Identificação de episódios de picos de concentração dos aerossois submicrométricos na floresta amazônica no ano de 2015

Abstract

The mass concentration of the main chemical components composing the fine particulate matter (PM1) in the atmosphere of the Amazonian forest central basin present high seasonality, with larger values in the dry and lower in the wet season. The temporal distribution presents peaks that could represent episodes of aerosol material locally produced or carried by the air masses. Although the identification of such episodes is important, there is no standardization of a methodology to perform this identification. This work aimed to study the temporal distribution of the concentrations of the six main components of the Amazonian PM1 (organic compounds, sulfates, nitrates, ammonium, chlorides and black carbon) and to identify the differences between the mass concentration presented in the wet and dry seasons during the year 2015. In addition, this study aims to investigate and propose a simple methodology to identify such episodes. The results show that the organic fraction dominates over all other fractions composing the PM1 in the Amazon, accounting for 55% in February, and reaching 86% in November. Different methodologies for identifying the episodes were tested due to the high disparity in the data sets distribution. The parameters “2x Geometric Mean” and “90th Percentile” were the most appropriate to identify the episodes during the wet season. However, the “Arithmetic Mean”, “Geometric Mean” and “1.5x Standard Deviation” were more appropriate for the dry season. Although a complete validation of the identified episodes was not achieved, the methodologies proposed in this study can be useful in future research work