Airborne pathogens diffusion: A comparison between tracer gas and pigmented aerosols for indoor environment analysis

Area of Science:

• Environmental Science
• Public Health
• Aerosol Science

Background:

• Airborne pathogen diffusion is critical for preventing diseases like COVID-19 in indoor settings.
• Current methods like tracer gas have limitations, including size differences with droplets and inability to account for evaporation.
• Understanding pathogen spread is vital for effective disease control strategies.

Purpose of the Study:

• To develop and evaluate a novel method for assessing respiratory droplet diffusion indoors.
• To compare the performance of the new method against the conventional tracer gas technique.
• To investigate the influence of relative humidity on airborne droplet diffusion.

Main Methods:

• Utilized an ultrasonic emitter to generate and disperse pigmented aerosols.
• Employed a colorimeter for quantitative evaluation of aerosol dispersion.
• Conducted comparative analysis with the established tracer gas diffusion method.

Main Results:

• The pigmented aerosol method demonstrated humidity-dependent responses in dispersion.
• Tracer gas dispersion showed no significant variation across different relative humidity levels.
• The new method provides a more nuanced understanding of droplet behavior compared to tracer gas.

Conclusions:

• Pigmented aerosols offer a more realistic assessment of airborne droplet diffusion, accounting for environmental factors like humidity.
• This novel approach overcomes limitations of tracer gas methods for indoor airborne disease transmission studies.
• The findings support improved strategies for controlling airborne pathogen spread in enclosed spaces.