The scattering of light by atmospheric particles (like air molecules) is described by Rayleigh scattering. The intensity of scattered light is inversely proportional to the fourth power of the wavelength ($\text{Intensity} \propto 1/\lambda^4$). Red light has the longest wavelength in the visible spectrum, meaning it is scattered the least. This allows red light to penetrate fog, smoke, and haze more effectively and be visible from a greater distance compared to colours with shorter wavelengths like blue or violet, which are scattered more easily.