A Quantitative Analysis of the Cairclip O3/NO2 Sensor

• Author / Creator

  Reid, Brenda L

• Ozone (O3) and nitrogen dioxide (NO2) are two criteria pollutants that can result in adverse outcomes that effect both natural environments and human health. As these outcomes have a significant impact on people and their environments, it is necessary to closely monitor the levels of these gases in the ambient air. Currently, air quality monitoring in Edmonton is reported through the Air Quality Health Index (AQHI) as determined from measurements acquired from the four centralized ambient monitoring stations across the city. While the air quality data collected at the centralized monitoring stations provides the public with a generalized idea of the air quality for the day, they are unable to measure real time concentrations of near-field sources of pollutants based on an individual’s daily activity patterns. These unique activity patterns are specific to an individual and differ from one person to the next. The Cairclip sensor is representative of new technology in personal exposure monitors as they are small, lightweight and highly portable. In order to gain further understanding in the operational capacities and limitations of these sensors, the Cairclip O3 + NO2 sensor was tested in a two phase study. In phase one, the Cairclip was deployed at the Edmonton south monitoring station in order to determine their accuracy against the centralized monitor, as well as the level of precision between paired sensors. In phase two, the sensors were tested in various scenarios measuring near-field concentration exposures of O3 + NO2 at the personal level as well as at the subject’s residence. The findings of phase one precision resulted in a percent relative deviation (%RSD) for one hour averaged concentrations with outliers removed that ranged from +/-20% to +/-11%. Phase one accuracy was calculated using mean absolute percent difference (MAPD) for data sets screened for outliers and based on one hour averaged concentrations of O3 + NO2, these values ranged from +/-40% to +/-29%, respectively. In phase two, the Cairclips responded in a highly varied pattern when challenged during personal exposure monitoring in various settings where pollutant concentrations originated from near field sources. In conclusion, phase one determined that the level of accuracy of the Cairclips in contrast to the Edmonton south centralized station was poor. Personal exposure monitoring in various scenarios in phase two showed that the most significant findings were found in environments that are in close proximity to vehicular traffic and where sources of O3 and NO2 are prevalent due to gas-fired appliances. The specific settings were determined by the data collected in restaurants located close to high volumes of traffic and on public transit routes. Prior to use in further research, it is recommended that the accuracy and precision of the sensors be retested. In addition, further research in air monitoring of levels O3 and NO2 in closed, built environments and on various public transportation routes using the Cairclip may be warranted.  

• Subjects / Keywords

  • Real-time
  • Near-field sources
  • Personal air monitors

• Graduation date

  Spring 2015

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3CN6Z70T

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.