Indoor air quality and effect on health

Indoor air, often influenced by outdoor pollutants, can further exacerbate the effects of these pollutants, especially in environments with poor ventilation. As many individuals spend a significant portion of their time indoors, understanding the combined effects of outdoor and indoor air pollutants on metabolic pathways is essential for comprehensive health assessments.

Two recent studies investigated the effect of short- and long-term exposure to NO2 and PM2.5 species on different metabolic pathways. Both studies found that several metabolic pathways were affected and all had in common that these pathways are crucial in inflammation, oxidative stress, immunity, and nucleic acid damage and repair(Nassan et al., 2021b) (Nassan et al., 2021a).

In a high-risk asthma cohort, COPSAC2000, the long-term exposure to indoor air pollution (PM2.5, NOx, NO2, formaldehyde, and black smoke) and effect on wheezing symptoms were investigated. The study found no associations between air pollution concentrations and the number of wheezy episodes or any wheezing. In conclusion, most children were exposed to low concentrations of the particles, and previous studies showing short-term associations between higher concentrations and wheezing could not be translated to associations of cumulative low-dose exposure to air pollution (Raaschou-Nielsen et al., 2010). The main contributors to PM2.5 were smoking, heavy traffic, and winter. For black smoke the main contributor is smoking (Raaschou-Nielsen et al., 2011). More research is needed to clarify this.

The indoor environmental microbiome consisting of fungi and bacteria might also be important for development of disease. We are currently looking into this.

References

Nassan, F.L., Kelly, R.S., Koutrakis, P., Vokonas, P.S., Lasky-Su, J.A., Schwartz, J.D., 2021a. Metabolomic signatures of the short-term exposure to air pollution and temperature. Environ. Res. 201, 111553. https://doi.org/10.1016/j.envres.2021.111553

Nassan, F.L., Wang, C., Kelly, R.S., Lasky-Su, J.A., Vokonas, P.S., Koutrakis, P., Schwartz, J.D., 2021b. Ambient PM2.5 species and ultrafine particle exposure and their differential metabolomic signatures. Environ. Int. 151, 106447. https://doi.org/10.1016/j.envint.2021.106447

Raaschou-Nielsen, O., Hermansen, M.N., Loland, L., Buchvald, F., Pipper, C.B., Sørensen, M., Loft, S., Bisgaard, H., 2010. Long-term exposure to indoor air pollution and wheezing symptoms in infants. Indoor Air 20, 159–167. https://doi.org/10.1111/j.1600-0668.2009.00635.x

Raaschou-Nielsen, O., Sørensen, M., Hertel, O., Chawes, B.L.K., Vissing, N., Bønnelykke, K., Bisgaard, H., 2011. Predictors of indoor fine particulate matter in infants’ bedrooms in Denmark. Environ. Res. 111, 87–93. https://doi.org/10.1016/j.envres.2010.10.007