When water vapor and dust are present in the atmosphere, additional effects are observed: The vapor turning the blue sky whitish because most of the visible wavelengths are now being scattered to the ground observer's eyes. Dust makes sunrises or sunsets red as only the longer wavelengths survive the direct journey to our eyes when traveling just above the horizon. As the particles get denser and as their size increases, visible imaging of any distance becomes very difficult. This is illustrated by the visible camera movie. This movie was taken of the San Francisco Bay Bridge in July 2008, and you can hardly see the bridge, let alone the car traffic on the bridge.
Contrast that to the movie taken by the SWIR camera (Goodrich model SU640KTSX), which responds in the 0.9 to 1.7 micron wavelength range. Longer wavelengths penetrate the haze, providing clear detail of the ship traffic, buildings and vegetation on the hills behind the bridge.