hygrometerLCS Laboratory offers testing of Relative Humidity (RH) of air as a part of our Indoor Air Quality (IAQ) survey. RH is measure of water vapour concentration relatively to it highest (saturated) concentration at the same temperature. For example 5-15% RH would be a typical humidity of the Death Valley (California). On the opposite end of the scale is humid air on a rainy day with RH 90-100%.

Comfortable range of RH depends on your acclimatization (which changes with season) and air temperature. For most people, optimal humidity lays between 40 and 50%. Health Canada recommends 30% RH as the lower acceptable limit for winter or summer (Health Canada. Exposure Guidelines for Residential Indoor Air Quality. 1987, ISBN: 0-662-17882-3). The upper limit is 55% in winter and can be as high as 80% during summer.

pexels-photo-286951Very dry air with humidity below 25% can be harmful. Our skin gets dry and requires more attention. Dry air can cause such respiratory ailments as asthma, bronchitis, sinusitis, and nosebleeds, or general dehydration since body fluids are depleted during respiration. Irritative effects, such as static electricity which causes mild shocks when metal is touched, are common when the air moisture is low.

High Relative Humidity in combination with elevated temperature first cause discomfort, and if not controlled properly may lead to heat exhaustion and eventually to heat stroke. In addition, some micro organisms survive better in humid environment. When humidity rises above 55-60% mold starts to grow.

Effect of relative humidity can be better understood in connection with other parameters, that are tested aa part of our extensive Indoor Air Quality screening. To learn more about this service, please visit the IAQ webpage