Physical state of air Solar radiation ultraviolet radiation vUV-A:320-400nm √UVB:275-320nm VUV-C: 200-275nm Meteorological factor: adjust, pollutant Air ionizationPhysical state of air • Solar radiation: ultraviolet radiation ✓UV-A: 320-400nm ✓UV-B: 275-320nm ✓UV-C: 200-275nm • Meteorological factor: adjust, pollutant • Air ionization