How will smoking two cigarettes a day effect CO2 laser resurfacing ?

Cigarette smoking, in any amount, effects the healing process from surgery or procedures like chemical peels and laser resurfacing.  The best results would be achieved without any cigarette smoking.  If you did smoke, you could compromise your results.  

As others have noted, smoking will only slow your healing down.  Nicotine serves as a vasoconstrictor which impedes blood flow to your skin and carbon monoxide (released in the smoke) competes with binding sites on your red blood cells.  Both of these factors diminish oxygenation of your skin and impair healing. If you commit yourself to doing a procedure like laser resurfacing, it makes sense to take every step necessary to allow for predictable wound healing.

Cigarette smoking decreases the amount of oxygen delivered to the treated area and thus can slow wound healing.  In the case of laser resurfacing where a large surface area needs to heal, the smoke can also act as an irritant, further delaying the rate of wound healing and potentially causing complications that would not have otherwise occurred (prolonged redness, scarring).  I STRONGLY discourage patients from smoking prior to and during recovery from full face laser resurfacing.  I also encourage family members who smoke and are unable or unwilling to stop do so to smoke outside so that the patient is not exposed to secondhand smoke.

Although you only smoke two a day, smoking decreases the blood flow to the face which will slow down healing.  Healing from a full face CO2 is difficult enough that you certainly don't want to do anything that would affect the process.  If you really only smoke two a day shouldn't be too hard to quit for a month or two beforehand  

Smoking will negatively effect any surgical procedure, especially those that impact skin. Smoking reduces the concentration of oxygen in regions that are healing from laser treatments and slows the healing of surgical wounds. You must also avoid second hand smoke as this has the ability to further slow the healing process. Furthermore you should consider the benefits of quitting smoking as it will reduce the need for further skin treatments. The combination of sun exposure and smoking has proven to require more intensive treatments with prolonged exposure to either.

Smoking decreases the oxygen in your blood and change it to carbon monoxide, a toxin to tissues. If you smoke do not waste your time and money in ablative procedures that need the best tissue response for healing.