Indoor Microclimate Research Articles

CFD Simulation of Dynamic Temperature Variations Induced by Tunnel Ventilation in a Broiler House.

Maintaining the optimal microclimate in broiler houses is crucial for bird productivity, yet enabling efficient temperature control remains a significant challenge. This study developed and validated a computational fluid dynamics (CFD) model to predict temporal changes in indoor air temperature in response to variable ventilation operations in a commercial broiler house. The model accurately simulated air velocity and airflow distribution for different numbers of tunnel fans in operation, with air-velocity errors ranging from -0.22 to 0.32 m s-1. The predicted airflow rates through inlets and cooling pads showed good agreement with measured values with an accuracy of up to 108.1%. Additionally, the CFD model effectively predicted temperature dynamics, accounting for chicken heat production and ventilation effect. The model successfully predicted the longitudinal temperature gradients and their variations during ventilation cycles, validating its reliability through comparison with experimental data. This study also explored different variable inlet configurations to mitigate the temperature gradient. The variable inlet adjustment showed the potential to relieve the high temperatures but may reduce overall ventilation efficiency or intensify temperature gradients, which confirms the importance of optimising ventilation strategies. This CFD model provides a valuable tool for evaluating and improving ventilation systems and contributes to enhanced indoor microclimates and productivity in poultry houses.

External Thermal Insulation Composite Systems—Past and Future in a Sustainable Urban Environment

In recent decades, the sustainable development of the planet has been negatively affected by a number of factors, including the construction industry. The construction industry includes, among other things, the highly topical energy reconstruction of existing prefabricated residential housing, which is implemented to improve their condition from a thermal engineering and energy perspective. Composite materials, known as external thermal insulation composite systems (ETICSs), have come to the fore, bringing a number of undeniable benefits to society. After more than 20 years of experience, it turns out that in addition to the benefits, ETICSs also bring new research challenges to the discussion, which are related to the issue of the biocorrosion of the external envelope of ETICSs, and also to the issue of the indoor microclimate. Based on the literature review and case studies, we aim to show that ecologically friendly building materials require a multidisciplinary approach. At the same time, we want to contribute to the discussion of whether the diversity of microorganisms on ETICS composites is a potential source of health risks and whether the transport of microorganisms to the indoor environment can be ruled out through natural ventilation from the outdoor environment to the interior.

Comprehensive analysis of classroom microclimate in context to health-related national and international indoor air quality standards.

Indoor air quality (IAQ) and indoor air pollution are critical issues impacting urban environments, significantly affecting the quality of life. Nowadays, poor IAQ is linked to respiratory and cardiovascular diseases, allergic reactions, and cognitive impairments, particularly in settings like classrooms. Thus, this study investigates the impact of indoor environmental quality on student health in a university classroom over a year, using various sensors to measure 19 environmental parameters, including temperature, relative humidity, CO2, CO, volatile organic compounds (VOCs), particulate matter (PM), and other pollutants. Thus, the aim of the study is to analyze the implications of the indoor microclimate for the health of individuals working in the classroom, as well as its implications for educational outcomes. The data revealed frequent exceedances of international standards for formaldehyde (HCHO), VOC, PM2.5, NO, and NO2. HCHO and VOCs levels, often originating from building materials and classroom activities, were notably high. PM2.5 levels exceeded both annual and daily standards, while NO and NO2 levels, possibly influenced by inadequate ventilation, also surpassed recommended limits. Even though there were numerous exceedances of current international standards, the indoor microclimate quality index (IMQI) score indicated a generally good indoor environment, remaining mostly between 0 and 50 for this indicator. Additionally, analyses indicate a high probability that some indicators will exceed the current standards, and their values are expected to trend upwards in the future. The study highlighted the need for better ventilation and pollutant control in classrooms to ensure a healthy learning environment. Frequent exceedances of pollutant standards can suggest a significant impact on student health and academic performance. Thus, the present study underscored the importance of continuous monitoring and proactive measures to maintain optimal indoor air quality.

