Since the beginning of industrialisation, pollution has become an increasing environmental problem. In Western countries, the amount of pollution has been continuously increasing. What is interesting to note is that the number of people suffering from allergies has also been on the rise.
The types of pollution can range from chemical air pollutants such as particle matter, nitrogen dioxide and ozone associated with high traffic areas, to natural outdoor pollutants such as pollen.
Is there a link between pollution and allergy? This article will investigate the link between allergies and a range of different pollutants.
Diesel particles account for up to 90% of airborne particle matter in the atmosphere of the world’s largest cities. These particles are known to stimulate the growth of cells that lead to high allergic risk.
Scientists in Japan exposed diesel exhaust to guinea pigs to determine its affect on allergies. They found a clear result that diesel exhaust increases allergen-induced airway responses, typical to allergic diseases such as hayfever. This is backed up by many other studies. Recent research from the UK and Netherlands found that children living close to roads and high traffic areas suffered from increased respiratory problems and a reduction in their lungs ability to function. As the level of particles in the air increased, so too did the symptoms produced.
Environmental tobacco smoke is a very common indoor pollutant. Clear links between tobacco and respiratory symptoms such as asthma are well established. Studies of tobacco smoke administered to rats found an increased production of cells linked to allergic disease.
Pollen is an allergen largely responsible for respiratory diseases such as hayfever.
It is interesting to note that landscapers in most cities in the world tend to use male plants in their designs rather than female. The reason for this is that female trees drop seeds, seed pods, messy fruit and other litter whilst male trees are “litter-free” yet they produce huge amounts of pollen. This has some significance as many people are allergic to pollen and by increasing the amount of it polluting the air, it could have some effect on the increase in prevalence of allergies.
A study in Japan found a higher number of people who are allergic to cedar trees living close to the highway than in people living further away. Both groups of people had the same amount of exposure to the pollen. A recent study in four European cities found allergens like pollens would stick to pollution particles in the air. This suggests that as exhaust pollution in the air increases, they become carriers for allergens like pollens. Findings like this show that various pollutants are acting together and increasing their impact on society.
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