Airmine recently visited Nairobi, and had the dubious joy of contributing to its traffic jams. They are notorious, to the extent that Nairobi traffic jams recently won a not-particularly-glamorous 2nd place globally.
The roads to pollution
But Nairobi traffic is not only a problem because it's a huge waste of people's time. Global Burden of Disease data show that Kenyans overall live longer and healthier lives than before, but respiratory diseases such as chronic obstructive pulmonary disease (COPD) claim a larger share of deaths and lost life-years.
Air pollution is one of the main culprits. Most of the main sources of outdoor air pollution in Kenya have to do with roads: traffic, roadside rubbish fires, road dust, and emissions from industry. Nairobi is no different, and the problem is increasing.
Who needs catalytic converters anyway?
Nairobi traffic would have been less of a challenge if vehicle emission control regulations were strict. They're not, at least not in practice. In their absence, car owners in Nairobi remove catalytic converters because they believe this improves the car's performance. The result is that they emit a lot more carbon monoxide, nitrogen oxide and hydrocarbons. Those removing the catalytic converters earn money from selling them on, as they contain rare metals such as platinum, rhodium and palladium. Little consolation, then, in the fact that they at least avoid piling up on Nairobi's already overfilled landfills...
Don't be tricked by measurements
Previously available air pollution data for cities such as Nairobi are useful - for exactly the location in the city it is measuring in. For example, the real time air quality index from Nairobi Alliance Girls' High School shows that Nairobi air pollution is just fine - because it is located outside the city.
Similarly, although the sensors.Africa initiative has deployed a number of air quality sensors in Nairobi over the last few years, they display huge variations, although they are located within a relatively limited area in the Nairobi city centre. This shows how important it is to have site-specific measurements.