Kampala’s Cleaner-Air Reading Raises a Bigger Question About Urban Dust

Kampala’s cleaner-air reading raises a bigger question about urban dust, exposed ground, unpaved surfaces and other persistent sources of particulate pollution.

Air-quality measurements in Greater Kampala showed a short-term improvement during the recent crackdown on taxis in dangerous mechanical condition, with average PM2.5 concentrations declining from 36.8µg/m³ during August 17–23 to 32.4µg/m³ during August 24–30. The decline coincided with enforcement against defective vehicles, whose poorly maintained engines can emit particulate matter and other pollutants. Even after the improvement, however, measured PM2.5 remained more than twice the World Health Organization’s 24-hour guideline of 15µg/m³.

The figures are useful, but they should not be interpreted as proof that defective taxis are the principal cause of Kampala’s particulate pollution. Research on the city repeatedly identifies several sources, including vehicle exhaust, biomass and waste burning, construction activity and resuspended road dust. A four-year Kampala study found higher particulate levels during dry conditions and specifically linked pollution to dust from unpaved roads, construction and traffic. Earlier spatial research found significantly higher PM2.5 concentrations in residential areas with unpaved roads than in comparable paved areas, while soil and crustal particles have also been identified as major components of Kampala’s particulate load.

Kampala’s air quality improved during a crackdown on defective taxis

Removing smoky and mechanically unsafe vehicles is therefore a legitimate public-health and road-safety intervention, but Kampala cannot inspect its way out of dirty air. Large areas of exposed earth, unpaved shoulders and access roads, deteriorated surfaces, construction sites and inadequate ground cover continue to produce and re-suspend dust throughout the metropolitan area. A sustainable air-quality strategy will have to treat road surfacing, drainage, sidewalks, landscaping, construction-site controls, waste management and public transport as part of the pollution solution rather than placing disproportionate emphasis on vehicle exhaust alone.