Practice of Part 3-Theory-Air Quality.pdf

Practice of Part 3: Air Quality 1- Which gases contribute the most to the composition of the atmosphere? More than 99% of the atmosphere is made up of nitrogen (N2), oxygen (O2), and argon (Ar) gases. 2- Apart from the combustion of fossil fuels, what sources cau...

Practice of Part 3: Air Quality 1- Which gases contribute the most to the composition of the atmosphere? More than 99% of the atmosphere is made up of nitrogen (N2), oxygen (O2), and argon (Ar) gases. 2- Apart from the combustion of fossil fuels, what sources cause the increase of carbon dioxide in the atmosphere? Only mention the names of these sources. 1- Cultivation of native soils, 2- Agricultural plants, 3- Deforestation or clearing of forests. 3- What is the source of methane in the atmosphere? Major sources of methane (CH4), are swamps, marshes, and wetlands. 4- Which gases contribute to acid rain? Just name it or write the chemical formula of them. Nitrogen dioxide and sulfur dioxide (NO2 and SO2). 5- On the global scale, carbon monoxide (CO) is not considered an air pollutant. Why? because soil microorganisms adsorb it relatively rapidly and oxidize it to CO2. In urban areas, however, carbon monoxide can accumulate during rush hour traffic. 6- Under what conditions is ozone gas considered a pollutant? Ozone (O3) is considered an air pollutant in the lower atmosphere because it harms plants and humans. 7- How is ozone gas produced? Ozone is produced by the action of ultraviolet (UV) sunlight on polluted air that contains nitrogen oxides (NO and NO2) and organic gases such as industrial solvents, fuels, and partially oxidized hydrocarbons. 1  8- Under what conditions is ozone gas useful for life on Earth? Explain it with reason. In the upper atmosphere, ozone is useful to life on Earth because it absorbs much of the UV fraction of sunlight. The UV fraction of sunlight can cause skin cancer in humans and animals and plant growth. 9- Explain the following diagram. The above diagram shows year-to-year variations in the average size of the ozone hole. According to this diagram, until 2000, a significant increase in the hole size in the ozone layer is observed. But, after the year 2000, the ozone layer changes are not noticeable. 10- Name the greenhouse gases. Greenhouse gases include carbon dioxide, methane, ozone, nitrous oxide, chlorofluorocarbons, and water vapor. 11- Explain the following diagram. As shown in this diagram, the pressure and density of the atmosphere decrease with height. 2  12- On the global scale, carbon monoxide (CO) is not considered an air pollutant. Why? Because soil microorganisms adsorb it relatively rapidly and oxidize it to CO2, in city areas. 13- Under what conditions is carbon monoxide considered a pollutant? Carbon monoxide is a pollutant in closed spaces and during busy traffic hours. 14- What is the definition of relative humidity? Relative humidity is defined as the ratio of the actual vapor pressure to the saturation vapor pressure of the air, which is solely a function of air temperature. 15- What happens at dew point temperature? Condensation of water vapor into cloud and fog droplets occurs at the dew point temperature. 16- What is the meaning of wet deposition? Precipitation in the form of rain or snow clears the air of many types of particulate matter and gaseous pollutants. This removal of air pollutants is known as wet deposition. 17- Explain the following diagram. This figure shows the changes related to the increase in global temperature. After the industrial revolution and the increase of greenhouse gases such as carbon dioxide gas, a significant increase in the average temperature of the earth is observed. 18- Which layer of the atmosphere is called the troposphere? Why is this layer of the atmosphere important to us? Explain. 3 The troposphere is the lowest major layer. It is tropospheric air that we breathe. Also, most of our weather occurs in the troposphere, including cloud formation, rain, winds, and other weather- related processes. 19- What potential hazards may be associated with indoor air? Potential hazards that may be associated with indoor air include particulates, microbes, and chemicals. 20- Name the immediate effects of future developments on indoor resources. These effects include eye irritation, headaches, dizziness, and fatigue, often short-term and treatable. 21- The immediate reactions of indoor air pollutants depend on which factors? Indoor air pollutants' immediate reactions depend on age, preexisting medical conditions, and individual sensitivity, with some becoming sensitized after repeated exposure. 22- What diseases may occur if indoor air quality is not improved? Indoor air quality should be improved to prevent health effects like respiratory diseases, heart disease, and cancer. 23- Name the sources of indoor air pollution. 1- Fuel-burning combustion appliances, 2- Tobacco products, 3- Building materials and furnishings, 4- Products for household cleaning and maintenance, personal care, or hobbies, 5- Central heating and cooling systems, and humidification devices, 6- Excess moisture. 