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Air in Metsimaholo

Air in 2025 (modelled): nitrogen dioxide near the ground averaged 27 µg/m³, 2.7 times WHO’s guideline of 10; winters 32 µg/m³, summers 21 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 202523 µg/m³53 µg/m³116 µmol/m²145 µmol/m²
November 202521 µg/m³52 µg/m³121 µmol/m²131 µmol/m²
October 202525 µg/m³58 µg/m³134 µmol/m²153 µmol/m²
September 202527 µg/m³53 µg/m³142 µmol/m²183 µmol/m²
August 202537 µg/m³44 µg/m³167 µmol/m²199 µmol/m²
July 202536 µg/m³35 µg/m³175 µmol/m²216 µmol/m²
June 202531 µg/m³35 µg/m³174 µmol/m²186 µmol/m²
May 202532 µg/m³35 µg/m³176 µmol/m²193 µmol/m²
April 202528 µg/m³34 µg/m³135 µmol/m²139 µmol/m²
March 202528 µg/m³47 µg/m³134 µmol/m²152 µmol/m²
February 202520 µg/m³49 µg/m³133 µmol/m²163 µmol/m²
January 202522 µg/m³52 µg/m³121 µmol/m²142 µmol/m²
December 202419 µg/m³58 µg/m³114 µmol/m²150 µmol/m²
November 202424 µg/m³61 µg/m³130 µmol/m²156 µmol/m²
October 202423 µg/m³67 µg/m³133 µmol/m²181 µmol/m²
September 202425 µg/m³57 µg/m³133 µmol/m²174 µmol/m²
August 202429 µg/m³47 µg/m³140 µmol/m²167 µmol/m²
July 202432 µg/m³35 µg/m³147 µmol/m²141 µmol/m²
June 202434 µg/m³33 µg/m³198 µmol/m²220 µmol/m²
May 202439 µg/m³39 µg/m³174 µmol/m²216 µmol/m²
April 202427 µg/m³38 µg/m³145 µmol/m²177 µmol/m²
March 202427 µg/m³49 µg/m³154 µmol/m²198 µmol/m²
February 202422 µg/m³50 µg/m³120 µmol/m²165 µmol/m²
January 202420 µg/m³55 µg/m³98 µmol/m²133 µmol/m²

Over the last five years the NO2 column averaged 172 µmol/m² in winter against 119 µmol/m² in summer, and the SO2 column 196 µmol/m² against 148 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: 20 µg/m³2004: 20 µg/m³2005: 20 µg/m³2006: 20 µg/m³2007: 20 µg/m³2008: 22 µg/m³2009: 22 µg/m³2010: 23 µg/m³2011: 22 µg/m³2012: 23 µg/m³2013: 22 µg/m³2014: 24 µg/m³2015: 24 µg/m³2016: 24 µg/m³2017: 24 µg/m³2018: 25 µg/m³2019: 26 µg/m³2020: 25 µg/m³2021: 25 µg/m³2022: 27 µg/m³2023: 26 µg/m³2024: 27 µg/m³2025: 27 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
200320 µg/m³
200420 µg/m³
200520 µg/m³
200620 µg/m³
200720 µg/m³
200822 µg/m³
200922 µg/m³
201023 µg/m³
201122 µg/m³
201223 µg/m³
201322 µg/m³
201424 µg/m³
201524 µg/m³
201624 µg/m³
201724 µg/m³
201825 µg/m³
201926 µg/m³
202025 µg/m³
202125 µg/m³
202227 µg/m³
202326 µg/m³
202427 µg/m³
202527 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 Metsimaholo · 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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