while in clean air, my lungs gives me the impression that the air is dirty

I was sick for roughly 3 weeks before I went to the hospital. I was diagnosed with pneumonia but the doctor did not give me enough medicine to get rid of it, two weeks later I went to the doctor and I have finally healed (three months after the hospital) up to where I feel close to normal.  I have never in my life had a breathing problems, but now I feel liking I am only running on 70% of my lung capacity (all of the time) and the doctor says I have asthma. Two weeks ago I went and had a pulmonary test (I believe that is what it is called) and still not have heard the results.
My question is that I have noticed several times while breathing outside and in side areas that it seems as if I am breathing dirty polluted air. Does anyone know of a condition that would cause this?

[National Jewish]

It may take a month or two after finishing the course of antibiotics for pneumonia, until you feel completely back to normal.  It is possible for inflammation or irritation to remain in the lungs for 6 to 8 weeks after the actual infection is gone.  A feeling like you are only running on 70% of your lung capacity all of the time may linger.  This is very similar to asthma, but your symptoms should gradually improve and eventually go away completely.  You should let your doctor know if your symptoms worsen or do not go away.  A follow-up chest x-ray is helpful to show whether or not the pneumonia has completely gone away.

To know for sure if your symptoms are due to asthma testing is done.  Generally testing starts with a simple breathing test called spirometry.  This test provides detailed information about how your lungs are working.  It will show if there is obstruction in your airways.  To really test for asthma it is best to repeat this test after using a rescue inhaler, an inhaled bronchodilator.  This measures how much the bronchodilator helps your lungs by reversing the problem.  When there is a 20% increase the test is positive for asthma.  Air pollution is can certainly be one of many things that can make asthma worse.  When asthma is well controlled with medicine, generally air pollution causes less breathing difficulty.  Your doctor should be able to tell you whether or not you have asthma based upon the results of your breathing test.  If it is not clear from the test results whether or not you have asthma you might consider seeing a local board certified pulmonologist for help in finding out what your problem is and getting the best treatment.