Análise de poluentes gasosos e material particulado fino em Manacapuru, AM

Orientador : Prof. Dr. Ricardo Henrique Moreton GodoiDissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia Ambiental. Defesa: Curitiba, 26/08/2016Inclui referências : f. 94-107Resumo: A presente pesquisa tem como principal objetivo a análise da qualidade do ar em um local que representa a transição entre meio natural e urbano na região amazônica. Para isso, o estudo foi desenvolvido como parte de um experimento pré-existente de maior escala, denominado GOAmazon 2014/5, que se localiza no município de Manacapuru (região metropolitana de Manaus, que recebe influência das massas de ar vindas dessa). Baseado em seus potenciais poluidores, foram selecionados os seguintes poluentes atmosféricos: Material particulado inalável fino (MP2,5), os gases dióxido de nitrogênio (NO2), dióxido de enxofre (SO2), ozônio (O3) e sulfeto de hidrogênio (H2S) e os compostos orgânicos voláteis benzeno, tolueno, etilbenzeno e meta-, orto-, para-xileno (BTEX). A amostragem ocorreu em dois períodos distintos, o primeiro durante a estação chuvosa (março e abril de 2014) e o segundo durante a estação seca (agosto a outubro de 2014). A velocidade do vento no período indica que os poluentes medidos na área de estudo provêm de fontes localizadas próximo ao local estudado. Verificou-se também que a quantidade de focos de queimada no entorno foi muito maior durante a estação seca do que na estação chuvosa. Os resultados mostraram um aumento significativo na concentração mássica (chuva: 0,003-10 ?g m-3; seca: 9,8-69 ?g m-3) e no conteúdo de NH4+ (chuva: 13-125 ?g m-3; seca: 86-323 ?g m-3) e K+ (chuva: 11-168 ?g m-3; seca: 60-356 ?g m-3) do MP2,5 durante a estação seca e altos níveis de O3 (chuva: 1,4-14 ?g m-3; seca: 1,0-40 ?g m-3) em ambos os períodos, indicando influência de emissões provenientes de queima de biomassa no local. As concentrações de BTEX, embora bastante baixas em ambos os períodos, também foram mais altas na estação seca. As baixas correlações entre os diferentes poluentes, por outro lado, sugerem que ocorre uma combinação de diferentes fontes. A composição elementar do MP2,5 apresentou S como único elemento enriquecido (FE = 627), sugerindo que a combinação de focos de queimada (majoritária) e emissão de veículos contribuem como as principais fontes de MP2,5 no local estudado. Os resultados também sugerem possível geração de NO2 por raios e de H2S por bactérias sulforredutoras no local. Comparando a presente pesquisa com estudos similares na literatura, observa-se que, em relação à poluição por material particulado (BC e concentração mássica), a atmosfera do T3 durante a estação seca assemelha-se à atmosfera de grandes cidades (o que não se observa durante a estação chuvosa), mas em relação aos poluentes gasosos (com exceção do O3), esta aproxima-se mais da atmosfera de meios florestais, em ambas as estações. Palavras-chave: Qualidade do ar; Poluentes Gasosos; Material Particulado; Amazônia; Manacapuru; GOAmazon; Poluição atmosférica.Abstract: This research has as main goal the air quality analysis in a location representing the transition between a natural and an urban environment at the Amazon region. Thus, this study was developed as a part of a pre-existent large-scale experiment, the GOAmazon 2014/5, which is located at the city of Manacapuru (in Manaus' metropolitan region, receiving air masses coming from its direction). Based on their pollutant potential, the following atmospheric pollutants have been selected for analysis: Inhalable fine particulate matter (MP2,5), the inorganic gases nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3) and hydrogen sulfide (H2S) and the volatile organic compounds benzene, toluene, ethylbenzene and meta-, orto-, para-xylene (BTEX). Sampling happened in two different periods; the first during the region's wet period (March and April 2014) and the second during the dry season (August to October 2014). The wind speed during the period indicates that the pollutants detected at the study area come from sources located near the site. It was also verified that the amount of forest fires at the surroundings was much higher during the dry season than during the wet season. Results show a significant increase in the mass concentration (wet: 0,003-10 ?g m-3; dry: 9,8-69 ?g m-3) and in the NH4+ (wet: 13-125 ?g m-3; dry: 86-323 ?g m-3) and K+ (wet: 11-168 ?g m-3; dry 60-356 ?g m-3) contents of the MP2,5 and high O3 levels (wet: 1,4-14 ?g m-3; dry: 1,0-40 ?g m-3) during both wet and dry periods, indicating influence of biomass burning emissions at the site. BTEX concentrations, even though very low in both periods, also increased during the dry season. Low correlation among the different gaseous pollutants, however, suggest a combination of different sources. Elemental composition of the MP2,5 presented S as the only enriched element (FE = 627), suggesting that the combination of forest fires and vehicle emissions might contribute as the main sources of MP2,5 at the studied site. Results also suggest possible NO2 production by lightning and H2S production by sulfur-reducing bacteria at the site. Comparing these results to similar studies found in the literature, one may observe that, regarding particulate matter pollution (BC and mass concentration), T3's atmosphere during dry season resembles large cities' atmospheres (which is not observed during the wet season). However, regarding gaseous pollutants (except O3), T3's atmosphere is closer to forest environments. Keywords: Air quality; Gaseous Pollutants; Particulate Matter; Amazon; Manacapuru; GOAmazon; Atmospheric Pollution

