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In the context of energy saving, new buildings are becoming more airtight and purpose-provided, often central mechanical ventilation is required to create and sustain a healthy indoor air quality (IAQ). This policy is summed up by the well-known energy efficiency mantra “Build tight, ventilate right”.

Achieving energy-efficient dwellings has become a vital part of the global climate action plan to reduce energy usage and carbon emissions. Deep energy retrofits (DER) can help reduce residential energy use significantly. However, evidence on how DER impacts on indoor air quality (IAQ), and consequently, occupant health, is scarce. More in-depth analysis of IAQ data before and after energy retrofits is essential to understand the indoor environmental challenges of adopting energy efficiency measures.

The measurement of particulate matter (PM) in rooms has gained interest in the last decade. However, the sensors that are currently used are intended for use in still standing air and cannot be applied to ventilation ducts with a typical velocity up to a couple of meters per second. Therefore, a prototype of a measurement module for particulate matter has been developed for use in ducts of ventilation systems. To the author’s knowledge, this has not been done before.

In the residential sector, there are several indoor sources of pollutants related to activities such as cooking, cleaning and heating, besides those from occupants, building materials, finishing and furniture. Considering these sources, the kitchen appears as the space in the house that has the largest number of sources, with cooking being the most relevant source. In addition, meal preparation generates derivative processes related to cleaning utensils and the environment, in which detergents, air fresheners and other categories of cleaning products are used.

Particles generated from cooking activities are the biggest contributor to the concentration of indoor particles in most homes, and they are not easily removed without natural or mechanical ventilation. As more focus is directed on human health, kitchen range hoods have drawn increasing attention and their performance in various conditions needs to be evaluated. Consequently, in this study, we performed measurements to establish the particle capture efficiency of a kitchen range hood for various particle diameters at different exhaust flow rates.

Indoor air pollution can pose a serious threat to human health and can increase the risk of early mortality. Studies have shown that human exposure to indoor pollution is more common than to outdoor pollution, especially where people spend the majority of their time indoors at home. Heating, ventilating, and air conditioning (HVAC) systems are used in buildings to regulate internal climate to improve the comfort level for occupants. In addition, ventilation rates are often increased to maintain appropriate Indoor Air Quality (IAQ).

Building energy behaviour and indoor environmental conditions have been changing due to different external events that have been taking place at global level from 2020, from the COVID pandemic (2020-2022) to the energy crisis (mainly from the war in Ukraine from February 2022). During these events, existing naturally ventilated (NV) buildings have had to balance minimum thermal comfort, high levels of ventilation (to reduce CO2 concentration and risk of infection) and the lowest energy costs.

The world has experienced the devastating nature of airborne transmitted diseases through the COVID-19 pandemic. Significant actions were taken in order to reduce the number of new infections, such as quarantines, social distancing, mask wearing, frequent hand washing and surface disinfection. However, all these measures have proven insufficient to eradicate short and long-range infections, confirming the need for engineering tools to control the indoor air quality.

The offer of air cleaners has increased significantly since the SARS-CoV-2 pandemic. However, it is not clear to what extent they can contribute to indoor air quality. There are multiple standards that describe test methods for air cleaners, but no consensus can be found on how to determine the performance of the air cleaners.

The COVID-19 pandemic increased the awareness and importance of infectious pathogens as contaminant in the indoor air, especially for non-residential buildings with a high occupational density like schools. During the COVID-19 pandemic air cleaning is often proposed as mitigation strategy for infectious risk in these types of buildings. However, indoor air quality (IAQ) in general comprises of a large range of possible contaminants and factors that can equally impact the health, comfort and well-being of occupants.