Answer:
They can worsen symptoms for people with breathing difficulties.
Explanation:
Ultrafine particles are small particles found in dirty air. They aren’t filtered due to their very small size. They enter the lungs and cause certain conditions such as oxidative stress, inflammatory mediator release, and could induce heart disease, lung disease and other systemic effects.
People who have breathing difficulties have their case worsened due to these particles. 
 
        
                    
             
        
        
        
its b i took the quiz and got it right
 
        
                    
             
        
        
        
Silt would be your answer here