Effect of temperature, pressure and humidity on carbon dioxide concentration-simulation study

Abstract

The growing application of infrared carbon dioxide (CO2) sensor now needs an accurate and precise measurement of human respired CO2 concentrations. CO2 concentration measurement is influenced by a number of environmental parameters. The objective of this study is to perform a simulation study on the list of environmental parameters which have a major influence on the precision and accuracy of the infrared CO2 sensor. Here, we designed a CO2 concentration estimation circuit that comprises temperature, pressure and humidity sensor, Arduino Uno, and liquid crystal display. Besides, a program is written and uploaded to the Arduino board to compute the CO2 concentration. A simple mathematical equation is employed to calculate the instantaneous CO2 concentrations with respective temperature, pressure and relative humidity. We observed a change in CO2 concentration from 31.11% to 30.60% and 21.25% to 26.18% corresponding to changes in temperature from 25oC to 30oC and pressure 21.53kPa to 26.52kPa, respectively while keeping the temperature (250C) and pressure (31.52kPa) constant with respect to each other. In addition, with a change in relative humidity from 28% to 30%, change in CO2 values (6.26% to 9.39%) were observed while temperature kept at 25 0C. Results show that pressure, temperature, and relative humidity have a significant effect on the output of CO2 concentration. Hence, this should not be underestimated while developing a CO2 sensor and barometric pressure, temperature, and relative humidity sensor should be integrated with CO2 sensor for automatic adjustment in CO2 concentration based on the current pressure, temperature and humidity in contrast to manual.