The diagnostic study of the plaster replicas of the Trajan’s Column conserved at the Museum of Roman Civilisation (Rome)

The management of indoor microclimate in museums has recently received growing attention. Museum climatology and the mechanism for the degradation process, defined as a result of progressive and cumulative decay, depends on environmental variables and their changes. In fact, temperature and relative humidity gradients are often the main causes of chemical and physical decay of artefacts. This research focuses on assessing the state of conservation of 34 gypsum-based plaster replicas of Trajan’s Column at the Museum of Roman Civilisation and on the microclimate monitoring of Room LI, where they are conserved. The decay assessment of the studied plaster casts was performed using a multidisciplinary analytical approach to characterize the constituent materials and to identify the main degradation patterns by i) on-site investigation with non-destructive methodologies; ii) chemical and petrographical characterization on collected micro samples. Microclimate variables (temperature, relative humidity and dew point) were measured along seven months to define the actual environmental conditions and the response of the materials to the microclimate.

The effect of structural retrofitting and ventilation scenarios on the indoor microclimate of a historical library: The Necip Pasa Library, Turkiye

Structural retrofitting in buildings may result in changes in the indoor microclimate. Chemical, mechanical and biological deterioration can be seen in the cultural properties as a consequence of substrates and inappropriate microclimatic conditions such as high indoor temperature, relative humidity and fluctuations of them. The primary aim of the study is to evaluate the effect of the structural retrofitting, that the building underwent, on the chemical degradation risk of the library collection based on two different ventilation scenarios. One is natural ventilation which is an existing situation since the building is free-floating. The other one implementing a mechanical ventilation system into the building. To be able to compare the microclimate that affects the library collection pre- and post-retrofitting, two models are developed in DesginBuilder and simulated for both scenarios. According to the results of the post-retrofitting model, mechanical ventilation reduced the risk of chemical degradation by 38 %, while natural ventilation did not cause any effect. Natural ventilation gives a similar output in the pre-retrofitting model as in the post-retrofitting model. Mechanical ventilation in the pre-retrofitting model achieves a 33 % reduction in chemical degradation risk. Structural retrofitting only achieves a 1 % reduction in the chemical risk level for both ventilation scenarios. Thus, its effect on the indoor microclimate is insignificant. This study shows that creating simulation models effectively assesses potential risks pre-post-structural retrofitting or any retrofitting in historical buildings. Simulations reveal that mechanical ventilation is a better choice for decreasing chemical degradation risks for the library.

Experimental Measurements in Schools with Natural Ventilation

Abstract Facilities for children and young people should be established in a healthy environment that is protected from external health-damaging factors, such as noise, air pollution, and negative educational influences. A school building should also be a safe and healthy environment for pupils and students, as legally required. However, although some school buildings have been renovated, most were constructed in the last century, and their indoor microclimate remains unsatisfactory. Schools must maintain optimal thermal and humidity conditions to ensure the healthy development of children and their ability to function properly in a classroom. While natural ventilation through opening windows is a good practice, it may not always guarantee sufficient air exchange, especially for schools located in busy traffic areas. This paper presents experimental measurements and a comparison between two primary schools in Bratislava, which describes the current thermal and humidity conditions in the indoor environment of both schools. Experimental measurements were carried out on five school days in each primary school to determine the thermal-humidity conditions and indoor air quality, depending on the concentrations of carbon dioxide.

ОЦЕНКА ТЕПЛОВОГО КОМФОРТА ДЕТЕЙ В ЖИЛЫХ И ОБЩЕСТВЕННЫХ ЗДАНИЯХ

In calculating children's thermal comfort, it is important to consider internal heat emissions, one of the main sources of which are the children themselves (heat exchange with the body surface, breathing, sweating). The accuracy of the calculation is influenced by their number, nature and intensity of activity, age, gender, and other parameters. Most regulatory documents base heat input calculations on a person with the following parameters: male, 20-30 years old, 70 kg, living in a temperate climate. This approach does not account for the physiological and age-specific characteristics of different age groups. The paper examines and refines the physiological parameters of children and uses models to numerically reflect the level of thermal comfort in a room. A calculation method is proposed that uses refined physiological parameters of children and evaluates thermal sensation of the indoor microclimate through the determination of Predicted Mean Vote (PMV) and Predicted Percentage Dissatisfied (PPD). Calculations of several microclimatic regimes were carried out, assessing the state of children of different ages and physical activity levels within the considered microclimate parameters. Analyzing the obtained data led to the conclusion that assessing human comfort using refined energy expenditures allows for a more flexible consideration of the thermal states of children in specific age groups. This enables higher quality regulation of the indoor microclimate of a specific room considering the examined factors.

