Dear Elly,

just for clarification: You want to measure the VOC in pig sties, that are responsible for the typically bad smell? Then you want to compare them before and after you installed a system to reduce the smell?

There are a lot of variables to consider and my answer - by all means - won't be comprehensive, but hopefully it will still be helpful.

For VOC analysis I would suggest glass desorption liner (as used for GC-MS systems) stuffed with a suitable adsorbent, for which I would also suggest to use Tenax TA. This adsorbent shows good results for all kinds of VOCs and is standard for VOC analysis in some fields. Also you won't have much problem with higher humidity as Tenax shows low retention of water.

This desorption liner can be thermally desorbed with a Thermal Desorption Unit (TDU) coupled to a GC-MS system.

With a GC-MS analysis you can identify your VOCs and either try a calibration to quantitate them (which proves rather difficult with some substances) or you can just qualitatively compare your peak areas before and after the installation of your system and check if some substances are not present any more. Depending on the kind of statement you want to make. A calibration surely gives your statement a better stand but it is also coupled to a greater workload.

Do you already have identified the VOC that are responsible for the “bad smell” or is this a task you will also perform? Because you will find a lot of VOCs in your air samples regardless of how well your system works. So first of all you should identify the typical substances that one would identify with the smell of a pig sty. Which will mean a whole lot of measurements of the pig sty (at best different pig sties). And there is another immense list of factors and variables to consider when you try to identify smell components.

Let’s assume you already have identified at least a few of them, then you should check only for these substances and if they get fewer after your installation.

As for the equipment you need and the costs, that depends on what you already have. You would clearly need air pumps, desorption liners filled with Tenax (that are suitable for your TDU), a GC-MS System with such a TDU – or a GC-MS System which you can upgrade with such a sampler device….

If you want to calibrate you will need standard solutions of your analytes and if you want to identify unknown substances with the MS you would surely need a database to compare your findings to.

You should make yourself a list of the different parts of your experiments, then it will be easier to say which kind of equipment you will definitely need need.

I hope this helps you and gives you some new input.

Best regards,

Kristina

Dear Elly - Iowa State University has a very good "starting point" for air quality and animal production systems - i.e., Air Management Practices Assessment Tool (AMPAT):

http://www.agronext.iastate.edu/ampat/homepage.html.  

AMPAT's purpose is "The purpose of the Air Management Practices Assessment Tool (AMPAT) is to provide an objective overview of mitigation practices best suited to address odor, emissions and dust at your livestock operation so that livestock and poultry producers may compare and narrow their options of mitigation techniques. Practices are divided into three categories by source: 1) Animal Housing; 2) Manure Storage & Handling; and 3) Land Application."

The cost is addressed in AMPAT with user-friendly $-to-$$$ ranking.  Your point is well-taken - the cost is critically important especially for agricultural applications. 

We also published an open access companion review article on performance data for mitigation technologies: 

Maurer, D., J.A. Koziel, J.D. Harmon, S.J. Hoff, A.M. Rieck-Hinz, D.S Andersen. Summary of performance data for technologies to control gaseous, odor, and particulate emissions from livestock operations: Air Management Practices Assessment Tool (AMPAT).  Data in Brief, 7, 1413-1429. doi: 10.1016/j.dib.2016.03.070.

The AMPAT website has a direct access to the Summary spreadsheets on Scientific Literature that shows if and how effective control technologies were in actual farm-scale applications:

http://www.agronext.iastate.edu/ampat/database/homepage.html

Good luck with your research,

Jacek

http://www.agronext.iastate.edu/ampat/homepage.html

http://www.agronext.iastate.edu/ampat/database/homepage.html

http://dx.doi.org/10.1016/j.dib.2016.03.070

Thank so much Kristina and Jacek for your responses! The questions Kristina is asking for clarification are the exact ones I am also asking.

Thanks once again.

Elly

I would add to Kristina's comment that SPME could be a cheaper option: a desorption unit is not needed, but you still nedd the GC. The proper SPME phase should be chosen. Perhaps this is of help:

http://www.ncbi.nlm.nih.gov/pubmed/17679445

Article Characterization of volatile effluents of livestock building...

Thanks Jorge!