Indicadores de poluição atmosférica no MP2,5 rural e urbano na região metropolitana de Manaus

Abstract

Biomass burning and fossil fuels combustion are the main causes of increasing particulate matter concentration in the atmosphere, as well as some toxic chemical compounds. The exposure to high concentrations of fine particles (PM2.5) can cause respiratory problems due to their ability to reach the pulmonary alveoli, resulting in diseases such as asthma, pneumonia, cardiac arrhythmias, etc. Depending on the concentration of some chemical compounds in PM2.5, for example, Polycyclic Aromatic Hydrocarbons (PAHs), the particle can be mutagenic and carcinogenic to humans. The city of Manaus and its surroundings have potential sources of these compounds to the atmosphere, but few are known about PM2.5 levels and their chemical composition in the metropolitan region of Manaus. Thus, this work evaluated PM2.5 and concentrations of PAHs, levoglucosan (Lev), organic carbon (OC), water-soluble organic carbon (WSOC), elemental carbon (EC), nitrate (NO3-) and sulfate (SO42-) in a rural area (Manacapuru-AM) and an urban area (Manaus – AM) in 2015 and 2016. The maximum concentrations of PM2.5 were observed in the dry period of 2015, which was attributed mainly to biomass burning. Benzo[a]pyrene (BaP), which is considered as carcinogenic and mutagenic to humans, was detected exclusively during the period of intense biomass burning in 2015, but its concentrations values were below the limit stipulated by the regulatory agencies. In this period, the highest concentrations of Lev, SO42-, NO3-, OC, WSOC, and EC were obtained. These data shown the anthropic influence in the rural region and an additional displacement of the plume of pollution from Manaus urban area and the fires in the metropolitan region of Manaus. The concentration of PM2.5 and its compounds in the urban area of the city in 2016 were lower than those determined in the rural area, except for SO42-, NO3-, since these are originated mainly from the vehicular emission. This work indicates that biomass burning and vehicular emission are the main sources of PM2.5 to the atmosphere of the metropolitan region of Manaus, reaching levels higher than those recommended by the international regulatory agencies and can cause damages to the environment and the health of the population.