Air pollution is the fourth highest risk factor for premature mortality worldwide. And there is growing recognition that even at relatively low levels air pollution can cause significant health impacts, such as heart attacks and strokes. Fine particulate matter (PM2.5) – such as dust, dirt, soot, or smoke – is 70 times smaller than a human hair and is one of the most significant contributors to urban air pollution. In Kigali, the amount of PM2.5 in the air is approximately double the level deemed permissible by the World Health Organisation. This emphasises the need for action and the scale of the potential benefit to be achieved. A challenge, however, lies in a lack of analysis on the sources of air pollution and the opportunities for action. Using datasets on urban air pollution, we assessed the impact of car-free days – an innovative programme which encourages walking and cycling – and the COVID-19 lockdown in Kigali, Rwanda. Researchers found that PM2.5 was reduced by 15% on car-free days. We also found that the COVID-19 lockdown in 2020 – which reduced travel activity by over 80% – reduced air pollution by around 33%. A consequent partial lockdown, which allowed cars but not motorcycles, reduced travel activity by 41% and air pollution by around 21%. Results from these analyses help us to understand both the causes of air pollution and the opportunities for policy action to address it.
SOURCE: THE CONVERSATION