Water quality issues in rivers, lakes and reservoirs in Asian countries: an approach to the problems and the methodologies

Water covers over 70% of the Earth's surface, and is vital for all known forms of life. But only 3% of the Earth's water is fresh water, and less than 0.3% of all freshwater is in rivers, lakes, reservoirs and the atmosphere. However, rivers and lakes are an important part of fresh surface water, amounting to about 89%. In this Master Thesis dissertation, the focus is on three types of water bodies ��� rivers, lakes and reservoirs, and their water quality issues in Asian countries. The surface water quality in a region is largely determined both by the natural processes such as climate or geographic conditions, and the anthropogenic influences such as industrial and agricultural activities or land use conversion. The quality of the water can be affected by pollutants discharge from a specific point through a sewer pipe and also by extensive drainage from agriculture/urban areas and within basin. Hence, water pollutant sources can be divided into two categories: Point source pollution and Non-point source (NPS) pollution. Seasonal variations in precipitation and surface run-off have a strong effect on river discharge and the concentration of pollutants in water bodies. For example, in the rainy season, heavy and persistent rain wash off the ground, the runoff flow increases and may contain various kinds of pollutants and, eventually, enters the water bodies. In some cases, especially in confined water bodies, the quality may be positive related with rainfall in the wet season, because this confined type of fresh water systems allows high dilution of pollutants, decreasing their possible impacts. During the dry season, the quality of water is largely related to industrialization and urbanization pollution. The aim of this study is to identify the most common water quality problems in Asian countries and to enumerate and analyze the methodologies used for assessment of water quality conditions of both rivers and confined water bodies (lakes and reservoirs). Based on the evaluation of a sample of 57 papers, dated between 2000 and 2012, it was found that over the past decade, the water quality of rivers, lakes, and reservoirs in developing countries is being degraded. Water pollution and destruction of aquatic ecosystems have caused massive damage to the functions and integrity of water resources. The most widespread NPS in Asian countries and those which have the greatest spatial impacts are urban runoff and agriculture. Locally, mine waste runoff and rice paddy are serious NPS problems. The most relevant point pollution sources are the effluents from factories, sewage treatment plant, and public or household facilities. It was found that the most used methodology was unquestionably the monitoring activity, used in 49 of analyzed studies, accounting for 86%. Sometimes, data from historical databases were used as well. It can be seen that taking samples from the water body and then carry on laboratory work (chemical analyses) is important because it can give an understanding of the water quality. 6 papers (11%) used a method that combined monitoring data and modeling. 6 papers (11%) just applied a model to estimate the quality of water. Modeling is a useful resource when there is limited budget since some models are of free download and use. In particular, several of used models come from the U.S.A, but they have their own purposes and features, meaning that a careful application of the models to other countries and a critical discussion of the results are crucial. 5 papers (9%) focus on a method combining monitoring data and statistical analysis. When there is a huge data matrix, the researchers need an efficient way of interpretation of the information which is provided by statistics. 3 papers (5%) used a method combining monitoring data, statistical analysis and modeling. These different methods are all valuable to evaluate the water quality. It was also found that the evaluation of water quality was made as well by using other types of sampling different than water itself, and they also provide useful information to understand the condition of the water body. These additional monitoring activities are: Air sampling, sediment sampling, phytoplankton sampling and aquatic animal tissues sampling. Despite considerable progress in developing and applying control regulations to point and NPS pollution, the pollution status of rivers, lakes, and reservoirs in Asian countries is not improving. In fact, this reflects the slow pace of investment in new infrastructure for pollution control and growing population pressures. Water laws or regulations and public involvement in enforcement can play a constructive and indispensable role in environmental protection. In the near future, in order to protect water from further contamination, rapid action is highly needed to control the various kinds of effluents in one region. Environmental remediation and treatment of industrial effluent and municipal wastewaters is essential. It is also important to prevent the direct input of agricultural and mine site runoff. Finally, stricter environmental regulation for water quality is required to support protection and management strategies. It would have been possible to get further information based in the 57 sample of papers. For instance, it would have been interesting to compare the level of concentrations of some pollutants in the diferente Asian countries. However the limit of three months duration for this study prevented further work to take place. In spite of this, the study objectives were achieved: the work provided an overview of the most relevant water quality problems in rivers, lakes and reservoirs in Asian countries, and also listed and analyzed the most common methodologies.

