Pollution and the Environment Flashcards
Pollution and Pollutants
Pollution:
Pollution is an unwanted change in the environment caused by the introduction of harmful materials or the production of harmful conditions, such as hear, cold or sound.
Pollutants:
Pollutants are substances that bring about a change in the environment. It is important to distinguish between ‘pollution’ and ‘contamination’.
Examples of Pollutants:
Air pollutants include dust, soot, and particulate matter from sea spray. Gases such as carbon dioxide and sulphur dioxide are also examples of air pollutants.
Water tends to be polluted by heavy metals such as mercury and lead, as well as sediment from agricultural runoff. Nitrates and phosphates from fertilisers and detergents are also significant water pollutants.
The land tends to be the focus of solid waste pollution, especially from household, industrial and municipal waste, but the soil can also be polluted by fallout from air pollution or ruff from water pollution.
Effects of Pollution:
- nuisance and aesthetic effect: offensive smells, reduced visibility
- property damage: corrosion, dissolving of buildings, soiling of clothes and buildings, damage to car finish
- disruption of natural ecosystem functions at local, regional and national levels: decreased nutrient cycling, loss of biodiversity, climate change
The Nature of Pollutants
The impact that pollutants have on the environment depends on a number of factors and characteristics. These include the length of time they stay in the air or water before being broken down; their chemical composition; how reactive they are with other substances, and the rate at which they move through the environment.
Persistence:
Persistence is a measure of how long a substance stays in the environment before it is degraded or broken down.
Mobility:
The mobility of a pollutant refers to the ability of the pollutant to move through the environment. This may be the result of the pathways available for the transport of these pollutants as well as the nature of the pollutant itself. Air pollution from mobile sources such as vehicles can travel easily from one region to another, making it difficult to trace the original pollution source.
Synergism:
Synergistic reactions occur when the combination of two chemicals or conditions produces a reaction, which has an effect greater than the sum of the two chemicals or conditions individually,
Toxicity:
Toxic chemicals are those that cause adverse reactions in living organisms and can also cause death.
Causes of Pollution
Inappropriate Technology:
Technology can be described as inappropriate when it does not fit with the needs of the people and it causes environmental damage and pollution.
Industrialisation:
Industrialiation in many countries also tends to become concentrated on certain parts of the country, where infrastructure may be readily available, or there are already industries, which act to supply new activities. This can lead to concentration of pollution on a particular part of the country.
Causes of Pollution: Population Growth
As a population’s numbers increase, more and more resources are needed just to meet people’s basic needs for water, clothing and shelter in poor countries.
In some countries the high rate of population growth demands ever-increasing resources. The manufacture of items from these resources often generates large amounts of waste.
Behaviour Patterns:
Longstanding or entrenched behaviours can also affect the level of population in a country. When people are accustomed to littering without fear or punishment, or where the consequences of littering have not been made clear enough, people tend to discard waste in inappropriate ways.
Lifestyle:
As countrie become more developed the tastes and desires of their populations also change. A more affluent population can afford the lifestyle and the associated items seen in developed countries. With this comes associated pollution problems.
In Barbados for example, as people are becoming from affluent they prefer fast food over home cooked meals. With leads to plastic pollution.
Consumption Patterns:
The nature of items that tend to be purchased also changes with increased affluence and prosperity. The population is constantly under pressure to buy more and more goods. Waste is generated when the new items are produced, and then when the outdated items are thrown away.
Lack of Environmental Consciousness:
Many people see environmental issues as the responsibility of others, and not themselves. Some may believe that the issue is simply too huge to be tackled by one person, and the problems are insurmountable.
Institutional Framework:
Environmental Standards:
In many Caribbean countries, environmental standards exist, but are often not implemented, while penalties in place for environmental pollution may be outdated and inadequate considering the amount of damage that the pollution could cause. The fines levied for polluting relate to an earlier time when there was much less scope for damage, and there were fewer types of pollutants and less of them.
Limited Economic Instruments:
Charging for plastic bags has helped to largely replace them with re-usable canvas or cloth bags. Many supermarkets no longer offer free plastic bags, but instead have re-usable bags for sale to consumers, or charge shoppers a small fee for each plastic bag used.
Lack of Enviromental Ethics:
Environmental ethics deals with the relationship between people and the natural environment. Often how people view the planet determines how they interact with and use their physical environments.
Atmospheric Pollution
Structure of the Atmosphere:
The atmosphere is divided into a number of layers, each of which plays a role in protecting the Earth from radiation and producing weather and climatic conditions, which affect life on Earth.
Troposphere:
This is the atmosphere layer closest to the Earth’s surface. It is located 0-12 km above the Earth’s surface and contains most of the atmosphere’s gases. It is composed of oxygen and nitrogen gases.
Stratosphere:
This layer extends 17-48km above the Earth’s surface. It has a similar composition to the troposphere, but it contains less matter and much less water vapour, and
a significantly higher
concentration of ozone.
Mesosphere:
In this layer, temperatures fall rapidly. There is no water vapour, dust or ozone to absorb radiation from the sun. The mesosphere has the atmosphere’s lowest temperatures.
Thermosphere:
Temperature rise rapidly with height in this outermost layer. This is due to the increasing levels of oxygen which absorb incoming radiation.
Atmospheric Conditions:
The Earth gets its energy as solar shortwave radiation, which drives climate and weather and facilitates the production of food via photosynthesis.
