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Under the influence of biological hazards including COVID-19, it is required sufficient ventilation to decrease the infection risk in the indoor area. In particular, the natural ventilation with window opening is recommended in rooms with inadequate ventilation. However, the ventilation rate, energy loss, and indoor thermal environment with window opening in air-conditioned room varies hourly with given environment. In addition, opening windows in winter causes serious problems such as deterioration of the indoor thermal environment and reduction of absolute humidity.

The ALLO project aims to be innovative in the way it approaches information and its dissemination to residents who are concerned about air quality in their home or are not familiar with the subject. In this paper, we are focusing on one important pollutant, i.e. PM2.5, on more particularly on low-cost sensors that provides PM2.5 data in rooms at short timesteps (usually 5 min.).

When designed and operated adequately, natural ventilation (NV) can improve the buildings’ energy efficiency and indoor environmental quality. There is a plethora of factors that limit the effectiveness of NV, such as the climate, surrounding buildings, noise, and ambient air pollution, especially in urban environments. Nevertheless, the existing NV potential (NVP) calculation methods are complex and difficult to be used. This study proposes a new methodology for quantifying the NVP by considering the exterior climate and ambient air pollution.

Deep Energy renovation (DER) adopts a whole building approach and achieves much larger energy savings than shallow energy renovations that typically only included a small number (one or two) of upgrade measures. DER includes the installation of high levels of insulation, uses renewable energy technologies and minimises uncontrolled air leakage by achieving air permeability levels no greater than 5 m3/h.m2 to achieve building energy ratings (BER) of at least A3.

Current building regulations are designed to ensure that buildings, including newly built and retrofitted residential dwellings, are more energy efficient. This has raised concerns and practical challenges in relation to maintaining acceptable indoor environmental and air quality. However, there are minimal data available regarding long-term indoor air pollutant concentrations in low-energy residential buildings.

There has been substantial concern about the potential for radon levels to increase in homes undergoing energy retrofits, especially those including substantial air sealing. This study evaluated if precautionary measures could curb increases in radon in over 250 homes receiving energy efficiency retrofits. The goal of these precautionary measures was not to provide full radon mitigation, but rather to avoid increases in radon following retrofit.

People spend approximately 90% of their time within indoor environments, and consequently, characterizing the chemistry of indoor air is valuable from a human health perspective. A simple-to-run indoor air chemistry model is needed as an initial screening tool for public health applications. The Simplified Indoor Air Chemistry Simulator (SIACS), which is currently in development by EPA, incorporates 78 chemical species with 211 chemical reactions and aims to fit this need.

Radon is a naturally occurring gas that is hazardous to human health, making it desirable to minimize exposure. Radon can infiltrate buildings and accumulate to concerning levels, especially in those with tight exterior envelopes and low fresh air exchange rates. Previous research has suggested that air sealing, a common tool for improving building energy efficiency, can increase indoor radon concentrations (Pigg et al. 2017).

This paper reports preliminary analysis from a large field study of 100 university classrooms in Central Texas. Lecture classrooms and auditoriums were sampled for three consecutive weekdays in the 2019 – 2020 academic year. Carbon dioxide (CO2) concentrations, used as a marker for both ventilation and exposure, and temperature were measured in the general room area and when able, the supply airstream. HVAC control data that relates to ventilation was also saved for comparison.

Ventilation and source control (e.g. using low volatile organic compound (VOC) emitting materials) are two recommended approaches to control indoor air pollution and VOC’s in particular. Decisions on how to minimize exposure can be supported by indoor air chemistry modeling, since the relationships between VOC’s, their precursors, and building ventilation is so complex. For example, modeling could be used to examine the impact of altering building ventilation.