The Amazon Basin plays key role in atmospheric chemistry, biodiversity and climate change. In this study we applied nanoelectrospray (nanoESI) ultra-high-resolution mass spectrometry (UHRMS) for the ...analysis of the organic fraction of PM2.5 aerosol samples collected during dry and wet seasons at a site in central Amazonia receiving background air masses, biomass burning and urban pollution. Comprehensive mass spectral data evaluation methods (e.g. Kendrick mass defect, Van Krevelen diagrams, carbon oxidation state and aromaticity equivalent) were used to identify compound classes and mass distributions of the detected species. Nitrogen- and/or sulfur-containing organic species contributed up to 60 % of the total identified number of formulae. A large number of molecular formulae in organic aerosol (OA) were attributed to later-generation nitrogen- and sulfur-containing oxidation products, suggesting that OA composition is affected by biomass burning and other, potentially anthropogenic, sources. Isoprene-derived organosulfate (IEPOX-OS) was found to be the most dominant ion in most of the analysed samples and strongly followed the concentration trends of the gas-phase anthropogenic tracers confirming its mixed anthropogenic–biogenic origin. The presence of oxidised aromatic and nitro-aromatic compounds in the samples suggested a strong influence from biomass burning especially during the dry period. Aerosol samples from the dry period and under enhanced biomass burning conditions contained a large number of molecules with high carbon oxidation state and an increased number of aromatic compounds compared to that from the wet period. The results of this work demonstrate that the studied site is influenced not only by biogenic emissions from the forest but also by biomass burning and potentially other anthropogenic emissions from the neighbouring urban environments.
As worldwide evidence shows that the predominant transmission route of SARS-CoV-2 and other respiratory pathogens is airborne, the need for suitable methods for the sampling of bioparticles directly ...from the air is more urgent than ever. The present paper describes the development of a method for the collection of biological aerosols, using a preexisting cyclonic impinger, the Coriolis μ, combined with a lysis buffer and subsequent qPCR analysis of the generated samples in lab. Four phases of method development are described: exploratory, validation, blank tests, and application. The application phase consisted of a field experiment in which the method was simultaneously applied at two daycare facilities. The method achieved a good level of accuracy and reliability in detecting different types of infectious agents in the air, with a global uncertainty of 19.6%. Furthermore, our method allows the simultaneous detection of 26 different respiratory pathogens in air samples, it is relatively simple, and the equipment is easy to use. Additionally, the time to collect a representative sample is short compared to other methods. The method does not cause significant disturbance to those present in the sampled rooms, and it is safe for operators and flexible, meaning it can be used in virtually any environment regardless of use, size, or occupancy. Further research is being developed to allow quantitative analysis of the collected samples and to test the methods’ ability to assess the viability of the microorganisms collected in the sample.
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: <0.01–10 μg m−3; dry: 9.8–69 μg m−3), NH4+ soluble content (wet: 13–125 μg m−3; dry: 86–323 μg m−3) and K+ soluble content (wet: 11–168 μg m−3; dry 60–356 μg m−3) of the PM2.5, and O3 levels (wet: 1.4–14 μg m−3; dry: 1.0–40 μg m−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.
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•Air quality analysis in transitional site between city-forest at the Amazon region•Particulate and gaseous pollutants measured in wet and dry seasons•Several evidences indicate strong influence of biomass burning emissions.•During dry season, atmospheric pollution in the site rises significantly.
