Online & Oslo, Norway
21-23 June 2021
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Please note that all times are shown in the time zone of the conference. The current conference time is: 29th July 2021, 04:57:35am CEST
Session 15: Indoor exposure and health
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10:30am - 10:42am
Measurements of indoor air quality in schools
1Department of Energy and Process Engineering, NTNU, Kolbjørn Hejes v 1B, Trondheim, Norway; 2Department of Industrial Economics and Technology Management, NTNU, Sem Sælands vei 5, Trondheim, Norway
Children spend a minimum of six hours per day in Norwegian schools. Their exposure to different indoor air quality it is known to affect their performance. It is very common to use demand-controlled ventilation (DCV) in schools as is estimated to save about 50 % of the conventionally used energy for ventilation. CO2 and temperature are the preferred control parameters. Usually, it was expected that these human-centric controls resulted in high indoor air quality as occupants are the largest source of contaminants. This study presents measurements for two months to up to one year in the supply and room air in the four classrooms whose ventilation is CO2-based DCV. Using low-cost sensors formaldehyde, PM1, PM2.5, relative humidity CO2 and temperature were monitored.
Even when the CO2 concentration lied below 1000 ppm 1) the concentration of formaldehyde surpassed the recommended WHO thresholds in 30 % of the time and 2) RH is below 20 % during 56 % of the time.
10:42am - 10:54am
Inflammatory effects of exposure to different stone types used in Norwegian asphalt
1Department of Industrial Economics and Technology Management, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; 2Department of Occupational Medicine, St. Olav’s Hospital, Trondheim University Hospital,; 3Department of Public Health and Nursing, NTNU, Trondheim, Norway; 4Norwegian Institute of Public Health (FHI), Oslo, Norway
During the winter in Scandinavian countries, up to 90% of traffic-related particulate matter (PM) is from non-exhaust emissions sources such as asphalt wear. Measures to reduce urban PM have focused mainly on exhaust emissions, while the contribution from asphalt has received less attention. In vitro studies suggest that the composition of asphalt can affect the inflammatory potential of road dust. Using a whole-body human exposure chamber, we have explored whether different stone materials used in Norwegian asphalt impose different inflammatory reactions in plasma of healthy volunteers. Our results show no acute increases in the inflammatory markers SP-D, P- selectin, or CC16. However, quartz diorite induced an apparent increase in ICAM-1, not seen for rhomb porphyry or placebo dust (lactose). Although this did not reach statistical significance, it resembles previously observed fibrinogen-effects, and may suggest that different types of stone minerals provoke different inflammatory reactions in humans compared to placebo dust.
10:54am - 10:59am
FireDAVG – Fire related Damages with Attention to Vulnerable Groups. Guidance for vulnerable groups on handling of fire, soot, and smoke related damages in indoor environment.
The Norwegian Asthma and Allergy Association, Norway
The Norwegian Asthma and Allergy Association (NAAF) has received numerous counseling requests to assist people in vulnerable groups in relation to fire damaged homes. Some were in the process of having their homes repaired, and others reached out for help when their ailments or disease worsened after repairs had been made. Damages from fire, flue gases and soot deposits affect the indoor environment, and proper measures must be taken to repair such complex damages to ensure a healthy outcome when the home is restored.
These requests inspired the development of an online resource catalog (FireDAVG) offering neutral public advice to better prepare homeowners to take actions before, when and after a fire incidence has occurred. FireDAVG is publicly available and compiled by sourcing information and advice necessary to offer guidance to the reader. Emphasis have been made on documenting assets, construction methods, measures, and maintaining constructive dialogues between the parties.
10:59am - 11:11am
Trihalomethanes in indoor swimming pools: estimating exposure and assessing carcinogenic risk among non-competitive attendees
1Environmental Health Department, National Institute of Health, Porto, Portugal; 2EPIUnit-Instituto de Saúde Pública, Universidade do Porto, Porto, Portugal
Health risk estimation for exposure to trihalomethanes (THM) in indoor swimming pools would represent a useful tool for public health management. The aim of this study was to estimate the carcinogenic health risks from exposure to THM through multiple pathways among non-competitive swimming pool attendees.
Exposure factors of participants were collected via questionnaires and THM levels were obtained from water quality records.
