Low Humming Sounds in Air in Amherst Area

For the past week or so, I've been hearing a very low frequency humming sound. It's not coming from anything electronic in the house.

It's hard to hear, and my business partner only can hear it a little from time to time. For me, it's constant with only a few breaks here and there.

Spraying this week has been horrible too. Salty metallic taste to the air in the daytime. Chemical taste to the air at night.