Assessment of the Potential for Increasing the Energy Efficiency in the Cooling Sector

Cooling supply to ensure the indoor microclimate is becoming more important as global average air temperatures rise. With growing societal demands for higher thermal comfort and increasing individual cooling solutions in the building sector, global energy consumption for cooling is increasing accordingly. Scientific literature and studies estimate that the demand for cooling energy will have a significant impact on global energy demand in the future. In compliance with the European Union goal of achieving climate neutrality by 2050, it is essential to find solutions for reducing energy consumption in the building sector, which is already among the largest energy consumers and greenhouse gas emission producers. Replacing individual cooling solutions with district cooling in urban areas where higher energy density can be reached is one of the solutions for decarbonizing the building sector. To spatially assess the feasibility of district cooling in certain areas, energy demand mapping can be performed. Within this research mapping is carried out using a geographical information system (GIS) tool. The purpose of the mapping is to identify the places in the city of Riga with the highest district cooling potential. Spatial assessment using a GIS tool can be done in different ways – mostly it depends on the available data. The spatial data (buildings) of the cadastral information system and additional detailed information about buildings were obtained from the Latvian open data portal. Information on the type of use of the building, indoor area and the age of building was attached to each building on the map. Then building energy certificate data containing information on specific energy consumption for cooling (kWh/m2 per year) was obtained from the same portal. By processing the data of energy certificates of buildings, excluding outliers, a specific index was obtained for different types of buildings. For the residential sector, the age of the building is also used. Using cadastral data on the indoor area of buildings and the type of building use, the theoretical cooling demand in Riga is calculated and results are quantified and displayed visually. By visualizing the results with the GIS tool, hot spots with the highest cooling energy demand were detected. Results can be further used to calculate the technical and economic justification for the district cooling solutions in specific areas as well as assess the energy efficiency that would be provided by implementation of district cooling solutions.

Indoor Microclimatic Conditions and Air Pollutant Concentrations in the Archaeological Museum of Abdera, Greece

Indoor microclimate conditions and air pollutant concentrations (O3, TVOC, CO, CO2, and particulate matter mass concentrations in six size bins) were measured in the Greek Archaeological Museum of Abdera, which houses priceless works of art from the birthplace of the ancient philosopher Democritus. The monitoring campaign took place during the spring and summer months, when there were the greatest number of visitors. In the exhibition rooms, daily variations in relative humidity ranged from 4% to 10%, and daily variations in air temperature ranged from 0.9 °C to 2.6 °C. These uncontrolled changes may endanger the housed antiquities. The microclimate in the storage rooms varied substantially less than in the exhibition halls due to dehumidifiers and the lack of visitors. Concerning air pollution, indoor O3 concentrations were higher than the recommended limit values for the conservation of artwork. Even more worrisome are particulate matter mass concentrations above the air quality guidelines. Despite the fact that the building is well insulated and that only artificial lighting is used in the exhibition halls, it is difficult to achieve adequate conditions for the protection of the works of art.

Evaluation of the indoor environment in a historic museum during the COVID-19 lockdown in Northwest England

ABSTRACT Monitoring the quality of the indoor environment is a practice commonly adopted by museums as part of operational risk management. Recorded environmental data are often used to assess the safety of the indoor environment for artefacts, and their suitability for visitors' comfort. Previous studies reported monitoring campaigns assessing the performance of museums and level of compliance with regulatory standards. These analyses were typically conducted in normal circumstances assessing indoor microclimate quality under normal operating procedures. Museum closures during the 2020 pandemic and the global lockdown measures, introduced by governments, presented the heritage sector with an unprecedented situation with empty galleries where collections, in several museums, were held ‘dormant’ in free-running environments. Assessing the indoor environment in such exceptional circumstances offers a unique insight into the performance of these heritage repositories in other unpredicted situations and potential opportunities for microclimate optimization. This paper reports the results of an extended pre and post-pandemic monitoring that was performed in a historic museum in Northwest England. It contributes to the ongoing universal debate about the application of standardized strict environmental guidelines and the shift towards more contextualized standards in museums in the face of the decline in heritage funding and the pledges for carbon reductions.

