Tunis Air Quality Index
Tunis — Tunisia’s Mediterranean capital of 2.7 million — enjoys the cleanest air among North African capitals. Regular sea breezes, Atlantic frontal rains, and a relatively smaller vehicle fleet keep AQI in the Moderate range. The main pollution risks are Sirocco dust storms from the Sahara (May–September) and winter inversions when the Mediterranean calm reduces natural ventilation.
Monthly AQI Pattern
Mediterranean breezes clean summer air; winter anticyclones and Sirocco events are the main risk periods
Annual Pollutant Levels vs WHO Guidelines
| Pollutant | Tunis | WHO | Excess |
|---|---|---|---|
| PM2.5 | 21 μg/m³ | 5 μg/m³ | 4.2× |
| PM10 | 46 μg/m³ | 15 μg/m³ | 3.1× |
| NO₂ | 26 μg/m³ | 10 μg/m³ | 2.6× |
| SO₂ | 14 μg/m³ | 40 μg/m³ | 0.4× |
| O₃ | 52 μg/m³ | 60 μg/m³ | 0.9× |
Mediterranean Climate: A Natural Air Quality Advantage
Tunis sits at the southern tip of the Mediterranean basin, where the climate provides more natural air quality flushing than cities further south or east. Atlantic low-pressure systems regularly sweep through the western Mediterranean from October to April, delivering rainfall and wind that clears accumulated pollution. The Gulf of Tunis to the northeast and the Cap Bon peninsula create sea-breeze circulation that ventilates the city during summer afternoons.
Advantages
- • 500–700 mm/year rainfall — among highest in N. Africa
- • Regular Atlantic fronts Oct–Apr
- • Sea breezes from Gulf of Tunis (NE)
- • No mountain barrier blocking ventilation
Disadvantages
- • Winter anticyclones = still air episodes
- • Sirocco dust 10–25 days per year
- • Summer ozone formation (Mediterranean UV)
- • Bizerte industrial zone upwind on N/NW days
Seasonal Health Advisory
Winter anticyclones reduce sea-breeze ventilation. Sensitive groups should monitor air quality apps (IQAir, ANPE stations). Generally safe for most outdoor activity.
Best air quality season. Atlantic fronts clean the air regularly. Sirocco events begin in May — watch for PM10 spikes. Ideal for outdoor exercise and tourism.
Sea breezes dominate June–July. August Sirocco peak: on dust event days, PM10 can reach 150–300 μg/m³ for 1–3 days. Close windows and limit outdoor time during events.
Dust events taper off. Autumn rains begin in October, improving air quality. Traffic and schools returning in September drive a brief AQI rise.
North Africa & Mediterranean City Comparison
Annual average AQI 2024. Tunis highlighted.
Frequently Asked Questions
What is Tunis's annual AQI and how does it compare to other North African capitals?
Tunis's annual average AQI is approximately 68 (Moderate), with PM2.5 around 21 μg/m³ — about 4× the WHO annual guideline. Among North African capitals, Tunis is the cleanest: better than Algiers (82), Casablanca (75), and dramatically better than Cairo (148). The Mediterranean climate with regular sea breezes and frontal rains provides consistent air quality flushing. Tunisia's relatively small fleet size (about 2 million vehicles nationally) and the coastal geography both help. Worst months are December–January (winter calm reduces ventilation) and August (Sirocco peak).
What is the Sirocco and how bad does it get in Tunis?
The Sirocco (locally known as Chili in Tunisia) is a hot, dust-laden wind from the Sahara that affects Tunisia intermittently from April through September, with peak intensity in July–August. It originates over the Libyan and Algerian desert and accelerates through the Gulf of Gabès before reaching the Tunis region. During Sirocco events, PM10 can reach 150–300 μg/m³ over 24 hours, and visibility drops to a few kilometres. The air feels abrasive and gritty. Events typically last 1–4 days. Annual frequency: 10–25 Sirocco days per year in Tunis. The 2021 event was particularly severe, with PM10 exceeding 400 μg/m³ for brief periods.
What is the Bizerte industrial zone and how does it affect Tunis?
Bizerte, 65 km north of Tunis, is Tunisia's primary heavy industrial area: it hosts STIR (Société Tunisienne des Industries de Raffinage), a 34,000 barrel/day oil refinery; SOTACIB cement plant; chemical and fertilizer plants; and a major naval port. Prevailing northerly winds typically carry Bizerte emissions away from Tunis toward the Sahel. However, when winds shift to northwesterly or during temperature inversions, industrial pollution from Bizerte can reach Tunis. SO₂ and PM10 are the main industrial pollutants. The STIR refinery is scheduled for modernisation under Tunisia's energy transition plan, which should reduce sulfur emissions.
Is Tunis a good place for expats with respiratory conditions?
Yes, relatively. Tunis is one of the more air-friendly North African cities for people with respiratory conditions. The key risks are: (1) Sirocco dust events — brief but PM10 can be extreme. Set up IQAir or local ANPE (Agence Nationale de Protection de l'Environnement) air quality alerts. (2) Winter inversions (December–January) when stable anticyclonic conditions trap vehicle emissions. The Lac de Tunis waterfront area and La Marsa coastal suburb consistently have better air than the city centre (Médina, Bab Souika). HEPA purifier in the home is a practical investment. Overall, the Tunis climate is more forgiving than most African capitals.
What is Tunisia doing to improve air quality?
Tunisia has made moderate progress. The national fleet has been partially upgraded — Euro 4 fuel standards apply since 2016, and a vehicle scrapping program periodically removes the oldest vehicles. The Tunis Metro (Réseau Ferroviaire Rapide) operates 6 lines covering key commuter corridors, reducing car dependency in central Tunis. The 2023 Transport Law mandated annual vehicle inspections, previously unenforced. EU partnership programs (LIFE, EUROMED) have funded AQI monitoring stations. Challenges remain: the post-2011 economic instability reduced enforcement capacity, and the vehicle fleet has grown faster than clean-fuel availability. Gradual improvement is happening but slowly.