Airborne particle deposition onto the ocular surface

Area of Science:

• Environmental Health
• Occupational Health
• Aerosol Science

Background:

• Eye irritation is a common complaint in office environments.
• Current research lacks a consistent link between airborne particle concentration and eye irritation prevalence.
• External physical factors may significantly influence particle deposition on the ocular surface, potentially masking the role of particle concentration.

Purpose of the Study:

• To investigate the influence of external physical factors on particle deposition velocity onto the ocular surface.
• To determine the impact of turbulence, gravitational settling, electrical fields, and thermophoresis on particle deposition.
• To assess how variations in these factors affect deposition velocity and its potential role in eye irritation.

Main Methods:

• Utilized previously published semi-empirical models to describe deposition velocity.
• Incorporated parameters such as turbulence, gravitational settling, electrical fields, and thermophoresis.
• Employed a probabilistic approach to calculate deposition velocity percentile ranges under varying conditions.

Main Results:

• External physical factors can cause deposition velocity differences of one order of magnitude or more, independent of particle size.
• Calculations indicate significant variability in particle deposition velocity due to factors like turbulence and electrical fields.
• These findings suggest that external physical factors play a crucial role in ocular surface particle deposition.

Conclusions:

• External physical factors, beyond mere concentration, significantly influence airborne particle deposition rates on the ocular surface.
• Future studies on airborne particles and eye symptoms require size-resolved concentration measurements.
• Multivariate analysis including other relevant external physical factors is essential for accurate exposure-response assessments.