Dusan Licina

École Polytechnique Fédérale de Lausanne | EPFL · School of Architecture, Civil and Environmental Engineering

This study aims to characterize human convective boundary layer (CBL) in a quiescent indoor environment. The study has two objectives: first, to characterize the velocity field around the thermal manikin under two ambient temperatures and body postures; and secondly, the influence of clothing insulation/design, chair design, table positioning and s...

Unlabelled: The effects of the human convective boundary layer (CBL), room airflow patterns, and their velocities on personal exposure are examined. Two pollutants are studied which simulate particles released from the feet and generated at distances of 2 and 3 m by a human cough. A thermal manikin whose body shape, size, and surface temperatures...

Premature infants in neonatal intensive care units (NICUs) have underdeveloped immune systems, making them susceptible to adverse health consequences from air pollutant exposure. Little is known about the sources of indoor airborne particles that contribute to the exposure of premature infants in the NICU environment. In this study, we monitored th...

Inhalation exposure to elevated particulate matter levels is correlated with deleterious health and well-being outcomes. Despite growing evidence that identifies humans as sources of coarse airborne particles, the extent to which personal exposures are influenced by particle releases near occupants is unknown. In a controlled chamber, we monitored...

Strong evidence suggests that clothing serves as a reservoir of chemical pollutants and particles, including bioaerosols, which may have health significance. However, little is known about the role that clothing may play as a transport vector for inhaled airborne particles. Here we contribute toward bridging the knowledge gap by conducting experime...

Personal care products (PCPs) contain diverse volatile organic compounds (VOCs) and routine use of PCPs indoors has important implications for indoor air quality and human chemical exposures. This chamber study deployed aerosol instrumentation and two online mass spectrometers to quantify VOC emissions from the indoor use of five fragranced PCPs an...

Natural ventilation (NV) presents an attractive solution for achieving high energy performance and indoor environmental quality (IEQ). Yet, dusty outdoor air poses a threat to building occupants. Our study of a low-energy, high-IEQ office building in the Mediterranean region revealed indoor particulate levels that met WHO standards, even amidst dus...

Nanocluster aerosols (NCAs, <3 nm particles) are associated with climate feedbacks and potentially with human health. Our recent study revealed NCA formation owing to the reaction of ozone with human surfaces. However, the underlying mechanisms driving NCA emissions remain unexplored. Squalene is the most abundant compound in human skin lipids that...

Radon, a naturally occurring radioactive gas, poses a significant health risk by accumulating in buildings and potentially leading to lung cancer. Depending on building construction and geographical location, radon levels can vary substantially both within individual buildings and between different buildings. While previous studies have primarily f...

Humans are the primary sources of CO2 and NH3 indoors. Their emission rates may be influenced by human physiological and psychological status. This study investigated the impact of physiological and psychological engagements on the human emissions of CO2 and NH3. In a climate chamber, we measured CO2 and NH3 emissions from participants performing p...

The fundamental goal of building ventilation is to provide indoor conditions conducive to occupant health with low energy use. However, given the dynamic interplay of indoor and outdoor environmental conditions, there is limited knowledge on benchmarking human health and energy performance in relation to different ventilation systems. We coupled ou...

Naturally ventilated (NV) buildings, when well designed and operated, can provide adequate indoor environmental quality (IEQ) while reducing the building energy demand. However, in dusty outdoor air, this ventilation technique may increase the penetration of outdoor particulate matter (PM) indoors, leading to adverse health effects. Given the incre...

As the world’s population grows in cities, urban dwellers spend a large amount of time inside their home, making housing health ever more important. Critical for residents’ health, the interactions between indoor residential environments and outdoor environmental conditions (e.g. air pollution, noise, heat) are mediated by the controversial and evo...

Modern health and productivity concerns related to air pollutant exposure in buildings have sparked the need for occupant-centric monitoring and ventilation control. The existing personal exposure monitoring is often restricted to stationary air quality sensors and static occupancy. This study aims to identify optimal stationary sensor placement th...

People are exposed to myriad of airborne pollutants in their homes. Owing to diverse potential sources of air pollution and human activity patterns, accurate assessment of residential exposures is complex. In this study, we explored the relationship between personal and stationary air pollutant measurements in residences of 37 participants working...

