Unit 7+8 Review Book Pt. 3 Flashcards
(32 cards)
Indoor air pollutants In developed countries
VOCs
carbon monoxide (CO)
Smoke
Radon
Dust
Asbestos
formaldehyde
lead
certain living organisms, such as tiny insects, fungi, and bacteria are considered pollutants.
VOCs
the most abundant indoor pollutants are volatile organic compounds (VOCs).
VOCs are found in carpet, furniture, plastic, oils, paints, adhesives, pesticides, and cleaning fluids.
Even dishwashers are responsible for the creation of VOCs, when chlorine detergent reacts with leftover foods.
carbon monoxide (CO)
is an asphyxiant; CO arises in indoor air as a result of gas leaks or poor gas combustion devices.
Smoke
Tobacco smoke affects not only the health of the smoker, but the health of those around the smoker, as well.
Secondhand smoke causes many of the same symptoms in nonsmokers who simply breathe it in as smoking can cause to the smokers themselves.
Secondhand smoke, which contains over 4,000 different chemicals, has been classified by the EPA as a Group A carcinogen (meaning that it causes cancer in humans).
It’s estimated that secondhand smoke causes 35,000–40,000 deaths per year from heart disease, and 3,000 deaths from lung cancer.
In children younger than 18 months, it is responsible for 150,000–300,000 lower respiratory tract infections annually, and it increases the number and severity of asthma attacks in about one million asthmatic children.
Radon
second leading cause of lung cancer (after smoking) in the United States.
Radon is a gas that’s emitted by uranium as it undergoes radioactive decay.
It seeps up through rocks and soil and enters buildings via basements or cracks in the walls or foundations.
It can also sometimes be found in groundwater that enters homes through a well.
It is not found everywhere and must be tested for specifically. Homes that were built after 1990 have radon-resistant features.
Dust
Dust is simply a catch-all term for fine particles of solid matter—from various sources such as soil and volcanic eruptions, plant pollen, human and animal hair, textile fibers, paper fibers, etc.
In homes, dust is composed of about 50% dead skin cells.
It poses health risks to humans because of allergic reactions and the exacerbation of asthma and lung conditions.
Asbestos
a naturally occurring silicate mineral that was often used as a building material in years past due to its insulating and heat-resisting properties.
It has been shown to be dangerous to human health, as the fibers, when inhaled, can cause a host of lung problems.
Mesothelioma is a type of cancer caused mainly by exposure to asbestos.
Though its use is completely banned in many countries and strictly controlled in others, it remains in many older buildings.
formaldehyde and lead
formaldehyde, often found in building materials, upholstery, and carpeting
lead, which was often used in paints and can be found in older paint layers (which may become uncovered over time) even when the newer layers are lead-free.
The final indoor pollutants we’ll review are actually living: certain living organisms, such as tiny insects, fungi, and bacteria are considered pollutants.
Many people are allergic to mold spores, mites, and animal dander, but asthma attacks can also be triggered by these living pollutants.
The water tanks for large air conditioning units are good places for certain types of bacteria to grow, and as air is distributed throughout the house, the bacteria are also distributed.
Some bacteria can cause diseases; one example of this is Legionella pneumophila, which causes Legionnaires’ disease.
Sick building syndrome (SBS)
term that’s used when the majority of a building’s occupants experience certain symptoms that vary with the amount of time spent in the building and for which no other cause can be identified.
SBS is somewhat difficult to diagnose, and specific culprits are very difficult to identify.
A condition is referred to as a building-related illness when the signs and symptoms can be attributed to a specific infectious organism that resides in the building.
One example of a building-related illness is Legionnaires’ disease.
Some symptoms of SBS include the following:
irritation of the eyes, nose, and throat
neurological symptoms, such as headaches and dizziness; reduction in the ability to concentrate; or memory loss
skin irritation
nausea or vomiting
a change in odor or taste sensitivity
There are many ways in which people can reduce the amounts of indoor pollutants that they’re exposed to
for many people, simply quitting smoking or encouraging roommates to quit can make a huge difference.
Other precautions that people can take are to limit the amount of exposure they have to certain chemicals, such as pesticides or cleaning fluids.
Perhaps the most important step to take is making sure that buildings are as well ventilated as possible.
Urban heat islands, urban heat island effect
Urban environments are generally about 20 degrees Fahrenheit warmer than the countryside that surrounds them, and this is due to the heat absorbing capacity of buildings, concrete, and asphalt, which radiate the heat that they have absorbed. Industrial and domestic machines also directly warm the air.
Because of their high temperatures, urban areas are known as heat islands.
The high temperatures of heat islands increase the rates of photochemical reactions, which adds to photochemical smog.
The temperature profile of an urban area shows peaks and valleys in temperature based on how the land is used.
For example, green spaces have lower temperatures than commercial areas, which have lots of parking lots, cars, buildings, and asphalt.
wo ways in which the heat island effect can be significantly reduced are:
(1) replacing dark, heat-absorbing surfaces (such as roofs) with light-colored heat-reflecting surface
(2) planting trees and adding to green spaces.
Trees shade the urban environment from solar radiation; in addition, the process of transpiration (the release of water through plant leaves) creates a cooling effect for the surrounding area.
Another reason why urban areas are often less cool than rural areas is because the concrete and asphalt in cities increase water runoff.
Runoff leads to increased temperatures because the deep pools of water that are created as a result of runoff are less affected by evaporation than are areas where water is spread out thinly over a larger surface area.
