The quality of air in Gauteng was poor this winter, with industrial activities, vehicle tailpipe emissions, domestic burning of fossil fuel, unpaved roads and climate variables all sending pollution levels upwards.

There could also be knock-on contributing factors from emissions in Mpumalanga and Free State, which hit Gauteng due to its location according to the South African Air Quality Information System (SAAQIS).

Sebokeng, a highly industrialised region near the Vaal River, recorded the poorest air quality this winter, followed by Jabavu in Soweto, which was mainly affected by emissions from domestic fuel burning and other ambient air quality factors in the area.

A significant proportion of households in the area use coal and biomass for heating and cooking.

“In winter there is generally low air quality. We always see a spike on our graph. People are burning coal, tyres because of protests, and other contributing factors. But there are no spikes in summer.

“Though we can’t speak on the health effects, some people get affected by eye irritation due to the dust. Ambient air changes every now and then, so it’s hard to tell whether this year is particularly bad or not,” said Lenni Motha, a Gauteng air quality official.

According to SAAQIS, any exceedances of its minimum standards indicate pollution above acceptable limits, with potential to harm those exposed to those high pollution levels.

“When exceedances are reported, there must be action to remedy the situation, using various mitigation strategies, relevant to contributing sources within a specific location where exceedances are reported.

“Ozone is a secondary pollutant and its formation depends on the availability of NOx (nitrogen oxides), hydrocarbons and sunlight. Therefore, ozone cannot be directly related to any particular source,” said the ambient air quality organisation.

In February, the environment, forestry, and fisheries department said it would investigate concerns of pollution in and around Gauteng and Mpumalanga after widespread complaints of a sulphuric smell that has caused headaches and nausea. The report is not out yet.