The Earth's Atmosphere and Air Pollution

Due to Carbon Dioxide being a soluble gas, much of it dissolved into the oceans. The reason for this was that organisms that lived in the sea needed to form the chemical needed for their shells and skeletons

The atmospheres of Mars and Venus today, which contain mostly carbon dioxide, are similar to the early atmosphere of the Earth. (Shown in fig 1)

• The air around us is a mixture of gases, mainly nitrogen and oxygen, (these two gases alone make up 99% of the atmosphere). However there are many other gases in the atmosphere in very small proportions such as Carbon Dioxide. They are shown in Table Fig. 2. The Earth’s gravity stops these gases escaping into Space.

About 0.033% of the Earth’s atmosphere is Carbon Dioxide.

But now back in the present day, carbon dioxide is being added to atmosphere faster than it can be removed. This means that the level of carbon dioxide in the atmosphere is increasing.

Most of the chemicals that make up living tissue contain carbon. When organisms die the carbon is recycled so that it can be used by future generations. The model that describes the processes involved is called the carbon cycle.

Carbon enters the atmosphere as carbon dioxide from respiration and combustion.

Carbon dioxide is absorbed by producers to make carbohydrates in photosynthesis.

Animals feed on the plant passing the carbon compounds along the food chain. Most of the carbon they consume is exhaled as carbon dioxide formed during respiration. The animals and plants eventually die.

The dead organisms are eaten by decomposers and the carbon in their bodies is returned to the atmosphere as carbon dioxide. In some conditions decomposition is blocked. The plant and animal material may then be available as fossil fuel in the future for combustion.

Plants use carbon dioxide and sunlight to make their own food and grow. The carbon becomes part of the plant. Plants that die and are buried may turn into fossil fuels made of carbon like coal and oil over millions of years. When humans burn fossil fuels, most of the carbon quickly enters the atmosphere as carbon dioxide.

 

The processes releasing and absorbing carbon dioxide form part of the carbon dioxide.

Carbon dioxide is a greenhouse gas and traps heat in the atmosphere. Without it and other greenhouse gases, Earth would be a frozen world. But humans have burned so much fuel that there is about 30% more carbon dioxide in the air today than there was about 150 years ago, and Earth is becoming a warmer place. In fact, ice cores show us that there is now more carbon dioxide in the atmosphere than there has been in the last 420,000 years.

Deforestation in tropical rainforests adds more carbon dioxide to the atmosphere than the sum total of cars and trucks on the world’s roads. Deforestation contributes to over 15% of the world’s carbon emissions. The reason that deforestation effects the composition of air is that trees and plants are being cut down, and this meaning there are fewer plants to photosynthesise thus leaving more carbon dioxide in the atmosphere, also some of the trees that have been cut down maybe bound to clear the land quickly this also releases carbon dioxide. Also with growing populations there is a greater demand for electricity, fuel and fossil fuels in general this will lead to more fossil fuels being burnt therefore producing more carbon dioxide in addition to this as the population increases, more people will have to respire leading into a decrease in oxygen and an increase in carbon dioxide in the atmosphere.Atmospheric pollutants are substances that are released into the environment that may damage living things including us these are released into the air, pollutants in general may be released to the soil all water. Eight fuels are not burnt properly due to a lack of oxygen this will produce carbon monoxide this can sometimes happen in car engines and machinery this often leads to sickness and sometimes fatalities

99% of the air made up of nitrogen and oxygen, Normally nitrogen is unreactive but in high temperatures and pressure such as in the engine war and allow them to react and produce NOX.

Also feels actually contains small amounts of sulphur compounds.  These impurities form sulphur dioxide when the fuel is burned.  This gas dissolves into water in the clouds, forming acid rain. The acids make rain more acidic than normal. Such acid rain erodes stonework and corrodes metals.  Aching killed trees, and living things in the river and lakes. NOx causes acid rain too.  It can also react with other atmospheric pollutants, particularly in sunlight, to produce photochemical smog.

Vehicles on the road produce 14% of the world’s carbon emissions. Catalytic converters are fitted into the exhaust system on some vehicles, as they release large amounts of atmospheric pollutants levels of these must be controls through reduced damage to human health and the environment.

The main admissions of a car engine are:  nitrogen gas(most of this would pass straight through the car engine), carbon dioxide and water vapour.  But because the combustion process is ever perfect, some small amounts of more harmful emissions are also produced in car engines such as carbon monoxide and Nitrogen oxides.

Carbon Monoxide + Nitrogen Oxide → Nitrogen + Carbon Dioxide

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