Never heard of nanobots being sprayed in the Solar Radiation Management program run by the CIA and Air Force, but I definitely know about Aluminum Oxide NANO-PARTICLES which when injected in the atmosphere along with Sulphuric Acid H2SO4, the inert Aluminum Oxide becomes available and free.  Breathing free Aluminum into the lungs is very harmful, in your bloodstream it is a NEUROTOXIN which can affect the brain, loss of memory and motor functions.  These same NANOPARTICLES are also harmful to plant life as free Aluminum will DISPLACE Magnesium in chlorophyl (thylakoids) which is essential for photosynthesis.  Once this occurs photosynthesis in the leaf will stop.  Coniferous trees are the most susceptible and  will weaken, yellow with needle drop then die.