Bioaerosols are emitted from various sources into the indoor environment and can positively and negatively impact human health. Humans are the major source of bioaerosol emissions indoors, specifically for bacteria. However, efficient sampling to guarantee successful downstream analyses can be challenging due to the relatively low bioaerosol concen...

Residential ventilative cooling via natural ventilation is influenced by outdoor air pollution. However, relative to climate, outdoor air pollution is not comprehensively considered in determining the ventilative cooling potential of buildings. To assess the impact of outdoor air pollution on ventilative cooling potential, we coupled a longitudinal...

Personal cloud, termed as the difference in air pollutant concentrations between breathing zone and room sites, represents the bias in approximating personal inhalation exposure that is linked to accuracy of health risk assessment. This study performed a two-week field experiment in a naturally ventilated office during the COVID-19 pandemic to asse...

Background Modern health concerns related to air pollutant exposure in buildings have been exacerbated owing to several factors. Methods for assessing inhalation exposures indoors have been restricted to stationary air pollution measurements, typically assuming steady-state conditions. Objective We aimed to examine the feasibility of several proxy...

Occupants play a key role in determining final building energy consumption. Empirical evidence must support occupants' modelling. Experiments on human responses to Indoor Environmental Quality (IEQ) are usually performed in test rooms or as in-field monitoring. Between these two approaches, living laboratories, often abbreviated as living labs, rep...

Cities today encounter significant challenges pertaining to urbanization and population growth, resource availability, and climate change. Concurrently, unparalleled datasets are generated through Internet of Things (IoT) sensing implemented at urban, building, and personal scales that serve as a potential tool for understanding and overcoming thes...

Healthy building design is an emerging field of architecture and building engineering. Indoor air quality (IAQ) is an inevitable factor that should be considered in healthy building design due to its demonstrated links with human health and well-being. This paper proposes to integrate IAQ prediction into healthy building design by developing a simu...

Human inhalation exposure to fine particulate matter (PM2.5), including the PM2.5 of outdoor origin, predominantly occurs indoors. To limit outdoor PM2.5 penetration into buildings, ventilation standards often require the filtration of outdoor air with a minimum efficiency. Nevertheless, the PM2.5 filter selection recommended by the standards is ba...

Humanitarian tents provide emergency shelter for people displaced by conflict and disaster in diverse climatic conditions. This article compares the thermal performance of two standard humanitarian tents – the Standard Family Tent (SFT) and the Geodesic Family Tent (GFT). The SFT is the most widely used humanitarian shelter, while the GFT was recen...

Elevated exposure to indoor air pollution is associated with negative human health and well-being outcomes. Inhalation exposure studies commonly rely on stationary monitors in combination with human time-activity patterns; however, this method is susceptible to exposure misclassification. We tracked ten participants during five consecutive workdays...

Although indoor environmental quality (IEQ) and human health have been on the agenda of the green building industry, a new emphasis is being placed on building features that explicitly promote the experience of occupants. However, evidence of the performance of green-certified buildings from the occupant perspective remains inconsistent, with numer...

Defining indoor environmental conditions that meet the needs and preferences of occupants in open space offices can be challenging since the same space might be occupied by people with different individual needs and preferences regarding what constitutes a comfortable work environment. This study presents outcomes of a set of longitudinal point-in-...

Nanocluster aerosols (NCAs, particles <3 nm) are important players in driving climate feedbacks and processes that impact human health. This study reports, for the first time, NCA formation when gas-phase ozone reacts with human surfaces. In an occupied climate-controlled chamber, we detected NCA only when ozone was present. NCA emissions were depe...

Occupants’ comfort perception affects building energy consumptions. To improve the understanding of human comfort, which is crucial to reduce energy demand, laboratory experiments with humans in controlled environments (test rooms) are fundamental, but their potential also depends on the characteristic of each research facility. Nowadays, there is...

Air pollutant exposure in workplace environments has been associated with health and cognitive outcomes of workers. While green building certification programs have been instrumental in promoting indoor air quality (IAQ), the present literature indicates inconsistent evidence. Recent emergence and proliferation of WELL certification program that pr...

There is growing evidence that the clothing is an important source of exposure to various chemicals and particles on a daily basis. Emerging knowledge suggests that everyday clothing harbors various contaminants, which if inhaled, ingested, or dermally absorbed, could carry significant health risks. This chapter summarizes the state of the most rec...

