What Is a Humidity Table?
The hygrometer is an instrument for measuring the humidity in the air, that is, an instrument for measuring the moisture content in the air. In addition to its application in meteorological work, it is also commonly used in warehouses to check humidity. There are three main types of hygrometers: mechanical, electric, and cold or dew point. Commonly used hygrometers include wet and dry bulb thermometers, ventilated wet and wet bulb thermometers, manual wet and dry bulb thermometers, and hair hygrometers.
- Hygrometer A meter used to measure the humidity of the air. Common are
A commonly used electrical humidity measuring element is a resistive humidity sheet, which is coated with a hygroscopic conductive substance on both sides of a substrate. When the humidity of the air changes, the conductive medicine evaporates or absorbs water vapor in the air, causing the resistance value of the element to change. A humidity meter can be made by measuring the relationship between its resistance value and atmospheric humidity.
- There are three main types of hygrometers: mechanical, electric, and cold or dew point.
- Mechanical hygrometer
- In a simple mechanical hygrometer, the sensing element is generally an organic substance, which expands and contracts with the change of water vapor in the surrounding air or gas. The most commonly used substance is human hair. Other substances may be paper, animal tissues (such as the thin skin made from bovine intestinal membranes), and wood. Such as
- (1) Measure the relative humidity of the air.
- (2) In addition to the natural settlement of gravity in the atmosphere, pollutants are also affected by meteorological factors such as airflow (wind speed, wind direction), air humidity, atmospheric pressure, precipitation and solar radiation, forming a series of processes such as diffusion, transfer and evolution. , Which has different impacts on environmental pollution.
- Therefore, the monitoring of air quality in a certain city or industrial area is closely related to local meteorological observation data, analysis of air pollution trends, and correct evaluation of pollution control programs. To this end, the cooperation of the meteorological department should be obtained, and the general data of the regional climate situation usually observed by the local meteorological department should be used, such as the daily, yearly changes in measurement parameters such as wind speed, wind direction, pressure and temperature, and other commonly recorded measurement data , Such as precipitation, sunshine duration, relative humidity and absolute humidity, as well as parameters related to the formation of fog, observations of humidity gradients, and data on the height of the inversion layer.
- Therefore, the hygrometer can provide certain data for the study of atmospheric pollutants. [5]