Background
The City of Johannesburg Metropolitan Municipality is located within the Gauteng
Province, covering an area of approximately 1 664 km2. Gauteng Province is one of
nine provinces within South Africa. The City is situated on the eastern plateau
area of South Africa, known as the Highveld, at an elevation ranging from 1 500
m to 1 800 m. The City is located on the Witwatersrand, a string of low, rocky ridges
that constitutes the watershed between the subcontinental drainage divide into the
Indian and Atlantic Oceans. The City’s northern and western suburbs have undulating
hills while the eastern area is relatively flat.
The City has a temperate climate, experiencing over eight hours of sunlight per
day in both winter and summer. Temperatures are mild with average maximum day-time
temperatures of 26 °C in January, dropping to 16 °C in June. Rainfall averages about
710 mm per annum although significant inter-annual variation in total rainfall is
experienced. Rainfall occurs predominantly during the summer months in late afternoon
electrical storms.
Johannesburg is the economic and financial hub of South Africa, producing 16% of
South Africa’s Gross Domestic Product (GDP) and accounting for 40% of Gauteng’s
economic activity. Gold mining is the foundation of the Witwatersrand economy although
its importance is gradually declining. Johannesburg is the centre of mining administration
and service, manufacturing (steel and cement), commercial companies and finance
within South Africa.
In 2006, the City was restructured from eleven administrative regions to seven regions
to improve service delivery and planning within the City. These seven administrative
regions are Region A – Diepsloot and Midrand, Region B – Northcliff and Randburg,
Region C – Roodepoort, Region D – Greater Soweto, Region E – Sandton and Alexandra,
Region F – Inner City, Region G – Ennerdale and Orange Farm.
Air Quality Management Plan
As part of its obligations in AQA, the City initiated the development of an Air Quality Management Plan (AQMP) which was approved by Council in 2003. The City developed
the AQMP with the rationale to address the deteriorating air quality caused by domestic
fuel burning, industries, mining and vehicles.
The main goals of the Air Quality Management Plan are to:
• Achieve acceptable air quality levels throughout the City,
• Promote a clean and healthy environment for all residents within the City,
• Minimise the negative impacts of air pollution on health and environment,
• Promote the reduction of greenhouse gas emissions in support of the City’s climate
change protection programme.
The AQMP identified the main pollutants of concern in the City as well as the associated
contributing sources and areas of impact through an analysis of available air pollution
monitoring data and health studies. Particulate matter (PM) concentrations were
found to be elevated throughout most of the City even in areas remote from heavy industrial and domestic coal burning areas. Particulate concentrations were well
in excess of the guidelines in domestic coal burning areas. The major sources of
On emissions were identified to originate from domestic fuel burning (primarily
coal), diesel-driven vehicle tailpipe emissions, industrial operations, fuel burning
appliances as well as long-range transport from the Highveld and biomass burning
to the north. Ambient NO2 concentrations and O3 concentrations were elevated over
a large area of the City with exceedances of the guidelines recorded in the short-term.
Elevated NO2 concentrations are associated with the City’s highways (N3, N1, M2
and M1) and the Central Business District (CBD) due to vehicle tailpipe emissions.
Although elevated O3 concentrations were anticipated to occur across the City, the
main impact areas associated with the emission of O3 precursors from sources within
the City occur within areas to the south and south-east of the City due to the prevailing
airflow patterns. Although elevated ambient SO2, CO and VOC concentrations have
also been measured, concentrations are generally within the guidelines. Ambient
SO2 concentrations were reported to have stabilized with reductions noted in certain
areas. Ambient CO concentrations were found to be increasing although concentrations
were below the guidelines. The main source of these pollutants was identified to
be domestic coal burning.
The establishment of a comprehensive ambient air quality and meteorological monitoring
network was also recommended in the AQMP (Scorgie et al., 2003). This included the
establishment of eleven monitoring stations to measure the contributions from domestic
fuel burning, transportation, commercial and industrial operations to ambient pollution
concentrations across the City.
Specific monitoring objectives were identified in the Air Quality Management Plan,
including:
• To determine compliance with air quality guidelines and standards,
• To assess exposure of people, addressing both the highest levels and the levels
in other areas where the general population is exposed,
• Make adequate information available to the public,
• Provide objective inputs to air quality management, transportation and land-use
planning,
• Tracking progress made by pollution control measure implementation,
• Source contribution and trend analysis.
Ambient Air Quality Monitoring
The City of Johannesburg currently operates eight ambient air quality monitoring stations located at
Alexandra, Buccleuch, Delta Park, Diepsloot, Ivory Park, Jabavu, Newtown and Orange Farm. The stations
at Alexandra, Diepsloot, Ivory Park, Jabavu and Orange Farm were sited to measure emissions from
domestic fuel burning. A significant proportion of households use coal for heating and cooking purposes
in these areas. The station at Buccleuch is located at the intersection of the N1 and M1 highways to
measure vehicle emissions. The Newtown station within Johannesburg Central Business District measures
urban, commercial and industrial emissions. Delta Park was intended to be a background urban station
and is located with the Delta Park Environmental Centre. This station is not exposed to any direct
emissions from air pollution sources. However, measured concentrations at this station compare well with
the rest of the stations and it is therefore not representative of background concentrations anymore.