Nitrogen oxide emissions (NOx)

While being a very willing proponent for the RMH, I notice that there is a dearth of resource on the emissions with regards to products of combustion at high temperatures, specifically nitrogen in its varied oxidation states.  An appropriate analogy would be to make would be with the modern diesel emissions standards - while there is little visible smoke, as the diesel engine is running lean (and thus hot) NOx are greater than the cooler gasoline (or petrol for UK folk) engine.  In recent times, this has been modulated with ADBlue.
Is there any useful information out there on this issue?

There's some information available on NOx emissions for two different batchrocket heaters. The new EU rules stipulate that the NOx emissions shouldn't be higher than 200 mg/m³ on average for more than one test run, expressed as NO², at 13 % O².

One of the test results gives 134 mg/m³ as the average of two test runs. The other one gives 142 mg/m³ as the average of three test runs. Both well within the existing rules published on April 24, 2015.

Regarding results of testing J-tube rockets aren't available, to me anyway.