If there were significant amounts of heavy metals suspended in the atmosphere, then you would be able to do some spectroscopy of the sunlight and see the absorption lines that match various heavy metals. You could even build some pretty capable DIY spectroscopes using a webcam, a DVD for diffraction grating and a few other household items. There is freely available software for DIY and professional spectroscopes and large catalogs of absorption lines for many materials available on the internet. I've done a some experimentation with this years ago but never saw any characteristic absorption lines that would support the theory that there are aerosol metals in the atmosphere. Until someone can provide a source of some spectral analysis showing heavy metal absorption lines that can be reproduced by independent parties, then I will not subscribe to the notion that there is any significant quantity of such metals suspended in the atmosphere and causing weather/climate effects.