Worst air pollution Harrismith, today and tomorrow
Today (20 September): Air quality in Harrismith is moderate. AQI, PM2.5, and PM1 are moderate; PM10, NO2, and O3 are fair; SO2, CO, and HCHO are good. Pollution peaks around 10:00 PM (PM1: 57.5/100).
Tomorrow (21 September 2026): Air quality in Harrismith is poor. AQI worsens to poor; PM1 increases to poor; all other pollutants stay as today. Pollution peaks around 7:00 AM (PM1: 65.2/100). Airmine updates local air quality forecasts four times daily.
Get the full experience in the Airmine app.
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
Follow your pollen exposure and performance with the free Airmine–Strava integration. See your pollen and air quality exposure for every Strava activity.
Harrismith's air quality reflects the Free State Highveld position at 1,631 metres near the Drakensberg Amphitheatre, with vehicle traffic on the N3 and surrounding agricultural and logistics operations contributing local sources. The elevated highland position aids background dispersal on most days, while winter Highveld temperature inversions can concentrate vehicle and biomass burning emissions and the Drakensberg's dramatic escarpment creates significant topographic variation that influences the broader regional air quality environment throughout the year.
Today - 20 September | Pollution peaks at 22:00
AQI:
Moderate
57.5/100
PM2.5 (fine particles):
Moderate
49.9/100
PM10 (coarse particles):
Fair
32.3/100
NO2 (nitrogen dioxide):
Fair
27.4/100
O3 (ozone):
Fair
27.4/100
SO2 (sulfur dioxide):
Good
18.0/100
CO (carbon monoxide):
Good
1.1/100
HCHO (formaldehyde):
Good
10.0/100
PM1 (ultrafine particles):
Moderate
57.5/100
Levels show the poorest local air quality during the day
Tomorrow - 21 September | Pollution peaks at 07:00
AQI:
Poor
65.2/100
PM2.5 (fine particles):
Moderate
55.5/100
PM10 (coarse particles):
Fair
39.8/100
NO2 (nitrogen dioxide):
Fair
24.3/100
O3 (ozone):
Fair
32.4/100
SO2 (sulfur dioxide):
Good
9.5/100
CO (carbon monoxide):
Good
1.1/100
HCHO (formaldehyde):
Good
13.1/100
PM1 (ultrafine particles):
Poor
65.2/100
Pollen forecast in Harrismith
View pollen forecastAir quality forecasts for neighbourhoods and landmarks in Harrismith
Frequently Asked Questions
Is air quality bad in Harrismith right now?
On 20 September 2026, overall air quality in Harrismith is moderate. AQI is the main air quality indicator at 57.5/100. Pollution peaks around 10:00 PM (PM1: 57.5/100).
Will air quality be worse tomorrow in Harrismith?
On 21 September 2026, air quality conditions in Harrismith will be worse than today, with AQI forecast at poor at 65.2/100. Pollution peaks around 7:00 AM (PM1: 65.2/100).
When is air pollution at its worst in Harrismith?
At Harrismith, the poorest air quality usually occurs on still winter mornings from May to August, when smoke and vehicle emissions accumulate under a low temperature inversion typical of the Highveld plateau. From November onward, summer rains and afternoon winds generally restore clearer conditions that last through much of the warmer part of the year.
Are air quality levels in Harrismith based on measurements or forecasts?
It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.
Why doesn’t the forecast always reflect wildfire impacts?
Airmine’s forecast uses CAMS (Copernicus Atmosphere Monitoring Service) as its background atmospheric model. While CAMS includes wildfire emissions, these are derived from satellite observations and are not available in real time. During rapidly evolving wildfire events, there may therefore be a delay before increased emissions are incorporated into the model. As a result, the forecast may temporarily underestimate PM₂.₅ and other pollutants associated with wildfire smoke.
During rapidly evolving wildfire events, CAMS may lag by approximately 1–2 days before increased wildfire emissions are fully represented, which can lead to temporary underestimation of PM₂.₅ concentrations in Airmine’s forecast.
Want to see air quality forecasts for other cities in South Africa?
Check air quality in other popular cities:
Data provided by Airmine — Last update: 20 September 2026 at 14:33 CEST (Data is updated four times daily.)
This forecast is produced independently using Airmine's own atmospheric data and models.
Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.
Disclaimer: Forecasts are provided for informational purposes only and should not be relied upon as medical advice. Actual pollen and air quality conditions may vary from the forecast. If you have allergies, asthma, or another medical condition, consult a healthcare professional. Please see our Terms of Service for important information about limitations of liability.
Some text on this page may be generated or summarised using artificial intelligence (AI). Wherever possible, AI-generated content is enriched with Airmine's proprietary data to improve its accuracy and relevance. However, AI-generated content may still contain errors, omissions, or inaccuracies.
Get the full experience in the Airmine app.