A Compact Optical Virus Detection Analyzer (COVDA) uses light scattering and fluorescence to detect nanometer (nm) and micrometer (um) sized particles, such as biological particles and can be used to detect viruses such as coronavirus including SAR-CoV-2 responsible for COVID-19, pollen and bacteria. It can be used for prescreening, rapid detection of suspicious people. COVDA involves experimental and theoretical methods for particle and virus detection using Tryptophan as a key biomarker. Light sources in compact units include lamps such as Xenon (Xe) lamp with narrow band filters, LEDs (such as AlN) or laser diode, Q switched and mode lock Lasers for nanosecond and picosecond pulses (such as Nd Yag/Glass, Ti sapphire with Harmonic generator) in blue from 400 nm to 500 nm to generate second harmonic generation (SHG) in KDP/BBO crystals to produce 200 nm to 250 nm emission, or green laser pointers at about 530 nm to get emitters with harmonic crystals at about 270 nm or LEDS from 230 nm to 300 nm for pumping the samples at 230 nm to 289 nm to pump tryptophan and light scatter of nanometer particles of virus. The ultra high power ns and ps lasers in mJ to J can level can be used to locate Bio virus bacteria clouds in free space to image and destroy and kill virus.