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Updated: May 25, 2026
08:14
Ammonia Synthesis at Low Pressure
Published on: August 23, 2017
Ammonia chemistry within Danish churches
Lilian Skytte1, Kaare Lund Rasmusen, Morten Ryhl-Svendsen
1Institute of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
The Science of the Total Environment
|January 24, 2012
Summary
Ammonia from farming activities is higher inside rural churches than outside. While ammonia contributes to aerosol decomposition, it likely does not cause salt damage to church murals.
Area of Science:
- Environmental Science
- Art Conservation Science
- Atmospheric Chemistry
Background:
- Agricultural intensification in Denmark has increased ammonia emissions, posing environmental challenges.
- Deterioration of rural church murals is a concern, with potential links to ammonia exposure.
- Ammonia's role in atmospheric processes and material degradation requires further investigation.
Purpose of the Study:
- To investigate ammonia concentrations inside and outside rural Danish churches.
- To determine the sources and mechanisms of indoor ammonia enrichment.
- To assess the potential risk of ammonia-induced salt damage to church murals.
Main Methods:
- Continuous monitoring of ammonia concentrations over 12 months in nine rural churches.
- Comparison of indoor and outdoor ammonia levels.
- Mass balance calculations to model ammonia sources and indoor enrichment.
- Analysis of soluble salts on church wall surfaces.
Main Results:
- Outdoor ammonia concentrations exhibited a spring maximum, correlating with agricultural activities.
- Indoor ammonia levels were, on average, three times higher than outdoor levels.
- Ammonium nitrate aerosol decomposition was identified as the primary source of indoor ammonia.
- Calcium nitrate was the predominant soluble salt found on wall surfaces, but in small quantities.
Conclusions:
- Agricultural ammonia emissions significantly impact indoor air quality in rural churches.
- The elevated indoor ammonia originates from the decomposition of deposited ammonium nitrate aerosols.
- Despite elevated ammonia and the presence of calcium nitrate, the quantities are likely insufficient to cause salt damage to the murals.
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