Thanks for query,
We cannot decide the contents of semen by it's necked appearances.
You should go a semen test to confirm presence of pus or it's count.The same thing happens with urine.if you see reddish color or some remarkable appearance change only by smell it is very difficult to arrive any conclusion.
Alcohol & smoking
has no direct relation on semen but it disturbs the body process leads to disturbances.
You should relay on urine & semen report & then if abnormal then consult your doctor.