Evaluation of the impact of the national strike of the road freight transport sector on the air quality of the metropolitan region of Rio de Janeiro, Brazil

Abstract In May 2018, there was a road freight transport standstill in Brazil that lasted 11 days. During this period, several impacts on Rio de Janeiro’s daily life were reported, such as the reduction of road passenger transport services and lack of fuels. This study aimed to evaluate the impact on the air quality of the metropolitan region of Rio de Janeiro (MRRJ) of the reduction of heavy-duty vehicles on the streets and roads. For this purpose, the reductions of PM10, NOx, SOx and CO emissions, due to low circulation of buses and trucks, were estimated in order to assess the levels of air pollution indirectly. Besides, air quality data (PM10, NO2, SO2, and CO) monitored before and during the strike were used. The results showed a reduction in total emissions of local air pollutants, harmful to human health from 22 % to 43 % during strike days. However, the air quality reflexes were not observed in the same proportion, on the contrary, increases were observed in pollutant concentrations in the atmosphere during traffic stoppage in the study areas, due to different weather conditions in the two periods, which directly influenced air pollutants dispersion.