Indoor dust, air, and everyday products are exposing people to a rising array of “new contaminants” in homes, schools, and workplaces, according to a recent perspective published in the journal New Contaminants. Researchers warn that these emerging chemicals may silently increase the risk of heart disease, cancer, and developmental issues, while remaining largely unregulated and poorly monitored indoors.
Hidden Pollution Indoors
People now spend approximately 90% of their time indoors, yet most pollution research and safety standards focus on outdoor air. The study highlights that indoor spaces contain complex mixtures of chemicals from building materials, furnishings, cosmetics, cleaning products, and electronics. Modern energy-efficient buildings, which are often more airtight, can allow pollutants to accumulate over time, resulting in prolonged exposure.
“In many buildings, indoor pollution can be more severe than outdoor levels, which is especially concerning for children and older adults who rarely leave these environments,” said Wei Du, corresponding author and researcher at Kunming University of Science and Technology. “Our daily routines bring us into constant contact with chemical residues in the air, dust, and on surfaces—even when we cannot see or smell them.”
What Are “New Contaminants”?
Unlike traditional indoor pollutants such as formaldehyde or carbon monoxide, new contaminants include persistent organic pollutants, endocrine-disrupting chemicals, antibiotics, and microplastics—substances that have only recently come under scrutiny. These chemicals can be released from everyday items such as shampoos, sunscreens, plastics, carpets, paints, toys, electronics, and specialized office or childcare materials.
Once indoors, these contaminants can enter the body through inhalation, ingestion of dust, or skin contact, and have been detected in blood, urine, breast milk, and even human bone marrow.
Why They May Be More Dangerous
Indoor surfaces and dust can act as chemical “reactors,” transforming contaminants into new compounds that may be even more persistent or toxic than the original substances. Reactions driven by indoor light, ozone, and other oxidants can convert flame retardants or fragrance chemicals into derivatives with stronger neurotoxic or endocrine-disrupting effects.
“These processes make it difficult to predict health risks using outdoor studies alone,” the authors note, emphasizing the need for indoor-specific research.
Call for Standards and Protection
The perspective urges systematic monitoring of new contaminants across a variety of indoor settings, including homes, schools, hospitals, offices, and recreational facilities. The researchers advocate for high-resolution measurements, mechanistic studies of chemical transformations, and targeted toxicology research to inform next-generation indoor air standards.
“Protecting human health increasingly means looking inward—at the places where we live, learn, and work—and treating indoor environments as a critical frontier for pollution control,” said co-corresponding author Bo Pan.