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Water and the Science of Pollution
Published in Daniel T. Rogers, Environmental Compliance Handbook, 2023
This book addresses compliance with environmental regulations that pertain to water. Water vapor in the atmosphere is a major component that drives climate on Earth and is a component of the water cycle. Water vapor in the atmosphere reacts with various pollutants, and water can also remove contaminants from the atmosphere and return them to Earth. Water also erodes soil from the surface of the Earth, can transport contaminants a significant distance, and eventually returns to the ocean to begin the cycle all over again. Some of the soil that water erodes and transports contains contaminants such as herbicides, pesticides, and fertilizers that originate from anthropogenic activities, including agriculture. Another aspect where water acts as a transport mechanism of contaminants is groundwater. Therefore, in addition to addressing surface water, including the oceans, we will discuss water in the atmosphere and also include transport mechanisms in the uppermost portion of the lithosphere. We begin by first examining basic water chemistry and the distribution of water on Earth. We then move to discuss the toxicity of contamination and how contaminants affect humans. We conclude this chapter with discussing the meaning of pollution and how pollution is transported within the water systems on Earth.
House As a System
Published in Stan Harbuck, Donna Harbuck, Residential Energy Auditing and Improvement, 2021
Relative humidity is the amount of water vapor contained in a specific volume of air relative to the maximum amount of water vapor that the volume of air is capable of holding. This is expressed as a percentage or ratio. Thus, if the humidity or water vapor in the air is only half of what the air could maximally hold, the relative humidity is 50%. Relative Humidity=Weight of water vapor in airMaximum weight of water vapor that air can hold
Lexicon
Published in Samuel C. Sugarman, HVAC Fundamentals, 2020
water vapor: (Psychrometrics, Chemistry) In HVAC systems the amount of water vapor or moisture present in the air (outside air, return air, mixed air, or supply air) is measured in pounds of moisture or grains of moisture per pound of air. There are 7,000 grains of moisture in one pound of moisture. For example, 70 grains is equal to 0.01 pounds. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice.
Analysis of the kinetic parameters of clothes drying in an electric vented dryer. Part II: Influence of the type of fabric
Published in Drying Technology, 2023
Santiago Plata, William Vicente, Martín Salinas-Vazquez, Leonardo Urbiola
This study compares the drying results of two types of fabrics, polyester, and cotton, under the same conditions. The moisture absorption property is a valuable feature of clothing materials. Equilibrium moisture content is a material property independent of the drying rate or method. Hygroscopic materials, such as textiles, have an equilibrium moisture content under specific conditions of temperature and humidity.[18] The wet textile mass is a porous medium that can include three phases: 1) the solid phase (textile fabric), 2) the liquid phase (free water and the water bound or considered hygroscopically adhered to the textile fabric), and 3) the gaseous phase (air and water vapor). Water is transferred from the liquid phase to a gaseous mixture of water vapor and dry air (Figure 3). The maximum amount of water vapor in the air depends on the temperature and pressure. In this system, drying is carried out through the air; that is, the water is transferred from the liquid to vapor by vaporization based on the conditions of the air.[18] This study assumes that the initial moisture in the load adheres to the textiles due to the hygroscopic effect.
Direct radiative impacts of desert dust on atmospheric water content
Published in Aerosol Science and Technology, 2018
In this work we aim at quantifying the impact of dust produced over Arabian Peninsula, on an inter-annual scale on the precipitation and the mass of water in the atmospheric column. Water vapor is one of the main greenhouse gases in the Earth's atmosphere and its maximum amount is controlled by the temperature (Myhre et al. 2013). Therefore changes incurred by the dust radiative feedback will have an impact on the water mass inside the atmospheric column, a phenomenon that deserves further examination. For this purpose the desert dust cycle for the Arabian Peninsula and its impact on both shortwave and longwave, were simulated using the SKIRON/Dust model with an online dust production scheme (Spyrou et al. 2010; Mesinger et al. 2012; Spyrou et al. 2013; Campos et al. 2017). This area was selected, over the more commonly studied Saharan desert, due to close approximation of two very warm sea bodies: the Red Sea and the Arabian Gulf, which supply the area with evaporated water.
Probabilistic assessment of the potential indoor air impacts of vent-free gas heating appliances in energy-efficient homes in the United States
Published in Journal of the Air & Waste Management Association, 2018
Gary K. Whitmyre, Muhilan D. Pandian
The relationship of indoor relative humidity to indoor sources of water vapor, outdoor relative humidity, and building factors (e.g., air exchange rates, heat exchange) is complex. Relative humidity is defined as the percent saturation of air with water vapor at a given temperature. The warmer the air, the greater is the mass of water per cubic meter required to achieve a given relative humidity level (Dunn 1951). The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) has recommended an indoor relative humidity range of 40–60% as being desirable based on comfort; the U.S. Environmental Protection Agency (EPA) has recommended a range of 30–60% for indoor relative humidity based on comfort. During the heating season, cold “dry” air is often brought into the home via normal infiltration/air exchange (Liebmann 1965). Cold air entering the home in winter through infiltration is then heated, which results in a higher capacity to contain water vapor. A relative humidity level greater than 70% can result in active growth of mold and mildew on indoor surfaces (Kalliokoski et al. 1993; Morey et al. 1984). Indoor environments commonly contain a variety of mold and mildew species, including Penicillium, Aspergillus, Cladosporium, and Fusarium species (DeKoster and Thorne 1995; Lipkowitz and Novarra 2001; Pasanen, Niininen, and Kalliokoski 1992).