Air pollution statistics for Klickitat Co, Washington
3. Select a year
| Year | Percentage days with good air | Percentage days with moderate air | Percentage days with unhealthy air for sensitive groups | Percentage days with unhealthy air |
| 1997 | 99.07% | 0.93% | 0.00% | 0.00% |
| 1998 | 98.96% | 1.04% | 0.00% | 0.00% |
| 1999 | 98.70% | 1.30% | 0.00% | 0.00% |
| 2000 | 95.89% | 4.11% | 0.00% | 0.00% |
| 2001 | 96.75% | 3.25% | 0.00% | 0.00% |
| 2002 | 96.73% | 3.27% | 0.00% | 0.00% |
| 2003 | 94.57% | 5.43% | 0.00% | 0.00% |
| 2004 | 96.31% | 3.69% | 0.00% | 0.00% |
| 2005 | 99.28% | 0.72% | 0.00% | 0.00% |
| 2006 | 95.86% | 4.14% | 0.00% | 0.00% |