it could also be run-of-the-mill chemicals sprayed into the sky. I and my friend experienced a chemtrail cough that lasted for 2 weeks in December. Exact same timing, exact same symptoms after we drove through a cloud of fog crap / chemtrails that I’d been taking photos of on the drive. It smelled like burnt tires. We both immediately started coughing and felt unwell by the end of the night. One of the symptoms was lack of appetite and smell.