The Hygroscopic Tandem DMA (H-TDMA and HH-TDMA)

Der Hygroscopicity analyser (H-TDMA; Hygroscopic Tandem Differential Analyser) is an instrument to determine the hygroscopic growth of aerosol particles at high relative humidity (typically 90 %). In the atmosphere, such water uptake by particles typically leads to visibility reductions and for formation. Importantly, the intensity of incident solar radiation will be reduced by the increased light scattering.

TROPOS has developed and deployed H-TDMA instruments for many years, both within laboratory studies and field experiments.

The HH-TDMA (High Humidity Hygroscopic Tandem Differential Analyser) is a unique instrument, which accomplishes a controlled humidification of aerosol particles up to 99 % relative humidity (Hennig et al., 2005).

The picture illustrates hygroscopic particle growth in the HH-TDMA at relative humidities between 90-95 %. These measurements originate from the PEGASOS 2012 field experiment in San Pietro Capofiume (Italy).


  • Estimation of the radiative properties of atmospheric aerosols at ambient relative humidity
  • Quantitative separation of externally mixed particle types (more or less hygroscopic particles)
  • Estimation of the ability of particles to act as cloud condensation nuclei (CCN) at given supersaturations

H-TDMA References

  • Wu, Z., Birmili, W., Poulain, L., Wang, Z., Merkel, M., Fahlbusch, B., van Pinxteren, D., Herrmann, H., and Wiedensohler, A.: Particle hygroscopicity during atmospheric new particle formation events: implications for the chemical species contributing to particle growth, Atmos. Chem. Phys., 13, 6637-6646, 2013.
  • Wu, Z. J., Poulain, L., Henning, S., Dieckmann, K., Birmili, W., Merkel, M., van Pinxteren, D., Spindler, G., Müller, K., Stratmann, F., Herrmann, H., and Wiedensohler, A.: Relating particle hygroscopicity and CCN activity to chemical composition during the HCCT-2010 field campaign, Atmos. Chem. Phys., 13, 7983-7996, 2013.
  • Massling, A., Niedermeier, N., Hennig, T., Fors, E. O., Swietlicki, E., Ehn, M., Hämeri, K., Villani, P., Laj, P., Good, N., McFiggans, G., and Wiedensohler, A.: Results and recommendations from an intercomparison of six Hygroscopicity-TDMA systems, Atmos. Meas. Tech., 4, 485-497, 2011.

HH-TDMA references

  • Henning, T., A. Massling, F. J. Brechtel, A. Wiedensohler (2005). A Tandem DMA for highly temperature-stabilized hygroscopic particle growth measurements between 90% and 98% relative humidity. J. Aerosol Sci., 36, 1210-1223.
  • Poulain, L. , Z. Wu, M. D. Petters, H. Wex, E. Hallbauer, B. Wehner, A. Massling, S. M. Kreidenweis, F. Stratmann (2010). Towards closing the gap between hygroscopic growth and CCN activation for secondary organic aerosols - Part 3: Influence of the chemical composition on the hygroscopic properties and volatile fractions of aerosols. Atmos. Chem. Phys., 10, 3775-3785.
  • Liu, P. F., C. S. Zhao, T. Göbel, E. Hallbauer, A. Nowak, L. Ran, W. Y. Xu, Z. Z. Deng, N. Ma, K. Mildenberger, S. Henning, F. Stratmann, A. Wiedensohler (2011). Hygroscopic properties of aerosol particles at high relative humidity and their diurnal variations in the North China Plain. Atmos. Chem. Phys., 11, 3479-3494.
  • Chen, J., Zhao, C. S., Ma, N., Liu, P. F., Göbel, T., Hallbauer, E., Deng, Z. Z., Ran, L., Xu, W. Y., Liang, Z., Liu, H. J., Yan, P., Zhou, X. J., and Wiedensohler, A. (2012). A parameterization of low visibilities for hazy days in the North China Plain, Atmos. Chem. Phys., 12, 4935-4950.