Identifying Little Flying Biting Bugs?

What are all of these tiny little flying bugs, that bite? First off, we live in an apartment complex. My son and I were walking up to our door, and he pointed out on the ground in front of our neighbors door, what looked like the part of a dandelion that you can "make a wish" on, and blow. They looked like pieces of dandelion seeds (or whatever they are), hundreds of them. He said they were all dead bugs.

Well then this morning when I left home, really early, I opened the door, and there were hundreds of little bugs on our door, and flying around. There was a light on, in the hallway, also and they were all around it too.

In the evening when I'm standing on our balcony, there are constantly things biting me and you can't see them, it just feels like I'm getting pelted on the legs with grains of sand, or something. Does anyone know what these annoying bugs are? They just started coming out, within the last week or so, and I only notice them in the early evening, through to the night, and very early morning.

Please someone help! Ahhhhh!