A recent study from Purdue University has revealed that using common hair care products alongside heat styling devices can generate nanoparticle air pollution levels comparable to those found near busy roads. These minute particles, measuring up to 500 nanometers—approximately 200 times smaller than the width of a human hair—can penetrate deeply into the lungs, raising significant health concerns about daily hair care routines.
The research team employed a specially designed tiny house laboratory to investigate the air pollution produced during hair styling. This facility has previously been used to analyze chemicals released by hair products, but the current study focused specifically on the associated air quality effects.
Involving seven volunteers, the researchers examined a total of 21 hair care routines, which included five different products and various heat appliances such as straighteners, curlers, and wavers. Each routine, lasting between 10 to 20 minutes, resulted in the emission of over 100,000 nanoparticles per cubic centimeter. Simulation models indicated that individuals could potentially inhale more than 10 billion nanoparticles during these sessions, many of which reach the deepest areas of the lungs.
According to civil engineer Nusrat Jung, the number of nanoparticles produced during these routines exceeded initial expectations. “This is really quite concerning,” Jung stated. “Studies of this kind have not been done before, so until now, the public has had little understanding of the potential health risks posed by their everyday hair care routines.”
Heat Application as a Key Factor
The process of heating hair care products to temperatures exceeding 300 °F (149 °C) significantly contributed to the generation of nanoparticles. At lower temperatures, the formation of these particles was markedly reduced, with most remaining in the hair rather than dispersing into the air. Fellow researcher Jianghui Liu emphasized the role of heat: “Atmospheric nanoparticle formation was especially responsive to these heat applications. Heat is the main driver—cyclic siloxanes and other low-volatility ingredients volatilize, nucleate, and grow into new nanoparticles, most of them smaller than 100 nanometers.”
Though the specific health impacts of these nanoparticles remain uncertain, existing research indicates that micrometer-sized particles may pose risks associated with air pollution. Animal studies have suggested that inhaling nanoparticles can lead to increased inflammation and tissue damage in the lungs.
As a precaution, the researchers advise ensuring well-ventilated spaces when using high-heat hair products. They also advocate for further research to better understand the composition of these particles and their potential health implications.
“By addressing these research gaps,” Jung noted, “future studies can provide a more holistic understanding of the emissions and exposures associated with heat-based hair styling, contributing to improved indoor air pollution assessments and mitigation strategies.”
The findings of this study were published in the journal Environmental Science & Technology in July 2023, marking a significant step towards understanding the air quality implications of everyday beauty routines.
