Air Pollution In London - By Yoldas Yildiz

London is one of the biggest cities in the world. Therefore it is no surprise to the average person that London has high levels of pollution. However, what most people do not realize that according to recent studies, London is the most polluted city in the world – even more polluted than Beijing, China. London is the capital city of England. It is located in the south east side of England and has a population of approximately 8.31 million people. In a recent world wide study conducted in various cities around the world, the NO2 – Nitrogen Dioxide that is a pollutant gas – content of the air was measured and recorded. London, more specifically Marylebone Road, was found to have the highest amount of this gas in the air.  This blog aims to inform you about the many different pollutants present in London today, how they are released into our atmosphere and potentially our ecosystem but also how different initiatives can be taken place to reduce these emissions into the atmosphere.

First, there is the problem of Sulfur Dioxide. At standard atmosphere , it is a toxic gas with a pungent, irritating, and rotten smell.  Sulfur Dioxide is released through the combustion of fuel containing sulfur mostly coal and oil. Sulfur Dioxide is also produced during metal smelting and other industrial processes. Sulfur Dioxide causes breathing problems with asthmatic children and adults who are active outdoors. Short-term exposure to Sulfur Dioxide can cause wheezing, chest tightness and shortness of breath. Long Term exposure to Sulfur Dioxide can cause respiratory illness, alterations in the lungs' defenses and aggravation of existing cardiovascular disease. 

Next, as mention above, London also has a big problem with Nitrogen Dioxide. Nitrogen Dioxide is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year. This reddish-brown toxic gas has a characteristic sharp, biting odor and is a prominent air pollutant. Nitrogen dioxide inflames the lining of the lungs, and it can reduce immunity to lung infections. This can cause problems such as wheezing, coughing, colds, flu and bronchitis. Increased levels of nitrogen dioxide can have significant impacts on people with asthma because it can cause more frequent and more intense attacks. Both Nitrogen and Sulfur Dioxide have major environmental issues too. They are the major precursors of acid rain, which causes acidified soils, lakes and streams, accelerated corrosion of buildings and monuments, and reduced visibility. Sulfur dioxide also is a major precursor of fine particulate soot, which poses a significant health threat.

Another major pollutant is Carbon Monoxide. Carbon monoxide is a colorless, odorless, and tasteless gas that is slightly less dense than air. It is toxic to humans when encountered in concentrations above approximately 35ppm, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal biological functions. It has major negative effects to human health. Low levels of CO is most serious for those who suffer from heart disease, like angina, clogged arteries, or congestive heart failure. For a person with heart disease, a single exposure to CO at low levels may cause chest pain and reduce that person's ability to exercise; repeated exposures may contribute to other cardiovascular effects. Carbon Monoxide also has effects to the central nervous system. High levels of CO can affect even healthy people. People who are exposed to high levels of CO can develop vision problems, reduced ability to work or learn, and reduced manual dexterity & difficulty performing complex tasks. When a person is exposed to extremely high levels, CO is poisonous and can actually cause death.

Another major pollutant in London is Benzopyrene.  Benzopyrene is usually found as pale yellow crystals. The most serious environmental impact of Benzopyrene is its significant accumulation in organisms exposed to it. In water, Benzopyrene attaches strongly to sediments and any other solid matter. Benzopyrene released to soils tends to bind very strongly to the soils particles, but small amounts can leach to ground waters. Benzopyrene can enter the body either by inhalation of air containing benzopyrene, ingestion of water or food containing benzopyrene. It causes respiratory tract irritation, gut irritation and skin irritation.. Damage the reproductive system and cause cancer.  Common sources of CO include the following wood, oil or gas fuelled appliances like Boilers, Room heaters, Furnaces, Charcoal grills, Cooking ranges, Water heaters, Vehicles run in closed garages, Fireplaces, Portable generators and Wood burning stoves. Benzopyrene are used in dyes. The vast majority of Benzopyrene are released to the environment when combustion is incomplete (usually because there is insufficient oxygen). Thus, most Benzopyrene are released from vehicle exhausts and domestic wood and coal fires. Trace amounts are found in cigarette smoke. Benzopyrene are also released naturally from volcanoes and forest fires, but the amounts are very small compared to those released from man-made combustion sources.

There are many different methods to remove these toxic chemicals from the environment. Carbon Monoxide can be removed by using a chemical called Hopcalite.  Hopcalite is a mixture of copper and manganese oxides used as catalyst to convert carbon monoxide into carbon dioxide when exposed to the oxygen in air. It is composed in a approximate ratio of 3:1 manganese oxide to copper oxide. Sulfur and Nitrogen Dioxide are prevented from being released into the atmosphere using various different methods. There is reducing the sulfur content of the fuel before combustion but also sulfur removal during combustion. Sulfur is removed during combustion using a process called Flue Gas Desulphurisation (FGD). Various chemicals are used to purify the gas and remove toxic chemicals before released into atmosphere. The problem with these methods stated above are that they are expensive and do not give any financial benefits to the company. To improve this situation in London and all around the UK, government initiatives can be put in place to help and aid companies to encourage them to place protocols in place to remove and minimize the amount of pollutant being released into the atmosphere.

Websites Used: 

[1] - http://www.theguardian.com/environment/2004/aug/27/water.environment

[2] - http://www.theguardian.com/environment/2010/jun/25/london-air-pollution-europe

[3] - https://www.london.gov.uk/priorities/environment/vision-strategy/clearing-londons-air/air-pollution-london

[4] - http://www.theguardian.com/environment/2014/jul/30/boris-johnson-defends-londons-record-on-air-pollution

[5] - http://www.bloomberg.com/news/2014-05-27/london-s-dirty-secret-pollutes-like-beijing-airpocalyse.html

[6] - http://news.yahoo.com/eu-court-says-britain-must-cut-air-pollution-214626614.html

[7] - http://www.theguardian.com/environment/2014/nov/19/eu-court-rules-uk-government-must-clean-up-dangerous-air-pollution

[8] - http://www.theguardian.com/environment/2014/nov/20/london-air-pollution-not-the-world-worst

[9] - http://www.theguardian.com/environment/2014/nov/13/boris-johnson-admits-londons-oxford-street-is-one-of-worlds-most-polluted

[10] - http://www.air-quality.org.uk/27.php

[11] - https://www.london.gov.uk/priorities/environment/vision-strategy/clearing-londons-air/air-pollution-london