Mariya Bivolarova

• Master of Engineering
• Assistant Professor at Technical University of Denmark

The availability of systems that can locally adjust environmental parameters holds the potential to enhance building occupant satisfaction by considering individual sensitivities, expectations, and needs. To this aim, Personalised Environmental Control Systems (PECS) are being studied as solutions that can provide individually controlled environmen...

The availability of systems that can locally adjust environmental parameters holds the potential to enhance building occupant satisfaction by considering individual sensitivities, expectations, and needs. To this aim, Personalised Environmental Control Systems (PECS) are being studied as solutions that can provide individually controlled environmen...

This study aimed to explore an alternative solution for protection against cross-infection. Exposure reduction to exhaled airborne contaminants by wearing an exhaust nozzle was studied. Experiments were performed in a full-scale test room (64.8 m³) equipped with a small section of a stadium tribune with six seats. Two breathing thermal manikins and...

The ongoing project 'Bedroom Ventilation and Sleep Quality' investigates the effects of bedroom ventilation on sleep quality and next-day cognitive performance. As part of the project, 84 bedrooms in the Greater Copenhagen area of Denmark were inspected during the 2020 heating season. In the first week, participants slept under environmental condit...

Indoor Air Quality (IAQ) and sleep quality measurements over a period of two weeks were performed all night in 40 bedrooms in Denmark during the heating season. In the first week, the bedroom conditions were typical of what participants would normally experience during sleep. In the second week, the participants were asked to open the doors or wind...

Parameters describing the bedroom environment and sleep quality were measured overnight for one week in 84 randomly selected actual bedrooms in Denmark from September to December 2020. The median age of participants was 26 years (interquartile range (IQR) (Laverge et al., 2015; Fan et al., 2021; Berglund et al., 1999; Zhang et al., 2016; Bjorvatn e...

The impact of the supplied airflow rate on the distribution and exposure of exhaled airborne pathogens in a room with mixing ventilation was studied. Experiments were conducted in a field laboratory at three supply airflow rates: 20, 40, 60 L/s. Two breathing thermal manikins were used to resemble infected and susceptible occupants. Nitrous oxide (...

The objective of this study was to investigate the importance of room air distribution in airborne cross-infection. Tracer gas measurements were performed in a field lab arranged as an office with two breathing thermal manikins. The room was ventilated with a mixing air distribution operating at a constant supply airflow rate of 60 L/s (4 ACH) unde...

Indoor climate standards recommend maximum CO2 concentration levels in rooms. At present the CO2 exposure of occupants is assessed by measurements in a room's exhaust air or near the walls. However, most often room air is not perfectly mixed and CO2 emitted in air exhaled by occupants is non-uniformly distributed. It is more reliable to assess CO2...

Ten healthy young adults slept one by one in a specially designed and constructed sleep capsule located in a climate chamber at two temperatures (24 and 28 °C) and two ventilation rates that ensured that the resulting CO2 concentrations were 800 and 1700 ppm. Subjectively rated sleep quality was reduced at 28 °C and reduced ventilation, while sleep...

Poor air quality has been shown to reduce sleep quality. There is a limited number of studies reporting how occupants rate the air quality in their bedrooms. The present study sheds the light on this issue. It was conducted in actual bedrooms and asked occupants to rate air quality once awake in the morning using an online sleep diary. The study wa...

We performed a survey of the types of bedroom ventilation in Danish dwellings (January–February 2020) and the associated subjective sleep quality. Five hundred and seventeen people responded. Their median age was 33 years old and 55.4% of them were males. We used an online questionnaire and collected information on the type of bedroom ventilation,...

Numerous studies on ventilation of general patient rooms have been performed, while most of the studies have focused on total volume air distribution (mixing or displacement). This study presents results of local ventilation (LV) aimed to efficiently protect a lying person from cross-infection due to airborne respiratory viruses. Experiments perfor...

Current paper presents information, obtained by a human subjects experiment, about the impact of CO2 concentration in the inhaled air on the CO2 emission rate by people. Thirty subjects, 15 females and 15 males, participated in the experiment. All subjects, feeling thermally neutral at 26 o C, were exposed in a small chamber under perfect mixing co...

Indoor carbon dioxide (CO2) concentration (c-n) is measured in buildings for the assessment and control of the air quality. The indoor CO2 c-n, measured at only one location in the room-either in the exhaust room air or at one of the walls, is considered the same as the concentration in the inhaled air and is used for ventilation control. The main...

CO2 is used as a marker for exposure to indoor pollution. CO2 concentration measured in the air exhausted from the room or near the walls is used to estimate the CO2 exposure as well as to control supplied ventilation rate. However, research reveals that the CO2 concentration in the inhaled air can be more than 30% higher than the concentration mea...

In the current practice CO2 is used as an indicator of exposure to indoor pollutants. Complete mixing of room air is assumed with mixing air distribution. Under this assumption, the representative CO2 concentration used to assess the indoor air quality and/or to control the ventilation system is measured in the exhaust air or on the walls. However,...

It has been reported that CO2 concentration in the inhaled air may have negative impact on performance of occupants. The limits for inhaled CO2 concentration are specified in some building regulations. In the current practice, CO2 concentration measured in the exhaust or at the walls is used to assess the CO2 exposure. However, the CO2 exposure is...