Modela����o do transporte e dispers��o atmosf��rica de poluentes produzidos por uma refinaria: estudo de caso

Mestrado em Engenharia Qu��mica.Ramo Tecnologias de Protec����o Ambiental

Avalia����o da qualidade do ar interior e estudos CFD em espa��os do ISEP

Mestrado em Engenharia Qu��mica. Ramo Tecnologias de Protec����o Ambiental.

Produ����o de biodiesel via cat��lise heterog��nea b��sica

Mestrado em Engenharia Qu��mica. Ramo Tecnologias de Protec����o Ambiental.

Aspergillus genera fungal contamination in a Portuguese composting plant

Fungal contamination in composting facilities has been associated with increased respiratory and skin pathologies among compost workers. In this study we aim to characterize the fungal contamination caused by Aspergillus genera within a totally indoor composting plant located in Portugal. Air samples of 50L were collected from 6 sampling sites through an impaction method. Surfaces samples were collected by swabbing the surfaces of the same indoor sites. Pre-treatment and waste screw were the sampling sites of the analyzed composting plant with the highest Aspergillus load in the air. Globally, the genus Aspergillus presented the highest prevalence both in the air from (90.6%), and surfaces from the same sampling sites (60.8%). The results obtained in this study claim the attention to the need of further research regarding the fungal contamination dur to Aspergillus genus in composting plants.

Exposure to fungi in dockers

Several activities are ensured by dockers increase occupational exposure to several risk factors. being one of them the fungal burden from the load. In this study we aim at characterizing fungal contamination in one warehouse that storage sugar cane from a ship, and also in one crane cabinet that unload the same sugar cane from the ship. Air samples were collected from the warehouse and from inside the crane cabinet. An outdoor sample was also collected, from each sampling site, and regarding as reference. Sampling volume was selected depending in the contamination expected and the air samples were collect through an impaction method in a flow rate of 140 L/min onto malt extract agar (MEA) supplemented with chloramphenicol (0.05%), using the Millipore air Tester (Millipore). Surfaces samples from the warehouse were collected by swabbing the surfaces of the same indoor sites, using a 10 by 10cm square stencil according to the International Standard ISO 18593 (2004). The obtained swabs were then plated onto MEA. All the collected samples were incubated at 27��C for 5 to 7 days. After laboratory processing and incubation of the collected samples, quantitative (colony-forming units - CFU/m3 and CFU/m2) and qualitative results were obtained with identification of the isolated fungal species. Aspergillus fumigatus present the highest fungal load and WHO guideline was overcome in both indoor sampling sites. The results obtained in this study highlight the need to know better the exposure burden from dockers, and specifically to fungi contamination.

Remedia����o de solos contaminados com produtos farmac��uticos ��� oxida����o / redu����o qu��mica

Actualmente, a polui����o do ar, ��gua e solo s��o problem��ticas nas quais se t��m centrado diversos estudos. Reduzir ou eliminar a concentra����o dos diversos poluentes presentes nestes meios �� uma meta que se pretende atingir. Neste ��mbito, t��m sido desenvolvidos diversos estudos e trabalhos, utilizando diversas tecnologias, como qu��micas e biol��gicas, de forma a conseguir-se atingir este fim. Esta tese teve como principal objectivo estudar a remedia����o de solos contaminados com produtos farmac��uticos recorrendo �� oxida����o/redu����o qu��mica. Assim, come��ou por se estudar a remedia����o de ��gua contaminada com ibuprofeno, uma vez, que a matriz l��quida �� mais f��cil de estudar que o solo. Neste ��mbito escolheram-se os seguintes reagentes para estudar a descontamina����o da ��gua: permanganato de pot��ssio, reagente de Fenton e nanopart��culas de ferro zero valente. Analisando os resultados obtidos nestas an��lises, verificou-se que o permanganato de pot��ssio n��o foi capaz de reduzir a concentra����o de ibuprofeno presente na ��gua. No entanto, o reagente de Fenton e as nanopart��culas produzidas a partir do extracto da casca de castanha e do ch�� conseguirem reagir com o ibuprofeno, apresentando taxas de degrada����o de 90 % e 77 %, respectivamente, nas melhores condi����es experimentadas. Com os resultados obtidos, passou-se a analisar solos contaminados com o ibuprofeno, utilizando o reagente de Fenton e as nanopart��culas produzidas a partir de um extracto de ch��. Verificou-se que estes reagentes conseguiram reduzir a concentra����o de ibuprofeno presente no solo (areia) para valores residuais, obtendo-se taxas de degrada����o acima de 95 % ap��s 5 dias de reac����o. Conclui-se que, o objectivo principal desta tese foi cumprido pois foi reduzida, e quase eliminada, a concentra����o do ibuprofeno presente no solo, recorrendo �� oxida����o/redu����o qu��mica.