Indoor Parameters of Museum Buildings for Guaranteeing Artworks Preservation and People’s Comfort: Compatibilities, Constraints, and Suggestions

Since people tend to spend more and more time visiting museums, more accurate requirements are needed for the indoor environmental conditions of these confined spaces where two primary requisites coincide in defining their optimal indoor microclimate: the need for the appropriate artwork preservation and suitable levels of indoor comfort conditions for people visiting the exhibition buildings and/or working there. Regrettably, people and artwork requirements are sometimes characterized by different reference limits of the environmental parameters that, not rarely, could potentially conflict. Another important point to consider is that museums hosted by heritage buildings (particularly in Mediterranean climates, as is often the case in Italy) are often not equipped with climatization systems because of difficulty in installing generally bulky equipment such as HVAC systems. This circumstance represents another important limit for achieving suitable conditions for the two requisites. In addition, the recent pandemic-related occurrences are pushing technicians and designers to rethink the criteria for controlling the microclimate of public buildings, and museums among them. In this paper, this issue is addressed by reviewing current regulations, standards, and handbooks (and by means of a real case example related to the Italian context) in order to ascertain whether such documentation could facilitate the development of effective rules/guidelines for proper management of indoor parameters in museums.

Cumulative climate-induced fatigue damage in wooden painted surfaces: The case of wooden churches in Sweden

Environmental variations of Temperature (T) and Relative Humidity (RH) in air cause a superficial and/or sub-surface deformation (shrinkage/swelling) of organic hygroscopic objects, as for example wood. These environmental variations may be due to the natural variability of climate, to the use of Heating, Ventilation and Air Conditioning (HVAC) systems and to the presence of people. This contribution focuses on a group of wooden rural churches located in harsh climates in Sweden. The churches, which are still in use for the local communities, are heated during wintertime to reach acceptable indoor comfort levels causing potentially risky T and RH fluctuations for hygroscopic objects. In this framework, the main goal is assessing the risk of fracture on wooden structural elements caused by hygrothermal fluctuations. The method is based on a preliminary approach for reconstructing the climate history experienced by a typical wooden structural element of these churches and that, over time, results in a cyclic fatigue loading, naturally induced by the outdoor climate. Then, the effect of the artificial heating on the indoor microclimate and, therefore, on the reconstructed fatigue curve is assessed. Main outcomes were obtained by using a methodology that is preliminary based on simplifying assumptions, due to a severe lack of knowledge, in literature, about the fatigue behavior of wood. Finally, main considerations on the fatigue behavior of exposed wooden elements are drawn up, namely the estimation of their residual life (or “life-to-damage”), which may support conservators or church managers in better managing the microclimate to reduce the risk of fracture on valuable objects.

Assessment of the effect of moisture on the strength of concrete and ceramic masonry wall products

Introduction. The material of the article considers the strength characteristics of ceramic and concrete masonry products, the operation of which is carried out in difficult conditions. The analysis of domestic and foreign publications and sources carried out in this work, including the results of previously performed experiments and field studies, showed that the values of the tensile strength of concrete and ceramic masonry products largely depend on moisture saturation.
 
 Aim. When analyzing previously performed works, it was found that moisture saturation and operating conditions significantly affect the strength properties of concrete and ceramic masonry products in the form of bricks and small blocks. It is noted that in some cases, the effect of degradation of the physical and mechanical properties of the products was observed. When performing surveys of buildings and structures, it becomes necessary to determine the bearing capacity of the masonry of foundations and basement walls located below the mark of the adjacent ground surface. These structures are located in an environment of excessive humidity, therefore, the masonry products themselves are in a state of increased moisture saturation, for example, due to the absence or damage of waterproofing, violation of the heat and humidity regime of the indoor microclimate.
 
 Materials and methods. During the work, masonry ceramic products in the form of bricks were used – new ones made according to State Standard 530-2012; historical bricks selected during the inspection of buildings and structures of historical buildings, as well as concrete wall products made according to State Standard 6133-2019. The test procedure complies with the established standard State Standard R 58527-2019.
 
 Results. Conducting of the research and developing of methods to assess the effect of humidification of ceramic and concrete masonry products on the strength of masonry is important for assessing the reliability of buildings and structures.
 
