Air and Air Pollution - Class VI

Air is a mixture of gases. So, solute and solvent both are gases.

Greenhouse effect
* The progressive heating up of surface of the earth is earth is called green house effect or global warming.
 $CO _2$ and $H _2O$ block a part of the heat (IR) emitted by the earth & reflect back. Due to this earth surface gets heated up.
50% in $CO _2$ content of air can increase the surface temperature of the earth by $3^oC$.
* In addition to $CO _2$ , the other green - house gases are CFCs (17%), $O _3$ (18%), NO (4%), water vapour (2%).

* Incomplete combustion of fossil fuels liberate CO into air. 80% of CO is released from automobiles.

The ash can cause respiratory problems for young children, the elderly or those already with respiratory ailments.

Volcanic eruptions release a variety of gases, including sulfur dioxide, carbon dioxide, and hydrogen fluoride, all of which pose environmental and health risks.

The air gets polluted by the presence of dust particles.

Diesel vehicles on burning forms all these as a product so they are major pollutants.

A forest fire is a natural source of air pollution. 

Anthropogenic or man-made source of pollution is automobile exhaust. When fuel burns various gases like carbon dioxide, oxides of nitrogen, sulfur dioxide, carbon monoxide are released into the air.

According to the air pollution data, the suspended particulate level SPM level is highest in Delhi and Kolkata with 70% residents suffering from respiratory disorders and lung cancers due to high SPM levels in populated areas.

Oxides of carbon like $CO$ and $CO _2$, oxides of nitrogen, oxides of sulphur, lead, all are present along with particulate matter in the vehicular exhaust gases, but ammonia is not formed in these vehicular emissions.

Some measures indeed help to reduce the stress on the environment like a use of catalytic converters in vehicles and ESPs in chimneys reduce the air pollutants going in an atmosphere. Smoking is injurious to the health of smoker and passive smokers too who have to inhale the smoke in their lungs causing diseases. Incinerators produce a lot of ash and residue which is not suitable for burning so it increases the air pollution.

Vehicular exhaust consist of oxides of carbon mainly carbon dioxide and carbon monoxide, sulphur dioxide and various oxides of nitrogen present in the burning fuel.

Deforestation is the permanent destruction of forests in order to make the land available for other uses.
effects of deforestation:
Forests are complex ecosystems that affect almost every species on the planet. When they are degraded, it can set off a devastating chain of events both locally and around the world.
Loss of species: 
Seventy percent of the worlds plants and animals live in forests and are losing their habitats to deforestation, according to National Geographic. Loss of habitat can lead to species extinction. It also has negative consequences for medicinal research and local populations who rely on the animals and plants in the forests for hunting and medicine.
Water cycle: 
Trees are important to the water cycle. They absorb rain fall and produce water vapor that is released into the atmosphere. Trees also lessen the pollution in water, according to the North Carolina State University, by stopping polluted runoff. In the Amazon, more than half the water in the ecosystem is held within the plants, according to the National Geographic Society. 
Soil erosion: 
Tree roots anchor the soil. Without trees, the soil is free to wash or blow away, which can lead to vegetation growth problems. The WWF states that scientists estimate that a third of the worlds arable land has been lost to deforestation since 1960. After a clear cutting, cash crops like coffee, soy and palm oil are planted. Planting these types of trees can cause further soil erosion because their roots cannot hold onto the soil. "The situation in Haiti compared to the Dominican Republic is a great example of the important role forests play in the water cycle," Daley said. Both countries share the same island, but Haiti has much less forest cover than the Dominican Republic. As a result, Haiti has endured more extreme soil erosion, flooding and landslide issues.
Life quality: Soil erosion can also lead to silt entering the lakes, streams and other water sources. This can decrease local water quality and contribute to poor health in populations in the area.

Urbanization is the man-made cause of deforestation. Whereas forest fires and droughts are natural causes of deforestation.
Urbanization is due to increase population. It is caused due to human activities. Urbanization decreases the area under forests which leads to reduction in the number of CO2 consuming trees. Hence, CO2 accumulates in the air.

The significant natural causes of air pollution are volcanic eruptions and forest fires.

Burning oil, coal, gasoline and other fossil fuels are the major causes of man-made air pollution.

All forest fires emit carbon monoxide, sulphur dioxide, nitrogen dioxide, ozone, and particulate matter.

Windmill are used to produce energy by the motion of wind, it is a renewable source of energy and does not cause air pollution.

Peroxy acetyl nitrate is a component of photochemical smog, PAHs are carcinogens, Dioxins come from waste incineration, Indigo is a vat dye, and IR active molecules contribute to global warming.

Usage of nitrogen in tinned food products, in electric bulbs and as a refrigerant indicating the inactive nature of nitrogen.

The component of air which is essential for growth of plants and animals is nitrogen. Atmospheric nitrogen is converted by bacteria through nitrogen fixation to nitrate and nitrites, which is consumed by plants. Animals also need nitrogen, as all amino acids which are the building blocks of proteins have basic element of nitrogen.