Environmental and public health effects of vehicle emissions in a largemetropolis: Case study of a truck driver strike in Sao Paulo, Brazil

Özet

In 2018, a truck-driver strike in Sao Paulo, Brazil, provided conditions for conducting a real-world experiment on therelationship between vehicle emissions, air quality, and public health. During the strike, no truck traffic, a 40–70% bus-traffic reduction, and a reduction in auto traffic was observed. The objective of this study is to evaluate the effects ofvehicle-traffic reduction on the air quality and public health in Sao Paulo by taking advantage of the truck-driver strike.The corresponding analysis was based on the comparison of the air quality (NOx(nitrogen oxides), PM10(particlematter of diameter less than 10 μm), and O3(ozone) concentrations) during the strike and that registered on dayshaving similar meteorological conditions. A relative-risk function was used to associate the decrease in the PM10concentration during the strike with avoided mortality. The results demonstrated that, on workdays, the reduction invehicle traffic during the strike was responsible for a 29.4%–40.9% improvement in NOxair quality and 19.2%–21.4%in PM10concentration. The reduction in the PM10concentration resulted in the prevention of between six and eightdeaths during the strike, which implies between 321 and 442 avoided deaths in a year. In terms of the O3con-centration, no difference was identified between strike days and the comparative ones. An analysis of different sites ofthe city revealed that the greatest air-quality improvement was observed near an arterial road and near a bus terminal.Air-quality improvement was also detected in a park that was distant from the main roads. The results of the studyprovide evidence for supporting cleaner transportation investments and traffic restriction policies.