The future of passive techniques in air change rate measurement

Ventilation is critical in interpreting indoor air quality (IAQ), but only few IAQ assessments report ventilation rates; even when they do, the measurement method is often not fully de-scribed. Most ventilation assessments use a tracer gas test (TGT) approach to measure total air change rate, which consists in marking the indoor air with an easily identifiable gas (tracer) and then inferring the air exchange rate by monitoring the tracer’s injection rate and concen-tration (Persily, 2016). For this monitoring, two sampling options can be used: active sam-plers, costly and complex, or passive samplers (which work by absorption/adsorption without electricity use), overall more advantageous: cheaper, smaller, lighter, simpler and silent. Af-fordable passive samplers are commercialized by a range of companies and are already widely used in IAQ studies to analyse the presence of several gaseous pollutants (Stranger et al., 2008). However, currently employed TGTs in IAQ assessments are either active or not con-ceived to be executed together with common IAQ analysis, providing ventilation rates in a different time-scale than the pollutant concentrations. Thus, this paper proposes a new ap-proach for the TGT method, using as tracer a substance that can be co-captured and co-analysed using commercial passive samplers commonly used in IAQ studies

Proposing a new tracer gas for future field applications of passive tracer gas tests for air change rate measurement

This paper describes the ongoing development of a new adaptation of the traditional tracer gas test (TGT) used for total air change rates (ACH) measurement. This adapted TGT, based on constant tracer injection, is intended for use in large-scale IAQ assessments and employs an alternative tracer gas that is more adequate than the currently employed SF6 and perfluorocarbons, and that can be co-captured and coanalysed with commonly assessed VOCs by commercial passive IAQ-sampling. Via literature study and lab experiments, decane-D22 was found to be a suitable tracer substance. A passive source of decane- D22 was developed and optimized in lab, providing stable and repeatable emission rates under standard temperature, while unaffected by varying RH and ACH. The effect of the liquid solvent level over the source emission rate was only barely noticeable, but a range of adequate solvent level is suggested nevertheless. The selected tracer was also shown not to adhere/absorb significantly to surfaces. Additionally, a consistent exponential curve was derived for determining the source emission rate from the room temperature. Field applications of this new TGT adaptation are ongoing and will be published elsewhere shortly.publishedVersio

Adapting the passive tracer gas test technique to current challenges for simultaneous measurement of ventilation rates and indoor air quality indicators

De lucht binnen onze huizen en andere gebouwen kan schadelijker zijn dan de lucht buiten, zelfs als we in grote steden wonen. Binnenshuis bevinden zich veel bronnen van luchtverontreiniging. Het is vrijwel onmogelijk om al deze bronnen te elimineren, vooral omdat de mens er een van is. Ventilatie is een efficiënt hulpmiddel om ophoping van verontreinigingen binnenshuis te voorkomen. We weten echter zelden hoe goed de ruimtes waarin we ons bevinden geventileerde zijn, vooral omdat de beschikbare methoden om ventilatievouden te meten beperkt zijn. Daarom werd een praktische en laagdrempelige methode ontwikkeld om gelijktijdig ventilatievouden en luchtverontreiniging in gebouwen te meten, gebaseerd op de tracergastechniek. Bij deze techniek wordt de binnenlucht gemarkeerd met een gemakkelijk herkenbaar gas (het tracergas) en door de tracerconcentratie in de lucht te meten, wordt het ventilatievoud berekend. Met deze nieuwe methode heb je alleen een kleine bron van vloeibare tracer nodig die met een gekende snelheid verdampt, en luchtmonsternemers die passief tracer opvangen samen met andere gasvormige verontreinigende stoffen die gewoonlijk binnenshuis worden aangetroffen. Na laboratoriumanalyse kennen we voor elke monsternemer tegelijkertijd het ventilatievoud en het niveau van luchtverontreiniging van de beoordeelde ruimte, als basis voor een actieplan voor het verbeteren van de luchtkwaliteit

