4 Environmental health

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Unit 8: Air quality


When you have completed this unit you should be able to:

8-1 What are the major sources of air pollution?

Some major sources of outdoor air pollution are:

The major source of indoor air pollution is smoke from cooking fires. Cigarette smoke can also pollute the air, particularly in overcrowded homes.

8-2 What is particulate matter and what damage does it cause?

Particulate matter is a mixture of very small particles of dust, water droplets and several other chemicals, suspended in air. Particulate matter is a result of burning fossil fuels or wood and is seen as smoke or haze. It is a very important part of air pollution. If the particles are small enough, they penetrate deep into the lungs and cause inflammatory changes. Very small particles may even enter the circulation and cause damage in organs other than the lungs. Particulate matter can cause many diseases, including cardiovascular disease, chronic obstructive lung disease (emphysema and chronic bronchitis) and lung cancer.

Small particle air pollution can cause serious lung disease, such as cancer, as well as disease in other organs.

8-3 How big a problem is air pollution?

Air quality in South Africa is mostly good, except in some large cities. Worldwide, poor air quality is a major cause of ill health, particularly in rapidly developing countries such as China and India. The World Health Organisation’s Global Burden of Disease study puts air pollution 4th on the list of health risks, behind high blood pressure, poor diet and smoking.

Globally, air pollution is thought to be the 4th most important health risk.

8-4 What are the chemical air pollutants that have an effect on health?

Several chemical air pollutants have an effect on health and it is likely that there are some we do not know about. The important ones include:

Ozone, sulphur dioxide and nitrogen dioxide are important chemical pollutants in the atmosphere.

8-5 How can air pollution be reduced?

Most air pollution is a result of industry and mass road transport and is outside the control of individuals. Although there have been some successes stories where communities have been able to improve air quality locally, the control of industrial and vehicle emissions requires legislation, regulation and monitoring by national and local governments. Unfortunately, regulation of emissions in low- and middle-income countries is often weak.

In future the use of electric vehicles should help reduce outdoor air pollution due to the use of fossil fuels. In South Africa the introduction of electric trains has replaced many coal and diesel burning trains.

In 2016, a non- governmental organisation reported that European traders were exporting diesel too dirty for use in Europe to West Africa. As a result, 5 West African countries have introduced strict new regulations to control fuel standards and vehicle emissions.

There are however things that individuals and communities can do to reduce their smoke exposure:

Unit 9: Water and sanitation


By the end of this unit you should be able to:

9-1 How good is access to water in South Africa?

South Africa is a water scarce country, with about half the global average of rainfall. This means that the supply of good quality water is an issue for everybody, and that water should not be wasted. The 2016 General Household and Community surveys reported that nearly 90% of households in South Africa now have access to piped water but only 63% believe their water safe to drink. Water borne diseases remain common, with about 20% of deaths in South African children under 5 still due to diarrhoea.

Water related health problems can result from limited access to a sufficient quantity of water, or to poor quality water. Therefore access to good quality water remains a challenge in many areas

Many homes in South Africa still have poor quality water.

9-2 What are the water requirements for a human?

In South Africa, the basic daily requirement of good quality water is 25 litres per person.

During the 2016-2018 drought in Cape Town the aim was 50 litres per person per day for drinking, cooking, washing (showering) and flush toilets. Recycling water was strongly encouraged, especially for flushing toilets.

9-3 How do health problems result from an insufficient quantity of water?

Health problems from shortage of water are:

The main danger from too little water is dehydration.

9-4 How are health problems caused by poor quality water?

Illness can be a result of drinking contaminated water:

In addition, there can be disease causing agents living in or on water. For example, mosquitoes living in stagnant water may be vectors for diseases such as malaria, dengue and zika virus.

The main danger from poor quality water is infection.

9-5 What is environmental enteropathy?

In the past, health teams have been very aware of the risk of acute diarrhoea from contaminated water. It is now known that children drinking contaminated water are also at risk of a chronic condition called “environmental enteropathy”. In this condition, there is a change in the types of bacteria living in the gut (the “microbiome”). This results in chronic inflammation of the gut and thinning of the gut lining (atrophy of the villi). As a result, food is poorly absorbed (malabsorption). Therefore environmental enteropathy may be an important contributor to undernutrition and growth stunting in poorer communities. It also limits the effectiveness of nutrition supplementation programmes and oral immunisations.

