das wasserhaus

Areas of Work
Air Quality in Spas


defined by the "Definitions / Quality standards for spas and health resorts, climatic health resorts, recreational resorts - including the predicatization requirements - as well as for medicinal wells and medicinal springs" of the German Spas Association and the German Tourism Association.

  • Special guidelines regarding NO2 pollution:
    Air spas, mineral spas, thermal spas, mud spas, spas with peloid spa operation, spas with healing gallery spa operation, spas with healing spring spa operation, Kneipp spas, Kneipp health resorts, seaside resorts with a spa medical background, Felke spas, Felke health resorts, Schroth spas, Schroth health resorts.
  • Special guidelines regarding NO2 and suspended particulate matter PM10(fine dust) pollution:
    Seaside spas, climatic health resorts.
  • The specified spa guideline values must be complied with at the measuring and sampling point in the spa park and in the town center


NO2 [µg/m³]

PM10 [µg/m³]

The legal limit value
(annual mean value)




Spa Park/Local Center

Spa Park/Local Center

Air spas,
Inland spas

20 / 24

No measurement

seaside spas,
climatic health resorts

16 / 20

No measurement / 20


Relaxation area/therapy area

Relaxation area/therapy area

Healing cave spa

10 / 10

No measurement / 10

The measurements have to be repeated every ten years after the predicatization. In the case of spas with medicinal spring spa operations, spas with peloid spa operations, Schroth spas, Felke spas and Kneipp spas, the measurements must be carried out every ten years only if there is a reasonable suspicion that the limit values are not being complied with.

  • Measurement methods NO2:
    Passive measurement methods such as diffusion tubes and calculations according to Palmes or at least equivalent methods.
  • Measuring method PM10:
    usually with active samplers and subsequent gravimetric or at least equivalent optical evaluation.
  • Measurement period:
    1 year or mid-January to mid-July or mid-July to mid-January of the following year.



  • Reddish brown, irritating corrosive gas, causes headaches and dizziness. In higher concentrations, it damages mucosal tissue throughout the respiratory tract, irritates the eyes, causes shortness of breath, coughing, bronchitis, pulmonary edema, and reduced lung function, and increases susceptibility to respiratory infections.
  • Evidence suggests a link between near-time exposures to NO2 with increases in cardiovascular disease and mortality in the general population
  • Predominantly from anthropogenic sources: Combustion processes (traffic, fires, industrial processes).


  • Structure diffusion tube:
    Metal grids carrying the chemical triethanolamine are located at the sealed end of the plastic tube. By removing the red cap at the other end, the measurement begins. These tubes are fixed under a weather protection. For protection against wind turbulence, a membrane maybe placed at the open end.
  • How diffusion tubes work:
    Due to concentration differences between the surrounding air and the air inside of the tube, NO2 diffuses into the tube and is bound by triethanolamine in the form of nitrite.
  • Diffusion tube evaluation:
    The concentration of nitrite is detected in an ion chromatograph and recalculated to the concentration of nitrogen dioxide in the air. For this purpose it is important to know the exposure time of the tube.
  • Measurement in spas and health resorts:
    Since the measurements run for half a year or a whole year, the diffusion tubes must be changed regularly. Measurements are always made with at least two tubes, one in the spa park and one in the center of the resort. Blank and duplicate samples can be taken for control. Normally, the tubes are exposed for two weeks and then replaced. The tubes used are then resealed, stored in a cool place and sent to Hydroisotop GmbH for evaluation.



  • Particles with aerodynamic diameter (i.e. particles which have the same sinking velocity in still air as a spherical particle with the same diameter and density 1 g/m³ (water) of less than 10 μm.
  • PM10 penetrates to the nasal cavity,
    PM2.5 (fraction of PM10 with diameter smaller than 2.5 μm) up to the bronchi and alveoli,
    ultrafine dust (fraction with diameter smaller than 0.1 μm) to the lung tissue and bloodstream
  • Mucosal irritation, local inflammation in pharynx, trachea and bronchi up to plaque formation in blood vessels, tendency to thrombosis, alteration of regulatory function of autonomic nervous system
  • Anthropogenic sources:
    Motor vehicles, power and long-distance heating plants, waste incinerators, furnaces and heaters, bulk handling, animal husbandry, industrial processes
  • Natural sources:
    Emissions from volcanoes and oceans, soil erosion, forest and brush fires, biogenic aerosols (viruses, fungal and bacterial spores)


Active collectors suck ambient air via a pump. The fine dust collects on a filter. The filters are weighed before and after exposure and from the mass difference the suspended dust concentration can be calculated. Depending on the design of the active collector, the filters must be replaced after the exposure period or are replaced by the device itself. Active samplers require a power connection.