Low-cost Ozone Measurement Device in the Chappuis Band

Ground level ozone in the atmosphere is an air pollutant. This is formed in the atmosphere through a complex reaction of the chemical substances emitted from the vehicles, plants and many other sources. Its presence close to the earth is harmful to humans, animals, plants and non-living things. Different countries have different permissible level of concentration of ozone in the atmosphere. The Central Pollution Control Board of India has set the permissible limit for ozone concentration at 100 ?g/m3 over 8 hours. Hence, it is very essential to know the concentration of ozone in the atmosphere for healthy living. There are various types of ozone measurement devices. Optical absorption based UVC-type ozone measurement devices are costly and there is necessity to replace ozone scrubbers used in those devices at regular intervals. Mercury lamps used in these optical absorption based ozone measurement devices produce harmful UVC rays. Mercury lamps also have a shorter life period. To overcome these shortcomings, a low cost LED based Ozone measurement device has been developed and concentration of ozone can be measured by this device. In this investigation, Yellow-Green, Diffused Yellow, DIP Yellow, Amber, and Orange LEDs have been used to generate incident light sources from 573 nm to 605 nm wavelengths. In the detector stage, available 565 nm and 580 nm peak sensitivity photodiodes have been used to measure the reduced intensity using the Beer-Lambert Law. It is found that DIP and Diffused yellow LEDs show better results among these LEDs when tested by 565 nm and 580 nm photodiodes. The use of LEDs and Photodiodes makes this system low-cost in comparison to other available ozone-measuring systems.