Environmental enteropathy is a chronic gut condition caused by drinking contaminated water.

9-6 What are the main chemical risks to water safety in countries like South Africa?

The main risks are:

Mining, industries and farming can all cause chemical contamination of water.

9-7 Why is sanitation important?

Two factors make access to toilets important:

9-8 What are “improved toilet facilities” and what proportion of South African households have access to them?

Improved toilet facilities consist of flush toilets and ventilated improved pit toilets (latrines):

About 60% of the population have access to flush toilets while a further 18% have access to VIP toilets. This gives a total of 78% with access to improved toilet facilities. In future it may no longer be possible to use high quality drinking water to flush toilets in water scarce parts of South Africa.

Only 60% of the South African population has access to flush toilets.

9-9 What are “unimproved toilet facilities” and what percentage of South African households have access to them?

Unimproved toilet facilities are less acceptable options:

Unventilated pit toilets are used by 17% and the bucket system by 1% of the population. No toilet facilities are available for a further 4%. Therefore a total of 22% of the population have unimproved or no toilet facilities.

About 22% of South Africans have no access to improved toilets.

9-10 How many households in South Africa share toilet facilities?

Currently 16% to 20% of households in South Africa share toilet facilities with other households.

9-11 What are the other concerns around toilets?

Common concerns are:

9-12 Are there challenges with water and sanitation infrastructure?

Yes. There are a number of concerns:

There is concern about the future of both water and sanitation infrastructure in South Africa.

There are many concerns about meeting the water and sanitation needs in the future.

Unit 10: Climate change and health


By the end of this unit you should be able to:

10-1 What is the main cause of climate change?

Heat from the sun warms the planet and then is reflected back from the earth into space. Gases in the atmosphere, such as carbon dioxide and methane keep some of this heat trapped in the atmosphere and prevent it escaping into outer space. This is a good thing otherwise the planet would be much colder. These gases are called “greenhouse gases” because they provide the same function as the glass in a greenhouse which keeps the heat in.

Carbon is widely found in living things and for about 350 million years, the carbon in plants and small marine animals has been trapped and compressed in the rock, forming “fossils fuels” that we know as oil, coal and natural gas. Since the Industrial Revolution, humans have been burning more and more fossil fuels and the trapped carbon has been released into the air as carbon dioxide. As a result there has been a rapid build-up of greenhouse gases over the past few decades, which means that more of the sun’s heat is kept in the atmosphere and not allowed to escape. The result is excessive global warming leading to climate change.

Global warming is caused by the excessive burning of fossil fuels and results in climate change.

10-2 What will be the result of climate change?

There are 2 main results of climate change:

Trying to predict what will happen to the weather over the next 100 years is not an exact science. There are those people who deny that serious climate change is a real danger. However, the majority of scientists agree that climate change is happening and is probably the greatest threat to public health in this century, and that it is caused by humans burning increasing amounts of fossil fuels. Climate change is likely to increase the gap in health and wellbeing between rich and poor countries in the next few decades. It should not be ignored in the hope that it will not happen.

Climate change is leading to rising sea levels.

It is predicted that the western regions of South Africa will become drier while the eastern regions will become wetter. These changes in weather patterns are already becoming obvious with drought in Cape Town and floods in Johannesburg and Durban.

10-3 What are the risks to health from climate change?

It is likely that the greatest challenges and risks from climate change will be in low and middle-income countries. Health risks include:

Climate change is a major threat to health especially in low- and middle-income countries.

10-4 What can be done?

Reading about climate change and the likely consequences can be frightening. There are 2 main strategies for reducing the risk:

Increasing the use of wind, solar and hydro-electric energy can reduce the need for fossil fuels.

South Africa has started a programme dedicated to increasing the use of renewable energy. Generating cheap home-based or town-based “green energy” (wind and solar) on a large scale throughout the country in both urban and rural areas avoids energy loss in long power transmission lines from large central generating stations and promises to reduce greenhouse gasses and improve air quality.

10-5 Why are the consequences of climate change likely to be worse in low- and middle-income countries?

Reasons include:

Low- and middle-income countries are also least likely to be prepared and able to manage climate change.

The countries and communities most likely to be affected by climate change are also the least likely to be prepared for it.