of the lungs and evidence of airway inflammation. Although irritable and inflamed lungs are particularly seen in people with asthma and other lung diseases, these effects of ozone also occur in healthy subjects. Similar changes are also seen after exposure to nitrogen dioxide, although there is some disagreement about the concentration at which they occur.
Other studies have found that people living in areas with high levels of pollution have more symptoms and worse lung function than those living in areas with clean air.
Can air pollution cause asthma?
Smog and particles certainly trigger attacks in some people who already have asthma. For a long time it was thought that air pollution could not cause asthma to develop in previously healthy people. Some recent experiments challenge this belief. Scientists have shown that people exposed to ozone or nitrogen dioxide are more likely to react to allergens such as grass pollens and house dust mites than those who are not exposed. Also a combination of air pollution and allergens could cause some cases of asthma.
Previous studies show that air pollution can aggravate pre-existing lung ailments, however a new study of children in southern California reports that frequent, tiring, outdoor exercise, combined with high levels of ozone air pollution, can more than triple children's risk of developing asthma. This study, published in the Lancet, an important British medical journal, is the first study to find that air pollution might actually cause asthma, not just aggravate it. Officials of the California Air Resources claimed that its results applied not only to the six southern California communities where it was performed, but also too many cities across the country.
Though high ozone levels of the past may have caused asthma in some parts of southern California, children exposed to current levels of air pollution are at virtually no additional risk of developing asthma. However, the smog caused by air pollution noticisly causing children to cough and therefore have symptoms of asthma
In the Lancet asthma study, researchers followed two groups of children in southern California from 1993 to 1998. One group lived in six communities with low pollution levels; the other lived in six communities with high pollution levels. After accounting for factors besides pollution that could account for differences in asthma rates the study found that:
* Children in high-ozone communities who participated in three or more team sports were 3.3 times as likely to become asthmatic when compared with less-active children. Asthma was unrelated to sports participation in the low-ozone communities.
* Children who spent the most time outdoors were 1.4 times more likely than other children to become asthmatic in the six high-ozone communities, but not in the low-ozone communities.
* The study also measured other pollutants, such as airborne particulates and nitrogen dioxide, but found no relationship between these pollutants and asthma.
* Despite the increased asthma rate found for very-active children in polluted areas, asthma rates did not differ overall between the high- and low-pollution areas.
However, it is not proven that air pollution can cause asthma. There are many there are many other factors that can cause asthma apart from air pollution such as genetics and infections. A large percentage of babies and young children will experience wheezing at some point, usually during a viral respiratory infection. Some, but not all, of these children go on to have chronic asthma. It is unclear just what the role of the viral infection is, but it is possible that it is part of the cause of asthma. The viruses that most commonly cause wheezing in infants are RSV (respiratory syncytial virus), parainfluenza virus, and, in slightly older children, rhinovirus.
Another theory for explaining how asthma is caused involves a combination of original weakness with environmental exposures. Under such a model, it is believed that a person who is not born with a genetic susceptibility to asthma will never get the disease, no matter what the environment. A person who is born genetically vulnerable to asthma may also escape the disease if he or she is not exposed to enough exposures in the environment to bring it out. Asthma occurs, by this theory, only when a person both is at risk and experiences those factors that cause the disease to clear itself.
Also irritants and allergens can cause asthma. There are a variety of irritants such as Cigarette smoke, cold air or changes in weather, strong odors from painting or cooking and scented products. There are also a variety of allergens such as Animal dander (from the skin, hair, or feathers of animals), dust mites, cockroaches and pollen from trees and grass.
Also scientists have discovered that leaving children exposed to current levels of air pollution are at virtually no additional risk of developing asthma
There are many ways of reducing air pollution for example at home:
Cut down on your energy use in the home and consequently reduce the pollutant emissions from the burning of fuels.
* Draught proof your home, fit secondary glazing, have bath instead of a shower and fit a hot water jacket to the water tank.
* Use low-energy florescent light-bulbs which are economic in the long term.
Recycling reduces the need to mine for raw materials, it saves energy and it reduces the amount of waste buried in land fill sites.
* Make use of the glass and paper recycling sites near you.
* Reuse plastic carrier bags, or use a basket instead at the supermarket.
Road vehicles are a major source of many pollutants in urban areas.
* Before using the car ask yourself could I walk, cycle or take public transport instead? If using your car try and share the journey with other people.
* Adopt a calmer style of driving, by driving slower, more smoothly and avoid revving your engine unnecessarily!
* Maintain your car. Keep the energy properly tuned and the tires at the right pressure to improve fuel efficiency.
* Fit catalytic converters to your car.
To conclude this case study the statement "Does air pollution cause asthma" will ever be answered because many reasons causing asthma. Firstly it could be because of air pollution, as air pollution contains noxious substances that we breathe. The air is filled with chemical substances and air pollutants which usually come from cars, industries and trucks. They pollute the air by refueling cars, manufacturing and oil refining. I feel that air pollution triggers asthma as air pollution contains pollutants such has noxious substances. There are also many other factors that cause asthma such as smoking and cigarettes. After weighing out the for's and against's for if air pollution causes asthma, I feel that air pollution does trigger of asthma attacks however in not in all the cases
Bibliography:
Air pollution books
Asthma books
General knowledge
www.lbl.gov/Education/ELSI/pollution-main.html
en.wikipedia.org/wiki/Air_pollution
www.asthma.org.uk/
www.NoAttacks.org
