Could you critique, please?

It's all right. You could combine the first two sentences into, "The cool autumn air was so brisk that it stabbed at lung and froze throats." But really, the Second sentence doesn't make much sense. A cool air doesn't really stab lunges or freeze throats; that's more of a winter air. And again, it's mentioned that he's freezing, but that's more of a winter thing than autumn.