When people think about pollution, they often picture smog or traffic-related exhaust. But many chemical exposures occur indoors — in homes, schools, and workplaces where people spend most of their time.
Indoor air and dust can contain a growing mix of lesser-known contaminants released from everyday products and materials, according to a new perspective in the journal New Contaminants. Some of these substances are rarely monitored indoors and have been linked in past research to health risks such as heart disease, cancer, and developmental problems.
“In many buildings indoor pollution can be more severe than what we measure outside and that is especially worrying for children and older adults who rarely leave these environments” said coauthor, Wei Du, in a press release. “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.”
A Hidden Pollution Problem Indoors
People spend nearly 90 percent of their time indoors, yet indoor environments are often less studied than outdoor air. That gap may overlook how enclosed spaces influence both the intensity and duration of chemical exposure.
Unlike outdoor pollution, which is shaped by wind, sunlight, and weather, indoor chemicals are released into spaces with limited ventilation. In energy-efficient buildings designed to reduce airflow, those substances can remain in air or dust for extended periods.
Over time, that persistence — rather than high concentrations alone — may be particularly relevant for people who spend long stretches indoors, including children, older adults, and those with chronic health conditions.
Read More: Revived 40,000-Year-Old Microbes in the Arctic Could Release Greenhouse Gases
What Are New Contaminants — and Where Do They Come From?
Traditional indoor pollutants such as carbon monoxide or formaldehyde have been studied for decades. In contrast, new contaminants include persistent organic pollutants, endocrine-disrupting chemicals, antibiotics, and microplastics that have only recently become a focus of concern.
Infographic on new contaminants in indoor environments.
(Image Credit: Jinze Wang, Xinyi Zhou, Nan Fu, Shan Zhou, Shuo Yang, Jiangping Liu, Wei Du, & Bo Pan)
Many of these substances are released from everyday products people use and touch regularly, including shampoos, sunscreens, plastics, carpets, paints, toys, and electronic devices. Others come from specialized materials used in offices, hospitals, and childcare centers. Once inside buildings, these chemicals can enter the body through inhalation, ingestion of dust, or absorption through the skin.
Evidence suggests these contaminants don’t simply remain in the environment. They have been detected in human blood, urine, breast milk, and even bone marrow — indicating that routine indoor exposure can lead to long-term accumulation in the body.
Why Indoor Chemistry Makes Health Risks Harder to Predict
One of the biggest challenges in assessing indoor pollution is that indoor environments don’t just store chemicals — they can actively transform them.
Indoor surfaces and dust can act like chemical reactors. Exposure to indoor light, ozone, and other oxidants can trigger reactions that alter chemicals after they are released. In some cases, flame retardants or fragrance ingredients can break down into new compounds that may be more persistent or potentially more toxic than the originals.
These chemical transformations make it difficult to estimate health risks using outdoor pollution data alone and underscore the need for research designed specifically around indoor environments.
“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 coauthor Bo Pan.
This article is not offering medical advice and should be used for informational purposes only.
Read More: Indoor Allergies Spike in the Winter — Here's How to Avoid Impurities in Your Home
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
- This article references information from the recent study published in the New Contaminants: New contaminants in indoor environments: occurrence, transformation, and health risks
