What the hell do they put in those air fresheners?

I was sitting in the office last night wondering why my head was spinning and i was beginning to feel sick. Then I realised. We've just bought one of those ambi-pure plug in air freshener things. At first we had the fragrance that's meant to smell like newly bathed baby. (Molly reckoned it smelt more like baby poo, but we liked it).

But to stop us getting attenuated to the smell we swapped it for the one that's meant to smell like cut grass. To say it's stronger would be a huge understatement. It's overwhelming.
And it's making me ill.
Time for a change I think.