- Dust mites (in house dust)
- Cockroaches
- Pollen from trees and grass
- Mould (indoor and outdoor)
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Irritants:
- Air pollution
- Cigarette smoke
- Cold air or changes in weather
- Strong odours 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: Often worse at night/early in the morning, making it hard to sleep.
- Wheezing: A whistling or squeaky sound when you breathe.
- Chest tightness: 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. 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 'pea-souper' fog in December 1952, 4,700 people died in London. Most of these people were elderly and already had heart or lung diseases.
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.
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For Argument:
The Lancet Asthma Study
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.
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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.’
Although, 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.
I believe this study to be reliable and unbiased as it has been completed by California Air Resources Board, looked over by other scientists, been approved and printed in The Lancet, a prestigious British medical journal. If there were any reason to doubt this study it would not have been approved by such an important medical journal.
However the asthma study states that they carried out the investigation during a period of time at which the four ‘high-zone’ study area’s exceeded the federal ozone health standard by an average of about 50 days per year’, ‘such high pollution levels no longer occur anywhere in the United States.’ The study also states that ‘for children to be at risk, they would need to be frequently exposed to high ozone levels. Fortunately, they are not.’ `Children exposed to current levels of air pollution are at virtually no additional risk of developing asthma. However, the smog caused by air pollution notably causing children to cough, and therefore have symptoms of asthma.’ Also Lancet reported that after the study, results proved strenuous exercise combined with high pollution levels more than tripled the children’s risk of developing asthma.
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The Children’s Health Study
Traffic pollution has a major part in air-pollution. Therefore, if should not be shocking, that after looking at the relationship between traffic pollution and asthma, it is still being research in depth by ‘environmental health investigators’. Particular attention is currently on whether traffic pollution can cause asthma.
A number of studies have been published by the Children's Health Study, southern California, looking in detail, at the relationship between traffic pollution and asthma. ‘Recent results from this study for a cohort of 4700 children showed strong associations with medication usage (odds ratio, 1.50; 95% confidence interval, 1.16-1.95) and wheeze (odds ratio, 1.40; 95% confidence interval, 1.09-1.78) as well as lifetime asthma incidence (odds ratio, 1.29; 95% confidence interval, 1.01-1.86) for those children living within close proximity (< 75 m) of a major road.’
These results show us that the number of people that get asthma is linked to their exposure to traffic pollution and offer evidence for their hypothesis that ‘traffic-pollution exposure may contribute to the incidence of asthma.’
The Study looked at almost 6000 children in 12 California communities over five years, revealing that ‘the interquartile range increases in the concentration of NO2 (5.7 parts per billion), a traffic pollution surrogate, was positively associated with lifetime history of asthma diagnosis (odds ratio, 1.83; 95% confidence interval, 1.04-3.22).’ Asthma was also shown to be linked to traffic pollution from research conducted, showing residential distance from highways and the number of people with asthma.
‘Study results indicated that children’s lung function growth was adversely affected by air pollution, new cases of asthma and asthma exacerbations were associated with ambient air pollution levels, and school absences from acute respiratory illnesses followed rises in ozone levels.’
‘ARB Chairman Dr. Alan Lloyd said, "We've known for some time that smog can trigger attacks in asthmatics. This study has shown that ozone can cause asthma as well."’
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'Figure 2: Distributed lag estimates and 95% confidence intervals for the effect of 10 am-6 pm O3 (per 20 ppb) on respiratory illness-related absences (Air Pollution and Absence Study)'
This graph clearly shows that there is a positive link between the amount of traffic pollution in the air and the incidence rate of asthma. As the asthma rate of incidence increases, so does the amount of pollution. When one decreases, so does the other.
‘Table 7. Short-Term Effects of Ozone (O3) [Percentage Change and 95% Confidence Limits (CL)] on School Absence Incidence Rates, Stratified by Long-Term Average 10 am-6 pm O3 and 24-Hour Average Respirable Particles (PM10) or Nitrogen Dioxide (NO2), (Air Pollution and Absence Study)'
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Against Argument:
The Association of British Drivers Study
“(We assume that the use of a greater than 100% reduction in combined pollutants signifies that individual percentage falls for each of the four pollutants was recorded, and these values added together by the authors.)”
