In other words, my peak air flow is half or less and my inhalor is not working and my employer tells me no, I cannot leave work to go to a doctor. how can I explain the dangers of this in the best way?

I have asthma too. What kind of employer tells you no when you say you need to see a doctor? If you go back to work with a note from your doctor then there shouldn't be a problem. Sounds like you work for a jerk! Next time you see your doctor have him write something to your employer explaining your situation. they can't argue with doctors orders.

call 911 and wait for ambulance he will be billed for workmans comp.

go over his head!! That is a dangerous situation!! tell him that if the inflammation gets bad enough your airway could close!!

just say its really serious imagine if you were in this state

W.T. that is incorrect. Asthma does not fall under worker's compensation even if one does have an exacerbation while at work.

You know your condition and you know when it's time to seek medical attention. do not let your boss dictate necessity of you getting help.

Research the Family and Medical Leave Act. I believe your rights are protected therein. Wikipedia probably has an article.

God bless.