If you breathed near smokers for four years, you may already forget 20 percent more.
...the non-smokers who had been exposed to second-hand smoke forgot almost 20 per cent more in the memory tests than those non-smokers not exposed. However, both groups out-performed the current smokers who forgot 30 per cent more than those who were not exposed to second-hand smoking.
...the deficits associated with second-hand smoke exposure extend to everyday cognitive function.
I think I forgot how long I was exposed to second-hand smoke, but it was much more than four years.