Recent green building certification programs have put a strong emphasis on occupant health and well-being. For recently emerged WELL certification, we lack evidence about its effectiveness in relation to occupant satisfaction, productivity and health. Here, we compared the results of occupant satisfaction with the indoor environmental quality (IEQ)...

The fundamental goal of modern high-performance buildings is to achieve low environmental carbon footprint while securing indoor conditions that promote human health and well-being. Current procedures for indoor environmental quality (IEQ) assessment are often sporadic, expensive, intrusive and often limited to few parameters and experts-use only....

Particle release from human skin and clothing has been identified as an important contributor to particulate matter burden indoors. However, knowledge about modeling the coarse particle release from skin and clothing is limited. This study developed a new empirically validated CFD modeling methodology for particle release and transport from seated...

Human emissions of fluorescent aerosol particles (FAPs) can influence the biological burden of indoor air. Yet, quantification of FAP emissions from human beings remains limited, along with a poor understanding of the underlying emission mechanisms. To reduce the knowledge gap, we characterized human emissions of size-segregated FAPs (1-10 μm) and...

Recent technological advancements have enabled the development and deployment of low-cost consumer grade monitors for ubiquitous and time-resolved indoor air quality monitoring. With their reliable performance, this technology could be instrumental in enhancing automatic controls and human decision making. We conducted a comprehensive performance e...

The presence of growing fungi in the indoor environment has been associated with the development of respiratory problems such as asthma or allergic rhinitis, as well as the worsening of respiratory pathologies. Their proliferation indoors could be a result of water leakage or inadequate ventilation. Although the factors promoting mould growth have...

With the gradual reduction of emissions from building products, emissions from human occupants become more dominant indoors. The impact of human emissions on indoor air quality is inadequately understood. The aim of the Indoor Chemical Human Emissions and Reactivity (ICHEAR) project was to examine the impact on indoor air chemistry of whole‐body, e...

Since the inception of the first green certification scheme several decades ago, expectations for high-performance buildings have been evolving [...]

A significant corpus of research has shown that occupant behaviour is a key factor of uncertainty when predicting building energy use. Building occupants affect energy use directly and indirectly by regulating their indoor environment according to their comfort criteria and a wide range of contextual, psychological or social factors. Increasing res...

Exposure to elevated levels of certain volatile organic compounds (VOCs) in households has been linked to deleterious health effects. This study presents the first large‐scale investigation of VOC levels in 169 energy‐efficient dwellings in Switzerland. Through a combination of physical measurements and questionnaire surveys, we investigated the in...

As part of more stringent energy targets in Switzerland, we witness the appearance of new green-certified dwellings while many existing dwellings have undergone energy efficiency measures. These measures have led to reduced energy consumption, but rarely consider their impact on indoor air quality. Consequently, such energy renovation actions can l...

People spend a substantial amount of daily time in vehicle environments being exposed to variety of airborne chemicals. High concentrations of volatile organic compounds (VOCs) inside vehicle cabins have been of increasing concern owing to various health risks. Yet, there is a limited knowledge and data about VOC emissions from interior vehicular m...

We performed the first large-scale investigation of indoor air quality (IAQ), energy and occupant behavior and satisfaction, in 650 energy-efficient dwellings in western Switzerland. The investigation included comparative assessment of 217 green-certified Minergie (M) and 433 energy-renovated (R) dwellings. Data were collected through a combination...

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Inhalation exposure to pure and metabolic elevated carbon dioxide (CO2) concentration has been associated with impaired work performance, lower perceived air quality, and increased health symptoms. In this study, the concentration of metabolic CO2 was continuously measured in the inhalation zone of 41 subjects performing simulated office work. The...

Wildfires and associated emissions of particulate matter pose significant environmental and health concerns. In this study we propose tools to evaluate building resilience to extreme episodes of outdoor particulate matter using a combination of indoor and outdoor IoT measurements, coupled with survey-based information of occupants’ perception and b...

A growing body of evidence identifies clothing as an important mediator of human exposure to chemicals and particles, which may have public health significance. This paper reviews and critically assesses the state of knowledge regarding how clothing, during wear, influences exposure to molecular chemicals, abiotic particles, and biotic particles, i...

Expectations for high performance green buildings have been evolving over the last four decades. Green certification systems define, recognize, and demonstrate leadership in addressing building problems related to people and the environment. These systems are premised on a theory of change where making the distribution in building performance visib...

