I live in Redding, CA, where temps above 100 are pretty common. As long as you stay hydrated and keep moving, riding in temps up to 107 or so are not all that bad. It's important that it is a dry heat, because that allows your body's cooling systems to work more efficiently...especially since you're generating your own breeze as you ride.

I wouldn't want to tackle any big hills, or try to do interval training, when it's that hot. But for just getting home it's not too bad.

As for smoke - last summer we had intense forest fires nearby, with hazardous smoky conditions. I bought myself a Respro Sportsta filter, and found it worked really well. Without it, I could taste the smoke, and feel it in my lungs after my 7 mile commute. With it, the ride was tolerable...though the smoke still sucked.