Rodrigo Souza

Observations of particulate matter, NO2, SO2, O3, H2S and selected VOCs at a semi-urban environment in the Amazon region

This research aims to assess air quality in a transitional location between city and forest in the Amazon region. Located downwind of the Manaus metropolitan region, this study is part of the large-scale experiment GoAmazon2014/5. Based on their pollutant potential, inhalable particulate matter (PM2.5), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), hydrogen sulfide (H2S), benzene, toluene, ethylbenzene and meta-, orto-, para-xylene (BTEX) were selected for analysis. Sampling took place during the wet season (March-April 2014) and dry season (August-October 2014). The number of forest fires in the surroundings was higher during the dry wet season. Results show significant increase during the dry season in mass concentration (wet: <0.01-10u202fμgu202fm-3; dry: 9.8-69u202fμgu202fm-3), NH4+ soluble content (wet: 13-125u202fμgu202fm-3; dry: 86-323u202fμgu202fm-3) and K+ soluble content (wet: 11-168u202fμgu202fm-3; dry 60-356u202fμgu202fm-3) of the PM2.5, and O3 levels (wet: 1.4-14u202fμgu202fm-3; dry: 1.0-40u202fμgu202fm-3), indicating influence of biomass burning emissions. BTEX concentrations were low in both periods, but also increased during the dry season. A weak correlation in the time series of the organic and inorganic gaseous pollutants indicates a combination of different sources in both seasons and NO2 results suggest a spatial heterogeneity in gaseous pollutants levels beyond initial expectations.

EDDY COVARIANCE MEASUREMENTS OF LATENT HEAT, SENSIBLE HEAT, MOMENTUM AND CO2 FLUXES ON THE RESERVOIR OF THE HYDROELECTRIC PLANT CURUÁ-UNA – PA

Flux measurements of latent heat, sensible heat, momentum, and CO2 were performed from 15 to 26 June 2015 on the reservoir of the hydroelectric plant Curua-Una (PA). The flux system is located upstream of the main channel of the reservoir and installed at 3 m above the water surface on a floating structure. The hydroelectric plant Curua-Una was the first plant built in the Amazonia and it is in operation for almost 40 years. During installation, the vegetation around the river channel was not removed, which led to large emissions of greenhouse gases into the atmosphere. The wind speed was important to maintain turbulent mixing mechanically. Latent heat flux showed significant correlation with the wind velocity (r = 82%). As a result of the combined effect of turbulent mixing generated thermally and mechanically, the latent and sensible heat fluxes were positive throughout the investigation period and the atmospheric surface layer remained unstable. The CO2 flow was predominantly negative (84%), characterizing the reservoir as a CO2 sink.