Indoor air quality assessment in dwellings with different ventilation strategies in Nunavik and impacts on bacterial and fungal microbiota

Abstract

Indoor air quality is a major issue for public health, particularly in northern communities. In this extreme environment, adequate ventilation is crucial to provide a healthier indoor environment, especially in airtight dwellings. The main objective of the study is to assess the impact of ventilation systems and their optimization on microbial communities in bioaerosols and dust in 54 dwellings in Nunavik. Dwellings with three ventilation strategies (without mechanical ventilators, with heat recovery ventilators, and with energy recovery ventilators) were investigated before and after optimization of the ventilation systems. Indoor environmental conditions (temperature, relative humidity) and microbiological parameters (total bacteria, Aspergillus/Penicillium, endotoxin, and microbial biodiversity) were measured. Dust samples were collected in closed face cassettes with a polycarbonate filter using a micro‐vacuum while a volume of 20 m3 of bioaerosols were collected on filters using a SASS3100 (airflow of 300 L/min). In bioaerosols, the median number of copies was 4.01 × 103 copies/m3 of air for total bacteria and 1.45 × 101 copies/m3 for Aspergillus/Penicillium. Median concentrations were 5.13 × 104 copies/mg of dust, 5.07 × 101 copies/mg, 9.98 EU/mg for total bacteria, Aspergillus/Penicillium and endotoxin concentrations, respectively. The main microorganisms were associated with human occupancy such as skin‐related bacteria or yeasts, regardless of the type of ventilation.

Impact of improved indoor air quality in Nunavik homes on children’s respiratory health

“…Decreases in CO and CO 2 levels were also observed, but PM 2.5 levels were significantly reduced only for HRV group (see supplementary information). Results for microbial analyses were related to human occupancy regardless of ventilation system type 13 …”

Efficiency and sensitivity optimization of a protocol to quantify indoor airborne SARS-CoV-2 levels

“…Air quality is an important public health determinant globally. The COVID-19 outbreak has highlighted the poor knowledge we have concerning indoor air microbiota and has prompted a number of studies addressing the indoor microbiota in dwellings and public areas [ [1] , [2] , [3] , [4] ]. Such studies are expected to increase in number, to help improve the quality of, and control the infection risk of, indoor air quality.…”

An Assessment of Airborne Bacteria and Fungi in the Female Dormitory Environment: Level, Impact Factors and Dose Rate

“…To date, several studies have addressed both bacterial and fungal pollution in the air inside dwellings, and have reported concentrations of bacteria and fungi of approximately 10 2 –10 4 colony-forming units (CFU) m −3 [ 5 , 6 , 7 , 8 ]. Environment-related factors such as temperature, relative humidity (RH), ventilation, season, outdoor climate and number of occupants can affect the density and distribution of airborne microbes detected indoors [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. However, the fungi found in homes are primarily influenced by various characteristics of the homes [ 18 ].…”