Avalia����o de compostos halogenados em ��gua e ar de piscinas

A procura de piscinas para a pr��tica de atividades desportivas, recreativas e/ou terap��uticas tem sofrido um aumento gradual ao longo do tempo. No entanto, nas piscinas existem v��rios perigos associados �� sua utiliza����o. Relativamente aos perigos qu��micos, a utiliza����o de desinfetantes �� base de cloro, bromo ou compostos derivados vai, por um lado, inativar microrganismos patog��nicos mas, por outro, dar origem a subprodutos ao reagir com compostos org��nicos presentes na ��gua. Os trihalometanos s��o um exemplo de subprodutos que se podem formar e, entre os compostos principais, est��o o clorof��rmio (TCM), bromodiclorometano (BDCM), clorodibromometano (CDBM) e bromof��rmio (TBM). Este trabalho teve como objetivo o desenvolvimento de uma metodologia anal��tica para a determina����o de trihalometanos em ��gua e ar de piscinas e a sua aplica����o a um conjunto de amostras. Para a an��lise dos compostos, foi utilizada a microextra����o em fase s��lida no espa��o de cabe��a (HS-SPME) com posterior quantifica����o dos compostos por cromatografia gasosa com detetor de captura eletr��nica (GC-ECD). Foi realizada uma otimiza����o das condi����es de extra����o dos compostos em estudo em amostras de ��gua, atrav��s da realiza����o de dois planeamentos experimentais. As condi����es ��timas s��o assim obtidas para uma temperatura de extra����o de 45��C, um tempo de extra����o de 25 min e um tempo de dessor����o de 5 min. Foram analisadas amostras de ��guas de piscina cedidas pelo Centro de Estudos de ��guas, sendo avaliada a aplica����o da t��cnica HS-SPME e o efeito de matriz. O modo como se manuseiam as solu����es que cont��m os compostos em estudo influencia os resultados devido ao facto destes serem bastante vol��teis. Concluiu-se tamb��m que existe efeito de matriz, logo a concentra����o das amostras dever�� ser determinada atrav��s do m��todo de adi����o de padr��o. A carateriza����o da ��gua de piscinas interiores permitiu conhecer a concentra����o de trihalometanos (THMs). Foram obtidas concentra����es de TCM entre 4,5 e 406,5 ��g/L sendo que apenas 4 das 27 amostras analisadas ultrapassam o valor limite imposto pelo Decreto-Lei n��306/2007 (100 ��g/L) no que diz respeito a ��guas de consumo humano e que �� normalmente utilizado como valor indicativo para a qualidade das ��guas de piscina. Relativamente �� concentra����o obtida no ar de uma piscina interior, foi detetada uma concentra����o m��dia de 224 ��g/m3 de TCM, valor muito abaixo dos 10000 ��g/m3 impostos pelo Decreto-lei n��24/2012, como valor limite para exposi����o profissional a agentes qu��micos.

