A research team from Pusan National University in South Korea set up a special laboratory chamber to measure airborne nanoparticle emissions from various household appliances, including toasters, air fryers, and hair dryers. These particles are less than 100 nanometers in size, small enough to penetrate deep into the lungs.
The results showed that most household appliances emit significant amounts of these particles, with toasters being the worst offenders, emitting approximately 1.73 trillion microscopic particles per minute even when no bread is inside. These particles are so small that the nose cannot filter them, allowing them to reach the lungs. Children are particularly vulnerable due to their smaller airways.
Chang Hyuk Kim, an environmental engineer from Pusan National University, noted that "our study confirms the need to design electrical appliances with emissions in mind and to develop indoor air quality guidelines that suit different age groups."
He added: "Reducing ultrafine particulate emissions from everyday devices will contribute in the long term to healthier indoor environments and reduce the risk of chronic exposure, especially for young children."
The study pointed out that electric heating elements and brushed DC motors play a significant role in particle emissions. Experiments showed that brushless hair dryers emit 10 to 100 times fewer particles than dryers with internal motors. (Brushes: small parts, usually made of carbon or a carbon-metal alloy, used in some electric motors to transfer electrical current from the motor's stator to the rotor.)
The researchers also found heavy metals – such as copper, iron, aluminum, silver and titanium – within the airborne particles, and these metals are likely emitted directly from the coils and motors.
Kim explained that "these heavy metals increase the risk of cytotoxicity and inflammation when the particles enter the human body."
Although the study did not measure direct health effects, many previous studies have linked these particles to diseases such as asthma, cardiovascular disease, high blood pressure, diabetes, and cancer.
Researchers emphasize the need for greater efforts to improve the safety of household appliances and reduce emissions of ultrafine particles, noting that manufacturers can improve design and efficiency, but radical change may require stricter regulations.
The study was published in the Journal of Hazardous Materials.