 Conclusions. The current problem requires comprehensive studies of the strength characteristics of ceramic and concrete masonry wall products, taking into account the influence of humidity.

Are Design Strategies for High-Performance Buildings Really Effective? Results from One Year of Monitoring of Indoor Microclimate and Envelope Performance of a Newly Built nZEB House in Central Italy

As buildings are one of the major contributors to greenhouse gas emissions and energy consumption, they have a key potential for energy efficiency and indoor environmental quality improvement. Therefore, the development of nearly Zero-Energy Buildings (nZEBs) is strategic to respond to these challenges and to design and retrofit sustainable highly performing buildings. Actually, the nZEB target can also be reached with highly insulated wooden technologies. However, they must be critically revised and adapted when taking into account the warm climate peculiarities. The paper contributes to this attempt by dealing with the implementation of a methodology specifically focused on the long-term assessment of the real building envelope performance. The methodology is applied to a recently built wooden nZEB detached single-story dwelling constructed in 2017 in central Italy. One year monitoring data were collected about the envelope in-field dynamic performance and the indoor microclimate and well-being conditions. The theoretical design-stage data and the monitored data were compared. The positive aspects as well as the critical issues of nZEB target in the Mediterranean climate context and the performance gap were underlined. Accordingly, the main aspects to be considered in the design of nZEBs envelope were highlighted.

Microclimate Assessment in a 19th‐Century Heritage Building From Romania

The quality of the internal microclimate is a very important issue nowadays, considering that people in developed societies spend a good part of their day inside buildings and means of transport. But the poor quality of indoor air has a double effect; on the one hand, it can harm human health, and on the other hand, it can cause the degradation of materials. Thus, the current study considers the potential influence of a number of 20 pollutants on the exhibits, visitors, and employees of a synagogue that is over 140 years old in the Municipality of Oradea (Romania), which today is included in the list of historical monuments and is open to be visited. The monitoring period consisted of 9 months, during which parameters such as temperature, relative humidity, CO concentration, light intensity, concentration of particulate matter, and other pollutants were monitored. All the obtained values were then reported to the international standards in force for each indicator, both regarding the potential for human health and the integrity of the exhibits. The results indicate that the values of most pollutants respect the allowed thresholds, with more or less permitted exceptions. The most problematic are the values of temperature, relative humidity, HCHO, and VOC, which substantially exceed the allowed limits and vary a considerable difference. This can induce additional stress on the exhibits, leading over time to damage and premature aging; in terms of human health, the indoor microclimate can, in rare cases, cause discomfort associated with headaches, dizziness, and irritation, but the potential to cause persistent ailments is quite low. To maintain a clean internal microclimate, preventive conservation through the continuous monitoring of internal parameters as well as the establishment of long‐term strategies to stabilize the values of pollutants are necessary actions.

Mapping of Energy Consumption for Cooling – Assessment of the Cooling Demand Potential for the City of Riga

Abstract Considering the global increase in mean air temperature and society’s demand for a comfortable indoor microclimate, cooling solutions in buildings will play an essential role in achieving global climate goals. Researchers estimate that global energy consumption will be significantly affected by the energy required for cooling. Assessment of cooling demand potential is an essential step to further analyse cooling options for buildings in certain areas. Within the framework of this study, mapping of energy consumption for cooling in the city of Riga (Latvia) is carried out. Mapping allows to assess the demand in a spatial perspective, identifying areas with a denser energy demand indicator, and, accordingly, a higher potential for implementation of district cooling and this method can be used in other countries and cities as well. Energy consumption for cooling at the building level was calculated and visualized using cadastral data and building energy certificate data. The results show that the potential energy consumption for cooling in the city of Riga can reach up to 397 GWh per year and the largest proportion of energy consumption for cooling is predicted in the category of multi – apartment buildings (up to 155 GWh per year), highlighting the need to pay particular attention how cooling demand is addressed in residential building sector. Results can be further used to evaluate the technical and economic feasibility of the district cooling implementation in parts of the city.

