Aldehydes others than formaldehyde: exposure patterns and their significance in a set of Italian indoor workplaces - 2011-2020

Aldehydes are fragrant compounds with widely diversified smells (ranging from very pleasant to very unpleasant), presenting a potential for local irritation of the mucous membranes and other adverse health effects. Formaldehyde is the compound from this family receiving the largely prevalent attention in the fields of the industrial hygiene and of the occupational and environmental medicine; recognised as an irritating, allergenic and carcinogenic agent, it is ubiquitous, causing widespread exposures in both occupational and non- occupational scenarios, frequently rising up to relevant concentrations. In the vast majority of the anthropized indoor environments, formaldehyde is the most abundant aldehyde too (referring both to spreading and concentration levels in air) but it is worth noting that it is virtually always accompanied by a various cortege of other aldehydes. Some aldehydes, others than formaldehyde, can show a relevant presence in particular scenarios, notably acetaldehyde inside settings where flours are rising and being baked, acrylaldehyde (commonly known as acrolein) where cooking oils are heated overwhelming their smoke point, glutaraldehyde in healthcare contexts where the agent is used as a disinfectant, benzaldehyde and crotonaldehyde where these two chemicals are synthesized and used for industrial purposes.  In a preventive perspective, these facts call for an attention towards the whole family of aliphatic aldehydes. Different patterns of combined exposure to formaldehyde and other aldehydes in a set of Italian indoor workplaces are presented and discussed. Over the 2011 – 2020 period, a sequence of passive diffusive samplings was performed, partly in workplaces previously known for having relevant sources of formaldehyde and / or other aldehydes, partly in workplaces without no previously known source of these chemicals. The set of the studied workplaces didn’t comprehend scenarios where cooking oils were heated, glutaraldehyde was used as a disinfectant, benzaldehyde or crotonaldehyde were synthesized or used for industrial purposes. In several cases acetaldehyde showed significant concentrations in air, often presenting as the main companion of formaldehyde. Acetaldehyde concentrations in air reached 568 μg m-3 in agriculture and zootechnics, 144.9 μg m-3 in the plastics moulding sector, and 48.4 μg m-3 in hairdressers’ and beauticians’ workshops. In the bread and pastry baking sector, acetaldehyde concentrations in air resulted frequently relevant (up to 256.3 μg m-3), in the absence of a similar presence of formaldehyde (top level 29.2 μg m-3). Unexpectedly, in some samples from the healthcare sector, acetaldehyde concentrations reached significant levels (up to 159.5 μg m-3 from personal 15’ samplings), close to the corresponding formaldehyde ones (up to 332.6 μg m-3 from personal 15’ samplings).   Hexanal emerged as a relevant compound (concentrations in air up to 174.1 μg m-3) in miscellaneous scenarios comprising healthcare, plastics moulding, wood, plywood and chipboard, paper and paperboard, bakeries and pastries. Other aldehydes were detected in multiple situations, individually at levels never exceeding 10.0 μg m-3, but sometimes accounting for not fully negligible overall concentrations in air.    These results suggest that, in a variety of indoor workplaces, a skilled preventive attention deserves to be addressed not only to formaldehyde, but to the whole body of the aldehydes, in front of a reasonable possibility of synergic actions. Such an indication assumes a major relevance under the hypotheses that protracted oxidative stress and chronic inflammation are the driving modes of the formaldehyde’s carcinogenic effect, through the piling up of unrepaired damages to DNA.