24- By controlling which factor, the growth of biological sources inside the house is minimized? By controlling the relative humidity level in a home, the growth of some sources of biologicals can be minimized. A relative humidity of 30-50 percent is generally recommended for homes. 4  25- Name five types of indoor biological contaminants. 1-pollens, 2-viruses, 3-mold, 4-bacteria, and 5-droppings and body parts from pests or insects. 26- Define primary pollutants and name six types of them. Primary air pollutants enter the atmosphere directly from various sources. Primary air pollutants include the following: 1-carbon monoxide, 2-hydrocarbons, 3-particulate matter, 4-sulfur dioxide, 5-nitrogen oxides, 6- lead. 27- What is the Definition of Particulate Matter (PM)? Particulate matter is the fine microscopic or nano-particles suspended in the air. They can be volatile, semi-volatile, non-volatile, liquid, or solid. These particles can enter deep into our lungs via respiration, and then enter into the bloodstream. 28- What are the meanings of PM2.5 and PM10? PM10 means particles with a diameter of 10 micrometers or smaller and PM2.5 means particles of 2.5 micrometers or smaller. 29- What are the main sources of nitrogen oxides in the atmosphere? Nitrogen oxides (NO and NO2) are formed mainly from N2 and O2 during high-temperature combustion of fuel in cars. 30- Describe the effects of nitrogen oxides (NO and NO2) pollution. Nitrogen oxides cause a reddish-brown haze (fog or vapor) in city air that contributes to heart and lung problems and may be carcinogenic. Nitrogen oxides also contribute to acid rain because they combine with water to produce nitric acid (HNO3). 31- What are the sources of nitrogen oxides (NOx) in the atmosphere? There are two major sources for NOx: Human-caused sources and natural sources. Human-caused sources of NOx are formed mainly from N2 and O2 during high-temperature combustion of fuel in cars. Natural sources of NOx include those produced during the metabolism of certain soil bacteria. 5  32- Explain the secondary air pollutants. Secondary air pollutants are formed during chemical reactions between primary air pollutants and other atmospheric constituents, such as water vapor. Generally, these reactions must occur in sunlight; thus, they ultimately produce photochemical smog. 33- Write the reactions involved in photochemical smog formation. N2 + O2 → 2NO 2NO + O2 → 2NO2 NO2 + hv → NO + O O + O2 → O3 NO + O3 → NO2 + O2 HC + NO + O2 → NO2 + PAN 34- What are the favorable conditions for ozone formation? Ozone formation is closely tied to weather conditions. Favorable conditions for O3 formation include: 1-air temperatures more than 32°C 2-low winds 3-intense radiation 4-low precipitation 35- In what ways can pollution be removed from the atmosphere? Pollution can be removed from the atmosphere by gravitational settling, dry deposition, condensation, and wet deposition. 6  36- Explain the gravitational settling. Gravitational settling removes most particles whose diameters are greater than about 10 µm. Particles less than 10 µm in diameter are often small enough to stay in the atmosphere for long periods. Particles greater than about 10 µm in diameter quickly settle out. 37- Explain the Dry deposition. Dry deposition is a mass-transfer process that results in adsorption of gaseous pollutants by plants and soil. 38- What is the role of condensation in removing pollution from the atmosphere? Volatile organic compounds can condense on cold surfaces during winter in temperate and polar regions. The process of evaporation, transport, and condensation of toxic compounds, may be responsible for causing high levels of toxic organic pollutants in the polar regions. 39- Explain the wet deposition. Rain is very effective at removing gases and small particulates. Raindrops increase in size as they fall toward the ground, and thus they increasingly capture more pollutants. Raindrops, in effect, “sweep up” pollution as it falls through the air. The ability of the rain to remove pollutants depends upon the rainfall intensity, the size and electrical properties of the drops, and the solubility of the polluting species. 40- Explain the acid rain. The polluted rain contains SO2 and NOx. These acidic oxides are produced by burning fossil fuels. Their main effect is to produce acid deposition, called acid rain. 41- What is the meaning of deforestation? Deforestation means the cutting down of forests that have occurred since prehistoric times. For example, all of Europe was once densely forested, but the trees were cut down to provide wood and to clear the land for agriculture. 42- What is the meaning of desertification? Land degradation in the drylands is called desertification. 7  43- What are the meanings of the following abbreviations? UV: Ultraviolet EPA: Environmental Protection Agency CFCs: Chlorofluorocarbons SBS: Sick building syndrome IAQ: Indoor Air Quality HCs: Hydrocarbons VOCs: Volatile organic carbons NMHCs: Nonmethane hydrocarbons PM: Particulate Matter PAN: Peroxyacetyl nitrate HAPs: Hazardous air pollutants SST: Supersonic transport 8