Impact of diesel vehicle inspection on health: the experience of Sao Paulo, Brazil

摘要

Around 25% of the Brazilian population lives in 6 Metropolitan Regions. Because of their quick growth without necessary urban planning, mobility was mainly provided by vehicles using fossil fuels, which constitute the most significant air pollution source, consistently associated to adverse health effects. In fact, traffic may be considered as a new epidemical condition relevant to public health. Diesel is by far the dominant source of particulate matter in urban areas. Previous studies have shown that diesel emissions account for 40% of the PM2,5 concentration in Sao Paulo Metropolitan Region (SPMR). Its use has been restricted with the adoption of a progressive reduction on emission limits and a mandatory annual inspection and maintenance (I/M) program but this program is running only in Sao Paulo city. Our objective is to assess the impact of this program on health for the population of the SPMR in 2011. Vehicles that fail the emission test must undergo maintenance before a new inspection. The reduction induced by the I/M program is defined as the difference between the first and last inspection emissions of failed vehicles, weighted by annual mileage average and engine and fleet characteristics. Here, mortality refers to individuals over 40 years of age. As suggested by the WHO (2006), an increment of 10 μg/m3 on PM2.5 concentration induces an increment of 6% in mortality. Economic valuation was based on the DALY method as recommended by the WHO (1996), adapted to Brazilian conditions, and related to the increase in life expectancy attributed to air pollution reduction. Only 75% of Sao Paulo's diesel fleet was inspected during 2011 but this program may be associated to a reduction of 1.18 μg/m3 in PM2.5 concentration and avoided about 584 deaths with an economic impact of US$ 77.1 million. Assuming that the same results hold for the whole SPMR, 1,560 deaths could be avoided with an equivalent economic impact of US$ 206.0 million annually.