Impacto da influ��ncia do ar novo na climatiza����o de edif��cios

Este trabalho surgiu do ��mbito da Tese de Disserta����o do Mestrado em Energias Sustent��veis do Instituto Superior de Engenharia do Porto, tendo o acompanhamento dos orientadores da empresa Laborat��rio Ecotermolab do Instituto de Soldadura e Qualidade e do Instituto Superior de Engenharia do Porto, de forma a garantir a linha tra��ada indo de acordo aos objectivos propostos. A presente tese abordou o estudo do impacto da influ��ncia do ar novo na climatiza����o de edif��cios, tendo como base de apoio �� an��lise a simula����o din��mica do edif��cio em condi����es reais num programa adequado, acreditado pela norma ASHRAE 140-2004. Este trabalho pretendeu evidenciar qual o impacto da influ��ncia do ar novo na climatiza����o de um edif��cio com a conjuga����o de v��rios factores, tais como, ocupa����o, actividades e padr��es de utiliza����o (hor��rios), ilumina����o e equipamentos, estudando ainda a possibilidade do sistema funcionar em regime de ���Free-Cooling���. O princ��pio partiu fundamentalmente por determinar at�� que ponto se pode climatizar recorrendo ��nico e exclusivamente �� introdu����o de ar novo em regime de ���Free-Cooling���, atrav��s de um sistema tudo-ar de Volume de Ar Vari��vel - VAV, sem o apoio de qualquer outro sistema de climatiza����o auxiliar localizado no espa��o, respeitando os caudais m��nimos impostos pelo RSECE (Decreto-Lei 79/2006). Numa primeira fase foram identificados todos os dados relativos �� determina����o das cargas t��rmicas do edif��cio, tendo em conta todos os factores e contributos alusivos ao valor da carga t��rmica, tais como a transmiss��o de calor e seus constituintes, a ilumina����o, a ventila����o, o uso de equipamentos e os n��veis de ocupa����o. Consequentemente foram elaboradas diversas simula����es din��micas com o recurso ao programa EnergyPlus integrado no DesignBuilder, conjugando vari��veis desde as envolventes �� pr��pria arquitectura, perfis de utiliza����o ocupacional, equipamentos e taxas de renova����o de ar nos diferentes espa��os do edif��cio em estudo. Obtiveram-se v��rios modelos de forma a promover um estudo comparativo e aprofundado que permitisse determinar o impacto do ar novo na climatiza����o do edif��cio, perspectivando a capacidade funcional do sistema funcionar em regime de ���Free-Cooling���. Deste modo, a an��lise e compara����o dos dados obtidos permitiram chegar ��s seguintes conclus��es: Tendo em considera����o que para necessidades de arrefecimento bastante elevadas, o ���Free-Cooling��� diurno revelou-se pouco eficaz ou quase nulo, para o tipo de clima verificado em Portugal, pois o diferencial de temperatura existente entre o exterior e o interior n��o �� suficiente de modo a tornar poss��vel a remo����o das cargas de forma a baixar a temperatura interior para o intervalo de conforto. Em rela����o ao ���Free-Cooling��� em hor��rio nocturno ou p��s-laboral, este revelou-se bem mais eficiente. Obtiveram-se presta����es muito interessantes sobretudo durante as esta����es de aquecimento e meia-esta����o, tendo em considera����o o facto de existir necessidades de arrefecimento mesmo durante a esta����o de aquecimento. Referente �� ventila����o nocturna, isto ��, em per��odos de madrugada e fecho do edif��cio, concluiu-se que tal contribui para um abaixamento do calor acumulado durante o dia nos materiais construtivos do edif��cio e que �� libertado ou restitu��do posteriormente para os espa��os em per��odos mais tardios. De entre as seguintes vari��veis, aumento de caudal de ar novo insuflado e o diferencial de temperatura existente entre o ar exterior e interior, ficou demonstrado que este ��ltimo teria maior peso contributivo na remo����o do calor. Por fim, �� ponto assente que de um modo geral, um sistema de climatiza����o ser�� sempre indispens��vel devido a cargas internas elevadas, requisitos interiores de temperatura e humidade, sendo no entanto aconselhado o ���Free- Cooling��� como um op����o vi��vel a incorporar na solu����o de climatiza����o, de forma a promover o arrefecimento natural, a redu����o do consumo energ��tico e a introdu����o activa de ar novo.

