A recent study has found that in addition to the harm caused by plastic particles in households, many commonly used appliances are also releasing billions of harmful particles every day. These particles, once entering the human body, can deposit in organs and respiratory systems, potentially increasing the risk of cardiovascular diseases, cancer, dementia, and other illnesses for the general public.
A research team at Pusan National University in South Korea conducted an in-depth study on the ultrafine particles (UFP) emitted by some household appliances available in the Korean market, aiming to analyze the chemical composition of these particles and their effects. The findings of this study were published in the journal “Dangerous Substances.”
The study focused on small household appliances: air fryers (AF), toasters (TS), and hair dryers (HD). The researchers categorized hair dryers into those with brushed DC motors and brushless DC motors, air fryers into basket type and oven type, and toasters into pop-up and oven types. It is noteworthy that while the toaster contains a heating coil with a mica cover, it does not have a fan or motor device.
Researchers placed these appliances in a one-cubic-meter sealed space, operated them for 3 to 30 minutes, and then used multiple instruments to measure the quantity and distribution of emitted particles as well as the chemical substances contained within.
The results showed that the “pop-up toaster” was the most heavily polluting device, generating a large number of particles within just 3 minutes, emitting an average of about 1.73 trillion ultrafine particles per minute with a diameter of approximately 100 nanometers.
The concentration of particles emitted by the “air fryer” increases as the temperature rises. Running at 200°C for 20 minutes, it releases 135 billion ultrafine particles per minute. The oven type air fryer produces four times more particles than the basket type.
While the hair dryer emits fewer particles, certain models still release over 100 billion particles per minute. Overall, most appliances emit a large number of ultrafine suspended particles smaller than 100 nanometers, containing substances such as copper, iron, aluminum, silver, titanium, sodium, chromium, magnesium, and zinc.
The researchers also used the MPPD model (Multiple-Path Particle Dosimetry model) to simulate how these tiny particles affect our respiratory system and identify the most vulnerable groups.
The results showed that ultrafine particles mainly deposit in the alveolar region deep within the lungs (the primary gas exchange area). Children under 8 years old are most susceptible because their lung size is only about 30% of that of adults, making them more prone to being covered by these pollutants, thus facing a much higher health risk than adults.
The research team pointed out that the heavy metals detected in air particles primarily come directly from the heating coils and motors inside small household appliances, arising from the sparks produced by motor brush friction and the evaporation-condensation effects of high temperatures along with incomplete combustion of indoor dust.
The study emphasized that these heavy metal particles pose an increased risk of cellular toxicity and inflammation upon entering the human body, seriously endangering user health. Therefore, indoor air quality is crucial for human health.
“Our study highlights the necessity of considering emission factors when designing appliances and setting up indoor air quality guidelines tailored to different age groups. Furthermore, this framework can be extended to other consumer goods, moving towards the direction of protecting human health,” said Professor Changhyuk Kim from Pusan National University’s Institute of Environmental and Energy Research, the lead author of the study.
The research suggests that the ultrafine particles generated by these appliances may have potential health impacts. In fact, many previous studies have indicated that a high concentration of particles can jeopardize human health, with conditions such as asthma, heart diseases, hypertension, diabetes, cancer, and dementia all linked to air pollutants.
In a study conducted in September 2024, King’s College London and St George’s College, University of London discovered that air pollution could lead to 60,000 new cases of dementia in the UK. These fine pollutants, once inhaled deep into the lungs and entering the bloodstream, may trigger brain inflammation, a major factor contributing to dementia.
Scientists from the University of Stirling in Scotland found that American women living in areas with severe air pollution are more likely to develop breast cancer. They explained that the BRCA gene plays a crucial role in tumor suppression, and the chemicals in traffic emissions inhibit the expression of the BRCA gene, thereby increasing the likelihood of women developing breast cancer.
Earlier this year, a study published by Purdue University revealed that common household products contribute to indoor air pollution. The research team cautioned against the dangers posed by air fresheners, scented candles, floor cleaners, and deodorizers.
Nusrat Jung, Assistant Professor at the Lyles School of Civil Engineering and Environmental and Ecological Engineering at Purdue University, stated, “Many people desire to create a forest-like ambiance using scented products rich in chemical fragrances. However, this inadvertently leads to indoor air pollution, exposing individuals to these pollutants and affecting their health.”
Numerous studies have also shown that children living in highly polluted environments exhibit reduced intelligence, motor skills, behavior, and lifespans. In the long run, reducing emissions of ultrafine particles from daily appliances may help create a healthier indoor environment for young children.
A study released in April 2025 by the National Institute of Child Health and Human Development (NICHD) revealed that children living less than approximately 500 meters from busy roads scored lower in infant communication ability tests and demonstrated poorer hand-eye coordination skills.
Research conducted on 14 children by the University of Cincinnati found that children living in areas with higher pollution levels exhibited higher levels of anxiety. The researchers believe that pollution may alter children’s brain structure, making them more susceptible to anxiety.
Researchers at Monash University in Australia found that children living in severely polluted areas have an 86% higher probability of developing Autism Spectrum Disorder (ASD). They explained that the developing brains of young children are more vulnerable to the impact of toxic substances in their environment.
Furthermore, studies by the University of California, San Francisco, and the Barcelona Institute for Global Health have indicated that children born to mothers living in polluted areas have an average IQ 7 points lower than children born in cleaner air regions and perform worse in memory tests.