‘The car is not to blame for any real or apparent asthma epidemic’, says the ABD, (Association of British Drivers). The graph above clearly shows that there is absolutly no correlation between asthma and traffic pollution. As the rate of asthma incidence increases, the recorded measurements of the 4 main pollutants (PM 10, SO2, NOx, CO) decreases.
The ABD uses a number of quotes that from different sources that support their argument.
’"Air pollution does not cause asthma"
"There is no correlation between levels of vehicle emissions and asthma incidence"
Dr Kenneth Calman, Department of Health Study on the Causes of Asthma, 1995’
’"In the last 40 years the level of (outdoor) air pollution has decreased dramatically"
"Nevertheless the incidence of asthma has risen"
"Pollution does not cause bronchitis or asthma, nor does wearing a so-called anti-pollution mask do anything except identify the wearer as a sucker"
Professor Emeritus Stanley Feldman, Charing Cross and Westminster Medical School, wrote in the London Weekly Times (03/02/1995)’
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Particulates - PM10:
Particulates are a type of air pollution, and could be one of the air pollutants that frequently affects people's health.
Particles can come in almost any shape or size, and can be solid particles or liquid droplets. They are divided into two major groups. One of the many differences in these groups is size, bigger particles are called PM10 and we call the smaller particles PM2.5.
The big particles are between 2.5 and 10 micrometers (from about 25 to 100 times thinner than a human hair). These particles are called PM10, which stands for Particulate Matter up to 10 micrometers in size. These particles cause less severe health effects compared to the small particles.
PM10 : Comes from smoke, dirt and dust from factories, farming, and roads. It can also come from mold, spores, and pollen. They are made by crushing and grinding rocks and soil and are then blown by wind.
PM10 (big) particles can stay in the air for minutes or hours and can travel as little as a hundred yards or as much as 30 miles.
When you inhale, you breathe in air along with any particles. The air and the particles travel into your lungs and airway. Along the way the particles can stick to the sides of the airway or travel deeper into the lungs. Bigger particles are more likely to stick to the sides or get wedged into a narrow passage deep in the lung.
PM10 particles can cause health problems; specifically affecting respiratory health. Health effects include the following:
- Coughing, wheezing, shortness of breath
- Aggravated asthma
- Lung damage (including lifelong respiratory disease)
-
Premature death in individuals with existing heart or lung diseases
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Particulate Matter - Air Quality Index (AQI) and Health Concerns:
Carbon Monoxide - CO:
Carbon Monoxide (CO), is a colourless, tasteless, and odourless gas. It is non-irritating but very poisonous.
Whenever you burn fuel, like gasoline in your car, CO is produced. Other sources of CO include almost anything with an engine, power plants that burn coal, gas, or oil, and incinerators used to burn rubbish. Inside your home, CO can come from your heater, burning fireplace, or cigarette smoke.
The details of CO poisoning: CO reduces the amount of oxygen that gets to the brain, the heart, and the rest of the body.
Every living thing needs oxygen to stay alive. When a person inhales, the air goes into the lungs. Oxygen travels from the air into the blood. The oxygen now needs help to get where it’s going. It’s helped by a special delivery molecule called haemoglobin. Haemoglobin grabs the oxygen and delivers it to the parts of the body that need it. If there is a lot of CO in the air, oxygen is not delivered.
The delivery molecule (haemoglobin) will deliver oxygen or the poisonous CO. When a person breathes air, the CO pushes the oxygen out of the way. Haemoglobin grabs the CO, and delivers CO instead of oxygen. This means: haemoglobin delivers less oxygen to the body. The brain and heart need a lot of oxygen and they don’t function normally. When exposed to high levels of CO, a person might notice shortness of breath or a slight headache. These symptoms will be more intense if the person is exercising or has a weaker heart or lungs.
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High CO concentrations can occur in heavy traffic areas in many cities. People who spend their days in the normal city streets may breathe more CO than others. Vehicle drivers are also exposed to CO from traffic, and possibly the exhaust of their own vehicle or cigarette smoke. When traffic is stopped, CO levels inside a car go up.
Individuals with cardiovascular or respiratory diseases, anaemia or irregular haemoglobin may experience more severe health effects or may experience health effects at lower exposures.
Children may be more vulnerable because their lungs are not fully developed, they breathe faster, and they often spend lots of time outdoors.
In healthy individuals, exposure to high levels of CO can affect vision and mental alertness.
