WTF is this on my leaves, anyhoo?

I've had some minor problems with nute burn and high PH but I thought I'd cleared them up... I was looking through my plants today and was shocked to find this damaged leaf. It is damaged extensively, far worse than any of the other older leaves which had problems previously. The damage looks pretty new; if anyone can tell me what this might be I'd greatly appreciate it so I can 'nip it in the bud', so to speak...

Your pictures are to blurry to really tell. My guess it's either nute burn or light burn. How close are your plants to the light?

-PEACE

it's breast cancer, nothing you can do

It looks like atmostsperic damage. Do you have an ionizer anywhere close to your plants area? Or any kind of odor cover other then a scrubber?