Efficacy of Paired Electrochemical Sensors for Measuring Ozone Concentrations

Details

• Personal Author:
  Afshar-Mohajer N ; Koehler K ; Peters T ; Tatum M ; Thomas G ; Zuidema C
• Description:
  Typical low-cost electrochemical sensors for ozone (O3) are also highly responsive to nitrogen dioxide (NO2). Consequently, a single sensor's response to O3 is indistinguishable from its response to NO2. Recently, a method for quantifying O3 concentrations became commercially available (Alphasense Ltd., Essex, UK): collocating a pair of sensors, a typical oxidative gas sensor that responds to both O3 and NO2 (model OX-B431) and a second similar sensor that filters O3 and responds only to NO2 (model NO2-B43F). By pairing the two sensors, O3 concentrations can be calculated. We calibrated samples of 3 NO2-B43F sensors and 3 OX-B431 sensors with NO2 and O3 exclusively and conducted mixture experiments over a range of 0-1.0 ppm NO2 and 0-125 ppb O3 to evaluate the ability of the paired sensors to quantify NO2 and O3 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 NO2 and OX-B431 sensors to NO2 and O3 were highly linear over the concentrations studied (R2 ? 0.99). The NO2-B43F sensors responded minimally to O3 gas with statistically non-significant slopes of response. In mixtures of NO2 and O3, quantification of NO2 was generally accurate with overestimates up to 29%, compared to O3, which was generally underestimated by as much as -187%. We observed changes in senor baseline over 4 days of experiments equivalent to 34 ppb O3, prompting an alternate method of calculating concentrations by baseline-correcting sensor signal. The baseline-correction method resulted in underestimates of NO2 up to 44% and decreases in the underestimation of O3 up to 107% for O3. Both methods for calculating gas concentrations progressively underestimated O3 concentrations as the ratio of NO2 signal to O3 signal increased. Our results suggest that paired NO2-B43F and OX-B431 sensors permit quantification of NO2 and O3 in mixture, but that O3 concentration estimates are less accurate and precise than those for NO2. [Description provided by NIOSH]
• Subjects:
  Nitrogen Dioxide Occupational Health Ozone Safety
• Keywords:
  Electrochemistry Environmental Health Gases Nitrogen Dioxide Sampling Sensors
• ISSN:
  1545-9624
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Iowa ; Maryland ; OSHA Region 3 ; OSHA Region 7
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  179-190
• Volume:
  16
• Issue:
  2
• NIOSHTIC Number:
  nn:20053619
• Citation:
  J Occup Environ Hyg 2019 Feb; 16(2):179-190
• Contact Point Address:
  Kirsten Koehler, PhD, Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St. Room E6632, Baltimore, MD 21205
• Email:
  kirsten.koehler@jhu.edu
• CAS Registry Number:
  Nitrogen dioxide (CAS RN 10102-44-0)
• Federal Fiscal Year:
  2019
• Performing Organization:
  Johns Hopkins University, Baltimore, Maryland
• Peer Reviewed:
  True
• Start Date:
  20140901
• Source Full Name:
  Journal of Occupational and Environmental Hygiene
• End Date:
  20180831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:035477fd0c9153ed425b0c96817e5fb5de325e541da90c2a54d8917e761b8fc13a21ab2617235ebc300931cec0fe1a258b48390886f2b991b507417b4f2cb585
• Download URL:
  https://stacks.cdc.gov/view/cdc/216345/cdc_216345_DS1.pdf
• File Type:
  [PDF - 2.21 MB ]