A major issue of air pollution is its affect on the ozone layer. CFC’s or Chlorofluorohydrocarbons released from aerosol spray cans and car engines, and nitrogen monoxide (NO), which comes from the exhausts of some flight craft such as Concorde’s. Both of these gases react with ozone (O3), and are oxidised as a result. The chemical equations for the reaction of CFC and Ozone is as follows:
Ozone + CFC → Oxygen + Oxidation products
The chemical equation for the reaction, which occurs between nitrogen monoxide and Ozone, is:
Ozone + Nitrogen monoxide → Oxygen + Nitrogen dioxide
O3 (g) + NO (g) → O2(g) + NO2(g)
These reactions have caused the Ozone layer to begin to become thinner. This is a bad thing because in some areas people will be left exposed to the harmful UV rays, from which the Ozone layer would usually protect us. This in turn puts people at risk of skin cancer and damages the plants and other living organisms.
Another form of pollution is water pollution. Water pollution means that water is polluted by wastes from factories, oil and the run off of surplus agrochemicals from the land. This type of pollution causes much damage to the environment; many businesses are located on riverbanks meaning that they discharge their waste into rivers. This has caused many of Britain’s largest rivers to become too dirty to keep fish alive. An example of this is in Mersey, where in the 1930s fishermen could make a living. However, now it is too foul to keep fish meaning fishermen can no longer earn a living in the area; this was caused by the dumping of waste by industries in the estuaries.
Thermal pollution is another type of water pollution. This is when power stations use the water from rivers for cooling and return the water at a higher temperature. When the temperature raises too much the biological oxygen demand increases. In other words, the organisms in the water require more oxygen. This can cause many problems such as the death of fish that cannot get the required amount of oxygen in time.
A very serious type of water pollution is pollution by agriculture. This involves the use of pesticides and fertilisers. When farmers use fertilisers, there is often excess fertiliser, which is not absorbed by the plants. This is washed into the lake, therefore providing the plants in the lake with an extra supply of nitrates and phosphates, meaning there is a mass production of algae in the lake, or an algae bloom. This means, that the natural cycle of the lake is disrupted, the mass algae in the lake soon dies, and is fed upon by bacteria. The high bacterial activity means that much of the dissolved oxygen is consumed causing many of the fish to die from lack of oxygen. This type of water pollution, involving the accidental fertilisation of lakes and rivers is known as eutrophication.
There are certain harmful pesticides, which are also washed into the river. These are sometimes referred to as the ‘drins’, dieldrin, endrin, and aldrin. These can cause many problems such as liver cancer at high levels, and because they are not excreted by fish, they can build up to 6000 times the level in the water.
As I stated above, not all human effects on the environment are negative, in fact, many are positive. The main way, which we have a positive affect on the environment is through conservation. Conservation means saving or conserving something. One thing, which we try to conserve for the benefit of the environment, is the use of non-renewable energy resources. By doing so we reduce the pollution usually caused by factories, by using wind turbines, which cause no pollution at all. By reducing use of non-renewable energy sources, such as fossil fuels (coal, oil, and gas), we are reducing the amount of dangerous gases, polluting the air.
Another example of conservation is the human conservation of species. This has been demonstrated through laws applied in certain countries to protect species’ such as elephants and the hunting of them. In addition, conservationist groups such as the Convention on international trade in endangered species (CITES) have asked governments to pass laws, which protect threatened species.
One of the most popular conservationist groups the WWF (world wildlife fund, conserved a whole ecosystem of tigers in India in 1973. They made sure laws were passed to protect them and this resulted in a dramatic increase in tigers. Their work has not stopped there, they have saved many species’ of animals such as the Arabian Oryx, Przewalski’s horse, Pere David’s deer and the European Bison through captive breeding programmes. In addition, the WWF proposed a plan called the world conservation strategy, which was aimed at political leaders and hoped to get them to focus on the economical and environmental problems.
Other conservationist groups include Friends of the earth and Green peace, who try to persuade people to adopt environmental friendly attitudes. Another strategy, which they use, is to try to convince governments and political parties, to adopt conservationist policies.
The problem with the ozone layer has become so serious that many leaders have felt the need to address the situation. This has been done in many countries. Two examples of this are the US and the UK. CFC’s the main cause of the ozone layer problem have been banned in the USA. In the UK, the government has agreed to reduce the amount of CFC’s by 50%. In addition, CFC free aerosols are being introduced in the UK meaning they are ozone friendly.
Over the past years, we as humans have had an overall negative effect on the environment. This has caused many of today’s environmental problems such as the holes in the ozone layer, and the greenhouse effect. However, we have also had many positive effects on the environment and have realised our past mistakes. This is shown through measures such as the reduction of CFC’s in aerosols. I believe that overall, our impact on the environment has been negative, however I feel that in the future we will continue to have a positive impact, and therefore create an overall positive effect on the environment.
