 The data has been very helpful. So on more than one occasion we've been changing location and the timing as well. Where we started by 8, we ended up starting by 10. The data has also been crucial in organizing big events. Last year's Nairobi City Marathon was almost cancelled due to adverse readings from the census. Despite the success of the monitors in countries like Kenya, it remains difficult to measure Africa's air pollution levels precisely due to lack of data.