Worst air pollution Signal Hill - Cape Town, today and tomorrow
Today (20 September): Air quality in Signal Hill is poor. AQI and PM1 are poor; PM2.5 and PM10 are moderate; NO2, O3, SO2, and HCHO are fair; CO is good. Pollution peaks around 12:00 PM (PM1: 68.0/100).
Tomorrow (21 September 2026): Air quality in Signal Hill is poor. PM10 decreases to fair; NO2 increases to moderate; all other pollutants stay as today. Pollution peaks around 11:00 PM (PM1: 66.3/100). Airmine updates local air quality forecasts four times daily.
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Signal Hill's exposed Cape position means strong, regular winds usually keep air quality favourable, with vehicle traffic and the city bowl, harbour, and southern suburbs contributing modest local emissions. Only on rare still days, typically in winter, does pollution build up noticeably before dispersing again. It's a fairly standard picture for this part of the Western Cape.
Today - 20 September | Pollution peaks at 12:00
AQI:
Poor
68.0/100
PM2.5 (fine particles):
Moderate
55.3/100
PM10 (coarse particles):
Moderate
43.0/100
NO2 (nitrogen dioxide):
Fair
22.2/100
O3 (ozone):
Fair
33.5/100
SO2 (sulfur dioxide):
Fair
33.6/100
CO (carbon monoxide):
Good
1.7/100
HCHO (formaldehyde):
Fair
27.2/100
PM1 (ultrafine particles):
Poor
68.0/100
Levels show the poorest local air quality during the day
Tomorrow - 21 September | Pollution peaks at 23:00
AQI:
Poor
66.3/100
PM2.5 (fine particles):
Moderate
51.1/100
PM10 (coarse particles):
Fair
39.4/100
NO2 (nitrogen dioxide):
Moderate
42.7/100
O3 (ozone):
Fair
22.4/100
SO2 (sulfur dioxide):
Fair
39.8/100
CO (carbon monoxide):
Good
2.4/100
HCHO (formaldehyde):
Fair
29.8/100
PM1 (ultrafine particles):
Poor
66.3/100
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Frequently Asked Questions
Is air quality bad in Signal Hill right now?
On 20 September 2026, overall air quality in Signal Hill is poor. AQI is the main air quality indicator at 68.0/100. Pollution peaks around 12:00 PM (PM1: 68.0/100).
Will air quality be worse tomorrow in Signal Hill?
On 21 September 2026, air quality conditions in Signal Hill will be similar to today, with AQI forecast at poor at 66.3/100. Pollution peaks around 11:00 PM (PM1: 66.3/100).
When is air pollution at its worst in Signal Hill?
Calm winter days are when air quality dips most at Signal Hill, as emissions from the city bowl, harbour, and southern suburbs linger without the Cape's usual ventilation. Spring and summer bring the return of the reliable southeasterly wind, which keeps particulate levels consistently low across the area, a seasonal pattern typical of the wider Cape region.
Are air quality levels in Signal Hill 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.
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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.
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