According to the results of this study, chronic daily exposure for total THM considering all pathways (ingestion, dermal absorption and inhalation) for male and female participants was 5.19×10-3 and 3.15×10-3 mg/kg/day, respectively (p=0.073). Inhalation was found to be the most relevant pathway and chloroform was the compound contributing the most to total THM chronic daily exposure. The mean values of lifetime cancer risk (LCR) for total THM and through ingestion, inhalation and dermal contact was found to be higher than U.S. EPA acceptable value (1×10-6) for both genders.
11:11am - 11:16am
Oxidative stress in individuals with Building Related Intolerance after exposure to acrolein
Umeå university, Sweden
This paper addresses a possible association between exposure to the reactive indoor air pollutant, acrolein and markers of oxidative stress in individuals with building related intolerance (BRI).
Individuals with self-reported BRI (n = 21) and controls without BRI (n = 16) were exposed in an exposure chamber. Participants were exposed twice (80 min) to heptane and a mixture of heptane and acrolein at a dose below previously reported sensory irritation thresholds.
Data from previous studies points towards the importance of acrolein in relation to indoor air health. Preliminary analysis of data from an on-going study show that individuals with BRI have a significantly lower HRV and lower GSH/GSSG ratio during/after exposure to acrolein. The results indicate increased oxidative stress in individuals with BRI due to exposure to acrolein. Whether measures of oxidative stress can be used as a predictor of BRI needs to be further studied.
11:16am - 11:21am
Particle exposure of cooks in commercial kitchens
bba binnenmilieu, The Netherlands
Cooking is a major source for particulate matter exposure indoors. Especially smaller particles (<2.5 micron, PM2.5) are known to negatively affect health. Therefore a good exhaust system in a kitchen is important to reduce the exposure to fine particles. Particularly in commercial kitchens of restaurants, where cooking is a continuous activity, adequate ventilation is important to prevent the chefs and other personnel from being exposed to high particle concentrations during their workday. For this reason, we studied the influence of different exhaust systems and the influence of the preparation of different meals on the chef’s exposure to PM2.5.
The study was carried out in the laboratory of Halton (Béthune, France). During the experiments PM2.5 was measured continuously in the breathing zone of the chef, using a personal device provided with the inlet at the collar of the chef, and at two locations in the room. The influence of the type of meal (Hamburgers, Pancakes, Chinese wok) that was being prepared was tested using a canopy hood at two different settings (“high” and “low”). The influence of the type of hood (Canopy and Backshelf) was tested at a “high” and “low” setting when baking hamburgers on a grill. The measured concentrations were compared with the WHO limit for general public health (25 µg/m3) and the WELL building standard limit for commercial kitchens (35 µg/m3).
For the “high settings”, the results revealed that the concentration in the room remained low ( below 25 µg/m3 for >99% of the time) for all meals prepared. On the other hand: in the breathing zone of the chef, the WHO limit of 25 µg/m3 was exceeded 23% of the time. Peak values reached 528 µg/m³ in the breathing zone when baking pancakes, but were considerably lower when baking hamburgers (30 µg/m³) and stir frying (149 µg/m³). The highest PM concentrations were measured in the breathing zone when using the Backshelf hood without the capture jet (“low setting”, median value of 384 µg/m³).
It was concluded that both hoods were very effective in reducing the PM-concentration when used in the high setting. Still the chef was exposed to increased PM2.5 concentrations (>25µg/m³) during cooking, mainly caused by movements of the head of the chef above the stove or grill. The lower setting of both hoods reduced the efficiency significantly, thereby demonstrating the need sufficient exhaust ventilation in commercial kitchens.
11:21am - 11:26am
Downscaling from material flow analysis to indoor CFD for health risk assessment associated with DEHP exposure
1Faculty of Engineering Sciences, Kyushu University, Japan; 2Department of Architectural Design and Engineering, Yamaguchi University, Japan; 3Graduate School of Environmental Engineering, The University of Kitakyushu, Japan
INTRODUCTION: Personal exposure to indoor air pollution and consequent health impacts must be assessed for creating a healthy indoor environment; field measurement for a specific space is considered a reasonable method for determining the current situation of indoor pollution. Furthermore, the long-term and extensive health impact of indoor air pollution is also important in terms of facility management of buildings. To reveal and visualize the potential hazards of indoor pollution by chemical compounds, an integrated and continuous framework is needed for assessing the extent of pollution, from macroscopic chemical contamination to microscopic individual exposure.
