Common appliances release trillions of ultrafine particles, yet regulatory standards have not addressed this chronic exposure pathway.
A 2025 study from Pusan National University has quantified a previously unregulated form of indoor air pollution. The research found that common electric appliances like toasters, air fryers, and hair dryers emit trillions of ultrafine particles (UFPs) per minute during operation. These particles, measuring less than 100 nanometers, are small enough to bypass the body’s respiratory defenses, penetrate deep into lung tissue, and potentially enter the bloodstream.
The study, published in the Journal of Hazardous Materials, identified metal particles—including copper, aluminum, and iron—shed from heating elements and motors. Children were found to be particularly vulnerable due to their smaller airways, with computer models showing deeper particle deposition that could elevate long-term risks for asthma and cardiovascular disease.
Image: Pusan
The Scale of Emissions and Regulatory Void
The measured emission rates were substantial. A pop-up toaster, the highest emitter, released 1.73 trillion particles per minute, even without bread inside. The research demonstrated that cleaner technology exists; hair dryers with brushless motors emitted 10 to 100 times fewer particles than traditional models. This indicates that the problem is one of design and material choice, not an unavoidable byproduct.
Despite these findings, a review of U.S. regulations shows no standards exist for ultrafine particle emissions from common electric appliances. The Consumer Product Safety Commission (CPSC) focuses on risks like electric shock and fire, while the Environmental Protection Agency’s (EPA) indoor air quality standards do not cover this emission category. The Association of Home Appliance Manufacturers (AHAM), which spends approximately $2 million annually on lobbying, states that “consumer safety is our priority” and that members comply with all existing safety standards.
Incentives and Unanswered Questions
The financial incentives to avoid costly redesigns are significant, with the global air fryer market alone valued at over $1 billion. This creates a structural dynamic where the health costs of chronic, low-level exposure are externalized to the public. The regulatory response has followed a familiar pattern of calling for more research, a tactic historically used to delay action on environmental health threats.
Independent researchers and public health advocates note the parallel to past battles over substances like asbestos and tobacco, where decades passed between initial evidence and regulatory action. The absence of direct epidemiological studies linking appliance use to disease rates remains a key evidential gap. It is unknown whether manufacturers have conducted internal studies on these emissions, as such documents are not public.
Further investigation is needed to determine the full scope of emissions across different brands and the effectiveness of mitigation strategies like air purifiers. The unresolved question is whether regulatory agencies will update safety standards to address this chronic exposure pathway or continue to prioritize industry stability over preventive health measures.
