Spatial and temporal variability of atmospheric ammonia using a dense network in an area with livestock, residential and natural environments intertwined

Le résumé fourni par la source

Atmospheric ammonia (NH 3 ) emissions and depositions have been linked to negative effects on human health and biodiversity. National monitoring networks have documented large spatial variation of NH 3 concentrations related to agricultural activities, including livestock pollution. Little is known about spatial and temporal variation of livestock-related ammonia concentrations in areas where residential and nature areas are located nearby intensive livestock farming. The objective of this study was to assess the spatial and temporal variability of ambient ammonia in such a mixed land-use area within the Netherlands. A dense air quality network was set up with 71 sites spanning over 1027 km 2 within rural and semi-urban (small towns) areas, and nature reserves. Ambient ammonia concentrations were measured monthly with passive samplers from March 2022 to February 2024. Ammonia measurements showed large spatial and temporal variation. Spatial variation was related to the number of livestock farms in a 3000m buffer around sites and inverse distance to the nearest farm. Mean concentrations were 13.6 μg/m 3 (rural), 9.6 μg/m 3 (semi-urban) and 5.1 μg/m 3 (nature sites). Seasonal patterns, highest in spring and lowest in winter, were similar in rural, semi-urban and natural sites. The highest concentrations were observed in March 2022, coinciding with manure application and stable weather conditions. Temporal variability related to temperature, rainfall, manure application, atmospheric pressure and relative humidity. Multivariate models explained 52-80% of the temporal variance component, depending on time period. Our spatial and temporal analyses provide further evidence that farming emissions impact NH 3 concentrations both locally and at greater distances.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.