Rant Brown Sky?

[Unstung]

Some people think brown sky is caused by lamp-lighting as a silly comeback to me on another forum. (From this lighting: http://en.wikipedia.org/wiki/Sodium-vapor_lamp) The light pollution is orange, according to the article.
And what I've seen, it produces an orange glow, and does not blanket the sky with a brown color like this; the color in the top-right with a bit less saturation:

http://www.spacetoday.org/images/Mars/MarsRovers2003/MarsRover2003_1.jpg
^(The top few pixels of the sky are somewhat similar color.)
And another point was that it's caused by a hazy sunset or sunrise, but from pictures, it does not seem so brown.

So, what do you think?

 

[Sunhillow]

I don't quite understand your point...

do you talk about brown sky over habitated areas or brown sky over wilderness? Or brown sky on Mars?
Orange and yellow do look brown if they are dark and reduced in saturation. I know no other source for a brown-orange-yellow tint of night sky than human made light. Including fire sometimes. Take your colour patch, make it brighter and increase saturation.

The drawing of the Mars Rover is just an artist's impression.

 

[Unstung]

I am talking about an area around and by an airport, by a population, with brownish sky.
This color brown exactly:

The two excuses are that it is caused by the lamp lighting, or a hazy sunset/sunrise.