Air Pollution And Greenhouse Gases (T4)

Question 1

What is ozone and the ozone layer?

Answer 1

Ozone is a gas that occurs naturally in our atmosphere.

Most of it is concentrated in the ozone layer, a region located in the stratosphere several miles above the surface of the Earth.

Question 2

Why is ozone and the ozone layer important?

Answer 2

Ozone plays a vital role by shielding humans and other life from harmful UV light from the sun.

Ozone molecules absorb the dangerous UV rays emitted from the sun, reducing the amount of UV rays that get through to the Earth’s surface.

Question 3

What are CFC’s and how have they affected the ozone layer?

Answer 3

In the pas few decades humans have produced chemicals such as chlorofluorocarbons (CFC’s) which were used in fridges, aerosols, air con units and polystyrene foam.

When released in the atmosphere CFC’s break up ozone molecules and thus destroy the protective ozone layer.

Question 4

What is the most common source of air pollution?

Answer 4

The combustion of fossil fuels

Question 5

Most fossil fuel combustion takes place in vehicle engines and power stations which burn fossil fuels such as coal, natural gas and petroleum. The gases released include..

Answer 5

• carbon dioxide
• sulphur dioxide
• oxides of nitrogen

Question 6

Smoke is a common air pollutant. Describe the effects it can have on the environment..

Answer 6

Deposits soot on living things, stopping them from growing.

Permeates the air, causing breathing difficulties in animals and humans.

Question 7

Carbon monoxide is a common air pollutant. What is the main negative effect on humans and animals?

Answer 7

Carbon monoxide binds very strongly to haemoglobin in the blood, restricting the body’s ability to take up oxygen.

Question 8

What is the main gas that contributes to acid rain?

Answer 8

Sulphur dioxide

Question 9

Lead in petrol is still a problem in some countries. List 6 countries that were still using leaded petrol in 2011..

Answer 9

• Afghanistan
• Algeria
• Iraq
• North Korea
• Myanmar
• Yemen

Question 10

Why was lead added to petrol and who suggested it?

Answer 10

It makes engines run more smoothly and stops them pinking or knocking.

The idea of adding lead was developed by Thomas Midgely, the same chemist who invented the first CFC’s.

Question 11

How does lead in petrol damage the environment?

Answer 11

• when leaded petrol burns in the engine it also releases lead into the air, which eventually contaminates soil and water
• lead accumulates in the soil where it can remain for as long as 2000 years
• in undisturbed ecosystems, organic matter in the upper layer of soil surface retains some atmospheric lead
• however in cultivated soils this lead gets mixed throughout the layers of soil where it reaches the roots of plants and affects - sometimes destroying whole populations of - microorganisms
• many of these microorganisms are essential decomposers and their elimination cam seriously disrupt the food chain
• there is also some evidence that microorganisms can make lead more soluble and therefore more easily absorbed by plants
• some species of plant also have the capacity to accumulate hit concentrations of lead, which can affect grazing animals

Question 12

How can lead in petrol affect human health?

Answer 12

• lead is a cumulative toxin, particularly damaging to children
• studies have shown that children living near motorways appear to have lowered brain function and IQ compared to those living in areas with less lead pollution

Question 13

What is the ‘greenhouse effect’ when we talk about the Earth’s atmosphere?

Answer 13

It refers to the way greenhouse gases such as methane and carbon dioxide accumulate in the Earth’s atmosphere, allowing heat fro mother Sun to penetrate closer towards they Earth, but preventing some of the heat from radiating back out again

Question 14

How is methane produced and how does it contribute to the greenhouse effect?

Answer 14

• marshland and bogs produce methane naturally, as it bubbles up from decaying plant material
• however, increasing amounts are produced through agriculture, particularly through rice production and cattle rearing;
• cows pass wind each day in great volume
• the flooding of paddy field causes anaerobic respiration, which is a major producer of methane

Question 15

What is acid rain and how does / did it come about?

Answer 15

• the effects of acid rain were first identified in the 1970’s
• when we burn fossil fuels in cars and power stations it releases, amongst other things, sulphur dioxide and various oxides of nitrogen
• sulphur dioxide and the oxides of nitrogen mix with the rainwater in clouds and form acidic solutions, which fall as acid rain

Question 16

What effects does acid rain have on the environment?

Answer 16

• it can kill trees and damage limestone, including limestone buildings
• it makes lakes and rivers more acidic, which in turn kills fish and other aquatic life
• the increased acidity of the water also allows poisonous aluminium salts to dissolve more easily, which in turn can kill wildlife

Question 17

Canaries used to be sent into mines as ‘detectors’ of escaping gas, which would cause them to die.

What organisms are also a good ‘indicator species’ of pollution?

Answer 17

• Lichens are plants that grow in exposed places such as rocks or tree bark
• they are good at surviving on just the nutrients that rainwater provides
• this makes them particularly vulnerable to air pollutants dissolved in rainwater, especially sulphur dioxide
• some types of lichen, like bushy haired lichens, require very clean air
• others, like leafy lichens, can survive air pollution at low levels
• crusty lichens can survive in more polluted air
• so, in places where there are no lichens growing at all, it is often a sign that the air is heavily polluted with sulphur dioxide

Question 18

Briefly, how can we reduce at least some of the impacts of human activity on the environment, animals, and our own survival and health ? And what problems do we face with regards to this?

Answer 18

• produce less greenhouse gas, however we are very dependent on fossil fuels and alternatives are still either expensive or at very early stages of development and testing
• reduce use of materials and energy
• some technologies can remove the gases before they are released, such as power stations which can capture and store carbon dioxide
• power stations can be fitted with acid gas scrubbers to remove these gases from the chimneys
• catalytic converters in our car exhausts can break up the greenhouse gases as they leave out cars