Can you elaborate on criminal activities? And how do your parents "hurt" you with their smoke? You need to clarify what this hurt is. By erratic behavior, do you mean he can be normal at times and other times he is in a fit of rage?
I did read one of your earlier posts regarding your parents and smoking. I agree with Marty and recommend that you should not tell the cops because there are repercussions that could affect you in very detrimental ways.... If you don't want to be there when your dad's actions catch up to him, have a backup plan when that event does come. This is your life. There are options.
Your options are as Tyme2k had suggested, which was to plan for the future and doing what you can now by getting a job, saving money, and developing some work experience. Another option is, as Marty suggested, talking to them, but based on your last post it seems to be that you have done so in the past before yet they refuse to make any effort to change. I really can't imagine living inside a house where cigarette smoke permeates the atmosphere constantly. My dad smokes but I get it in small doses as he is walking from the kitchen (uses the stove to light them) to the patio.
If you really do still want to move out of your parents house it is possible. A foster home is an option. Your parents can place you in one voluntarily. I'm sure you'll be able to visit them, you'll just be living under foster care, which is typically a better environment for your growth and development as a human being. Other ways you can end up in foster care are truancy or running away, but I don't think that's what you want to do so discuss with your parents about their problem and if they aren't willing to make a compromise with you then tell them that you can't do "This" anymore; by "this", I mean living in the environment that is detrimental to your health and your brothers health, must cause you guys some stress, and to some extent, makes the thought of coming home a dreadful one. A switch might flip in your parents head that makes them think, "What am are we doing with our lives that my own child tells me that they don't want to live with us anymore." There is the chance they will act in anger, thinking, "How dare you... etc." but stand firm and calm and let them know that it isn't that you don't love them, but that you don't like what they are doing and you've tried and since they aren't listening or making any sort of effort to change (I mean really, getting up and going outside to smoke... really not that hard), you are now taking some sort of "extreme" measure.
My mom's brother and one of her sisters are foster parents. I've met some of them when they would visit on vacations and I have to say that the difference of strong guardians in your life makes a huge difference in the long run. I do remember times when some of the children would cry at night because they were dreaming about their parents and wanted to see them, but couldn't because they were in jail, rehab, or their parents weren't mature enough to care for them. Your case is not severe like there's is, but a foster home provides structure and an environment for a young individual to grow and flourish much more efficiently. I don't know what your environment is like, but I have an idea of what it must be like and I think you'd be better off in another environment.
I don't know how desperate you feel about moving away. It seems to be that you want to but you just don't know what to do. Consider your attachment to your parents. Their effect on your life. Is it more detrimental than beneficial? Will you be able to handle living with other people who are not your biological parents but want to raise you as if they were (my uncle and his wife and my aunt and her husband had difficulties conceiving so they opted for foster care because they wanted children). Will you be able to handle missing your parents at times?
Understand that you can work and study better in a foster care environment if you see that it is a struggle to do so at home. Your foster parents may know a lot more than your parents with regards to getting you a good education and college. At the end of the day, you will be able to see your parents. You don't love them any less, but parenting wise, they could do better but haven't made an effort to do so.
I don't know if this relates to your situation, but my dad was a pretty crappy parent growing up. If it wasn't for my mom, the life for me and my siblings could have been much like yours cos my dad didn't seem to care much about developing me and my brothers, just as his dad didn't put much into developing him when he was growing up. I don't know if you resent your parents, but I resented my dad growing up. It wasn't until this year that I've been able to forgive him because at the end of the day... he just didn't have the knowledge of how to be a great father because his father wasn't there for him. If you resent your parents, understand that maybe they might have gone through a similar situation. Environment is so so so important in the development of human beings. If there is any lesson to take from your parents, just as I've taken from my dad, it is that they teach you who you do not want to become when you grow up, the kind of person you want to be for your kids if you ever plan on becoming a dad.
Anyways, I hope this helps man. Just keep looking up and understand that life gets better if you are feeling trapped