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  • Artigo IPEN-doc 30789
    Evaluation of the potential for greenhouse gas (CO2, CH4) emissions in the southern São Paulo coastal region, Cananéia-Iguape system
    2024 - ARAUJO, ELAINE C.; CORREA, THAIS; ANDRADE, IZABEL da S.; MACEDO, FERNANDA de M.; MARQUES, MARCIA T.; ANDRADE, THAIS; SOUTO-OLIVEIRA, CARLOS E.; BRAGA, ELISABETE S.; ANDRADE, MARIA de F.; LANDULFO, EDUARDO
    The emissions of CH4 and CO2, the primary greenhouse gases, have a significant impact on radiative forcing. This study investigated these gases along the Cananéia-Iguape estuarine system on the southern coast of the State of São Paulo, Brazil, which is a mangrove region characterized by low anthropogenic impact and a sparse population. As such, this area provides an ideal location for identifying natural emissions and background concentrations. The data for this study were collected using a portable gas analyzer (LGRICOSTM GLA131), known for its high sensitivity and precision in detecting gases, mounted on a research boat. The results obtained were promising for both gases. A small variability in CH4 concentrations was observed along the route, ranging from 1.84 ppm to 1.95 ppm, while CO2, showed greater variation in values obtained during routes, ranging from approximately 411 ppm to 575 ppm. This study underscores the importance of investigating areas with minimal environmental impact. Together with future analyses, this research should help improve Greenhouse Gas (GHG) inventories in Brazil by providing valuable baseline data for comparisons with more impacted areas.
  • Resumo IPEN-doc 28971
    Methane determination in São Paulo coastal regions using the Cavity Ring-Down Spectroscopy (CRDS) technique
    2021 - CORREA, THAIS; MACEDO, FERNANDA M.; ARAUJO, ELAINE C.; ANDRADE, IZABEL S.; GOMES, ANTONIO A.; SILVA, JONATAN; LANDULFO, EDUARDO
    Methane is one of the main greenhouse gases due to its high radiation absorption capacity. The increase in methane emissions from anthropogenic sources causes concern in the entire scientific community due to the aggregated uncertainties, generating several works focused on the identification and quantification of generating sources. This work aims to quantify methane in two distinct regions, the first study region is in Cubatão city, located in the São Paulo coast. It is an important petrochemical complex with high industrial activities and environmental impact, presenting 25 large companies in the chemical sector, distributed in an area of 143 Km2. Another region observed is Intanhaém, on the coast of the state of São Paulo. This region doesn´t present industrial activity and has a low population index. The technique used to detect methane in the atmosphere was Cavity ring-down spectroscopy (CRDS), which consists on analysis of atmospheric components, in a small cavity that has a laser and high reflectivity mirrors of 99.999%, allowing the signal travel for kilometers inside the cavity, in a short time, increasing the sensitivity of detection of compounds in the sample.
  • Artigo IPEN-doc 28401
    Methane detection in the lower troposphere related to the burning of biomass and leakage in a petrochemical pole, using Raman lidar technique
    2021 - MACEDO, FERNANDA de M.; CORREA, THAIS; ARAUJO, ELAINE C.; ANDRADE, IZABEL da S.; GUARDANI, ROBERTO; VESELOVSKII, IGOR; LANDULFO, EDUARDO
    Fugitive emissions, defined as unintended or irregular leaks of gases and vapors, are an important source of pollutants to the atmosphere, which is difficult to monitor and control. These sources are present in different sites, especially in regions that are growing in size and economic activity. In this study, we present the results of the capability to detect methane profiles at low troposphere combining data retrieval correlations between a rotacional/vibracional Raman lidar (RVRL) and a cavity ring-down spectrometer (CRDS). The measurements were made at two different sites, metropolitan area of São Paulo (MSP) and industrial area of Cubatão (IC). The lidar is based on a tripled Nd:YAG laser with a 20 Hz repetition rate, operating on the 355 nm wavelength elastic channel, the 353 nm and 396 nm wavelength inelastic channels. A measurement protocol was established, considering acquisition time for signal accumulation, climatic conditions and data above and below the planetary boundary layer. The idea was to establish specific measurement procedures for situations related to product leakage in the oil process and natural events, such as biomass burning. With over 150 hours of data acquisition, the results pointed the possibility of analyzing data from distances up to 1500 m with an initial resolution of 7.5 m which was extended to 100 - 300 m after data smoothing for obtaining final results. The concentration was calculated from the ratio between the methane Raman backscatter signal and the nitrogen signal, at 396 nm and 353 nm, respectively. The temporal variation of methane concentrations was correlated with CRDS data, in order to obtain a first degree calibration.