METHOD: In this study, we propose a numerical method for health risk assessment that integrates inhalation exposure analysis using a computer-simulated person and computational fluid dynamics (CFD) with material flow analysis (MFA). We targeted di(2-ethylhexyl) phthalate (DEHP), for which indoor concentration guideline values (100 μg/m3) have been established in Japan. Eleven types of DEHP-containing products, for example, plasticizer, were selected and dynamic MFA in the life cycle of production, manufacturing, use, disposal, and recycling was conducted using the DEHP production data in Japan and the life function considering the product lifetime data.Based on the MFA results and statistical data in Japan, we conducted an integrated analysis of CFD and computer-simulated person for DEHP inhalation exposure using the estimation result of the total accumulation per house in Japan. In this integrated analysis, the target room was assumed to be covered with wallpaper containing DEHP. The DEHP emission rates from building materials were measured via micro-chamber method ISO 16000-25.
RESULTS: We estimated the amount of long-term domestic accumulation of DEHP by MFA. The amount of DEHP accumulated in Japan increased after the 1950s but reached a maximum value of approximately 2.7 million tons in 1997. After this peak, it decreased monotonically to approximately 1.8 million tons in 2019. This can be converted from a mass-based domestic accumulation to an area-based value, and the results indicated values of 2.3 × 109 m2 (25% of the total) for the general film sheet, 4.8 × 109 m2 (53%) for wallpaper, and 7.7 × 108 m2 (5.3%) for the floor material. As a result of the integrated analysis of CFD and computer-simulated person for a general residential house, the room averaged concentration of DEHP was estimated to be 43.3 μg/m3 under the worst-case scenarios.
11:26am - 11:38am
Thermal Comfort and Occupant Adaptive Behaviours in Naturally Ventilated Hospital Wards in a Hot-humid Post-epidemic Context
University of Cambridge, United Kingdom
Naturally conditioned hospital buildings comprise a significant part of the healthcare infrastructures in countries with the weakest public health systems. In these hospitals, unmet space-cooling demand being driven not only by the accelerating climate crisis but also by higher medical care expectations as the COVID-19 pandemic escalates could cause severe indoor overheating. To date, we lack a comprehensive understanding of human thermal adaptability in naturally ventilated inpatients facilities. Building on the complex links between thermal comfort and occupant adaptive behaviours as these unfolded in real-time in eight naturally ventilated multi-patient wards, this paper aims to explore how occupant behaviours can mitigate critical differentiation in overheating and airborne infection exposures among hospital occupants. A mixed-methods longitudinal survey, which was co-designed with health workers, was conducted with 771 hospital occupants during the rainy and dry seasons over fieldwork of nine weeks at the main tertiary hospital in a post-epidemic context. The collected dataset, which consisted of physical (7,933 hours) and subjective measurements (45,000 data) and window-opening behaviours (1,914 photos), was analysed using predictive correlations, probit regression, CFD and narrative analysis. The findings revealed that nurses directed the operation of the building-controls. Comparisons between reported and observed, individual adaptive behaviours showed that nurses drank water, visitors moved to cooler places and patients asked for help. Occupant-controlled window operation was irresponsive to outdoor and indoor environmental fluctuations with median changes between shifts standing at 0.00% (SD=2.69). Nurses were exposed to higher air velocities (t-test effect size: 0.42, 95%C.I.=0.27-0.57, p-value<0.001). Whereas severe, frequent, and prolonged night-time overheating (>4K over more than 50% of the monitoring period) was modelled according to adaptive thermal comfort indexes (ANSI/ASHRAE Standard 55:2017), daytime thermal discomfort was overestimated. Reported thermal comfort was defined by lower tolerance levels to elevated temperatures during the warm season (Top: 28.20-29.38oC) and higher relative humidity levels during the rainy season (R.H.:66.25%-67.50%) with older patients expressing higher sensitivity. Occupants' preferences for higher indoor airflows (0.90 m/s) displayed minor seasonal variation. Thermal comfort restoration among patients and visitors was strongly linked with water and food consumption (Cramer's V coefficient: 0.50-0.66, p-value<0.001). In the strictly regulated hospital environment, where physiological and behavioural adaptive capacity among patients, staff and visitors differs, and the effectiveness of natural ventilation in the dilution of airborne pollutants remains highly unstable the integration of occupant adaptive behaviours in established safe practices of healthcare can alleviate unequal vulnerabilities while strengthening climate-resilient and zero-carbon hospital operations.