Avalia����o ecotoxicol��gica de solos contaminados por ibuprofeno

Os produtos farmac��uticos s��o subst��ncias qu��micas muito utilizados em medicina, veterin��ria e ainda na agricultura. Nos anos 90, foi descoberta a presen��a de f��rmacos em meio aqu��tico, verificando-se que a sua remo����o nas Esta����es de Tratamento de ��guas Residuais (ETAR) n��o era completa. Durante as duas ��ltimas d��cadas foi identificada a presen��a de mais de oitenta compostos no meio ambiente e actualmente s��o considerados poluentes emergentes. Podem contaminar solos e ��guas, depois de serem usados e excretados (inalterados ou metabolizados) por humanos e animais, ou quando s��o indevidamente lan��ados directamente no meio ambiente. Os estudos ecotoxicol��gicos efectuados com estes poluentes t��m sido direccionados, sobretudo, para as ��guas, existindo uma aus��ncia de trabalhos sobre solos. O Ibuprofeno (IB) �� um anti-inflamat��rio n��o ester��ide, utilizado tamb��m como analg��sico e antipir��tico, sendo um dos produtos farmac��uticos mais vendidos em todo o mundo, o que justifica a sua forte presen��a no meio ambiente. Por isso, e dada a aus��ncia de trabalhos ecotoxicol��gicos de solos contaminados por f��rmacos, o IB foi o produto farmac��utico selecionado para a realiza����o deste trabalho. A ecotoxicidade pode ser avaliada atrav��s de bioensaios. Estes t��m a capacidade de avaliar a toxicidade de uma determinada subst��ncia de forma global, usando organismos vivos que funcionam como bio-indicadores. O presente trabalho tem como objectivos avaliar o impacte causado nos solos pelo IB, testar a toxicidade de dois processos de descontamina����o para remover o referido f��rmaco dos solos assim como avaliar a toxicidade provocada por ��guas residuais, de tr��s unidades hospitalares e de uma ind��stria farmac��utica. Esta avalia����o foi efectuada atrav��s de ensaios de toxicidade aguda de germina����o e de alongamento de raiz de sementes de alface, variedade bola de manteiga (Lactuca sativa), em solo arenoso. Os ensaios de ecotoxicidade aguda em solos contaminados por IB foram realizados para uma gama de concentra����es entre 0,1 e 1000 ��g/L. Verificou-se uma redu����o do n��mero de sementes germinadas e do comprimento m��dio da planta no solo contaminado com 0,5 e 20 ��g/L de IB. No solo contaminado com 1000 ��g/L de IB observou-se uma redu����o da germina����o, acompanhada por uma indu����o de crescimento da raiz da esp��cie Lactuca sativa. Os dois tratamentos de descontamina����o de solos, reagente de Fenton e Nanopart��culas de ferro zero valente, revelaram toxicidade, tendo-se obtido uma percentagem de germina����o entre 32,2 �� 3,5 e 48,5 �� 6,2 e inibi����o do crescimento da raiz do organismo teste em cerca de 85,0 %. Em rela����o ��s ��guas residuais hospitalares verificou-se uma redu����o da percentagem de germina����o entre 31,1 �� 5,0 e 72,3 �� 12,4 e uma inibi����o do crescimento da raiz situada entre 13,0 �� 6,4 e 20,2 �� 10,0 %. Para a ��gua residual industrial ocorreu uma inibi����o da percentagem de germina����o de 60,5 �� 13,1, contudo nas plantas germinadas observou-se uma indu����o do crescimento da raiz de 14,9 �� 7,7 %.

Toxicological Assessment of Coated versus Uncoated Rubber Granulates Obtained from Used Tires for Use in Sport Facilities

Reuse of tire crumb in sport facilities is currently a very cost-effective waste management measure. Considering that incorporation of the waste materials in artificial turf would be facilitated if the rubber materials were already colored green, coatings were specifically developed for this purpose. This paper presents an experimental toxicological and environmental assessment aimed at comparing the obtained emissions to the environment in terms of polycyclic aromatic hydrocarbons (PAHs), heavy metals, and ecotoxicity for coated and noncoated rubber granulates. This study is a comprehensive evaluation of the major potential critical factors related with the release of all of these classes of pollutants because previous studies were not systematically performed. It was concluded that between the two types of coatings tested, one is particularly effective in reducing emissions to the environment, simultaneously meeting the requirements of adherence and color stability.

