A coating of salt (mostly NaCl) may build up on the radiation shield, sensor, filter and even the
sensor element. A buildup of salt on the filter or sensors will delay or destroy the response to
atmospheric humidity.
Long-term exposure of the relative humidity sensor to certain chemicals and gases may affect
the characteristics of the sensor and shorten its life. The resistance of the sensor depends
strongly on the temperature and humidity conditions and the length of the pollutant influence.
The sensor should be calibrated annually. Please refer to the
and
sections at the end of the manual for more information.
10. Attributions and References
E+E Elektronik® is a registered trademark of E+E Elektronik Ges.m.b.H.
Santoprene
®
is a registered trademark of Exxon Mobile Corporation.
AASC, 1985: The State Climatologist (1985) Publication of the American Association of State
Climatologists:
Heights and Exposure Standards for Sensors on Automated Weather Stations
,
v. 9, No. 4 October, 1985. (www.stateclimate.org/publications/state-climatologist/NOAA-
NCY-SCBOOKS-SC77097/00000029.pdf)
EPA, 2000:
Meteorological Monitoring Guidance for Regulatory Modeling Applications
, EPA-
454/R-99-005. Office of Air Quality Planning and Standards, Research Triangle Park, North
Carolina 27711.
EPA, 2008:
Quality Assurance Handbook for Air Pollution Measurement Systems
, Vol. IV,
Meteorological Measurements, Ver. 2.0, EPA-454/B-08-002 (revised 2008). Office of Air
Quality Planning and Standards, Research Triangle Park, NC 27711.
Goff, J. A. and S. Gratch, 1946: Low-pressure properties of water from -160° to 212°F,
Trans. Amer.
Soc. Heat. Vent. Eng.
, 51, 125-164.
Lowe, P. R., 1977: An approximating polynomial for the computation of saturation vapor pressure,
J. Appl. Meteor.
, 16, 100-103.
Weiss, A., 1977: Algorithms for the calculation of moist air properties on a hand calculator,
Amer.
Soc. Ag. Eng.
, 20, 1133-1136.
WMO, 2008.
Guide to Meteorological Instruments and Methods of Observation
. World
Meteorological Organization No. 8, 7th edition, Geneva, Switzerland.
EE181 Temperature and Relative Humidity Probe
16
