Tang Y.S1., Peters D2., McGurk C2., Ul-Haq I2. and Emekwuru, N3

1UKCEH, 2STFC-UKRI, 3Coventry University

Each month we highlight one of our Scoping Studies, each funded through our Collaboration Building Workshops. This month we welcome a blog post from Dr Yuk Sim Tang and the team developing a next generation DELTA-Mi sensor that can be deployed in a wider range of settings, particularly in low-resource regions.

Nitrogen pollution, in particular increasing global emissions of ammonia (NH3), is a major driver of biodiversity loss in the 21st century. The reaction of NH3 with atmospheric acid gases also forms secondary inorganic ammonium (NH4+) aerosols (Figure 1) that contribute to fine-mode particulate matter (PM2.5) implicated in adverse health impacts and increased mortality.

Figure 1: Reaction scheme showing the emissions, atmospheric chemistry and fate of NH3, acid gases and secondary inorganic NH4+ aerosols [1].

Understanding chemical species composition is necessary to assess impacts on ecosystems and human health, and to direct and target options to mitigate poor air quality. Worldwide, observation data on the reactive gas and aerosol phase components are sparse. In this context, there is an ongoing need for cost-effective, easy-to-operate, time-integrated atmospheric measurement at sufficient spatial and temporal scales.

The UKCEH DELTA® system [2] is a leading diffusion denuder-filter pack method for speciated measurement of reactive gases and aerosols, implemented in high density air quality networks (e.g. UK [3] and China [4]) and recommended in EMEP Level I monitoring [5]. A study from a European DELTA® network (Figure 2) for example provided evidence for the dominance of NH3 gas and NH4NO3 aerosol in the inorganic atmospheric pollution load.

The DELTA-Mi project aims to upgrade the UKCEH DELTA® system with flow sensing capabilities and telemetry, to achieve miniaturisation and permit remote monitoring of air flow. We will modify and test components from a UAV-ready sensor” developed by STFC RAL Space UAV facility in a previous SAQN scoping study [6]. In parallel, we will also field test compact gas and aerosol sample trains, based on UKCEH Mini-ANnular DEnuders (MANDE), for further miniaturisation.

Figure 2: Atmospheric chemical species composition measured in a European DELTA® network [2].

Other key challenges are in optimising power requirements and to produce a DELTA-Mi with low unit cost, to maximise flexibility in deployment options and affordability, particularly in low-resource countries. Collaboration with Coventry University and their work in Sub-Sahara regions will identify pathways to build infrastructure in air quality monitoring to increase data availability for understanding air quality drivers and impacts in low-resource regions.

Find out more about all our Scoping Studies on our dedicated web pages.


[1] Tang, Y. S., Flechard, C. R., Dämmgen, U., Vidic, S., Djuricic, V., Mitosinkova, M., Uggerud, H. T., Sanz, M. J., Simmons, I., Dragosits, U., Nemitz, E., Twigg, M., van Dijk, N., Fauvel, Y., Sanz, F., Ferm, M., Perrino, C., Catrambone, M., Leaver, D., Braban, C. F., Cape, J. N., Heal, M. R., and Sutton, M. A.: Pan-European rural monitoring network shows dominance of NH3 gas and NH4NO3 aerosol in inorganic atmospheric pollution load, Atmos. Chem. Phys., 21, 875–914, https://doi.org/10.5194/acp-21-875-2021, 2021.

[2] https://www.ceh.ac.uk/services/delta-active-sampler-system

[3] Tang, Y. S., Braban, C. F., Dragosits, U., Simmons, I., Leaver, D., van Dijk, N., Poskitt, J., Thacker, S., Patel, M., Carter, H., Pereira, M. G., Keenan, P. O., Lawlor, A., Conolly, C., Vincent, K., Heal, M. R., and Sutton, M. A.: Acid gases and aerosol measurements in the UK (1999–2015): regional distributions and trends, Atmos. Chem. Phys., 18, 16293–16324, https://doi.org/10.5194/acp-18-16293-2018, 2018.

[4] Xu, W., Wu, Q., Liu, X. et al. Characteristics of ammonia, acid gases, and PM2.5 for three typical land-use types in the North China Plain. Environ Sci Pollut Res 23, 1158–1172 (2016). https://doi.org/10.1007/s11356-015-5648-3

[5] https://unece.org/fileadmin/DAM/env/documents/2009/EB/ge1/ece.eb.air.ge.1.2009.15.e.pdf

[6] Feature Scoping Study: A UAV-ready sensor package for rapid deployment during volcanic crisis (saqn.org)