#Trebs inorganic gases and aerosol verification

Accordingly, mixing ratios of NH 4 + exceeded those of other inorganic aerosol contributors by a factor of 4 to 10. Mixing ratios of acidic trace gases remained below 1ppb throughout the measurement period, while NH 3 levels were an order of magnitude higher. Median LOD values (3σ-definition) were ≤0.015ppb for acidic trace gases and aerosol anions and ≤0.118ppb for NH 3 and aerosol NH 4 +. The limit of detection (LOD) was determined for each single data point measured during the field experiment. Overall measurement uncertainties of the ambient mixing ratios usually remained below 15%.

#Trebs inorganic gases and aerosol verification

A detailed description and verification of the inlet system for simultaneous sampling of soluble gases and aerosol compounds is presented.

Measurements were made continuously using a wet-annular denuder (WAD) in combination with a Steam-Jet Aerosol Collector (SJAC) followed by suitable on-line analysis. Sampling was performed from 12 September to 14 November 2002, extending from the dry season (extensive biomass burning activity), through the transition period to the wet season (background conditions). This study was conducted within the framework of LBA-SMOCC (Large Scale Biosphere Atmosphere Experiment in Amazonia - Smoke Aerosols, Clouds, Rainfall and Climate: Aerosols from Biomass Burning Perturb Global and Regional Climate). This study demonstrates how African aerosol sources, such as volcanic sulfur emissions, can substantially affect the aerosol cycling and atmospheric processes in Amazonia.We measured the mixing ratios of ammonia (NH 3), nitric acid (HNO 3), nitrous acid (HONO), hydrochloric acid (HCl), sulfur dioxide (SO 2 and the corresponding water-soluble inorganic aerosol species, ammonium (NH 4 +), nitrate (NO 3 -), nitrite (NO 2 -), chloride (Cl - and sulfate (SO 4 2-), and their diel and seasonal variations at a pasture site in the Amazon Basin (Rondônia, Brazil). Airborne measurements and satellite data indicate that the transatlantic transport of volcanogenic aerosols occurred in two major volcanic plumes with a sulfate-enhanced layer between 4 and 5km of altitude. The substantial sulfate injection increased the aerosol hygroscopicity with κ values up to 0.36, thus altering aerosol–cloud interactions over the rain forest. Under the volcanic influence, hourly mean sulfate mass concentrations in the submicron size range reached up to 3.6µgm−3 at the Amazon Tall Tower Observatory, the highest value ever reported in the Amazon region.

Comprehensive ground-based and airborne aerosol measurements together with satellite observations are used to investigate the volcanic event. This study provides observational evidence for the influence of emissions from the Nyamuragira–Nyiragongo volcanoes in Africa on Amazonian aerosol properties and atmospheric composition during September 2014. The transatlantic transport of volcanic sulfur emissions from Africa has been considered as a source of particulate sulfate in the Amazon however, direct observations have been lacking so far. Sulfate aerosols originate to a substantial extent from LRT sources and play an important role in the Amazonian atmosphere as strongly light-scattering particles and effective cloud condensation nuclei. The long-range transport (LRT) of trace gases and aerosol particles plays an important role for the composition of the Amazonian rain forest atmosphere.