I think except for firefighters your picture are not really exciting
I think you should take less shot & try to put more personnal feeling on each. I don't think why I say is really clear but what I want to say is that, firefighting is your passion , Great but show us more passionated picture.
Take your time make some close-up on firefighter face in action, show us more than trucks, backside, furthermore centred and cropped.
You can do better I am sure, put more of you in your picture, don't be too neutral
My passion was left inside to die...... my MtDew! I should have ran in a saved it.
Picture 9 4 and 3 I put some effort into, you can't just go rushing into a fire scene and I don't have a telophoto lens. So close ups of the "guys" are out of the question. Besides a fire fighter is nothing without his truck!