Presentation Title

Low Cost Instrument That Measures Ozone Concentration in Air Based on Optical Scattering

Start Date

November 2016

End Date

November 2016

Location

HUB 302-110

Type of Presentation

Poster

Abstract

The purpose of this research is to propose a portable low-cost device capable of detecting concentrations of ozone (O3) in the air using the principle of Optical scattering. Detection is important because high concentrations of O3 in the ambient air damages plants and animals. Peak absorption for O3 is in the ultraviolet (UV) range (220 - 290nm) but UV lamps are expensive. O3 has a second absorption peak in the visible spectrum (600 - 630nm) and therefore an inexpensive light-emitting-diode (LED) may be able to be substituted for a UV lamp. The device consists of a small rectangular prism with three mutually orthogonal cylindrical ducts that meet in a dark sensing chamber at the center of the device. Sampled air is pumped using a micro pump at a constant rate through the chamber where the light emitted from the LED will cross the stream of air orthogonally. The light is scattered by the molecules in the sampled air and a fraction is detected by a phototransistor which is placed in the duct orthogonal to the steam of air and the LED. The signal from the phototransistor is amplified and fed into a microcontroller for signal processing to determine the concentration of O3 in the air. Estimates of the cost of the device puts it in a range of $90 to $120. This is significantly less than O3 testing devices made with a UV lamp. The device is also small enough that it could be made portable if focus is put on the overall design. Construction and testing is needed to determine the feasibility and accuracy of the device in practice.

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Nov 12th, 1:00 PM Nov 12th, 2:00 PM

Low Cost Instrument That Measures Ozone Concentration in Air Based on Optical Scattering

HUB 302-110

The purpose of this research is to propose a portable low-cost device capable of detecting concentrations of ozone (O3) in the air using the principle of Optical scattering. Detection is important because high concentrations of O3 in the ambient air damages plants and animals. Peak absorption for O3 is in the ultraviolet (UV) range (220 - 290nm) but UV lamps are expensive. O3 has a second absorption peak in the visible spectrum (600 - 630nm) and therefore an inexpensive light-emitting-diode (LED) may be able to be substituted for a UV lamp. The device consists of a small rectangular prism with three mutually orthogonal cylindrical ducts that meet in a dark sensing chamber at the center of the device. Sampled air is pumped using a micro pump at a constant rate through the chamber where the light emitted from the LED will cross the stream of air orthogonally. The light is scattered by the molecules in the sampled air and a fraction is detected by a phototransistor which is placed in the duct orthogonal to the steam of air and the LED. The signal from the phototransistor is amplified and fed into a microcontroller for signal processing to determine the concentration of O3 in the air. Estimates of the cost of the device puts it in a range of $90 to $120. This is significantly less than O3 testing devices made with a UV lamp. The device is also small enough that it could be made portable if focus is put on the overall design. Construction and testing is needed to determine the feasibility and accuracy of the device in practice.