indoor air quality

In recent years, earth-to-air heat exchanger (EAHE) systems, which is a method of pre-cooling and pre-heating outdoor air with earth-to-air heat, have been attracting attention as one of the technologies to achieve ZEB. However, at the operational phase, in order to achieve both energy saving and suppression of dew condensation control, EAHE control methods such as the timing or amount of outdoor air introduction have not been established.

Elderly people residing in nursing homes spend a vast majority of their times indoors and often in common recreation areas, to allow for socialization and interaction. Elderly people are a vulnerable age group. Hence, it is essential to provide them with good breathable air quality during these common activities and reduce cross contamination through ventilation. Prolonged exposures of elderly to contaminants may adversely affect their health, quality of life and increase medical expenditures due to frequent hospitalizations.

Most current building materials are industrially processed, resulting in increased carbon emissions. Global annual carbon emissions due to construction materials reached its peak in 2013, 9.5 gigatons of CO2 were produced. Upcoming circular economies can have a positive impact on the environment since reusing materials can lower carbon emissions. This economy encourages the use of more innovative materials (e.g., textile insulation, cellulose insulation, hemp, and cork) and recycling old materials.

The quality of indoor air in buildings depends on many factors. Some of these factors have internal sources, and some have external sources. The internal loads of the room include those generated by people: CO2 and moisture emissions from breathing, heat emissions from room equipment: volitale organic compaunds VOC. External sources are, for example, particulate matter present in the air, which is the result of emissions from cars and the burning of fossil fuels. The scientific literature states that car traffic can contribute a large share.

Nowadays, people spend most of their time indoors. Homes, offices, leisure and workplaces must meet people’s needs and provide safe, healthy and productive environments. The supply of fresh air plays an important role in achieving these goals. Not only by providing the right temperature and humidity but even more with the purity of the air inside the rooms. A recent study of the World Health Organization showed a significant correlation between yesterday’s particulate matters concentration in outdoor air and today’s death rate counting 7 million deaths in 2022 caused by air pollution.

Outdoor PM2.5 has a continuous and significant effect on the indoor environment, and lobby floors, in particular, can be exposed to high concentrations due to entrance doors and greater airflow rates than other floors. In this study, the PM2.5 indoor-to-outdoor (I/O) ratio for lobby floors was evaluated according to the operation type and configuration of entrance doors. Airflow analysis was conducted for an office building with multi-zone network simulation, and the I/O ratio was evaluated for different entrance strategies according to the occupant traffic schedule.

The predicted and measured carbon dioxide (CO2) emitted by human respiration into an occupied space has been used as an indicator for controlling buildings' ventilation rates. However, this application assumes a constant emission rate for the entire population. Conversely, new knowledge has shown that this variable depends on the number of people in the room and their sex, diet, height, and above all, body mass and metabolic rate.

We performed residential indoor fine particle (PM2.5) measurement from 26 homes and three outdoor monitoring locations. Six PM2.5-bound phthalate easters (PAEs) — including dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), butyl benzyl phthalate (BBP), di(2-ethylhexyl) phthalate (DEHP), and di-n-octyl phthalate (DnOP) — were measured using a thermal desorption-gas chromatography/mass spectrometer method. Average concentrations of summation of six PAEs (Σ6PAEs) in residential indoors (646.9 ng/m3) were slightly lower than the outdoor levels.

Since 2018, Renson has introduced a range of cloud-connected residential ventilation systems, including central and decentral mechanical extract ventilation (MEV), as well as fully mechanical systems with heat recovery (MVHR) (see Fig. 1). These systems incorporate smart control mechanisms that utilize different IAQ sensors (CO2, VOC, RH), to adjust the airflow rate(s) locally or centrally to the detected needs. The IAQ sensors are located at the control valves or at the central unit, but not within the rooms.

This manuscript discusses the energy-saving benefits of gas-phase air cleaning in Nordic buildings. Ventilation systems are crucial in creating a healthy and comfortable indoor environment. These systems account for around 30% of building heat losses in cold climate regions. Indoor emissions from materials, occupants, and outdoor pollutants are key to ensuring acceptable indoor air quality levels. Therefore, this study focuses on using gas-phase air cleaning technologies in low-energy centralized air handling units.