11:38am - 11:43am
A method to visualize and quantify "aerosols" of outwards leakage around the perimeter of barrier masks.
Delft University of Technology
Wearing a barrier mask has become obligatory in most countries due to the surge of SARS-CoV-2. Barrier masks are designed as a preventive measure to protect people surrounding the wearer, in case the wearer is a carrier of the virus. This type of mask has been encouraged to be worn by the public over medical masks, and companies have capitalized on the public’s need to wear them to put on the market a wide range of masks.
Official guidelines exist in certain countries specifying different types of tests to be performed on masks, such as visual inspections (tears, looseness, fit, etc.), filtration, resistance material for daily wear, and filter breathing resistance. However, tests specific to the performance and leakage through the face seal perimeter of the mask or fit tests have not been specified in guidelines yet.
The aim of this study is to design a method to visualize and quantify ‘mist’ exhaled by a mask wearer, to assess the outward leakage of barrier masks.
A setup was designed by using a Styrofoam head that was carved to mimic an adult head’s respiratory cavities, and was connected to a breathing apparatus that imitates the human exhalation rate. A container with a solution of 9 parts of water to 1 of fluorescent tracing liquid acted as a chamber where the fluorescent mist was built up with the use of an ultrasonic mist maker. Ultrasonic mist makers are devices generally used to create fog for indoor humidifiers. Six UV lights were set pointing at different areas surrounding the head, and a GoPro Hero 8 camera was used to record the exhaled fluorescent mist.
Fourteen different masks were used having footage from the front and the side. The footage was recorded during 2 minute runs of exhalations, in which one picture was taken every two seconds. For the analysis, a two-step process took place: 1- background subtraction was performed with FFmpeg, in order to highlight the moving mist and eliminate the static background, and 2- the resulting images were statistically analysed, by clustering the colours (mist vs background) and producing a percentage of mist on the frame.
T-tests were performed to compare the means of the runs in order to validate the reproducibility and reliability of the method. The results show that the method is promising in quantifying and visualizing leakage, however, the surrounding conditions of the setup need to be well controlled.
11:43am - 11:48am
Analysis of workers’ tendency to answer questionnaires of positive and negative questions, along with understanding the relationship between comfort and self-efficacy
1Kogakuin University, Japan; 2Tokyo Gas Co., Ltd, Tokyo, Japan
In recent years, in Japan, the view that environmental, social, and corporate governance considerations are necessary for corporate management and growth (e.g., ESG) has become an important element in architecture, and the need to reduce environmental impact while ensuring user comfort, health, and resilience has become a necessity.
Current indices for measuring comfort include thermal environment assessment such as the predicted temperature and cold declaration PMV and standard effective temperature SET*. However, these indices are used in the steady state, and it should be noted that there are many points to be considered when these indices are used directly as an evaluation index in the non-steady state, such as the actual office space, where the spatial components are constantly changing. Therefore, it is effective to ask the workers directly to measure the comfort of the office in a realistic way.
In order to improve the comfort of the office, it is necessary to extract workers' complaints about the office environment from these backgrounds, and it is important to conduct questionnaires focusing on the psychological elements of workers, their living and working patterns, etc. in addition to measuring the physical environment elements. However, human beings sometimes unconsciously understand the intentions of others and act in response to them. Even in response to questionnaires, they are unable to collect accurate opinions, for example, they try to predict the purpose of the research and respond in the better direction. This is called a demand characteristic. It is important to take measures against the demand characteristics and to collect accurate opinions from the administrators. Therefore, this study reports the results of understanding and evaluating the physical and psychological characteristics of office workers by using several questionnaire methods, focusing on the changes in the psychological quantity of individual workers. In addition, actual measurements of the physical environment are conducted for two consecutive years and the results of the actual measurements are compared. The purpose of this study is to understand the characteristics of the change in the psychological quantity of the workers and to consider the relationship between the change and the thermal environment.
