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Air in Dipaleseng

Air in 2025 (modelled): nitrogen dioxide near the ground averaged 26 µg/m³, 2.6 times WHO’s guideline of 10; winters 32 µg/m³, summers 18 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

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

MonthNO2 near the groundOzone near the groundNO2 columnSO2 column
December 202520 µg/m³56 µg/m³110 µmol/m²129 µmol/m²
November 202518 µg/m³55 µg/m³120 µmol/m²119 µmol/m²
October 202523 µg/m³59 µg/m³138 µmol/m²148 µmol/m²
September 202524 µg/m³57 µg/m³142 µmol/m²171 µmol/m²
August 202536 µg/m³49 µg/m³163 µmol/m²177 µmol/m²
July 202537 µg/m³37 µg/m³179 µmol/m²196 µmol/m²
June 202531 µg/m³37 µg/m³177 µmol/m²168 µmol/m²
May 202532 µg/m³37 µg/m³184 µmol/m²179 µmol/m²
April 202528 µg/m³35 µg/m³142 µmol/m²125 µmol/m²
March 202524 µg/m³51 µg/m³128 µmol/m²135 µmol/m²
February 202517 µg/m³50 µg/m³124 µmol/m²148 µmol/m²
January 202519 µg/m³51 µg/m³110 µmol/m²119 µmol/m²
December 202417 µg/m³59 µg/m³113 µmol/m²135 µmol/m²
November 202422 µg/m³65 µg/m³131 µmol/m²145 µmol/m²
October 202420 µg/m³70 µg/m³134 µmol/m²175 µmol/m²
September 202423 µg/m³62 µg/m³130 µmol/m²154 µmol/m²
August 202429 µg/m³51 µg/m³142 µmol/m²155 µmol/m²
July 202432 µg/m³39 µg/m³153 µmol/m²125 µmol/m²
June 202434 µg/m³35 µg/m³194 µmol/m²188 µmol/m²
May 202438 µg/m³41 µg/m³171 µmol/m²194 µmol/m²
April 202425 µg/m³40 µg/m³145 µmol/m²158 µmol/m²
March 202424 µg/m³48 µg/m³150 µmol/m²184 µmol/m²
February 202420 µg/m³51 µg/m³118 µmol/m²153 µmol/m²
January 202419 µg/m³58 µg/m³93 µmol/m²120 µmol/m²

Over the last five years the NO2 column averaged 174 µmol/m² in winter against 115 µmol/m² in summer, and the SO2 column 176 µmol/m² against 134 µmol/m²: still winter air holds what is burnt close to the ground, and more is burnt to keep warm.

Every year since 2003

2003: 17 µg/m³2004: 17 µg/m³2005: 18 µg/m³2006: 18 µg/m³2007: 18 µg/m³2008: 20 µg/m³2009: 20 µg/m³2010: 20 µg/m³2011: 20 µg/m³2012: 21 µg/m³2013: 21 µg/m³2014: 22 µg/m³2015: 22 µg/m³2016: 22 µg/m³2017: 23 µg/m³2018: 23 µg/m³2019: 25 µg/m³2020: 24 µg/m³2021: 23 µg/m³2022: 25 µg/m³2023: 25 µg/m³2024: 25 µg/m³2025: 26 µg/m³200320082013201820232025
Nitrogen dioxide near the ground, each year’s mean (modelled). The line is WHO’s yearly guideline, 10 µg/m³.
Show the numbers
Nitrogen dioxide near the ground, the mean of each year, 2003 to 2025: every figure
When or whatFigure
200317 µg/m³
200417 µg/m³
200518 µg/m³
200618 µg/m³
200718 µg/m³
200820 µg/m³
200920 µg/m³
201020 µg/m³
201120 µg/m³
201221 µg/m³
201321 µg/m³
201422 µg/m³
201522 µg/m³
201622 µg/m³
201723 µg/m³
201823 µg/m³
201925 µg/m³
202024 µg/m³
202123 µg/m³
202225 µg/m³
202325 µg/m³
202425 µg/m³
202526 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 · Everything we hold for Dipaleseng · 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.

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