Had a dream bout children wearing gas masks

I feel compelled to share this with you all. I had this dream that I was in a larger city, the sky was blue and the weather was early spring (warm but not hot). There was a lot of activity in the sky, lots of airplanes, helicopters, and jets. Then we heard a loud boom, and I was scrambling to get out of this city. Before we left this city, I stopped at a store and paid for three gas masks for my children. It's probably just a dream, but it hasn't left me since I had it, and I can still feel it on the top of my head pounding my heart.