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Air in Dannhauser

Air in 2025 (modelled): nitrogen dioxide near the ground averaged 19 µg/m³, 1.9 times WHO’s guideline of 10; winters 26 µg/m³, summers 12 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 202514 µg/m³52 µg/m³81 µmol/m²94 µmol/m²
November 202513 µg/m³51 µg/m³97 µmol/m²104 µmol/m²
October 202520 µg/m³55 µg/m³124 µmol/m²156 µmol/m²
September 202522 µg/m³51 µg/m³135 µmol/m²173 µmol/m²
August 202532 µg/m³38 µg/m³185 µmol/m²234 µmol/m²
July 202527 µg/m³37 µg/m³165 µmol/m²196 µmol/m²
June 202527 µg/m³33 µg/m³171 µmol/m²172 µmol/m²
May 202522 µg/m³32 µg/m³141 µmol/m²146 µmol/m²
April 202520 µg/m³31 µg/m³130 µmol/m²126 µmol/m²
March 202515 µg/m³42 µg/m³92 µmol/m²97 µmol/m²
February 20259.6 µg/m³45 µg/m³77 µmol/m²83 µmol/m²
January 202513 µg/m³49 µg/m³78 µmol/m²92 µmol/m²
December 202413 µg/m³60 µg/m³109 µmol/m²153 µmol/m²
November 202418 µg/m³59 µg/m³117 µmol/m²145 µmol/m²
October 202416 µg/m³63 µg/m³101 µmol/m²118 µmol/m²
September 202425 µg/m³55 µg/m³169 µmol/m²204 µmol/m²
August 202426 µg/m³48 µg/m³163 µmol/m²178 µmol/m²
July 202426 µg/m³37 µg/m³163 µmol/m²148 µmol/m²
June 202426 µg/m³34 µg/m³151 µmol/m²153 µmol/m²
May 202427 µg/m³35 µg/m³140 µmol/m²168 µmol/m²
April 202417 µg/m³36 µg/m³127 µmol/m²143 µmol/m²
March 202413 µg/m³46 µg/m³94 µmol/m²126 µmol/m²
February 202413 µg/m³50 µg/m³82 µmol/m²119 µmol/m²
January 202412 µg/m³51 µg/m³66 µmol/m²89 µmol/m²

Over the last five years the NO2 column averaged 170 µmol/m² in winter against 84 µmol/m² in summer, and the SO2 column 186 µmol/m² against 100 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: 15 µg/m³2004: 15 µg/m³2005: 16 µg/m³2006: 16 µg/m³2007: 16 µg/m³2008: 16 µg/m³2009: 17 µg/m³2010: 17 µg/m³2011: 16 µg/m³2012: 17 µg/m³2013: 16 µg/m³2014: 16 µg/m³2015: 17 µg/m³2016: 17 µg/m³2017: 17 µg/m³2018: 18 µg/m³2019: 18 µg/m³2020: 18 µg/m³2021: 18 µg/m³2022: 20 µg/m³2023: 19 µg/m³2024: 19 µg/m³2025: 19 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
200315 µg/m³
200415 µg/m³
200516 µg/m³
200616 µg/m³
200716 µg/m³
200816 µg/m³
200917 µg/m³
201017 µg/m³
201116 µg/m³
201217 µg/m³
201316 µg/m³
201416 µg/m³
201517 µg/m³
201617 µg/m³
201717 µg/m³
201818 µg/m³
201918 µg/m³
202018 µg/m³
202118 µg/m³
202220 µg/m³
202319 µg/m³
202419 µg/m³
202519 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 Dannhauser · 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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