Ozone Module Siting Guide

The Clarity Node-S + Ozone Module needs to be sited properly to provide useful ozone data: the ozone module placement should ultimately be based on the goals of the project, but a few things should be kept in mind for ozone monitoring:

• Ozone is titrated by NOx, so if the monitor is placed in an area with sources of NOx the measured concentration will be lower than in nearby areas farther from the source of NOx
• Ozone is scrubbed by vegetation such as trees and bushes, so adequate distance between vegetation and the monitor should be maintained
• The US EPA has guidelines for siting ozone monitors that addresses the above considerations in Section 7 of the Quality Assurance Handbook for Air Pollution Measurement Systems and in United States’ Code of Federal Regulations Appendix E to Part 58 - Probe and Monitoring Path Siting Criteria for Ambient Air Quality Monitoring

Siting Distance Guidance

• Distance of monitoring path to an obstacle, such as a building, must be at least twice the height the obstacle protrudes above the monitor.
• The monitor should have unrestricted airflow 270 degrees around the probe or sampler; 180 degrees if the probe is on the side of a building.