1. China is trying to expand use of natural gas to reduce reliance on dirtier oil and coal.
2. Both Roberts and Katz said that the ice is likely dirtier because machines aren't cleaned and people use unwashed hands to scoop ice.
3. The air is becoming smoggier, the rivers dirtier and the soil polluted with chemicals and pesticides.
4. Now we know it is really dirty, dirtier than we can imagine.
5. The air we breathe has gotten dirtier and our rivers and streams are no longer clean.