Control of temperature, humidity and other important parameters in hospitals

The survival of viruses, bacteria, and fungi in the air is influenced by temperature and relative humidity. The transmission of infectious diseases via aerosol or airborne infection necessitates strict environmental control in hospitals.

During this travel between hosts, all such organisms (whether viruses, bacteria, or fungus) are exposed to the environment. Temperature, relative and absolute humidity, UV light exposure, and even atmospheric contaminants can all act to inactivate free-floating, airborne pathogenic germs.

Maintaining a specific temperature and relative humidity (percent rh) in hospital settings is believed to minimize airborne survivability and, as a result, influenza virus transmission. Summer and winter temperatures and relative humidity (rh) settings in different regions of a hospital change slightly. In the summer, recommended room temperatures in the emergency room, including in-patient rooms, vary from 23°C to 27°C.

Temperature affects the condition of viral proteins and the virus DNA, making it one of the most critical elements controlling virus survival. Virus survival diminishes when the temperature rises from 20.5°C to 24°C, then to 30°C. This temperature-temperature association held true across a humidity range of 23 percent relative humidity to 81 percent relative humidity.

What is the purpose of measuring relative humidity?

Virus: rh levels play a role in the survival of viruses and other infectious agents. At a temperature of 21°C, influenza survival is at its lowest, with a mid-range of 40 %–60 %rh. Temperature and relative humidity (rh) will constantly interact to affect the survival of airborne viruses in aerosols.

Bacteria: Carbon monoxide (CO) increased the death rate of bacteria when the relative humidity (rh) was less than 25%, but it protected bacteria when the rh was greater than 90%.

Temperatures above roughly 24°C appear to reduce bacterial survival in the air.

Regular calibration is important

Humidity and temperature measuring instruments are precision instruments that must be serviced regularly to maintain reliability. Even though our instruments and systems have excellent long-term stability, we recommend that probes are calibrated regularly – once a year is normally sufficient.

What else to consider for a good indoor air quality?

Indoor air quality can be improved using dehumidification and HEPA filtration and through regular fresh air supply. This is when CO2 is focused as an additional important parameter. Its effect on indoor air or breathing air in particular is often underestimated and neglected. If the CO2 value (ppm: parts per million) rises above 1000 fatigue and loss of concentration become apparent.

Aerosols are difficult to measure. Consequently, the carbon dioxide that is emitted together with the aerosols when breathing is measured. A lot of CO2 is therefore synonymous with a high aerosol concentration.

Finally, differential pressure measurement can be used to verify that the correct positive or negative pressures are applied in rooms to prevent the ingress or egress of unwanted substances such as particles or bacteria.

Fungi: Ventilation systems that control temperature and humidity have a substantial impact on interior levels of airborne fungi, with air-handling units reducing indoor concentrations while natural ventilation and fan-coil units increase them.

One stop shop for high-precision measurements in hospitals

Process Sensing Technologies offers a complete air quality range from single instruments to a full system for hospital measurement applications. Tried-and-tested solutions that allow healthcare facilities to control and monitor their conditions while adhering to internal and external regulatory criteria. Contact us to find out more.