He's on too many asthma meds. I don't even think it's asthma

Hello there.  My son is 18 months old and has been hospitalized 4 times because of respiratory distress.  
First time (2 months old): diagnosed with pneumonia
Second (12 months old): rhino-virus
Third (15 months old): asthma
Fourth (16 months old): asthma
His breathing problem seems to be triggered by viral infections and air pollution.  As soon as he gets a cold of a virus, he starts to wheeze and breathes shallow rapid breaths.  Another trigger happens when we are at someone's house where the air doesn't circulate well.  This past month, he has spent only 3 days breathing normally.  He seems to work so hard to breath.
Here is my question.  He is on 1) Flovent 2 puffs twice daily 2) Singulair 1xdaily 3) Ventolin PRN
We were told to use the ventolin when he is in distressed or when he starts to become sick.  This will prevent him from getting bronchitis.  The ventolin does nothing.  If it is asthma, shouldn't we see immediate improvement 5-10 minutes after giving the ventolin?  He will be on ventolin for 3 days straight, and there is no improvement.
Could the pneumonia (at 2 months old) have caused permanent damage?  Does it sound like asthma? Now he's going to get tested for allergies (isn't he too young?)
Thank you for taking the time to read this.
-worried maman.