Housing-related determinants of lung health in Nunavik, Canada

The impact of climate change on lung health has been long established. The Inuit Nunangat region of Nunavik in Quebec, Canada has long started to face the consequences of climate change. In conjunction with the region’s existing vulnerabilities rooted in social determinants of health and historic injustices, this leads to poor lung health across Nunavik as evidenced by much higher lung disease rates than the Canadian average. This paper aims to describe the aims, objectives and methodology of a new project that has recently been launched to address these issues with specific emphasis on mould detection as well as indoor and building fabric survey: “Resilient Responses to Protect Lung Health in Nunavik” (Anirniq, 2022-2025) funded as part of the Canada-Inuit Nunangat-United Kingdom (CINUK) Arctic Research Programme

Cancer Biomarker Discovery: The Entropic Hallmark

Background: It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods. Methodology/Principal Findings: Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer. Conclusions/Significance: We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-throughput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases

Impact of room supply register location on predicted thermal comfort and IAQ

For residential forced air heating and cooling systems conventional thinking is that air supply registers should be located under exterior windows. There were good reasons for this in the past (primarily to counteract the cold downdraught from the window) but new construction standards (well-insulated walls, better glazing and air tight wall/window interface) mean that there is now less downdraught. Positioning the supply air register away from a window could have a large impact for new construction as duct lengths could be shortened (saving materials and construction time). This could also allow greater architectural freedom as the forced air system would not need to be ducted to the building perimeter. This paper presents results from experiments conducted in a new, well-constructed building to evaluate whether the supply registers can be moved away from the traditional location without impacting indoor air quality or predicted thermal comfort. The physical experiments showed that in both traditional and non-traditional placement: (1) there are minimal changes in predicted thermal comfort (a measure of thermal discomfort - vertical air temperature difference much lower than 3K), and (2) contaminant-removal effectiveness (a measure of indoor air quality) values were in the same range.Peer reviewed: YesNRC publication: Ye

Residential dual core energy recovery ventilation system for ventilation of northern housing

Abstract Heat/energy recovery ventilation systems are types of HVAC that can reduce energy consumption and improve the ventilation rate of housing in cold climates. Their performance achieved to date has been inadequate due to equipment failures (freezing of cores, noise, etc.). Freezing of cores is common in extremely cold climates. Single core HRV/ERV units are usually equipped with defrost strategies such as recirculation of exhaust stale air across the heat exchanger and back into the supply air to the house. These defrost strategies can undermine ventilation standards (ventilation rate requirement not being met during recirculation). This paper presents a rigorous investigation on the performance of dual core energy recovery system that provided a continuous ventilation rate at outdoor temperatures below -10°C without frost protection. The dual core ERV had higher apparent sensible effectiveness (up to 12% more) and apparent total effectiveness (up to 9% more) than a conventional single core ERV. It showed no sign of frost problems after four weeks of winter testing, continuously provided outdoor air without stopping to defrost, unlike the conventional single core ERV which required up to 7.5 hours defrosting per day, and also provided a higher supply air temperature (up to 3°C) to indoors with a total whole-house energy saving of 4.7%.</jats:p

Air change effectiveness with displacement ventilation in heating season

Peer reviewed: YesNRC publication: Ye

Making the case for reducing ventilation requirements through selection of low-emission materials

Most ventilation rates have not been based on pollutants emitted from building materials and furnishings. Anapproach using the existing Material Emission Database and Indoor Air Quality computer model is presented. The approach examines by how much ventilation rates can be reduced through control of indoor sources of air pollutants while still maintaining acceptable IAQ for residential settings and the consequences on indoor air contaminant concentrations of reductions in ventilation rates below current design requirements.La plupart des valeurs de taux de renouvellement d'air n'ont pas \ue9t\ue9 fond\ue9es sur les agents polluants qui sont \ue9mis par les mat\ue9riaux et les ameublements des b\ue2timents. On pr\ue9sente une m\ue9thode utilisant le mod\ue8le existant de qualit\ue9 de l'air \ue0 l'int\ue9rieur existant et de base de donn\ue9es sur les \ue9missions de substances. Dans le cadre de cette approche, on examine dans quelle mesure les taux de renouvellement d'air peuvent \ueatre r\ue9duits par le contr\uf4le des sources int\ue9rieures d'agents polluants atmosph\ue9riques tout en maintenant une QAI acceptable dans les milieux r\ue9sidentiels, ainsi que les cons\ue9quences sur les concentrations \ue0 l'int\ue9rieur des agents contaminants qu'a une r\ue9duction des taux de renouvellement d'air en de\ue7\ue0 des exigences nominales ayant cours.Peer reviewed: YesNRC publication: Ye

Residential balanced ventilation and its impacts on indoor pressure, ventilation and IAQ

Abstract This paper presents results from a project on the assessment of the indoor air quality (IAQ) benefits that might accrue from the use of a balanced ventilation system. The study compared the whole-building pressure, IAQ and ventilation performance of energy recovery ventilation (exhausting from kitchen and bathrooms) with that of exhaust-only ventilation (continuous exhaust from master bathroom). The side-by-side comparisons included various indoor mixing scenarios (no mixing, partial mixing and continuous mixing) using the NRC’s twin research houses. The side-by-side testing showed that balanced ventilation (energy recovery ventilation) was superior as a whole-house ventilation strategy, compared to unbalanced ventilation (single-point exhaust ventilation). It was superior because of the positive indoor pressure (1 to 3 Pa), higher air change rate (6% to 34%), uniform inter-zonal air flows, lower concentration of formaldehyde (by 37% to 70% in winter and 6% to 34% in summer), lower concentration of VOCs in winter (alpha-Pinene by 26% to 89% / Toluene-d8 (dTol) by 8% to 76%) and in summer (α-Pinene by 87% to 339% / Toluene-d8 by 45% to 88% / Heptane by 40% to 91% / Benzaldehyde by 35% to 406%), and as expected lower whole-house heating/cooling and ventilation energy consumption by up to 8.5%.</jats:p

Hybrid ventilation

Aussi disponible en fran\ue7ais: Ventilation hybridePeer reviewed: NoNRC publication: Ye