__________________ causes respiratory problems such as asthma, coughing, and wheezing.

Ozone triggers asthma because it is very irritating to the lungs and airways. 

It is well known that ozone concentration is directly related to asthma attacks. 

It has also caused the need for more doses of asthma drugs and emergency treatment for asthma. 

Ozone can reduce lung function. It can even make it more difficult for you to breathe deeply.