Aspergillus flavus contamination in two Portuguese wastewater treatment plants

Filamentous fungi from genus Aspergillus were previously detected in wastewater treatment plants (WWTP) as being Aspergillus flavus (A. flavus), an important toxigenic fungus producing aflatoxins. This study aimed to determine occupational exposure adverse effects due to fungal contamination produced by A. flavus complex in two Portuguese WWTP using conventional and molecular methodologies. Air samples from two WWTP were collected at 1 m height through impaction method. Surface samples were collected by swabbing surfaces of the same indoor sites. After counting A. flavus and identification, detection of aflatoxin production was ensured through inoculation of seven inoculates in coconut-milk agar. Plates were examined under long-wave ultraviolet (UV; 365 nm) illumination to search for the presence of fluorescence in the growing colonies. To apply molecular methods, air samples were also collected using the impinger method. Samples were collected and collection liquid was subsequently used for DNA extraction. Molecular identification of A. flavus was achieved by real-time polymerase chain reaction (RT-PCR) using the Rotor-Gene 6000 qPCR detection system (Corbett). Among the Aspergillus genus, the species that were more abundant in air samples from both WWTP were Aspergillus versicolor (38%), Aspergillus candidus (29.1%), and Aspergillus sydowii (12.7%). However, the most commonly species found on surfaces were A. flavus (47.3%), Aspergillus fumigatus (34.4%), and Aspergillus sydowii (10.8%). Aspergillus flavus isolates that were inoculated in coconut agar medium were not identified as toxigenic strains and were not detected by RT-PCR in any of the analyzed samples from both plants. Data in this study indicate the need for monitoring fungal contamination in this setting. Although toxigenic strains were not detected from A. flavus complex, one cannot disregard the eventual presence and potential toxicity of aflatoxins.

Occupational exposure to Aflatoxin B1 in Portuguese swine farms

In 1987, the International Agency for Research on Cancer concluded that there was sufficient evidence for carcinogenicity of naturally occurring aflatoxins in humans. Regarding occupational exposure to this chemical agent, farmers and other agricultural workers present a higher risk due to airborne aflatoxin via inhalation of dust. This study was carried out in 7 swine farms located at the district of Lisbon, Portugal. Blood samples were collected from a total of 11 workers. In addition, a control group (n = 25) was included that conducted administrative tasks in an educational institution without any type of agricultural activity. Results obtained suggest that occupational exposure to AFB1 by inhalation occurs and represents an additional risk in this occupational setting that need to be recognized, assessed and, most important, prevented.

Potential poultry and meat products contamination by aflatoxin B1 due to fungal presence in Portuguese poultry units

The impact of mycotoxins on human and animal health is well recognized. Aflatoxin B1 (AFB1) is by far the most prevalent and the most potent natural carcinogen and is usually the major aflatoxin produced by toxigenic fungal strains. Data available, points to an increasing frequency of poultry feed contamination by aflatoxins. Since aflatoxin residues may accumulate in body tissues, this represents a high risk to human health. Samples from commercial poultry birds have already presented detectable levels of aflatoxin in liver. A descriptive study was developed in order to assess fungal contamination by species from Aspergillus flavus complex in seven Portuguese poultry units. Air fungal contamination was studied by conventional and molecular methods. Air, litter and surfaces samples were collected. To apply molecular methods, air samples of 300L were collected using the Coriolis �� air sampler (Bertin Technologies), at 300 L/min airflow rate. For conventional methodologies, all the collected samples were incubated at 27��C for five to seven days. Through conventional methods, Aspergillus flavus was the third fungal species (7%) most frequently found in 27 indoor air samples analysed and the most commonly isolated species (75%) in air samples containing only the Aspergillus genus...

Contribution of traffic and tobacco smoke in the distribution of polycyclic aromatic hydrocarbons on outdoor and indoor PM2.5

Traffic emissions and tobacco smoke are considered two main sources of polycyclic aromatic hydrocarbons (PAHs) in indoor and outdoor air. In this study, the impact of these sources on the level of fine particulate matter (PM2.5) and on the distribution of 15 PAHs regarded as priority pollutants by the US-EPA on PM2.5 were evaluated and compared. Outdoor and indoor PM2.5 samples were collected during winter 2008 in Oporto city in Portugal, for sampling periods of 12 and 24 hours, respectively. The outdoor PM2.5 were sampled at one site directly influenced by traffic emissions and the indoor PM2.5 samples were collected at one home directly influenced by tobacco smoke and another one without smoke. A methodology based on microwave-assisted extraction and liquid chromatography with fluorescence detection was applied for the efficient PAHs determination in indoor and outdoor PM2.5. PAHs in indoor PM2.5 concentrations were significantly influenced by the presence of traffic and tobacco smoking emissions. The mean of ��PAHs in the outdoor traffic PM2.5 was not significantly different from the value attained in the indoor without smoking site. The tobacco smoke increased significantly PAHs concentrations on average about 1000 times more, when compared with the outdoor profile samples suggesting that tobacco smoking may be the most important source of indoor PAHs pollution.