According to NewScientist, greasy hair may reduce the amount of ozone that you inhale.

Researchers at the university of Missouri in Rolla found that, on average, unwashed hair absorbs around seven times more ozone than washed hair.

"Ozone is probably reacting with components of hair oil," says one of the researchers. "For dirty hair, the ozone concentration around the head is likely to be substantially lower than the level in the room."

Ground-level ozone can cause respiratory problems and trigger asthma attacks; it has also been associated with increased mortality.

However, before you throw out all of your shampoo, note that ozone may form secondary respiratory irritants when it reacts with hair oil.

A better option would be to switch to non-toxic hair-care products - because chemicals in personal care products like shampoo and conditioner can also react with ozone in the air to form other harmful chemicals.

I recommend non-toxic personal care products, like Free & Clear Shampoo and Conditioner.

I also recommend avoiding those "ionic" air cleaners that emit ozone; opt for a safe, effective HEPA air purifier instead.