I've had exercise + cold + allergy induced Asthma since age 5; or at least that's when I was diagnosed with Asthma. The best drug out there for my Asthma is Serevent. It allows me to operate pretty well down into the lower 30's. I had a good ride starting out at 31 degrees just a few weeks ago. I always take a puff of Albuterol about 15 minutes before riding. Asthma is aggravated by sinus problems. I use Claritin to keep that under control.
Most Asthmatics need to avoid sulphites (wine, dried fruits) and many of us are allergic to Aspirin; one now and then are OK, but taking them for a few days will bring on the Asthma.
Miami is pretty pollen free. My parents moved there when I was 11 and I had the fewest attacks there than other places in Florida, the North E and the South E. The Gulf Coast where I live now is probably one of the worst places.
I've always refused to regulate my activities to control the Asthma. It's far better to push through it by warming up slowly and charging ahead aided by medication. The more fit you are, the less of a problem Asthma becomes. I've followed that regime since age 26 when the drugs were not nearly as good as they are today.
Al