Efficacy of Paired Electrochemical Sensors for Measuring Ozone Concentrations

Details

• Alternative Title:
  J Occup Environ Hyg
• Personal Author:
  Zuidema, Christopher ; Afshar-Mohajer, Nima ; Tatum, Marcus ; Thomas, Geb ; Peters, Thomas ; Koehler, Kirsten
• Description:
  Typical low-cost electrochemical sensors for ozone (O|) are also highly responsive to nitrogen dioxide (NO|). Consequently, a single sensor's response to O| is indistinguishable from its response to NO|. Recently, a method for quantifying O| concentrations became commercially available (Alphasense Ltd., Essex, UK): collocating a pair of sensors, a typical oxidative gas sensor that responds to both O| and NO| (model OX-B431) and a second similar sensor that filters O| and responds only to NO| (model NO2-B43F). By pairing the two sensors, O| concentrations can be calculated. We calibrated samples of three NO2-B43F sensors and three OX-B431 sensors with NO| and O| exclusively and conducted mixture experiments over a range of 0-1.0 ppm NO| and 0-125 ppb O| to evaluate the ability of the paired sensors to quantify NO| and O| concentrations in mixture. Although the slopes of the response among our samples of three sensors of each type varied by as much as 37%, the individual response of the NO2-B43F sensors to NO| and OX-B431 sensors to NO| and O| were highly linear over the concentrations studied (R| ≥ 0.99). The NO2-B43F sensors responded minimally to O| gas with statistically non-significant slopes of response. In mixtures of NO| and O|, quantification of NO| was generally accurate with overestimates up to 29%, compared to O|, which was generally underestimated by as much as 187%. We observed changes in sensor baseline over 4 days of experiments equivalent to 34 ppb O|, prompting an alternate method of calculating concentrations by baseline-correcting sensor signal. The baseline-correction method resulted in underestimates of NO| up to 44% and decreases in the underestimation of O| up to 107% for O|. Both methods for calculating gas concentrations progressively underestimated O| concentrations as the ratio of NO| signal to O| signal increased. Our results suggest that paired NO2-B43F and OX-B431 sensors permit quantification of NO| and O| in mixture, but that O| concentration estimates are less accurate and precise than those for NO|.
• Subjects:
  Air Pollutants Electrochemical Techniques Environmental Monitoring Nitrogen Dioxide Ozone
• Source:
  J Occup Environ Hyg. 16(2):179-190
• Pubmed ID:
  30412037
• Pubmed Central ID:
  PMC10494896
• Document Type:
  Journal Article
• Funding:
  R01 OH010533/OH/NIOSH CDC HHSUnited States/ ; R01OH010533/ACL/ACL HHSUnited States/ ; T42 OH008428/OH/NIOSH CDC HHSUnited States/ ; T42OH008428/ACL/ACL HHSUnited States/
• Volume:
  16
• Issue:
  2
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:5b00b76662d76fea3d5f8b92adf28341ade46176901f6454772ac8202a4ee96c
• Download URL:
  https://stacks.cdc.gov/view/cdc/132904/cdc_132904_DS1.pdf
• File Type:
  [PDF - 853.09 KB ]