1.   You can purify the air with a filtration system.

2.   At home, where the air is purified, their lungs and skin remain clear and clean.

3.   It is the anguished human face of policies that even miners acknowledge have purified the air they breathe and the streams they fish in.

4.   The companies he founded worked on purifying the air and converting low-grade coal into inexpensive, transportable and high-voltage electrical energy.

5.   The hum produces water from the ambient humidity while purifying the air at the same time.

6.   Trees, which provide shelter and help purify the air, fit the bill.

7.   Might diesel vehicles be purifying the air in cities like Los Angeles?