Human health risks of formaldehyde indoor levels: An issue of concern

Formaldehyde is a carcinogenic substance for humans. Exposure to formaldehyde may also cause eye and respiratory tract irritation, as well as skin sensitization. The main indoor sources of formaldehyde are wood-pressed products, insulation materials, paints, varnishes, household cleaning products and cigarettes, among others. Although this chemical is a well-known indoor pollutant, data on indoor concentrations of formaldehyde are still scarce in some countries. In February 2014, 10 homes in Catalonia, Spain, were randomly selected to collect indoor (bedroom and living room) and outdoor air samples. Ten additional samples were also collected at different workplaces (e.g., offices, shops, classrooms, etc.). Formaldehyde air levels found in homes ranged from 10.7 to 47.7 µg/m3, from 9.65 to 37.2 µg/m3, and from 0.96 to 3.37 µg/m3 in bedroom, living room, and outdoors, respectively. Meanwhile, at workplaces indoor air levels ranged from 5.86 to 40.4 µg/m3. These levels are in agreement with data found in the scientific literature. Non-carcinogenic risks were above the threshold limit (HQ>1), and carcinogenic risks were not acceptable as well (>10-4). Despite the current study limitations, the results confirm that formaldehyde indoor levels are a matter of health concern, which must be taken into account by policy makers and regulatory bodies.