I started from the Portal on the 4th as well.
There was some haze due to fire smoke drifting from the west that worried me (low oxygen + smoke particles = not great for breathing). Some people coming down mentioned it affected the view from the summit the prior day. Fortunately, it cleared up by the afternoon (wind shifted) and had a great sunset and sunrise at Trail Camp before my summit hike on the 5th (made it!).
What a view all the way up and down. I'll probably put together a trip report when I have a chance to sort through my 2500+ photos.