ОПРЕДЕЛЕНИЕ СКОРОСТИ ВЫХОДЯЩЕГО ВОЗДУШНОГО ПОТОКА И ДАВЛЕНИЯ В ВОЗДУХОВОДЕ АВТОМАТИЗИРОВАННОЙ СИСТЕМЫ ДЛЯ СНИЖЕНИЯ ТЕПЛОВОГО СТРЕССА КРС

The management of commercial dairy cattle breeding requires optimal maintenance for animals’ genetic potential obtaining. This contributes to high cattle milk production achieving. Microclimate regulation plays a key role at animal’s health and preventing diseases maintaining. The comfortable conditions for animals make it possible their longevity and high milk production creating. Currently, there is the planet’s temperature increasing that affects animals’ negatively, leading to their health and production deterioration. Microclimate control and regulation can be provided with specialized materials and modern equipment helping. Artificial ventilation including supply, exhaust and a control system, minimizes the influence of human factor on indoor microclimate parameters maintaining. Temperature, humidity and ventilation indicators are important for comfortable conditions ensuring. The automated controller contributes to more efficient operation’s system, errors’ risk reducing and regulation’s accuracy increasing. The aim of this study was outgoing airflow velocity calculate methodology developing and automated system’s pipe pressure at cattle thermal stress reducing. Computer designing and data processing programs (Compass-3D and Microsoft Office) were used. This study results allow to determine the air flow rate at the time of duct’s exit from air pipe (0,475 m/s) and pressure changing in duct’s various sections from 34,15 Pa till 17,95 Pa (up to 52,56% of initial pressure). The study is important for animals’ keeping comfortable conditions ensuring and heat stress reducing, that in turn contributes to livestock production and health improving.

Влияние заполнения прослоек малотеплопроводными газами на тепловую защиту оконных блоков с экранами

ISPU scientists have developed energy-saving constructions of window units with heat-reflecting screens, have tested them in a climate chamber, and have carried out simulation modeling of the heat transfer process through these constructions. Despite a large number of scientific papers that consider experimental laboratory studies and numerical simulation of heat transfer processes through translucent constructions, there is no data on the effect of the application of low thermal conductivity gases in the gaps formed by glass and metal elements on increasing the thermal protection of window units with screens. The correct calculation of the reduced heat transfer resistance of window units with screens and low-thermal conductivity gases affects the correctness of the heat balance for premises and, consequently, the quality of the design of energy systems to ensure the indoor microclimate. Thus, the development of models of heat transfer process through a window unit with screens is an urgent task to ensure the indoor microclimate. Simulation numerical modeling is carried out using the finite element method based on the fundamental laws of heat transfer. The authors have developed a two-dimensional simulation model of heat transfer through a window unit with heat-reflecting screens, in which the gaps between the glass and aluminum foil are filled with argon and krypton. The distribution of resistance to heat transfer along the height of a translucent enclosing structure has been studied. The adequacy of the proposed simulation model is confirmed by comparison with data of other scientists and regulatory documentation. Filling the gaps between glass and metal foil with argon makes it possible to increase the zonal heat transfer resistance of a window unit with screens in relation to the base-case scenario (air) by 6–23 %, krypton by 8–58 % (depending on the measurement location and the number of screens). The application of the developed simulation model will make it possible to more accurately determine the potential to use heat-reflecting screens in windows for intermittent heating systems of buildings.

Characteristics, source, and health risk assessment of aerosol polyaromatic hydrocarbons in the rural and urban regions of western Saudi Arabia

