This dataset contains information about meteorological conditions and ammonia concentration and deposition rates resulting from an experimental setup. An NH3 enhancement experiment along with a full suite of multi-height meteorological measurements was established in a tropical forest in central Sri Lanka. Under suitable wind conditions measured at the meteorological tower, NH3 is released towards two monitoring transects. Along the downwind monitoring transects, NH3 concentrations in the air are measured using monthly passive samplers. Deposition rates are modelled using a bi-directional resistance model based on measured NH3 concentrations in the air, micrometeorology and plant physiology. Additionally, NH3 concentrations were measured at high temporal resolution at a fixed downwind distance from the source to achieve the target enhancement concentrations. The work was supported by UKRI GCRF South Asian Nitrogen Hub (Grant NE/S009019/1). Full details about this dataset can be found at https://doi.org/10.5285/998c2b2b-7470-42b0-81e7-409b91752377

This dataset holds survey data of individual farming households in the Eastern region in Bhutan relating to their nitrogen use. The survey was conducted in 2022 and the questions covered two seasons (2022 and 2021 farming seasons) asked at a single visit in the 2022 season. The questions on the winter season were based on recall. The data cover the following topics: household characteristics, general farm characteristics, plot characteristics, crop production and harvest, synthetic and organic fertiliser use and compost production, labour, irrigation, pesticides, livestock, information sources, drivers of and barriers to adoption of sustainable practices, attitude, behaviour, perception and opinion, household expenditure and income, household asset and wealth, subsidies. The data were collected primarily to assess differences in nitrogen use efficiency (NUE) and sustainable nitrogen practices between households. The data also aim to enhance understanding of farmers’ attitudes, opinion and decision making affecting NUE in crop production and farm related factors which enable adoption of sustainable practices. The data are part of a wider SANH (South Asian Nitrogen Hub) harmonised household survey covering Bangladesh, India, Maldives, Nepal, Pakistan and Sri Lanka. Full details about this dataset can be found at https://doi.org/10.5285/cd35ca67-8121-4a0d-81c9-c4a7fae25117

This dataset holds survey data of individual farming households in the Terai region in Nepal relating to their nitrogen use. The survey was conducted in 2022 and the questions covered two seasons (summer and winter) asked at a single visit in the summer season. The questions on the winter season were based on recall. The data cover the following topics: household characteristics, general farm characteristics, plot characteristics, crop production and harvest, synthetic and organic fertilizer use and compost production, labour, irrigation, pesticides, livestock, information sources, drivers of and barriers to adoption of sustainable practices, attitude, behaviour, perception and opinion, household expenditure and income, household asset and wealth, subsidies. The data were collected primarily to assess differences in nitrogen use efficiency (NUE) and sustainable nitrogen practices between households. The data also aim to enhance understanding of farmers’ attitudes, opinion and decision making affecting NUE in crop production and farm related factors which enable adoption of sustainable practices. The data are part of a wider SANH (South Asian Nitrogen Hub) harmonised household survey covering Bangladesh, India, Maldives, Pakistan and Sri Lanka. Full details about this dataset can be found at https://doi.org/10.5285/3b7a3e0b-48e5-4395-b4c6-79bb43ae31e3

This dataset contains information about meteorological conditions, ammonia concentration and deposition rates resulting from an experimental ammonia (NH3) enhancement setup in a tropical forest in central Sri Lanka. The experiment is designed for controlled enhancement of ambient NH3 concentration within the study plot under natural field conditions so that effects of NH3 on tropical vegetation can be studied. This will help identify tolerance thresholds of vegetation to NH3 as an air pollutant and determine critical levels that can be incorporated into regional environmental policy. Meteorological measurements were recorded at multiple heights on a meteorological tower. Under suitable wind conditions, NH3 was released towards two vegetation monitoring transects replicating pollution from a point source, and NH3 concentrations in the air were measured using monthly passive samplers. Continuous meteorological data, NH3 release, and NH3 concentration data are provided in 15-minute intervals and this dataset relates to measurements taken in 2023 – 2024. Deposition rates were modelled using a bi-directional resistance model on a monthly timescale based on measured NH3 concentrations in the air, micrometeorology and plant physiology. This dataset provides an extension of the 2022 dataset to enable longer term analysis of NH3 deposition and its effects in a tropical forest. The work was supported by UKRI GCRF South Asian Nitrogen Hub (Grant NE/S009019/1). Full details about this dataset can be found at https://doi.org/10.5285/449e746d-6291-4653-a3e0-b18f897abc3e

[This dataset is embargoed until April 1, 2026]. The dataset contains field measurements of atmospheric ammonia under forest canopies in the Himalayas in India, Pakistan, Nepal and Bhutan and in a tropical forest in Sri Lanka between 2022 and 2024. Monthly mean atmospheric ammonia concentrations are provided from 33 sites across the five countries. This dataset provides the first ever empirical measurements of ammonia from South Asian forests and can be used to estimate ecological impact, inform policy decisions, validate atmospheric chemistry transport models and satellite data and design future air quality and ecological monitoring in the region. The ammonia concentration data was collected monthly by deploying passive citric acid-coated samplers at the study locations. Full details about this dataset can be found at https://doi.org/10.5285/9c4aee69-3693-4f18-97c8-ff740045f3de

The database includes the classification of 966 active nitrogen-relevant policies from South Asia (including Afghanistan, Pakistan, India, Nepal, Bhutan, Bangladesh, the Maldives and Sri Lanka). The collection during 2020 and 2021 focuses on national level policies; some subnational policies were also collected. Data collection involved building on an existing open access global database developed by Kanter et al., 2020 that contained 51 policies for South Asia established to 2017 sourced by the environmental law ECOLEX database. Further policies were collected mostly from online sources: such as international policy databases: FAOLEX and national government and ministry websites. A protocol for policy collection and classification was established and followed to ensure consistent and thorough collections across the eight countries. Policies were classified according to a variety of parameters including the sink (air, water etc.) and sector (agriculture, industry etc.) they address and by type of policy. Policies were clustered if they had a central node policy in place and if a ‘subordinate policy’ (including amendments) did not offer anything new in terms of content related to Nitrogen management. This data was collected as part of a collective partnership that brings together leading organisations from across South Asia and the UK to reduce the adverse global impacts of nitrogen pollution on the environment, health, and wellbeing. More specifically providing a resource for both SANH partners and the wider scientific and policy community to understand the nitrogen policy landscape in the south Asian region. Furthermore, this research contributes to efforts in building a nitrogen policy arena promoting sustainable management of nitrogen, mitigating adverse effects. The dataset provides a thorough overview of available nitrogen related policies in South Asia but does not provide a complete set of all the nitrogen relevant policies available in each country. In some cases, this was due to our dependency on policy availability online, and some websites were not maintained. In addition, we excluded policies established post 2020 to avoid policy responses to COVID19 and to align more closely with the original global study. Repealed policies were omitted from the database. Full details about this dataset can be found at https://doi.org/10.5285/e2f248d5-79a1-4af9-bdd4-f739fb12ce9a