Development of Control Methods for Submicron Particulate Matter Emissions and Inhalation Exposure from Cosmetic Spray...

Cosmetic spray products, widely used for personal care, are popular due to their ease of application and rapid, uniform coverage. However, the particulate matter (PM) that they emit can be inhaled and deposited in the respiratory tract, potentially posing respiratory health risks. Existing studies have seldom addressed emissions from cosmetic spray products applied directly to the human body, especially the face and neck, and few have proposed practical methods to reduce exposure. This study systematically evaluates the particle size distribution and number- and mass-based concentrations of 12 products under a laboratory setting that simulated real-use conditions. It is found that PM emissions from some spray products could be significant and strongly influenced by nozzle design and product chemical composition. The maximum PM₁₀ number concentration reached 1.03 × 10⁶ #/cm³, while the maximum PM₁₀ mass concentration was 36.17 mg/m³. Using the Multiple-Path Particle Dosimetry model, we quantified the deposition doses across different respiratory regions (head, tracheobronchial, and pulmonary). To reduce exposure risks, a new development of actuator structures on a spray bottle was proposed and tested by incorporating external tubing and modifying mechanical breakup designs, without impairing the delivery efficiency of the product. Among these, tapered tubing was most effective, reducing total number- and mass-based deposition doses of submicron particles by 88.6% and 65.7%, respectively. The study highlighted significant differences in exposure risk among product types and proposed cost-effective, highly compatible engineering controls through nozzle modification, offering practical strategies for minimizing inhalation exposure from cosmetic spray products.