11:48am - 11:53am
Improving the indoor thermal environment with ceiling radiant terminals
1The University of South China, China, People's Republic of; 2Central South University of Forestry and Technology
A CFD (computational Fluid Dynamics) simulation model of the porous ceiling radiant air-conditioning system was established to study the influence of the ceiling temperature and envelope temperature (including the temperature of the walls and the floor of a room) on the thermal environment in the room equipped with such a system. The results showed that, for the summer condition, higher ceiling temperatures would result in higher indoor air temperature and higher Predicted Percentage Dissatisfied (PPD), which meant potential discomfort of occupants in the room. For the winter condition, however, a higher ceiling temperature within 28°C would result in a lower PPD, thus improved the thermal comfort. Considering the energy-conservation, the thermal comfort could be assured if the ceiling temperature was not more than 28°C. As for the effect of envelope temperature, the result showed that the increase in the envelope temperature during summer could result in a higher indoor air temperature, but the thermal comfort of occupants could still be ensured under such condition. Considering both the thermal comfort and the energy-conservation, a ceiling temperature of 18°C (underside surface temperature of the ceiling) and an envelope temperature between 26°C and 32°C were proved appropriate for the summer. Similarly, based on the simulation results, a ceiling temperature of 26°C, and an envelope temperature between 8°C and 11°C were found appropriate for the winter. The results indicated that for the porous ceiling radiant air-conditioning system, ceiling temperature should be controlled to increase the ratio of radiant heat transfer in the summer, and the envelope temperature should be lowered to improve the energy-conservation of the system. In the winter, the heat transfer by radiation of the porous ceiling would account for a larger ratio, therefore the system showed good heating capacity and energy-conservation performance in winter.
11:53am - 11:58am
The effect of thermal conditions during working hours on thermal perception at home – methodological considerations
1Research and teaching area Healthy Living Spaces, Institute for Occupational, Social and Environmental Medicine, Medical Faculty, RWTH Aachen, Germany; 2Department of Nutrition and Movement Sciences, Maastricht University, the Netherlands; 3Heinz Trox Wissenschafts gGmbH, Aachen, Germany
People working in public and commercial spaces are often exposed to thermal conditions that differ greatly from naturally occurring outdoor temperatures. For example, in Central and Western European summers, when outdoor temperatures rise above 30˚C, the gap between thermal conditions during daytime working hours indoors (often ~21˚C, according to ASHRAE 55 recommendations), and thermal conditions outdoors or in residential buildings, can easily be greater than 10K. Large temperature differences likely affect thermal perception when people return home after work, as most dwellings in this part of the world are naturally-ventilated (NV). Consequently, thermal conditions outside air-conditioned (AC) spaces are likely to be perceived as less comfortable and warmer in the evening after exposure to cool conditions during the daytime. In contrast, people working in NV spaces (or even outdoors) will benefit from natural acclimatization effects, and be less affected by large differences in thermal conditions during and after work. The discrepancy in thermal exposure during daytime may also have an effect on sleep quality in people working in AC vs. NV buildings.
While long-term (seasonal) and acute, short-term effects have been studied in the past, information regarding the above-mentioned medium-term effects is lacking. The present study seeks to close this gap by evaluating the effect of cool versus warm conditions in a simulated office environment, representing a workday in an AC vs. NV building, on thermal perception and sleep quality at home.
In the process of setting up the study protocol, a series of methodological questions have arisen. To achieve statistical power, a group of 40 healthy participants between the age of 18-45 will have to be recruited for the experiment. The study will consist of two parts: a simulated workday at the Aachen Work Place Simulation Laboratory, and subsequent field observations at the participant’s private homes. All participants will undergo one cool (21˚C) vs. one warm (28˚C) condition, representing an AC and an NV office day. To perform laboratory and field measurements with a group this large, within a time frame of three months (summer season), 6-7 participant measurements have to be conducted per week. Hence, aspects concerning monitoring intensity, availability of measurement tools, finances, time management, and potential confounding variables have to be balanced against each other.
Within the scope of this conference presentation, methodological considerations, and decision-making for the present study set-up will be elaborated on and discussed.
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