Methods of Measuring Environmental Parameters

Yuriy Posudin

• Publisher: Wiley
• Year: 2014
• Print ISBN: 9781118686935
• eBook ISBN: 9781118914229
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Environmental Management
• Index: Technology & Engineering

Provides a systematic review of modern methods and instruments for measuring environmental parameters
•Profiles the most modern methods and instruments for environment control and monitoring
•Gives an assessment of biotic and abiotic factors and their effect on quality of atmosphere and indoor air, soil, water
•Provides a brief description of the main climatic (pressure, wind, temperature, humidity, precipitation, solar radiation), atmospheric, hydrographic, and edaphic factors
•Covers a wide range environmental methods and instrumentation including those used in the fields of meteorology, air pollution, water quality, soil science and more
•Supplied with practical exercises, problems, and tests that will help the reader to learn more deeply contents of the book

Part I
Climatic Factors

1
Pressure

1.1 Definition of Pressure

Pressure is a physical quantity that characterizes the intensity of normal force (perpendicular to the surface) with which one body acts on the surface of another. If the force exhibits a uniform distribution along the surface, the pressure p is determined as the ratio of force to area:

(1.1)

where F is the magnitude of the normal force on the surface and S is the area of this surface.

If the pressure is not uniform across the surface, the following expression defines the pressure at a specific point:

(1.2)

The SI unit for pressure is pascal (1 Pa = 1 N/m² = 1 kg/m·s²). The following pressure units are also used:

• 1 Pa = 9.87 × 10⁻⁶ atm = 7.5 × 10⁻³ mmHg = 0.000295 inHg = 7.5 × 10⁻³ Torr = 10⁻⁵ bar = 1.45 × 10⁻⁴ psi;
• 1 bar = 10⁵ Pa = 0.987 atm = 750.06 mmHg = 29.53 inHg = 750.06 Torr = 14.504 psi;
• 1 atm = 1.01325 × 10⁵ Pa = 1.01325 bar = 760 mmHg = 29.92 inHg = 760 Torr = 14.696 psi;
• 1 mmHg = 0.03937 inHg = 1 Torr = 1.3332 × 10⁻³ bar = 133.32 Pa = 1.315 × 10⁻³ atm = 19.337 × 10⁻³ psi;
• 1 psi = 6894.76 Pa = 68.948 × 10⁻³ bar = 68.046 × 10⁻³ atm = 51.715 mmHg = 2.04 inHg = 51.715 Torr;
• 1 inHg = 25.4 mmHg = 3386.38816 Pa = 0.03342 atm = 25.4 Torr = 0.03386 bar = 0.49 psi.

A pressure of 1 Pa is small; the following non-SI metric units of pressure such as hectopascal (1 hPa = 100 Pa) or millibar (1 mbar = 10⁻³ bar) are used in meteorology and weather reports. The National Weather Service of the United States uses both inches of mercury (inHg) and hectopascals (hPa) or millibars (mbar). The pound per square inch (psi) is still popular in the United States and Canada.

1.2 Atmospheric Pressure

Atmospheric pressure is defined as the weight of a column of atmospheric air that acts on a given unit of surface area. Air is a mixture of gases, solids, and liquid particles. As a whole, atmospheric pressure depends on height; also it is characterized with horizontal distribution. The density and temperature of atmospheric air also depends on height.

The idea of a uniform distribution of atmospheric molecules within a volume of air is erroneous. Molecules are subject to the Earth's gravitational field; in addition, there is the effect of their thermal motion on the spatial distribution of the molecules. The combined action of the gravitational field and thermal motion leads to the state that is characterized by a decreasing gas concentration and pressure with increasing height.

Atmospheric air can be considered as an ideal gas, which can be described as follows:

(1.3)

where p_A is the pressure of the air; V_A is the volume of the air; m_A is the mass of the air; M_A is the molar mass of atmospheric air (M_A = 0.029 kg/mol for dry air, M_A = 0.018 kg/mol for water vapor); R = 8.314 J/K·mol is the molar gas constant; T_A is the absolute tempe...

Table of contents

• Cover
• Title Page
• Copyright
• Dedication
• Epilogue
• Preface
• Acknowledgments
• About the Book
• About the Author
• Introduction
• Part I: Climatic Factors
• Part II: Atmospheric Factors
• Part III: Hydrographic Factors
• Part IV: Edaphic Factors
• Part V: Vegetation Factors
• Part VI: Physical Types of Pollution
• Part VII: Biotic Factors
• Appendix
• Index
• End User License Agreement