Colombia Air Quality
Bogotá sits at 2,600m in the Sabana plateau, where thinner air, diesel buses, and seasonal thermal inversions combine to create some of South America's worst urban air quality episodes.
Seasonal AQI Pattern — Bogotá
Two dry seasons (Jan–Mar, Jul–Aug) drive pollution peaks via thermal inversions
Why Altitude Makes It Worse
Bogotá's elevation of 2,600m above sea level means the atmosphere is ~25% thinner than at sea level. Diesel and gasoline engines run less efficiently in thinner air — they produce more incomplete combustion products, including black carbon (soot), CO, and VOCs. A bus engine that meets emission standards at sea level can exceed them significantly in Bogotá.
The Sabana de Bogotá plateau is surrounded on three sides by the Andes Cordillera Oriental. During dry season anticyclones (January–March and July–August), a thermal inversion lid forms at ~2,800–3,000m — just a few hundred meters above the city's surface. All vehicle and industrial emissions become trapped beneath this lid, concentrating rapidly during the morning rush hour.
IDEAM (Colombia's national meteorological agency) tracks inversion days. During inversion episodes, PM2.5 in Bogotá's southern residential zones can reach 60–80 μg/m³ — four to five times the WHO guideline — for multiple consecutive days.
Pollution Sources
Diesel Bus Fleet
Bogotá's bus fleet — mostly older diesel models — is the dominant air pollution source. TransMilenio BRT has improved somewhat, but thousands of legacy buses still operate on routes not served by BRT.
Private Vehicles
Over 1.8 million registered vehicles in Bogotá. Pico y Placa restriction (peak-hour ban by plate number) reduces rush-hour traffic, but car ownership has grown faster than restrictions.
Industry
Industrial zones in Soacha and Fontibón contribute PM2.5 and SO₂. Brick kilns on the urban periphery are a particularly dirty source during dry seasons.
Cooking & Heating
Low-income neighborhoods in the south and southwest still use wood and charcoal for cooking. At altitude, wood combustion is less efficient and produces more PM2.5 per kg burned.