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AQD-NOxWerx instruments are ruggedly constructed to withstand the adverse conditions often encountered where the gas concentrations become trace.  Our clients have deployed instruments from the Amazon to the polar regions. Long-term operation under some conditions requires periodic depot maintenance, so we also get the opportunity to assess what works best over time and thereby improve our designs from the experience. Working with the researchers that use our instruments to make the trace gas measurements they need is both our specialty and privilege. The "Featured Application" below presents an example of how and where our instruments are used.



Featured Application


The Cape Verde Atmospheric Observatory, NERC, U.K.

(click for pdf)


The field site

The Cape Verde Atmospheric Observatory (CVAO) is operated by the UK National Center for Atmospheric Science which is part of the UK National Environmental Research Council (NCAS/NERC). The site is a World Meteorological Organisation-Global Atmospheric Watch (WMO-GAW) global station. The location of the site is shown in Figure 1 and a photograph of the site is shown in Figure 2. For more information about their program visit:


The AQD system

A single channel high-performance snooper with NOx and NOy inlet converters was deployed at the site in 2006.

The system was upgraded to a two-channel instrument with additional NOy sampling modes in 2009.

The field site has proved difficult to keep instruments alive at due to the incessant surf spray and warm temperatures. In the same connection, the site has provided an opportunity for us to improve our instruments based on identifying the materials, components and processes that enable high performance in this severe environment. The research being performed by the NCAS scientists has required development of a couple of novel approaches for the sampling and speciation of NOy by AQD. 


 Figure 1.  The CVAO (yellow star) is located on the coast of the island of Sao Vicente in the Cape Verde Islands located 600 miles west of Senegal.  The Observatory is unique since the ocean floor drops precipitously around the islands, providing the opportunity to examine the air chemistry above the open ocean from a reasonably accessible ground site.


Figure 2.  View looking southwest across the CVAO.  The deep water near-offshore is a primary reason for the siting of the observatory.  


Air sampling over and on Antarctica, 2005.