Carbon Monoxide - Air Quality Index (AQI) and Health Concerns:
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Sulphur Dioxide - SO2:
Sulphur dioxide is known to be a major pollutant, produced in the combustion of fossil fuels and in volcanic eruptions.
Sulphur dioxide is used in the food industry as a preservative. It is effective against moulds, yeast and bacteria. In wines, it is used for its anti-browning and colour characteristics. Sulphur dioxide can be used as a fungicide on grapes. In the drugs industry it is used as a stabiliser and preservative. It can also be used as bleach. Levels of sulphur dioxide in food are strictly controlled as it is a toxin and people with autism are particularly susceptible to these additives.
The most important use of sulphur dioxide is the production of sulphuric acid, which is used in vast quantities in the chemical industry. In the USA alone, about 40 million tonnes are produced annually. Sulphuric acid has a wide range of uses and plays a part in the production of nearly all manufactured goods. Sulphuric acid is used in car batteries, explosives, in paints, detergents and soaps, in the treatment of heart disease and for cleaning metals.
Sulphur Dioxide - Air Quality Index (AQI) and Health Concerns:
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Nitrogen Oxide - NOx:
The most important forms of reactive nitrogen in the air are nitrogen monoxide (NO) and nitrogen dioxide (NO2) and together we call them NOx. Nitrogen oxides are formed in the atmosphere mainly from the breakdown of nitrogen gas (N2). Because the two nitrogen atoms in N2 are bound very strongly together, it isn't easy to break N2 down into its atoms. Vehicle engines operate at high enough temperatures and nitrogen oxides are emitted in the exhaust fumes. Nitrogen oxides can also be formed when biomass is burnt and during lightning.
“Smog is formed when NOx and volatile organic compounds react in the presence of sunlight.” Children, people with lung diseases such as asthma, and people who work or exercise outside are susceptible to adverse effects such as damage to lung tissue and reduction in lung function.
NOx reacts with ammonia, moisture, and other compounds to form nitric acid and related particles. Human health concerns include affected breathing and respiratory system, damage to lung tissue, and premature death. Small particles penetrate deeply into sensitive parts of the lungs and can cause or worsen respiratory disease.
Nitrogen dioxide is harmful to vegetation, can fade and discolour fabrics, reduce visibility, and react with surfaces and furnishings. Vegetation that is exposed to high levels of nitrogen dioxide can be identified by damage to foliage, decreased growth or reduced crop yield. Indoor domestic appliances (gas stoves, gas or wood heaters) can also be significant sources of nitrogen oxides, particularly in areas that are poorly ventilated.
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Conclusion:
Looking back at all the evidence that I have collected, it is obvious when I say that the argument whether traffic pollution causes asthma still remains. When reading over the Lancet study, I believed it to be unbiased but only partially reliable, as it is based on the fact the sufferer has been exposed to high levels of pollution for a long period of time. Also, the investigation was conducted when the four study areas had had high levels of pollution that exceeded the federal ozone health standard, such high levels of pollution no longer arise. The study also states that ‘for children to be at risk, they would need to be frequently exposed to high ozone levels and took part in frequent, strenuous outdoor activities. Fortunately, they are do not.’ This study bases their evidence on the fact the sufferer has been exposed to high levels of traffic pollution (which no longer exist) and subject to vigorous exercise. Lancet reported that after the study, results proved strenuous exercise combined with high pollution levels more than tripled the children’s risk of developing asthma.
When looking at the Children’s Health Study it showed sufficient evidence that there was a positive correlation between the rise in traffic pollution and the incidence rate of asthma. They provided graphs showing this result and surveys that showed more and more children were missing school due to respiratory problems. However, the Children’s Health Study was conducted in areas that had significantly high levels of pollution and chose to conduct their investigation near by busy roads and junctions.
Although the Association of British Drivers study states that traffic pollution is not the cause of asthma, it is not completely reliable. As a drivers association studying the affects of traffic pollution on asthma, they are likely to be a biased source, being ion favor of cars.
However, when looking at the graph they have provided us with, it concludes that as the rate of asthma incidence increases over a 20 year period, the amount of pollution decreases. They back up their points by using quotes from reliable sources, such as ’"Air pollution does not cause asthma" from Dr Kenneth Calman, Government Chief Medical Officer. By doing this they support their argument that traffic pollution does not cause asthma, making it a more solid argument compared to this opppsition.
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Bibliography
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