EE turned the a.c. fan on & dust flew out of the vents (450 Loader). At 10 pm on the same evening he went to 3 kiln cooler to sweep the curbs so dust & debris was flying around. He states that either incident could have gotten something in eye. He did not feel it until 5 am which woke him up. Pain & tearing woke him up. Drove to plant 9 30 am to report & 1st Aid initiated.