Movement of Pollutants
Winds: Pollutants can be carried long distances by winds through the atmosphere.
Topography: Temperatures usually decrease with altitude, but inversions occur when the reserve happens. This is when warm air lies over cold air, preventing the upward movement of air, trapping pollutants near ground level.
Microclimates: Urban environments create their own microclimates, forming ‘heat islands’ that are warmer than the surrounding countryside as building materials tend to be non-reflective; absorbing heat during the day releasing it at night.
Primary Air Pollutants
Air pollution is the presence of harmful chemicals in the atmosphere.
Primary Air Pollutants:
Carbon monoxide (CO)
Carbon Dioxide (CO2)
Nitrogen Oxides (NOx)
Sulphur Oxides (SOx)
Suspended particulate matter
Environmental Pathways and Receptors:
Primary air pollutants are emitted directly into the air. Many form part of natural chemical cycles, which govern their movement from the atmosphere to the hydrosphere and lithosphere. They move through wind currents, as well as through deposition into rivers and streams. Many of these pollutants cause severe harm and sometimes death to organisms.
Secondary Air Pollution: Smog
Secondary pollutants:
are formed by the interaction of primary air pollutants with each other or with other components of the atmosphere. They are widely responsible for the creation of other environmentally damaging substances, such as photochemical and industrial smog as well as acid rains.
Smog:
Is a combination of smoke ad fog, and is used to describe the heavily polluted air found in urban and industrialised areas. Photochemical smog results from the interaction of primary pollutants, and some secondary pollutants such as ozone, and nitric acid, with sunlight.
Impacts of Smog:
- affects health
- affects vegetation
Acid Deposition
Types of Acid Deposition:
Acid deposition refers to the combination of wet and dry deposition, which results from primary and secondary pollutants in the atmosphere. These pollutants can come naturally from volcanic eruptions and decaying vegetation, and via human activities such as fossil fuel combustion and nitrogen oxides.
Acid Rain:
Acid rain is a mild solution of sulphuric acid and nitric acid. When sulphur dioxide and nitrogen oxides are released from power plants and other sources, prevailing winds blow these compounds across state and national borders, sometimes over hundreds of kilometers. They react with water vapour in the atmosphere to form acid rain. The pH of acid rain is less that 5.6
Impacts of Acid Rain:
-can cause or exacerbate human respiratory diseases
- leaches toxic metals from water pipes
- causes acidification in lakes and streams.
Global Impacts of Atmospheric Pollutants
Greenhouse Effect:
The Earth’s average temperature is regulated by a natural process known as the greenhouse effect. Solar radiation is received as shortwave radiation. Some of it passes straight through the atmosphere and is absorbed and re-radiated from the Earth’s surface as long-wave radiation.
Enhanced Greenhouse Effect:
It is important to note that the greenhouse effect is not the same thing as global warming. Global warming is an increase in greenhouse gases, caused by human activities, such as deforestation, industrialisation, and the use of fossil fuels. This is known as the enhanced greenhouse effect.
Sources of Greenhouse gases:
- Carbon dioxide (CO2)
- Methane (CH4)
- Water vapour
- Nitrous Oxides
Impacts of Global warming:
- melting ice caps and glaciers
- sea level rise
- increased temperatures
Ozone Depletion
The Ozone Layer:
Ozone is the gas containing three oxygen atoms, which acts as the Earth’s sunscreen. It is found in the stratosphere, where it helps to prevent too much exposure to harmful UV rays.
Ozone Formation:
In the troposphere, ozone is formed when lightning breaks an oxygen molecule into free oxygen atoms, which then combine with O2 un the air to make O3.
Ozone Hole:
In the late 1970s and early 1980s, scientists moticed that the stratospheric ozone layer was thinning, especially in the southern hemisphere, and this depletion was seasonal in nature. The most extreme case occurs over some parts of Antarctica during periods of the Antarctic spring. It was described as the Antarctic ozone hole.
Noise Pollution
What is Noise Pollution:
Is human or animal- generated noise that disrupts the activities of ither humans or animals.
Sources of noise:
- industrial activities (factories, construction, processing)
- commercial activities (markets)
- transportation (road vehicles, aircrafts)
- social activities (nightclubs, sports)
Health Risks:
Can have a direct imp[act on human health. As the decibel level increases, so too does the potential damage to the eardrum of human beings. Excessive noise can be damaging to psychological health as well.
When noise levels are high over an extended period, people can become greatly stressed. This can lead to cardiovascular problems, or even hypertension.
Properties of Water
water quality refers to the physical, chemical and biological characteristics of water. The quality of water can be assessed by reference to a set of international standards for clean water.
Physical Characteristics of Water:
The physical characteristics of water are those properties that can be measured or observed without changing its state.
Colour and Appearance- pure water is not colourless, it appears blue. This blueness comes from the water molecules absorbing the red end of the spectrum of visible light.
Taste and Odour- Taste and odour are human perceptions of water quality. At room temperature water is odourless and tasteless in its pure form, but this does not exist naturally.
Turbidity- measures the relative clarity of a liquid. It is an optical characteristic of water and is determined by the amount of light that is scattered by the material in the water when a light is shined through the sample.
Salinity- refers to the concentration of salt in water, as expressed in parts per million (ppm)
Dissolved Oxygen-
