Jason

Do you mean Nitrogen (N2) or a nitrogen product such as nitrogen dioxide (NO2)?

If nitrogen then very unlikely to be an emissions issue, since the air around us is nearly four fifths nitrogen.

Could present a localised risk by creating a "confined space", as it is an asphyiant gas, so emissions could result in oxygen deficiency. But that would not usually be described as an "emissions" issue.

In contrast, some nitrogen products, including NO2 present significant environmental threats.

Sampling in itself is a waste of time. What you need to do is to establish is the likely exposure by your staff to the NO2 and find out if the exposure is likely to excess or even approach the WEL.

You will need to see how much it produces over what time frame and what the concentration will be in the work area. You will also need to establish how that the people will be actually breathing on the gas. A lot of high voltage equipment produces some NO2  but unless it is in a very small poorly ventilated area it is very rarely a problem.

You say that your customer is developing a machine, so that I take it means that they are the manufacturer, whether for sale or for their own use.

Therefore the primary legislation that they need to comply with is the Supply of Machinery Safety Regulations.

This requires compliance with the EHSR's of the legislation.  They have a route to conformity with a presumption of conformity should they wish by compliance with the harmonised standards.

The relevant EHSR is:

1.5.13. Emissions of hazardous materials and substances Machinery must be designed and constructed in such a way that risks of inhalation, ingestion, contact with the skin, eyes and mucous membranes and penetration through the skin of hazardous materials and substances which it produces can be avoided. Where a hazard cannot be eliminated, the machinery must be so equipped that hazardous materials and substances can be contained, evacuated, precipitated by water spraying, filtered or treated by another equally effective method. Where the process is not totally enclosed during normal operation of the machinery, the devices for containment and/or evacuation must be situated in such a way as to have the maximum effect.

I would suggest that your client follows the path in the relevant C-type standard for the equipment, failing this, then fall back on the B-type documents for guidance.  Some alternative C-type documents may give guidance also.  Then there is the A-type which gives them the procedure for this compliance.

If they do not follow the harmonised standards then their technical file will need to be much more complex and give details on how their design will meet the EHSR's with before and after safety systems have been implemented risk assessments of the equipment.

This we find is alien to most engineers and H&S practitioners because it is a mindset change. 

However, it is what is considered as required to meet the legislation and is certainly what the standards require.