Since COVID-19, HVAC industry professionals now know that protecting occupants from inhaling harmful indoor air particles is an essential part of their jobs. Even before the pandemic, managing inhalation exposures was fairly intuitive, since our noses, sinuses, or upper airways alert us to the presence of aromatic substances, allergens, or asthma triggers.
Another very important route from indoor air to our tissues and organs is diffusion through our skin. This transdermal penetration usually goes unnoticed by our five senses, yet the compounds that reach our tissues in this way can reach high concentrations and cause serious illnesses. Pharmaceutical companies value diffusion through skin as a painless yet effective medication delivery route. This is great as long as the medication is delivered in a thoughtful and controlled way. Unfortunately, unintentional exposure to pollutants in the indoor environment are neither healthy nor released in controlled “doses.”
There is value in understanding the similarities and differences between inhalation versus transdermal exposure so that the less emphasized transdermal pathway can be included in exposure assessments and, most importantly, be controlled by HVAC professionals. This column will not address the health impact of ingested (eaten) or radioactive compounds, such as radon.