Churning Up Pollution Edit Meaning

1.

Having horrible coughing fits and spitting up a lot, thus contaminating whatever is in the way.

He was churning up a lot of pollution so I moved back a few yards.

2.

This is when you are experiencing serious coughing fits and you spit a lot when you cough. These extreme coughing spells usually occur when you have a bad cold, the flu, etc.

Last night I was churning up pollution so much, so I finally had to take some Nyquil.