The WHO database collected data on the outdoor (or ambient) air quality of 1600 cities from 91 countries. The database revealed that Johannesburg, in particular, has very poor air quality resulting from coal-fired power generation and poor environmental governance. A situation, which according to Dominique Doyle Energy Policy Officer at Earthlife Africa Johannesburg [2], “is jeopardising the Constitutional right of citizens to an environment which is not harmful to their well-being and is placing increased pressure on the already overburdened health system”.

The WHO database made use of South African data sourced from the South African Air Quality Information System (SAQIS). SAQIS collects constantly measured air quality data from local monitoring stations and is managed by the South African Weather Services. The database included data on levels of Particulate Matter of the size 10 and 2.5 for Cape Town, Durban, Johannesburg, Tshwane, the Highveld Priority Area, the Vaal Priority Area and the Waterberg.

Particulate matter (PM) is a collective term for a number of pollutants found in the air such as: sulphate, nitrates, ammonia, sodium chloride, black carbon, mineral dust and water. PM is therefore a mixture of solid and liquid particles of both organic and inorganic substances that are found suspended in local air. PM is further known to affect more people than any other pollutant. Some particles of PM to have a diameter of 10 microns or less (PM10), which become lodged deep in human lungs and lead to respiratory and cardiovascular diseases, as well as lung cancer. PM 2.5 are much finer particles that can pass into the human blood stream and also leads to respiratory diseases and certain types of cancers [3].

According to the WHO, there is a close and measurable relationship between human exposure to high levels of PM 10 and PM 2.5 in ambient air and increased illness & related mortality over time. In other words, there is a strong correlation between improving ambient air quality and an increase in the quality and length of human life.

PM is understood by the WHO as such a grave threat to the quality of human life, that it actually claims that there is no level of PM which is deemed safe for people to be in contact with. However, the WHO has developed guidelines for countries and cities on acceptable levels of PM, given that PM’s release into the atmosphere is an inevitability of modern life. For PM 2.5, the WHO annual guideline is a mean 10 ?g/m3 and a mean of 20 µg/m3 annually for PM 10.

Of the South African cities included in the WHO database, Johannesburg was listed as having the highest levels of both PM 10 and PM 2.5 with a yearly average of 98 µg/m3 for PM 10 and 51 µg/m3 for PM 2.5. According to Rico Euripidou, Environmental Health Campaigner at environmental justice NGO groundWork [4] “These levels are almost 10 times higher than the WHO guidelines for PM 10 and 5 times higher those recommended for PM 2.5. The levels amount to environmental crime and are of grave concern.”

Additionally these levels are also reported to be higher than both the Highveld Priority Area and the Vaal Priority Area. The Highveld and the Vaal Priority Areas are both well-known pollution hotspots in South Africa because of their high concentration of Eskom coal-fired power plants and other polluting industries such as Sasol. Although Durban has the healthiest air, according to the WHO study, even here concentrations of PM 10 and PM 2.5 are above WHO guidelines at 26 µg/m3 and 14 µg/m3 respectively.

In South Africa, areas which are known to have high levels of ambient air pollution should be declared as priority areas. Priority areas are required by Section 19 (1) of the National Environmental Management Act (Act 39 of 2004) to develop an Air Quality Management Plan that will enable the area to improve its ambient air quality and maintain compliance with the air quality standards that the South African government has set. The Air Quality Management Plan makes use of the Constitutional principle of progressive realization of air quality improvements that ensure that source pollutants implement the measures necessary to improve ambient air quality towards levels that are safe for human inhabitation.

According to the WHO study, the City of Johannesburg has ambient air quality worse than priority areas of Witbank and the Vaal. The City of Johannesburg should then be declared a high priority area with immediate effect.