Free tools · From a European air-quality model
Air in Gauteng
Air in 2025 (modelled): nitrogen dioxide near the ground averaged 34 µg/m³, 3.4 times WHO’s guideline of 10; winters 44 µg/m³, summers 24 µg/m³.
Nitrogen dioxide (NO2) comes mostly from burning: power stations, vehicles, industry. Near the ground is what people breathe. The column is all of it in the air above, from the ground to the top of the sky, which is what a satellite sees. Sulphur dioxide (SO2) comes mostly from burning coal. Ozone forms in sunlight from other pollutants.
Modelled, not measured: these figures come from the Copernicus Atmosphere Monitoring Service’s reanalysis, a weather and chemistry model that takes in satellite readings. Its cells are about 80 km across, so a busy road or a smoky winter evening in one suburb is smoothed into the region around it. It is not a reading at any address.
2025
- 34 µg/m³Nitrogen dioxide near the groundThe year’s mean; 3.4 × WHO’s guideline
- 44 µg/m³In winterJune to August, against 24 µg/m³ in summer (last five years)
- 154 µmol/m²NO2 in the column aboveWhat a satellite sees, not what you breathe
- 166 µmol/m²SO2 in the column aboveMostly from burning coal
- 41 µg/m³Ozone near the groundThe year’s mean
WHO’s 2021 guideline for nitrogen dioxide is 10 µg/m³ as a yearly mean. It is a long-term health guideline, not a legal limit (South Africa’s national standard for the yearly mean is set separately), and these are modelled regional means, not readings where you live.
Month by month
| Month | NO2 near the ground | Ozone near the ground | NO2 column | SO2 column |
|---|---|---|---|---|
| December 2025 | 26 µg/m³ | 46 µg/m³ | 115 µmol/m² | 128 µmol/m² |
| November 2025 | 26 µg/m³ | 45 µg/m³ | 125 µmol/m² | 117 µmol/m² |
| October 2025 | 30 µg/m³ | 53 µg/m³ | 142 µmol/m² | 148 µmol/m² |
| September 2025 | 32 µg/m³ | 51 µg/m³ | 142 µmol/m² | 163 µmol/m² |
| August 2025 | 47 µg/m³ | 42 µg/m³ | 163 µmol/m² | 174 µmol/m² |
| July 2025 | 47 µg/m³ | 33 µg/m³ | 183 µmol/m² | 204 µmol/m² |
| June 2025 | 44 µg/m³ | 31 µg/m³ | 199 µmol/m² | 200 µmol/m² |
| May 2025 | 46 µg/m³ | 34 µg/m³ | 219 µmol/m² | 238 µmol/m² |
| April 2025 | 32 µg/m³ | 31 µg/m³ | 154 µmol/m² | 151 µmol/m² |
| March 2025 | 32 µg/m³ | 43 µg/m³ | 145 µmol/m² | 160 µmol/m² |
| February 2025 | 24 µg/m³ | 40 µg/m³ | 141 µmol/m² | 168 µmol/m² |
| January 2025 | 25 µg/m³ | 43 µg/m³ | 119 µmol/m² | 139 µmol/m² |
| December 2024 | 23 µg/m³ | 48 µg/m³ | 111 µmol/m² | 122 µmol/m² |
| November 2024 | 28 µg/m³ | 56 µg/m³ | 127 µmol/m² | 138 µmol/m² |
| October 2024 | 29 µg/m³ | 62 µg/m³ | 150 µmol/m² | 190 µmol/m² |
| September 2024 | 32 µg/m³ | 53 µg/m³ | 140 µmol/m² | 157 µmol/m² |
| August 2024 | 41 µg/m³ | 44 µg/m³ | 162 µmol/m² | 171 µmol/m² |
| July 2024 | 47 µg/m³ | 33 µg/m³ | 172 µmol/m² | 148 µmol/m² |
| June 2024 | 47 µg/m³ | 30 µg/m³ | 219 µmol/m² | 223 µmol/m² |
| May 2024 | 52 µg/m³ | 35 µg/m³ | 207 µmol/m² | 243 µmol/m² |
| April 2024 | 31 µg/m³ | 35 µg/m³ | 148 µmol/m² | 164 µmol/m² |
| March 2024 | 29 µg/m³ | 41 µg/m³ | 149 µmol/m² | 180 µmol/m² |
| February 2024 | 26 µg/m³ | 44 µg/m³ | 121 µmol/m² | 152 µmol/m² |
| January 2024 | 26 µg/m³ | 51 µg/m³ | 114 µmol/m² | 151 µmol/m² |
Over the last five years the NO2 column averaged 186 µmol/m² in winter against 123 µmol/m² in summer, and the SO2 column 194 µmol/m² against 143 µmol/m²: still winter air holds what is burnt close to the ground, and more is burnt to keep warm.
Every year since 2003
Show the numbers
| When or what | Figure |
|---|---|
| 2003 | 24 µg/m³ |
| 2004 | 23 µg/m³ |
| 2005 | 24 µg/m³ |
| 2006 | 25 µg/m³ |
| 2007 | 26 µg/m³ |
| 2008 | 28 µg/m³ |
| 2009 | 27 µg/m³ |
| 2010 | 28 µg/m³ |
| 2011 | 28 µg/m³ |
| 2012 | 29 µg/m³ |
| 2013 | 28 µg/m³ |
| 2014 | 29 µg/m³ |
| 2015 | 30 µg/m³ |
| 2016 | 30 µg/m³ |
| 2017 | 31 µg/m³ |
| 2018 | 31 µg/m³ |
| 2019 | 34 µg/m³ |
| 2020 | 32 µg/m³ |
| 2021 | 31 µg/m³ |
| 2022 | 34 µg/m³ |
| 2023 | 33 µg/m³ |
| 2024 | 34 µg/m³ |
| 2025 | 34 µg/m³ |
See it in the Copernicus Browser, the European Space Agency’s free viewer, on the newest image: Sentinel-5P, nitrogen dioxide · Sentinel-5P, sulphur dioxide. These are Sentinel-5P’s observed columns for one day, not our modelled yearly figures; days with cloud have gaps.
Every municipality, ranked · On the explore map
Source
Modelled, not measured: these figures come from the Copernicus Atmosphere Monitoring Service’s reanalysis, a weather and chemistry model that takes in satellite readings. Its cells are about 80 km across, so a busy road or a smoky winter evening in one suburb is smoothed into the region around it. It is not a reading at any address.
How we worked this out
What we changed: we averaged the reanalysis’s monthly means over each place by its area in each 0.75 degree cell, turned NO2 and ozone on the model’s lowest level from mass mixing ratio into micrograms per m3 with the month’s air density (surface pressure and temperature), and the columns from kg per m2 into micromol per m2.
Particles (PM2.5, PM10) and sulphur dioxide near the ground are not shown yet: the model reads them far higher over Gauteng and the Highveld than is plausible for a regional mean, so they wait for a check against ground stations.
Contains modified Copernicus Atmosphere Monitoring Service information 2003 to 2025. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains. Copernicus Atmosphere Monitoring Service (2020): CAMS global reanalysis (EAC4) monthly averaged fields. Copernicus Atmosphere Monitoring Service (CAMS) Atmosphere Data Store, DOI 10.24381/fd75fff2. Inness, A. and others (2019): The CAMS reanalysis of atmospheric composition, Atmos. Chem. Phys., 19, 3515 to 3556. Under CC BY 4.0.
Dataset: air quality by municipality, release of 12 November 2026.