Elevated exposure to airborne particulate matter is linked to deleterious health and well-being outcomes. Exposure assessment can be improved through enhanced understanding of source-receptor relationships, for example as expressed in the inhalation intake fraction metric. This study provides new knowledge about how inhalation intake of airborne pa...

Infants in neonatal intensive care units (NICUs) are vulnerable to environmental stressors. Few studies have reported on airborne particles in the NICU environment. During a four-day pilot study in a private-style NICU, we measured size-resolved particle number (PN) concentrations with 1-min resolution. The investigation included simultaneous sampl...

Particle number and CO2 data acquisition success rate in the hallway and across all baby rooms. The data yield also includes recordings from the nurses’ station and during the HVAC system maintenance that were not included in Table 1. (TIF)

Comparison of the real-time 1-h mean concentrations of size-resolved particles in the (a) baby room and the nurses’ station; and (b) baby room and the hallway. Time series are shown for 10 sampling days that correspond to B3. The solid line designates particle levels in the baby room, while the shaded area illustrates concentrations at the nurses’...

Time series (at 5-min resolution) of temperature, relative humidity, TPN and PM10 in a baby room, showing influence of the HVAC filtration system maintenance. These results are based on an analysis of data from 11 February, when filter change-out procedure began at 6:00 AM and lasted for 2.9 hours, as delimited by vertical dashed lines. (TIF)

Nurses’ station and HVAC filter maintenance. (DOCX)

Comparison of individual contributions to the total particle number concentration (TPN) in the baby rooms from three sources: Indoor (within-room) emissions, indoor (near-room) emissions, and outdoors. Individual source contributions to the total TPN were calculated in the same fashion as explained in relation to Fig 6. (TIF)

Adjustment factors obtained from optical particle counter (OPC) side-by-side tests with a reference instrument OPC3.1 (DOCX)

Size-resolved particle number concentrations measured in the baby rooms and hallway. The results include data from nurses’ station (for B1, B2 and the first week of B3) and HVAC filter maintenance (no post-processing). (DOCX)

Coefficient of determination for the linear correlation between concentrations in two simultaneously sampled baby rooms (B10 and B11) for a nine-day period. The results include 5-min means of small (0.3–0.5 μm) and large (>10 μm) particle number concentrations, and CO2 levels. (TIF)

This study investigates the ability of human convective boundary layer (CBL) to transport the pollution in a quiescent indoor environment. The impact of the source location in the vicinity of a human body is examined in relation to pollution distribution in the breathing zone and the thickness of the pollution boundary layer (PBL). The study, in ad...

Unlabelled: The inhalation intake fraction was used as an indicator to compare effects of desktop personalized ventilation and mixing ventilation on personal exposure to directly released simulated cough droplets. A cough machine was used to simulate cough release from the front, back, and side of a thermal manikin at distances between 1 and 4 m....

This study investigates the interaction between the human convective boundary layer (CBL) and uniform airflow with different velocity and from different directions. Human body is resembled by a thermal manikin with complex body shape and surface temperature distribution as the skin temperature of an average person. Particle image velocimetry (PIV)...

This study aims to investigate the interaction between the human convective boundary layer (CBL) and uniform airflow from two directions and with different velocities. The study has two objectives: first, to characterize the velocity field in the breathing zone of a thermal manikin under its interaction with opposing flow from above and assisting f...

In the offices of the future, human occupants will become a major heat source since the airflow generated by heat sources such as lighting and equipment will be less important due to increased use of low-powered devices. In that regard, the volume flux of the human convective boundary layer is comparable to the total ventilation flow, thus having a...

This study investigates the potential for energy and water sustainability in hot and humid climates by utilizing the condensate captured from large dedicated air handling units (AHUs) for pre-cooling outdoor air in another AHU and subsequently offsetting cooling tower water needs. In such climates, latent load is large enough throughout the year to...

In tropical and subtropical regions, air-conditioning is employed throughout the year, which poses a significant challenge to the designer in reducing its energy consumption. Buildings in these regions would have latent load that is large enough throughout the whole year to produce a substantial amount of low enthalpy condensate. This free natural...

This paper presents a study on the technical feasibility of efficient/cost-effective use of relatively low temperature geothermal waters for co- and tri-generation of electricity and heat for heating and/or cooling by absorption refrigeration for building integration. As a result of global warming a need for cooling, particularly air-conditioning o...