I noticed a trend of ticcing more when outside that I suspected was from increased lighting; particularly the glary type of light we get outside of the summer season. I was watching the interview of Billie Eilish and David Letterman and she even mentioned that lighting sets her tics off. Might be a sensory overload type of thing.
That said, yeah, soccer fields are sadly pesticide ridden (note pesticides include insecticides, herbicides, and fungicides).
Remember, it can be multiple aggravating factors coming together to push him over the limit.