Ok JJJ, Astroron and Suzy;
I'm not saying that micrometeorites don't exist ! After all, the entire Earth was some kind of meteor, at some stage !!
All I'm saying is that rooftops gather a lot of other contaminants, which would require separation by some, (several) means, before sending it off to a lab.
Depending on your location (remember there are lots of us who live in cities), you'd have to consider the history of the collection site.
David: Cool instrument .. that, and a microscope is what I'm talkin' about !
Cheers
PS: Does anyone know what the lab analysis costs ?
