Beitrag der Hofdüngerausbringung zu den Ammoniakimmissionen in ländlichen Gebieten der Schweiz : Eine Analyse der NABEL-Messungen 2006 – 2010

Abstract

Ammonia has been measured since 2006 in 10-minutes-resolution at five sites of the Swiss Air Pollution Monitoring Network, applying the photoacoustic method. Huge peak concentrations detected in the time series were suspected to originate from two types of emission sources: local application of (in particular liquid) farm manure or nearby stationary sources like stables or open manure storage basins. The aim of this study was to infer these two types of emission sources from the shape of the sequence of concentration of ammonia. Based on this identification, the ambient concentration was apportioned to these two types of emission sources for each site.Since the information on spreading farm manure was incomplete or did not exist at all at certain sites, a conventional statistical analysis such as a Random Forest analysis or a logistic regression could not be performed. However, typical temporal sequence patterns of ambient concentrations of ammonia could be constructed by comparing the sequences of ambient concentrations with corresponding logs of spreading farm manure, by comparing with data in literature, by statistical reasoning and by domain knowledge. Similar reasonings could be applied to temporal sequences dominated by stationary sources. These patterns were matched to the observed ambient concentration sequencies, using regular expressions. The signals found were finally compared to the logged events.An fünf Standorten des NABEL-Messnetzes wird seit 2006 Ammoniak (NH3) mit der photoakustischen Messmethode kontinuierlich gemessen. Erste Auswertungen zeigten immer wieder Spitzenbelas­tungen, von welchen vermutet wurde, dass sie durch örtlich nahe gelegene Ereignisse wie z.B. Dünge­aktivitäten der Landwirte oder Abluftfahnen von Ställen und Güllelagern verursacht worden waren. Ziel dieser Arbeit war zu untersuchen, ob aus dem Verlauf der NH3-Konzentrationen auf die Art der Emissionsquelle geschlossen werden kann. Insbesondere interessierte, welche beobachteten Peaks der Ausbringung von Gülle und Mist auf Feldern und welche den Abluftfahnen stationärer Quellen zugeordnet werden können. In einem zweiten Schritt sollte für die betrachteten Standorte der Anteil der Immissionen abgeschätzt werden, welche durch die lokale Ausbringung von Gülle und Mist verursacht wurde. Da die Informationen zu den Düngeaktivitäten an den verschiedenen Orten zu lückenhaft waren, konnte keine konventionelle statistische Analyse in Form einer Random-Forest-Analyse oder einer logistischen Regression durchgeführt werden. Durch Vergleich der Immissionsmessungen mit den Protokollen zur Ausbringung des Hofdüngers konnten jedoch unter Zuhilfenahme von lufthygienischen und statistischen Argumenten und mittels Vergleich mit Literaturangaben typische Immissionsverläufe konstruiert werden, welche nach Ausbringung von Hofdünger in der näheren Umgebung zu erwarten sind. Analoge Überlegungen wurden auch zu den Immissionsverläufen gemacht, welche durch emittierende stationäre Quellen beeinflusst werden. Mittels regulären Ausdrücken (regular expressions) wurden diese Muster anschliessend in den vorhandenen Immissionsdaten gesucht und die gefundenen Ereignisse mit den protokollierten verglichen.Ammonia has been measured since 2006 in 10-minutes-resolution at five sites of the Swiss Air Pollution Monitoring Network, applying the photoacoustic method. Huge peak concentrations detected in the time series were suspected to originate from two types of emission sources: local application of (in particular liquid) farm manure or nearby stationary sources like stables or open manure storage basins. The aim of this study was to infer these two types of emission sources from the shape of the sequence of concentration of ammonia. Based on this identification, the ambient concentration was apportioned to these two types of emission sources for each site. Since the information on spreading farm manure was incomplete or did not exist at all at certain sites, a conventional statistical analysis such as a Random Forest analysis or a logistic regression could not be performed. However, typical temporal sequence patterns of ambient concentrations of ammonia could be constructed by comparing the sequences of ambient concentrations with corresponding logs of spreading farm manure, by comparing with data in literature, by statistical reasoning and by domain knowledge. Similar reasonings could be applied to temporal sequences dominated by stationary sources. These patterns were matched to the observed ambient concentration sequencies, using regular expressions. The signals found were finally compared to the logged events