The conversation between human and AI assistant.
[|Human|] What is the issue in the given passage ?
[|AI|] The issue presented in the given passage is that air pollution, primarily caused by pollutants such as ozone, nitrogen dioxide, and particulate matter, is leading to a growing public health crisis in the United States. This pollution has been linked to serious health conditions such as asthma and emphysema.
[|Human|] 
What is the issue in the given passage ?