Mere looking at the prompt, it is obvious to me that it is a figurative expression than literal one. Because combining blast and air will give you no good yield, the air that comes after a blast is polluted already with fuel fumes.
So, the only solution is a figurative expression which can mean an abundance of air coming from a blast, while neglecting the polluted part because it is an expression, the blast never happened. It is a cracker, and a lovely. I really love the expression!
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