Fatores De Emissão De Compostos Carbonílicos Medidos Em Um Túnel Do Rio De Janeiro, Brasil, Em Condições Reais De Dirigibilidade

Abstract

REAL-WORLD EMISSION FACTORS OF CARBONYL COMPOUNDS MEASURED IN A RIO DE JANEIRO TUNNEL, BRAZIL. Real-world vehicle emissions of carbonyls compounds (CC) were determined at the Rebouças Tunnel, Rio de Janeiro (Brazil). The tunnel is a two-bore tunnel with three lanes in each direction and has a length of 2840 m, divided in two sections. On average, approximately 5,000 vehicles (95% light duty) were passing the tunnel per hour. Sixteen samples were simultaneously collected 500 and 1500 m inside from the entrance. The main CC were formaldehyde, acetaldehyde, acetone, propionaldehyde and benzaldehyde. A total of 16 samples were collected in each point in 8 different days. In 5 days, CO and CO 2 were also monitored during the sampling period. Emission factors were calculated. Using the Pierson method, emission factors were 7.5 ± 2.6 and 13.8 ± 5.7 mg km-1 for formaldehyde and acetaldehyde, respectively. Using the fuel consumption method, values were 6.3 ± 2.1 and 11.8 ± 3.9 mg km-1 for the same compounds. The differences between both methods were lower than 20% and may be considered acceptable considering all the approximations in the calculations. Ozone forming potentials (OFP) were also estimated as 90.4 ± 37.3 and 70.7 ± 24.6 mg km-1 for formaldehyde and acetaldehyde, respectively.

The Effect of Urban Green Spaces on Reduction of Particulate Matter Concentration

“…The RT is one of the main connection routes between the northern and southern parts of the municipality. With its 2840 m long, divided into two sections, one of 2040 m and the other of 800 m, the tunnel was inaugurated on October 16, 1967, and has an estimated daily volume of 190,000 vehicles, with an average of approximately 5000 per hour with peaks in the morning and late afternoon flow, which positions it as a major contributor to the emission of air pollutants of vehicular origin (Almeida et al 2020 ), such as fine particles (PM 2.5 ), since vehicular emissions are a significant source of PM, especially fine particles (Pacheco et al 2017 ).…”