Ventilation assessment in three teaching spaces at a Belgian university

In the wake of the COVID-19 pandemic, Ghent University (UGent) has been working out several security measures to contain the spread of the coronavirus, including general regulations of physical distancing, mouth mask usage, hand hygiene, disinfection and ventilation1. Regarding ventilation, each professor is responsible for creating a specific framework that complies with the safety measures for their classes. To help substantiate this framework, assessments were performed in selected UGent teaching spaces to evaluate the ventilation levels achieved in different scenarios. This paper describes measurements performed in three rooms of one UGent building

Proposing a new tracer gas for future field applications of passive tracer gas tests for air change rate measurement

This paper describes the ongoing development of a new adaptation of the traditional tracer gas test (TGT) used for total air change rates (ACH) measurement. This adapted TGT, based on constant tracer injection, is intended for use in large-scale IAQ assessments and employs an alternative tracer gas that is more adequate than the currently employed SF6 and perfluorocarbons, and that can be co-captured and coanalysed with commonly assessed VOCs by commercial passive IAQ-sampling. Via literature study and lab experiments, decane-D22 was found to be a suitable tracer substance. A passive source of decane- D22 was developed and optimized in lab, providing stable and repeatable emission rates under standard temperature, while unaffected by varying RH and ACH. The effect of the liquid solvent level over the source emission rate was only barely noticeable, but a range of adequate solvent level is suggested nevertheless. The selected tracer was also shown not to adhere/absorb significantly to surfaces. Additionally, a consistent exponential curve was derived for determining the source emission rate from the room temperature. Field applications of this new TGT adaptation are ongoing and will be published elsewhere shortly

Adapted tracer gas test for passive measurement of total air change rates using alternative tracer substance

This paper describes the development of a new adaptation of the traditional tracer gas test (TGT) used for total air change rates (ACH) measurement. This adapted TGT, based on constant tracer injection, is intended for use in large-scale IAQ assessments and employs an alternative tracer gas that is more adequate than the currently employed SF6 and perfluorocarbons, and that can be co-captured and co-analyzed with commonly assessed VOCs by commercial passive IAQ-sampling. As it is based on passive sampling, the proposed TGT yields long-term integrated ACH values, and is thus indicated only for studies focused on characterizations based on average estimations rather than on analyses requiring fine temporal resolution. By means of literature study and lab experiments, decane-D-22 was selected as a suitable tracer substance. The selected tracer was shown not to adhere/absorb significantly to surfaces. A passive source of decane-D-22 was selected and optimized in lab, providing stable and repeatable emission rates unaffected by varying RH and ACH. An exponential prediction curve was derived for determining the source emission rate from the average room temperature. Moreover, a range of adequate levels of liquid tracer inside the source is suggested. A successful field test application for validation of the new TGT is also described

Proposing a new tracer gas for future field applications of passive tracer gas tests for air change rate measurement

This paper describes the ongoing development of a new adaptation of the traditional tracer gas test (TGT) used for total air change rates (ACH) measurement. This adapted TGT, based on constant tracer injection, is intended for use in large-scale IAQ assessments and employs an alternative tracer gas that is more adequate than the currently employed SF6 and perfluorocarbons, and that can be co-captured and co- analysed with commonly assessed VOCs by commercial passive IAQ-sampling. Via literature study and lab experiments, decane-D22 was found to be a suitable tracer substance. A passive source of decane- D22 was developed and optimized in lab, providing stable and repeatable emission rates under standard temperature, while unaffected by varying RH and ACH. The effect of the liquid solvent level over the source emission rate was only barely noticeable, but a range of adequate solvent level is suggested nevertheless. The selected tracer was also shown not to adhere/absorb significantly to surfaces. Additionally, a consistent exponential curve was derived for determining the source emission rate from the room temperature. Field applications of this new TGT adaptation are ongoing and will be published elsewhere shortly