Diffusion of light in the atmosphere takes place due to

1 Diffusion of light (specifically, scattering) in the atmosphere is the phenomenon responsible for the blue color of the sky, twilight, and the visibility of non-luminous objects. 2 This scattering occurs when sunlight interacts with particles suspended in the atmosphere. 3 While atmospheric gases (like Nitrogen and Oxygen) cause Rayleigh scattering (which preferentially scatters shorter, blue wavelengths), larger particles like dust particles, water droplets (in clouds/fog), and aerosols cause Mie scattering, which scatters light more uniformly across wavelengths and contributes significantly to the overall diffusion and haze. 4 Among the options, dust particles are a major component responsible for scattering and diffusion of light, making the sky appear hazy and contributing to phenomena like red sunsets (where dust scatters away blue light). Carbon dioxide and Helium are gases and contribute less significantly to visible scattering than major gases or particles. Water vapours contribute mainly through condensation into droplets.