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São Paulo cyclists most in danger of harmful black carbon exposure, finds new study

Cyclists in São Paulo and London should think about an alternative route to work during morning peak-time hours to avoid breathing in harmful black carbon from vehicles, suggests a new air pollution collaborative study from the University of Surrey´s Global Centre for Clean Air Research, jointly with University of Sao Paulo (Brazil) and University of Twente (Netherlands).

In a study published by the Journal of Transport Geography scientists that developed this collaborative study, looked at the black carbon levels cyclists are likely to be exposed to on heavily trafficked main routes in three major cities – London (travelling to Liverpool Street), Rotterdam (travelling to Rotterdam Station) and São Paulo (travelling to Paulista Avenue). The scientists then compared this information with black carbon exposure using alternative routes between the same origin and destination in each city that featured parks, waterways and other green infrastructure.

Black carbon pollutants, which usually originate from vehicles, can result in an increased risk of coronary heart disease (CHD) hospitalisation or death. The results of Surrey’s study suggest that cyclists in São Paulo are more likely to suffer CHD hospitalisations and death than those in Rotterdam or London.     

Overall, the results showed that the main routes in London and São Paulo exposed cyclists to higher concentrations of black carbon compared with alternative routes. In Rotterdam, concentration levels on main and alternative routes were similar.

The results also found that cyclists were exposed to twice as much black carbon levels on main routes in São Paulo compared to London and Rotterdam. Interestingly, Londoners cycling home on the main route during the evening commute were exposed to more pollutants than those who took the same route in the morning, and twice as much black carbon than those who took the alternative route. Unsurprisingly, Rotterdam showed the smallest black carbon pollutant levels of all three cities.

This work was supported by the FAPESP-SPRINT project PEDALS (Particles and Black Carbon Exposure to London and Sao Paulo Bike-Lane Users) and ESRC-NWO-FAPESP project ASTRID (Accessibility, Social justice and Transport emission Impacts of transit-oriented Development). 

Details of the study can be found in:

Brand, V.S., Kumar, P., Damascena, A.S., Pritchard, J.P., Geurs, K.T., Andrade, M.F., 20019. Impact of route choice and period of the day on cyclists' exposure to black carbon in London, Rotterdam and São Paulo. Journal of Transport and Geography. https://doi.org/10.1016/j.jtrangeo.2019.03.007