Tiny White Pellets? - A Bizarre Question

I need to ask, because I am baffled...

Approx 5 days ago, i was out on my terrace on the border of CH & PH and at the very same time, a red helicopter and a commercial jet flew overhead. A few seconds after they passed i was being showered with teeny tiny white pellets. They resemble particles of styrofoam. It is days later and it has rained & been windy and they are still everuwhere, all over my oudoor spaces. Anyone have any clues about what the heck this could be? Im assuming it wasnt one of those pesticide spraying routines, but would really like to know what me & my family are surrounded by. Thanks neighbors.:)

Construction sites generate a lot of tiny styrofoam pellets.    They are all around us.

definitely construction debris. i used to live around all those Hello Living buildings on pacific st and when i'd leave my house on fine spring days i'd be showered with styrofoam from the construction. 

Hmmmm...i guess thats it...i think i assumed it was dropped by the helicopter or palne that flew overhead just as i was showered by them, but maybe the aircraft just stirred them up and forced them to disperse all over my place. Thanks for filling me in.

The pellets are safe. It's those "chemtrails" you need to be afraid of