Qualité de l’air à Sebokeng

What is the level of air pollution in Sebokeng now?

Sebokeng is a middle-class township in southern Gauteng, South Africa. According to the 2011 census, it had an estimated population of approximately 218,000 people.

Towards the middle of 2021, Sebokeng was going through a period when the air quality was classified as being “Unhealthy for sensitive groups” with a US AQI number of 138. This United States Air Quality Index number is an internationally used set of metrics supported by the World Health Organisation (WHO) and is used to compare air quality in different cities throughout the world using comparable standards. It is calculated by using the levels of the six most commonly found pollutants. If records for all six are unavailable, then it is calculated using what figures were recorded. For Sebokeng there were only two records held, those of PM2.5 - 42.2 µg/m³ and PM10 - 131.4 µg/m³. The figures are quoted in micrograms/microns per cubic metre.

With levels such as these, the advice is to close doors and windows to prevent the ingress of more polluted air. Those of a sensitive disposition are advised to remain indoors or if travel outside is unavoidable, then a good quality mask is recommended. It is also recommended that all unnecessary outdoor exercise is postponed until the air quality improves. Consider changing the venue to a sports hall or a gym instead. It is advisable to use an air purifier if one is available. The table at the top of this page will assist in making that decision.

Does the air quality vary in Sebokeng throughout the year?

Air quality can be very volatile as it can be affected by many things. The seasons of the year and even the speed and direction of the wind can make a big difference.

The Swiss air monitoring company, IQAir.com has published its findings for 2020 and it can easily be seen that the best quality of air was enjoyed from January to May and again from September until the end of December. During these periods, Sebokeng recorded “Moderate” levels of air quality with figures between 12.1 and 35.4 µg/m³. The remaining three months of June, July and August saw the quality slip into the lower category of “Unhealthy for sensitive groups” with figures between 35.5 and 37.7 µg/m³. As South Africa is in the Southern hemisphere, their seasons tend to be opposite to the ones in the Northern hemisphere. Hence, June, July and August would be the “winter” season in South Africa.

Recordings were first kept regarding annual air quality in 2019 when the figure was 32.7 µg/m³ followed by a decrease the following year in 2020 when it was 29.5 µg/m³. However, this may not be a truly accurate reading because of the restrictions imposed due to the COVID-19 pandemic. Many vehicles were no longer used as the drivers were furloughed and not required to commute to and from work. There were also many factories and other non-essential production units which were temporarily closed in an attempt to prevent the spread of the virus. The results for 2021 may be a better indication as to whether or not the situation is indeed getting better.

Where does all the air pollution come from in Sebokeng?

The sources of air pollution in the Vaal Triangle are coal mines, industries, power stations and vehicles. Exposure to nitrogen dioxide and particulate matter, both PM2.5 and PM10, may lead to an increase in all-cause mortality, a decline in lung function, an increase in susceptibility to respiratory illnesses, stroke and heart conditions.

Most air pollution comes from energy use and production. Burning fossil fuels releases gases and chemicals into the air.

Smog and soot are the most common types of air pollution. Smog, or “ground-level ozone,” as it is sometimes called, occurs when emissions from combusting fossil fuels react with sunlight. Soot, or “particulate matter,” is made up of tiny particles of chemicals, soil, smoke, dust, or allergens, in the form of gas or solids that are carried in the air. The sources of smog and soot are similar. Both come from cars and trucks, factories, power plants, incinerators, engines—anything that combusts fossil fuels such as coal, gas, or natural gas. The tiniest airborne particles in soot—whether they’re in the form of gas or solids—are especially dangerous because they can penetrate the lungs and bloodstream and worsen bronchitis, lead to heart attacks, and even hasten death.

The large concentrations of vehicles in cities contribute to various air pollutants, both gases and material particles. Motor traffic is one of the biggest sources of CO2, but it also disperses carbon particles. Vehicles that use diesel pollute on average four times more than those that use petrol. This type of vehicle emits hundreds of gaseous and solid substances into the air.

What can be done to reduce air pollution in Sebokeng?

To control air pollution, it is necessary to take measures to reduce the release of polluting gases and particles. This implies legal and technological measures such as the introduction of national and international legal provisions for the reduction of emissions. It is also necessary to reduce the dependence on fossil fuels and increase the use of clean energy (hydropower, solar, wind, geothermal energy).

What effects does air pollution have on human health?

Smog can irritate the eyes and throat and also damage the lungs—especially of people who work or exercise outside, children, and senior citizens. It’s even worse for people who have asthma or allergies—these extra pollutants only intensify their symptoms and can trigger asthma attacks.

Fine suspended particulates (PM2.5) have been classified as a first-class carcinogen by the World Health Organisation. It is easy to adhere to mercury, lead, sulphuric acid, benzene, dioxin and other carcinogens to penetrate into the trachea and bronchus, penetrate the air bubbles in the lungs, and enter directly the blood vessels circulate throughout the body and reach the various organs of the human body.

Ozone (O₃) has strong oxidizing power and is irritating to the respiratory system. It can cause coughing, asthma, headache, fatigue and lung damage, especially for children, the elderly, the sick or outdoor sportsmen. At the same time, it has an adverse effect on plants, including crops, and can cause harm to man-made materials, such as rubber (tyres, etc.) and paint.