Basic rule, don't open with weather or description. I would start with the sound of gunfire in the distance, that's much more interesting than sunbeams. But your whole first chapter could be cut. You've described a building in detail, and a man whose description amounts to "average brown haired man", and nothing interesting happens.
I perked up a bit at Marcus and Dominick, but there was too much set-up and description, and not enough sense of personality, and nothing to make me worry about the characters.
In the mugging incident, I couldn't understand what had happened, the description was too sporadic. If Marcus is some sort of military, surely his training should supersede his instinct to throw himself to the ground like that?
That conversation with Valerie freaked me out. Read it out loud, and then see if you can think of any way real people would say that.
Okay, as it stands, the story needs a lot of work before you could approach a publisher or agent. The main problem is that you haven't yet got to the point where the story really starts. So far, it's all set-up, you are introducing the reader to your world, rather than dumping Marcus into a pile of trouble.
You obviously have a very well developed world, and you know how it works. The trick is to put this world into the background and focus all the attention on Marcus, so that the reader picks up the details of the world without realising it. You'll have to weave the details in as you go, rather than giving big lumps of description.
As a rule, try not to introduce backstory or flashbacks before chapter three, and not then if you can avoid it. Start with your hero in a scene where something happens that alters his world.
On a technical note, I think your sentences and paragraphs are too long. Aim for about 15 words per sentence, and three sentences per paragraph. Sometimes you have to go more, but not too often. Big paragraphs encourage your reader to skip over to the next one.