indoor air quality

Chile has 1,626 social housing complexes with a total of 350,880 dwellings. Several studies have demonstrated a low thermal performance and high air permeability of the envelope of social houses throughout the country, causing surface condensation on walls, high heat losses in winter and low levels of thermal comfort for their occupants. The presence of high levels of indoor pollutants and/or indoor humidity has also been observed, causing respiratory and cardiovascular diseases in the occupants.

Mass gathering events were closed in 2020 to reduce the spread of SARS-CoV-2. These events included music concerts, theatre shows, and sports matches. It is known, however, that the long-range aerosol transmission of pathogens, such as SARS-CoV-2, can be reduced with sufficient ventilation indoors. This paper examines the risk of reopening these mass gathering events by measuring the CO2 concentration, as a proxy for ventilation effectiveness, at 58 events, with a specific focus on small enclosed spaces with short occupancy.

With many existing Austrian school buildings to be renovated in the coming years, there are debates between stakeholders, about which ventilation strategy to pursue in existing schools. Therefore, different intervention strategies such as retrofitting ventilation systems, installing CO₂-monitoring signals, or raising awareness among teachers and students should be evaluated. This paper presents the preliminary results of the project “DIGIdat” on air quality measurements in the first quarter of 2023.

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.