The video mentions a variety of hydrocarbons emitted from fracking sites (and a noticeable smell), which would be a plausible cause, no? That said, I don't have a dog in this fight and no strong opinions, and happy to be educated with better facts.

EDIT: Potentially of interest - "Fracking is linked to asthma increase, study finds" https://www.proquest.com/openview/38707d6ad223efa2d5ac7f3bb8...