Green spaces can reduce runoff by trapping the water and distributing it more evenly across a larger surface area.
One way people are trying to combat thermal pollution
adding green roofs to city buildings.
A green roof, or living roof, is a roof that is fully or partially covered with plants, greenery, gardens, and other vegetation planted over some type of waterproofing material.
Not only does this combat the heat island effect, but it also keeps the buildings cool in summer and warm in winter, reduces rainwater runoff, provides habitats for wildlife, and helps to clean the urban air.
temperature inversion
Another type of thermal pollution associated with many urban environments is temperature inversion. In this phenomenon, air pollutants become trapped over cities because they are not able to rise into the atmosphere. In normal atmospheric conditions, the warm, polluted air over a city rises into the cooler atmosphere. (Remember that warm air is less dense than the surrounding cool air, and less dense objects float!) In an inversion, the air above the city is warm and blocks the polluted air from rising. The polluted air remains hanging above the city and can cause respiratory problems. Inversions often occur in cities surrounded by mountains or cities bordered by mountains on one side and ocean on the other (for example, Los Angeles and Beirut). But thermal inversions can occur over any city where large masses of warm air can become stalled.
Clean WAter Act positive impact
When the Cuyahoga River near Cleveland, Ohio, caught fire in 1969, it became a symbol of polluted America.
This fire, along with many other problems that began to arise with polluted bodies of water at that time, eventually resulted in the Clean Water Act (CWA) of 1972, the primary U.S. federal law governing water pollution, which regulates water quality standards, point-source pollution, and water uses.
The CWA had a dramatic effect on the quality of water in the United States.
By 2016, 91 percent of community water systems met federal health standards—this number was up from the 79 percent that were considered clean by the government in 1993.
Experts say that Americans have some of the cleanest drinking (tap) water in the world.
From the time of the passage of the CWA to 2017, 60 percent of the stream lengths that were tested were found to be sufficiently clean to allow fishing and swimming, while only 36 percent of the streams that were tested in 1972 were clean enough.
Also as a result of the CWA, the annual loss of wetlands has slowed significantly since 1972.
Plus, the Clean Water Act needs to be constantly enforced, and the actions of specific citizens and companies need to be monitored.
The CWA has certainly had a positive effect on our water, but there are still plenty of water issues and bodies of water that need to be cleaned.
Plus, the Clean Water Act needs to be constantly enforced, and the actions of specific citizens and companies need to be monitored.
For example, the Flint water crisis represents a breakdown of Americans’ assurance in their clean water supply. The crisis began in 2014 when Flint, Michigan, changed its drinking water source from Lake Huron and the Detroit River to the Flint River. The water was not treated properly, and because of this, lead leached from water pipes into the water supply. Residents were exposed to dangerous levels of the toxin.
A federal state of emergency was declared for Flint in 2016, and Flint residents were told not to use the water supply for drinking, cooking, cleaning, or bathing. Water quality was deemed acceptable by 2017, and the lead pipes are being replaced.
One continual problem that contributes to water pollution is that runoff from land carries excess nutrients and pollutants to streams.
This can result in large dead zones due to declining levels of dissolved oxygen.
To track this, sometimes an oxygen sag curve is used—a plot of dissolved oxygen levels versus the distance from a source of pollution (usually excess nutrients and biological refuse).
For example , the dead zone in the Gulf of Mexico covers up to 5,000 square miles in the middle of what is the richest area for shellfish in the United States.
For example , the dead zone in the Gulf of Mexico covers up to 5,000 square miles in the middle of what is the richest area for shellfish in the United States.
This dead zone has caused the collapse of the shrimp and shellfish industries in that region.
The dead zone was created because the Mississippi River collects roughly 10,000 pounds of fertilizer and raw sewage pollution from 31 states and some of Canada as it travels south.
Then it dumps all of this nutrient-rich water into the Gulf.
The warm, nutrient-rich freshwater does not mix well with the colder salt water, and this results in eutrophication—the warm water being overly enriched with minerals and nutrients to the point that excessive growth of algae and other phytoplankton occurs (an algal bloom).
In turn, the zooplankton that feed on them also experience a population explosion.
When the phytoplankton and zooplankton die and sink to the bottom, bacteria metabolize the available dissolved oxygen as they decompose this detritus; the lack of oxygen creates a hypoxic zone (or dead zone), in which nothing that depends on oxygen can grow.
Die-offs of fish and other larger organisms can happen when the aquatic food chain is disrupted.
This zone stays in place from May until September, when colder, wetter weather helps to break it up.
To save this economically important fishery, a federal-state Hypoxia Task Force was formed in 1997 to reduce the size of the dead zone by two-thirds by 2015, but in 2015 it found that the zone was about the same size it was in 1994.
The target date was extended to 2035.
Situations like the Mississippi dead zone (eutrophcation)
Similar but less severe situations can occur in any waterway in which too much agricultural runoff and/or wastewater accumulates, bringing the nutrient levels to excess.
These are known as eutrophic waterways; if hypoxia results, they are called hypoxic waterways.
In contrast, oligotrophic waterways have low amounts of nutrients, stable algae populations, and high levels of dissolved oxygen.
Point vs. non-point sources
Like the terms that are used to describe sources of air pollution, particular sources that are responsible for water pollution, like paper mills, are called point sources, and pollution sources that do not have a definitive source (or result from contributions of many sources) are non-point sources.
