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ENV CHAPTER 12-1: WHAT CAUSES AIR POLLUTION?
Air pollution = harmful substances in the air (can be solids, liquids, gases)Most is the result of human activities but there are natural sources too (volcano, dust, pollen, spores)Primary pollutant = put directly into the air by human activity (soot from a smoker)1. carbon monoxide (CO) – cars, trucks, buses, industrial processes a. interferes with blood carrying O2, makes you sleepy, death2. nitrogen oxides (NOx) – burning fuels in vehicles, power plants, boilersa. lung infections, haze, acid rain3. sulfur dioxide (SO2) – burning fossil fuelsa. acid rain, harms plants and humans4. volatile organic compounds (VOCs) – burning fuels, vehiclesa. smog, cancer5. particulate matter (PM) – construction, agriculture, fires, industrial processesa. clouds, respiratory problems, corrosion, erosion Secondary pollutant = forms when a primary pollutant mixes with another one or with natural substances, and a chemical reaction takes place (ex: ground level ozone) Two major sources of air pollution in urban areas: motor vehicle emissions and industry How vehicle emissions are controlled:- elimination of lead in gasoline- catalytic converters clean pollutants from car exhaust (tailpipe emissions)- electric zero emission vehicles How pollution from industries is controlled:- scrubbers to remove pollutants (gasses move through a spray of water)- electrostatic precipitatiors to remove dust particles smog – when air pollution hangs over a city and decreases visibility forms when car exhaust reacts with air and sunlight to form ozone, ozone reacts with the exhaust to form smog. Air circulation usually keeps pollution levels in check so they don’t get dangerously high in one area. - Warm air moves up and carries pollutants away from the earth’s surface- But it can be trapped by a temperature inversion.- Temperature inversion = atmospheric situation where cool air is trapped close to the earth’s surface by a layer of warmer air above. o Pollutants can’t rise away.o Could happen if a city is located in a valley
ENV CHAPTER 12-2: AIR NOISE AND LIGHT POLLUTION
Air pollution can cause health problems.Especially dangerous for very young, very old, and people with heart or lung problems- Short-term health effects: nausea, irritation of mucus membranes, respiratory trouble- Long-term health effects: emphysema, lung cancer, heart disease. Air pollution can also happen indoors – poor air quality inside- can be caused by plastics and chemicals – carpets, building materials, paints- sick building syndrome = building with poor air quality, people get sick Ways to prevent indoor air pollution:- removing sources of indoor air pollution- improving ventilation (the mix of indoor with outdoor air) Dangerous indoor air pollutants:- Radon gas – colorless, odorless, tasteless, radioactive. From the decay of uranium. Causes lung cancer.- Asbestos – long, thin fibers, resistant to heat, strong. Used as insulation and fire retardants. When inhaled it will cut and scar the lungs Noise pollution = excessive unnecessary sounds (sound is measured in decibles dB)- 0 dB is the smallest sound the human ear can hear. 120 is at the threshold of pain. Exposure to sound over 120 can result in permanent deafness- Airplanes, traffic, factories, mowers- Can cause hearing loss, high blood pressure, stress, loss of sleep Light pollution- not directly bad for people but can hurt the environment- energy waste, can’t see the night sky- solutions: direct light downward, use time controls to use light only when needed, low-pressure sodium sources of lightENV CHAPTER 12-3: ACID PRECIPITATION
Acid precipitation – rain, sleet, or snow that contains a high concentration of acids- when fossils fuels are burned they release sulfur oxides and nitrogen oxides. The oxides combine with water in the atmosphere. They form sulfuric and nitric acid. Falls as acid precipitation- pH measures how acid/base something is (7, neutral; lower, acid; higher, base)- natural precipitation is a little acid. Acid precipitation is less than pH 5. Acid precipitation affects soil and plants- plants are adapted to specific water and soil pH range- acid precipitation can cause a drop in soil and water pH = acidification- can cause nutrients to leach away- toxins to be released Acid precipitation affects aquatic ecosystems- animals are adapted to live in a certain pH range- acid can kill fish, plants, animals; leaching out of toxins can kill stuff- acid shock = in the spring when snow melts and there’s an influx of acidic water into a body of water Acid precipitation affects humans- can release toxic metals into the environment (can get in our crops)- health/respiratory problems- decrease the standard of living by affecting fishing and forestry- can corrode/erode buildings, sculptures, monuments problem – pollutants can be released in one area and fall to the ground far away.So it’s a global concern and needs cooperationCountries are enacting international agreements to control acid precipitation.Google Sites
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