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Authors
Abstract(s)
A aferição e controlo das características físicas, químicas e biológicas em ambientes interiores é de extrema relevância na avaliação da saúde pública, dada a sua associação a doenças respiratórias e cardíacas, nomeadamente no que diz respeito à fração respirável do material particulado (PM2,5). É ainda comum encontrar uma qualidade do ar não homogénea nestes espaços, seja pela distribuição não uniforme das fontes de poluentes, do número de ocupantes, dos aspetos construtivos ou pelas diferentes taxas de ventilação. Uma compreensão abrangente e sistemática deste assunto envolve o estudo de fenómenos esporádicos e sazonais e implica a necessidade de escalas temporais e espaciais de monitorização nem sempre simples de se alcançarem, essencialmente, devido aos custos elevados, à baixa portabilidade e à dificuldade operacional de alguns equipamentos de medição disponíveis. Contudo, estas dificuldades promovem a expansão de dispositivos low-cost, com custos reduzidos e dimensões significativamente inferiores. Este trabalho teve por objetivo a construção de um equipamento capaz de contribuir para ampliar o conhecimento da qualidade do ar em ambientes interiores. O protótipo obtido incorpora sensores que quantificam a temperatura, a humidade relativa, a concentração de dióxido de carbono e as concentrações de PM2,5 e PM10. A sua fiabilidade foi aferida através de estudos de intercomparação e análises de correlação (Índice de Concordância de Willmott (d), Coeficiente de Correlação de Pearson (r) e Coeficiente de Determinação (R²)) com dados obtidos por equipamentos de elevada precisão e exatidão. Nesta avaliação foram conduzidos 4 ensaios num espaço laboratorial do Instituto Politécnico de Bragança. Cada ensaio teve uma duração de 24 horas e os registos foram obtidos com uma frequência de 1 minuto. Os resultados obtidos apresentam uma elevada correlação entre as concentrações de material particulado analisadas (PM2,5), onde d= 0,918, r= 0,943 e R²= 0,889 para a situação de maior distanciamento entre os dados e d= 0,983, r= 0,994 e R²= 0,972 para a situação de maior proximidade. Para concentração de dióxido de carbono foi verificada uma correlação muito forte (> 0,9) para todas análises estatísticas conduzidas, e para temperatura e humidade relativa, apesar das correlações não apresentarem valores elevados em todas as análises, o desvio entre equipamentos não foi superior a 1,6°C para temperatura e 5,9% para humidade relativa, o que sugere a aplicabilidade do equipamento desenvolvido na verificação dos parâmetros estudados na qualidade do ar interior.
Measurement and control of physical, chemical and biological characteristics in indoor environments is considered a subject with extreme relevance in the evaluation of public health, given its association with respiratory and cardiac diseases, especially with regard tothe respirable fraction of the particulate matter (PM2.5). Moreover, it is still common to find an inhomogeneous air quality in these spaces, either by the unequal distribution of sources of pollutants, number of occupants, constructive aspects or by different ventilation rates. A comprehensive and systematic understanding of this topic involves the study of sporadic and seasonal phenomena and implies the need of temporal and spatial monitoring scales not always simple to achieve, mainly due to the high costs, the low portability and the operational difficulty of some available measuring equipment. These difficulties promote the expansion of low-cost devices, with reduced costs and lower dimensions. The objective of this work aimed at constructing an equipment capable to improve the knowledge about indoor air quality. The prototype incorporates sensors that quantify the temperature, relative humidity, and concentrations of carbon dioxide, PM2.5 and PM10. Its reliability was assessed through inter-comparison studies and correlation analyzes (Willmott's Concordance Index (d), Pearson's Correlation Coefficient (r) and Determination Coefficient (R²)) with data obtained by equipment of high precision and accuracy. In this evaluation, 4 trials were conducted in a laboratory space of the Polytechnic Institute of Bragança. Each trial lasted 24 hours and the data was logged at a frequency of 1 minute. Main results show a high correlation for particulate matter (PM2.5), with d = 0.918, r = 0.943 and R² = 0.889 for the worst situation and d = 0.983, r = 0.994 and R² = 0.972 for the best one. For carbon dioxide a very strong correlation (> 0.9) was identified for all statistical parameters used in the evaluation. For temperature and relative humidity, although correlations have been weaker, the bias between data from both equipments were less than 1.6°C for temperature and 5.9% for relative humidity, which suggests the good applicability of the prototype in the evaluation of the studied in indoor air quality parameters.
Measurement and control of physical, chemical and biological characteristics in indoor environments is considered a subject with extreme relevance in the evaluation of public health, given its association with respiratory and cardiac diseases, especially with regard tothe respirable fraction of the particulate matter (PM2.5). Moreover, it is still common to find an inhomogeneous air quality in these spaces, either by the unequal distribution of sources of pollutants, number of occupants, constructive aspects or by different ventilation rates. A comprehensive and systematic understanding of this topic involves the study of sporadic and seasonal phenomena and implies the need of temporal and spatial monitoring scales not always simple to achieve, mainly due to the high costs, the low portability and the operational difficulty of some available measuring equipment. These difficulties promote the expansion of low-cost devices, with reduced costs and lower dimensions. The objective of this work aimed at constructing an equipment capable to improve the knowledge about indoor air quality. The prototype incorporates sensors that quantify the temperature, relative humidity, and concentrations of carbon dioxide, PM2.5 and PM10. Its reliability was assessed through inter-comparison studies and correlation analyzes (Willmott's Concordance Index (d), Pearson's Correlation Coefficient (r) and Determination Coefficient (R²)) with data obtained by equipment of high precision and accuracy. In this evaluation, 4 trials were conducted in a laboratory space of the Polytechnic Institute of Bragança. Each trial lasted 24 hours and the data was logged at a frequency of 1 minute. Main results show a high correlation for particulate matter (PM2.5), with d = 0.918, r = 0.943 and R² = 0.889 for the worst situation and d = 0.983, r = 0.994 and R² = 0.972 for the best one. For carbon dioxide a very strong correlation (> 0.9) was identified for all statistical parameters used in the evaluation. For temperature and relative humidity, although correlations have been weaker, the bias between data from both equipments were less than 1.6°C for temperature and 5.9% for relative humidity, which suggests the good applicability of the prototype in the evaluation of the studied in indoor air quality parameters.
Description
Mestrado de dupla diplomação com a UTFPR - Universidade Tecnológica Federal do Paraná
Keywords
Qualidade do ar Dispositivos low-cost