Abstract Air quality represents one of the most important parameters determining indoor microclimate and human comfort. Thus, the current study reports a comprehensive study on the dominant sources, organic compositions, and potential health impacts of the polyaromatic hydrocarbons (PAHs) in the atmospheric particle matters (PMs) ranging from 2.5 µm (PM2.5) to 10 µm (PM10) size in the rural and urban regions of western (Jeddah city) Saudi Arabia collected over 1 year between 2014 and 2015. The levels of PAHs in two locations namely Obhur (Urban) and Hada Alsham (Rural) were monitored over 1 year (2014 and 2015) using the gas chromatography coupled mass spectrometry. The level of ƩPAHs in Obhur (819.25 ng/m3) has a significantly high concentration of PAHs compared to Hada Alsham (Rural) (675.26 ng/m3). Indeno(1,2,3-CD)pyrene was the major contributor with an average value of 215.66 ng/m3 followed by benzo[k]fluranthene with a concentration of 150.68 ng/m3, respectively. The major contributors were indeno[1,2,3-cd]pyrene, benzo[k]fluranthene, dibenzo[a,h]anthracene, benzo[g,h]perylene, and benzo[b]fluranthene are the major contributors with contributing percentages of 26.32, 18.39, 9.07, and 8.29%, respectively. The rest of all compounds were below 4%. The highest concentrations of PAHs in Obhur (1836.99 ng/m3) and in Hada Alsham (1107.40 ng/m3) were observed in winter in January 2014. PAHs with 4–6 aromatic ring components are primarily emitted by high temperature combustion. The average values for the BaA/(BaA + Chr) and Flt/(Flt + Pyr) ratios at Obhur were found 0.58 and 0.43 and at Hada Alsham were found 0.63 and 0.38, respectively, indicating that coal/biomass burning is the major source of PAHs. Hada Alsham (rural area), the transportation system, is a significant contributor to the observed PAHs. These results reflect Saudi Arabia’s traffic load in both rural and urban areas. On road sites, the impact of petroleum combustion and vehicular emissions was also identified. The sum of the incremental lifetime cancer risk (ILCR) for all congeners for infants along the Obhur location was 2.13 × 10−6 and 1.38 × 10−6, respectively. ILCR values were less than 1.0 × 10−4, implying that PAH exposure posed an acceptable potential cancer risk in this study. Various local emission sources contributed more PAHs in many Saudi urban areas, increasing the risk of lung cancer, and the health risk. PAHs have an associated large surface area and are capable of deposition in the respiratory system with high efficiency. The total health risk assessment study also helps in alarming the toxicity at both the locations.

Characteristics, source, and health risk assessment of aerosol polyaromatic hydrocarbons in the rural and urban regions of western Saudi Arabia

Abstract Air quality represents one of the most important parameters determining indoor microclimate and human comfort. Thus, the current study reports a comprehensive study on the dominant sources, organic compositions, and potential health impacts of the polyaromatic hydrocarbons (PAHs) in the atmospheric particle matters (PMs) ranging from 2.5 µm (PM2.5) to 10 µm (PM10) size in the rural and urban regions of western (Jeddah city) Saudi Arabia collected over 1 year between 2014 and 2015. The levels of PAHs in two locations namely Obhur (Urban) and Hada Alsham (Rural) were monitored over 1 year (2014 and 2015) using the gas chromatography coupled mass spectrometry. The level of ƩPAHs in Obhur (819.25 ng/m3) has a significantly high concentration of PAHs compared to Hada Alsham (Rural) (675.26 ng/m3). Indeno(1,2,3-CD)pyrene was the major contributor with an average value of 215.66 ng/m3 followed by benzo[k]fluranthene with a concentration of 150.68 ng/m3, respectively. The major contributors were indeno[1,2,3-cd]pyrene, benzo[k]fluranthene, dibenzo[a,h]anthracene, benzo[g,h]perylene, and benzo[b]fluranthene are the major contributors with contributing percentages of 26.32, 18.39, 9.07, and 8.29%, respectively. The rest of all compounds were below 4%. The highest concentrations of PAHs in Obhur (1836.99 ng/m3) and in Hada Alsham (1107.40 ng/m3) were observed in winter in January 2014. PAHs with 4–6 aromatic ring components are primarily emitted by high temperature combustion. The average values for the BaA/(BaA + Chr) and Flt/(Flt + Pyr) ratios at Obhur were found 0.58 and 0.43 and at Hada Alsham were found 0.63 and 0.38, respectively, indicating that coal/biomass burning is the major source of PAHs. Hada Alsham (rural area), the transportation system, is a significant contributor to the observed PAHs. These results reflect Saudi Arabia’s traffic load in both rural and urban areas. On road sites, the impact of petroleum combustion and vehicular emissions was also identified. The sum of the incremental lifetime cancer risk (ILCR) for all congeners for infants along the Obhur location was 2.13 × 10−6 and 1.38 × 10−6, respectively. ILCR values were less than 1.0 × 10−4, implying that PAH exposure posed an acceptable potential cancer risk in this study. Various local emission sources contributed more PAHs in many Saudi urban areas, increasing the risk of lung cancer, and the health risk. PAHs have an associated large surface area and are capable of deposition in the respiratory system with high efficiency. The total health risk assessment study also helps in alarming the toxicity at both the locations.