The Amazon region is one of the most significant natural ecosystems on the planet. Of special interest as a major study area is the interface between the forest and Manaus city, a state capital in ...Brazil embedded in the heart of the Amazon forest. In view of the interactions between natural and anthropogenic processes, an integrated experiment was conducted measuring the concentrations of the volatile organic compounds (VOCs) benzene, toluene, ethylbenzene and meta, ortho, para-xylene (known as BTEX), all of them regarded as pollutants with harmful effects on human health and vegetation and acting also as important precursors of tropospheric ozone. Furthermore, these compounds also take part in the formation of secondary organic aerosols, which can influence the pattern of cloud formation, and thus the regional water cycle and climate. The samples were collected in 2012/2013 at three different sites: (i) The Amazon Tall Tower Observatory (ATTO), a pristine rain forest region in the central Amazon Basin; (ii) Manacapuru, a semi-urban site located southwest and downwind of Manaus as a preview of the Green Ocean Amazon Experiment (GoAmazon 2014/15); and (iii) the city of Manaus (distributed over three sites). Results indicate that there is an increase in pollutant concentrations with increasing proximity to urban areas. For instance, the benzene concentration ranges were 0.237–19.6 (Manaus), 0.036–0.948 (Manacapuru) and 0.018–0.313 μg m−3 (ATTO). Toluene ranges were 0.700–832 (Manaus), 0.091–2.75 μg m−3 (Manacapuru) and 0.011–4.93 (ATTO). For ethylbenzene, they were 0.165–447 (Manaus), 0.018–1.20 μg m−3 (Manacapuru) and 0.047–0.401 (ATTO). Some indication was found for toluene to be released from the forest. No significant difference was found between the BTEX levels measured in the dry season and the wet seasons. Furthermore, it was observed that, in general, the city of Manaus seems to be less impacted by these pollutants than other cities in Brazil and in other countries, near the coastline or on the continent. A risk analysis for the health of Manaus' population was performed and indicated that the measured concentrations posed a risk for development of chronic diseases and cancer for the population of Manaus.
•BTEX samples taken at ATTO tower, GoAmazon 2014/5 site and Manaus.•The interface forest-Manaus highlights the prevailing anthropogenic BTEX input.•In all sites, BTEX concentrations do not differ between dry/wet seasons.•There is indication of a biogenic toluene source near the ATTO tower base.•Results indicate chronic disease and cancer development risk for Manaus population.
The mitigation of pollution released to the environment originating from the industrial sector has been the aim of all policy-makers and its importance is evident if the adverse health effects on the ...world population are considered. Although this concern is controversial, petroleum refinery has been linked to some adverse health effects for people living nearby. Apart from home, school is the most important indoor environment for children and there is increasing concern about the school environment and its impact on health, also in developing countries where the prevalence of pollution is higher. As most of the children spend more than 40% of their time in schools, it is critical to evaluate the pollution level in such environment. In the metropolitan region of Curitiba, South Brazil, five schools nearby industries and highways with high density traffic, were selected to characterize the aerosol and gaseous compounds indoor and outdoor of the classrooms, during 2009–2011. Size segregated aerosol samples were collected for analyses of bulk and single particle elemental profiles. They were analyzed by electron probe X-ray micro-analysis (EPXMA), and by energy-dispersive X-ray fluorescence (EDXRF), to investigate the elemental composition of individual particles and bulk samples. The concentrations of benzene, toluene, ethylbenzene, and xylene (BTEX); NO2; SO2; acetic acid; and formic acid were assessed indoor and outdoor using passive diffusion tubes. BTEX were analyzed by GC–MS and other collected gasses by ion chromatography. Individual exposition of BTEX was assessed by personal passive diffusion tubes. Results are interpreted separately and as a whole with the specific aim of identifying compounds that could affect the health of the scholars. In view of the chemical composition and size distribution of the aerosol particles, local deposition efficiencies in the children's respiratory systems were calculated, revealing the deposition of particles at extrathoracic, tracheobronchial and pulmonary levels.
•Pollution in school environment can impact children's health, being critical to evaluate it.•Five schools were selected in Curitiba, Brazil to measure pollutants levels, in 2009–2011.•Results are interpreted aiming to identify compounds that could affect the scholars' health.