Bedroom ventilation is crucial for providing good indoor air quality, which may contribute to achieving undisturbed sleep. This study presents a detailed characterization of bedroom carbon dioxide (CO2) profiles and ventilation during the heating season in Denmark. The measurements were made in a naturally ventilated (NV) semi-detached house, equip...

Three novel air terminal devices (ATDs) for localized ventilation were designed (ATD with perforated inner plate, ATD with honeycomb diffuser, and ATD with lobbed nozzle). The ability of the ATDs to provide clean air to the breathing zone of a person lying in a hospital bed was studied. Experiments were performed in a simulated full-scale hospital...

Good sleep is essential for our health and daytime functioning; seven to nine hours of sleep each night are recommended for people age 18 to 64.(1,2) Noise, light, temperature and air quality affect our sleep. However, very few regulations address indoor air quality (IAQ) in bedrooms, and even fewer studies examine the relationship between sleep qu...

Sleep is essential for our health and well-being. Some research suggests that air quality influences sleep quality in bedrooms, but the evidence is limited. Research, until now, has focused on how indoor air quality affects health, comfort, and cognitive performance during waking hours. Less information is available on the levels of indoor air qual...

Dataset in Matlab Format

A particle exposure experiment inside a large climate‐controlled chamber was conducted. Data on spatial and temporal distribution of nanoscale and fine aerosols in the range of mobility diameters 8 – 600 nm were collected with high resolution, for sodium chloride, fluorescein sodium and silica particles. Exposure scenarios studied, included constan...

Proper sleep is of a big importance considering that people spend one third of their lives sleeping. Thermal conditions and indoor air quality have an impact on sleep and thus must be optimized and controlled to enhance sleep quality. However, changing the thermal environment in the whole bedroom is not efficient, because of unnecessary use of ener...

The accurate data of outdoor CO 2 concentration are important for the proper design of ventilation and thus for indoor air quality and energy use in buildings. Typical design practice is to assume outdoor CO 2 concentration to be 400 ppm. However, the outdoor CO 2 concentration may be different in different areas of cities. This paper presents prel...

An easy method to passively control the bed micro-environment and thus thermal comfort of people is to use a cover with appropriate thermal insulation. The purpose of this study was to find out the potential of generating uniform and non-uniform bed thermal micro-environment with quilts. The effect of the thermal resistance of quilts on the tempera...

CFD simulations were performed to investigate occupants’ exposure to metabolic CO 2 in a room with mechanical ventilation. A meeting room occupied by six adult people performing sedentary activity was simulated. Five of the six occupants were simulated to exhale air with realistic CO 2 content, while one occupant was inhaling, i.e. the exposed occu...

The impact of airflow interaction on air temperature and velocity measured at the breathing zone (BZ) of a seated person was studied. A breathing thermal manikin was used to resemble the flow of breathing and the free convection flow (FCF) around the human body. Personalized ventilation (PV) supplied flow from front against the face of the manikin...

Room airflow interaction, particularly in the breathing zone, is important to assess exposure to indoor air pollution. A breathing thermal manikin was used to simulate a room occupant with the convective boundary layer (CBL) generated around the body and the respiratory flow. Local airflow against the face of the manikin was applied to increase the...

The influence of the complex interaction of three airflows - breathing flow, convective flow around the human body and ventilation flow directed against the face - on the exposure to dermally-emitted effluents from a person's own body was examined together with the effects of source location and control. A breathing thermal manikin was used to simu...

The study investigated the separate and combined effects of ventilation rate, free convection flow produced by a thermal manikin, and the presence of objects on the distribution of tracer gas and particles in indoor air. The concentration of aerosol particles and tracer gas was measured in a test room with mixing ventilation. Three layouts were arr...

The performance of a ventilated mattress (VM) used as a bed-integrated local exhaust ventilation system combined with air cleaning fabric (acid-treated activated carbon fibre (ACF) fabric) was developed and studied. The separate and combined effect of the VM and the local air cleaning for reducing the exposure to body generated bio-effluents in a h...

Understanding the multitude of factors that control pulmonary deposition is important in assessing the therapeutic or toxic effects of inhaled particles. The use of increasingly sophisticated in silico models has improved our overall understanding, but model realism remains elusive. In this work, we use Large Eddy Simulations (LES) to investigate t...

A new method for minimizing the spread of bioeffluents emitted from hospitalized patients lying in beds was developed and studied. The method consists of a ventilated bed mattress that is able to exhaust the human bioeffluents at the area of the body where generated before spreading around in room. Full-scale experiments were conducted in a climate...

This study presents a novel method for advanced ventilation of hospital wards leading to improved air quality at reduced ventilation rate. The idea is to evacuate the bio-effluents generated from patients’ body by local exhaustion before being spread in the room. This concept was realized by using a mattress having a suction opening from which bio-...

A comparative study about the removability of ammonia gas in the air by activated carbon fiber (ACF) felt chemically treated with acid and a cotton fabric processed with iron phthalocyanine with copper (Cu) was performed in small-scale experiments. The test rig consisted of a heated plate and its purpose was to simulate surface body temperature of...

Unpleasant odor is a serious problem in hospitals and elderly facilities. One of the unpleasant odors is ammonia originating from human urine and sweat. The air cleaning efficiency of porous activated carbon fiber fabric which has been treated with acid, and porous activated carbon fiber fabric was evaluated as deodorant materials neutralising ammo...