Measurement of total reactive nitrogen, NOy, together with NO2, NO, and O3via cavity ring-down spectroscopy

US9804138B2 · kind B2 · utility

Assignee

• The United States of America · US

Inventors

• Steven S. Brown · Boulder, US
• William P. Dube · Denver, US
• Robert J. Wild · Boulder, US

Key dates

• Filing date: May 27, 2015
• Grant date: Oct 31, 2017
• Expiry date: May 27, 2035

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02A50/20
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A sensitive, compact detector measures total reactive nitrogen (NOy), as well as NO2, NO, and O3. In all channels, NO2 is directly detected by laser diode based cavity ring-down spectroscopy (CRDS) at 405 nm. Ambient O3 is converted to NO2 in excess NO for the O3 measurement channel. Likewise, ambient NO is converted to NO2 in excess O3. Ambient NOy is thermally dissociated at 700 C to form NO2 or NO in a heated quartz inlet. Any NO present in ambient air or formed from thermal dissociation of other reactive nitrogen compounds is converted to NO2 in excess O3 after the thermal converter. The precision and accuracy of this instrument make it a versatile alternative to standard chemiluminescence-based NOy instruments.