The assessment of damage to indoor cultural heritage, in particular by pollutants, is nowadays a major and growing concern for curators and conservators. Nevertheless, although many museums have been ...widely investigated in Europe, the effects of particulate matter and gaseous pollutants in museums under tropical and subtropical climates and with different economic realities are still unclear. An important portion of the world's cultural heritage is currently in tropical countries where both human and financial resources for preserving museum collections are limited. Hence, our aim is to assess the damage that can be caused to the artwork by pollution in hot and humid environments, where air quality and microclimatic condition differences can cause deterioration. As a case study, particulate matter as well as gases were collected at the Oscar Niemeyer Museum (MON) in Curitiba, Brazil, where large modern and contemporary works of art are displayed.
NO2, SO2, O3, Acetic Acid, Formic Acids and BTEX, in the ambient air, were sampled by means of passive diffusive sampling and their concentrations were determined by IC or GC–MS.
The particulate matter was collected in bulk form and analyzed with the use of energy dispersive X-ray fluorescence and aethalometer. The chemical compositions of individual particles were quantitatively elucidated, including low-Z components like C, N and O, as well as higher-Z elements, using automated electron probe microanalysis. The gaseous and particulate matter levels were then compared with the concentrations obtained for the same pollutants in other museums, located in places with different climates, and with some reference values provided by international cultural heritage conservation centers. Results are interpreted separately and as a whole with the specific aim of identifying compounds that could contribute to the chemical reactions taking place on the surfaces of artifacts and which could potentially cause irreversible damage to the artworks.
•Analysis of compounds that participate in reactions that damage artwork surfaces.•Aim: assess damage to artwork caused by pollution in hot and humid environments.•MON has satisfactory air quality when compared to other international museums.•The situation could improve by using higher efficiency filters in the HVAC system.
Ventilation is critical in interpreting indoor air quality (IAQ), yet most IAQ assessments do not report ventilation adequately. Most ventilation assessments use tracer gas tests (TGT) to measure ...total air change rate (ACH), but currently applied TGTs present three shortcomings: limited comparability between ACH and IAQ data, inadequate substances employed as tracer gases and tendency to bias arising from perfect-mixing assumption. This paper proposes a new TGT approach, employing an alternative tracer gas that is captured/analysed using commercial passive IAQ-samplers and including a careful planning-phase to account for imperfect-mixing. Two substances were selected as potential alternative tracers: 2-butoxyethyl-acetate (EGBEA) and deuterated decane (D-decane). Tracer-source tests were performed in lab, enabling enhancements to the source design. Results indicated RH influence over the emissions rates, and EGBEA's use as tracer was discarded due to hygroscopy. Further work includes evaluating D-decane's behaviour under varying conditions and computer-simulating TGTs to study the imperfect-mixing effects.
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 (PM
), nitrogen dioxide (NO
), sulfur dioxide (SO
), ozone (O
), hydrogen sulfide (H
S), 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: <0.01-10 μg m
; dry: 9.8-69 μg m
), NH
soluble content (wet: 13-125 μg m
; dry: 86-323 μg m
) and K
soluble content (wet: 11-168 μg m
; dry 60-356 μg m
) of the PM
, and O
levels (wet: 1.4-14 μg m
; dry: 1.0-40 μg m
), 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.
This paper describes the ongoing development of a new tracer gas test (TGT) for total air change rates measurement. This new TGT, intendedfor use in large-scale IAQ assessments and based on constant ...tracer injection, employs an alternative tracer gas that is more adequate than the currently employed SF6 and perfluorocarbons and that can be co-captured and co-analyyed along with commonly assessed VOCs using a commercial passive IAQ sampler. Via literature study and lab testing, decane-L22 was found to be a suitable tracer substance. Several laboratory tests have been performed under controlled environmental conditions to develop and optimize apassive source of decane-L22. The source design ultimately selectedprovides stable and repeatable emission rates under standard temperature and is unaffected by RH. A series of chamber tests were performed under different temperatures, and a consistent exponential curve was derivedfor determining the source emission rate from the room temperature. Future work includesfield test applicationsfor validation of the new TGT.
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