CH 17-19 APES notes

risk analysis

• involves identifying hazards and their associated risks(risk assessment)

• ranking risks(comparative risk analysis)

• determining options and making decisions about reducing or eliminating risks( risk management)

• informing decision makers and public about risks (risk communication)

Risk assesment

involves identifying hazards and their associated risks

comparative risk analysis

ranking risks

risk management

determining options and making decisions about reducing or eliminating risks

Risk communication

informing decision makers and the public about risks

Risk

possibility of suffering harm from a hazard that can cause injury, disease, economic loss, or environmental damage.

Expressed in terms of probability.

Cultural hazards

poor diet, drugs, driving, assault

Chemical hazards

harmful chemicals in the air, water, soil, and food

physical hazards

fire, weather, radiation

biological hazard

pathogens, allergen, and animals

toxic chemicals

chemicals that can ause temporary or permanent harm of death.

Hazardous chemicals

flammable or explosive 

irritating or damaging to the skin or lungs

interfering with oxygen uptake

inducing allergic reaction

mutagen

cause random mutations in DNA

carcinogens

promote growth of malignant tumors

Major problem with some chemical hazards

with heavy metals, and persistant organic pollutants (POPs) is bioaccumulation and biomagnification

Bioaccumulation

increase in the concentration in specific organs or tissues over time

Biomagnification

Increase is an increase in a concentration of chemicals in organisms at successively higher trophic levels

Minamata Disease

Is not a disease but refers to the neurological effects from mercury poisoning . It was first discovered in 1956 in Minamata, Japan, where methyl mercury from industrial wastewater bio accumulated in the fish and shellfish that people ate.

Median lethal dose

the amount of chemical received in one dose that kills exactly 50% of the subjects in a test population

poison

chemical that has an LD of 50 mg or less per kilogram of body weight

threshold level of toxicity

the dose below which no toxic effects are observed and/or above which the toxic effects are apparent

physical hazards

earthquakes resulting in loss of life and property

volcanoes result in loss of life and property

ionizing radiation in the form of X-rays, radiation from nuclear sources, and ultraviolet radiations from the sun or sunlamps.

Biological hazards

nontransmissble diseases

transmissble diseases

Non transmissible diseases

are not caused by living organisms and do not spread from one person to another.

• diabetes, bronchitis, malnutrition, and mesothelioma

transmissible diseases

caused by living organisms and can be spread from one person to another. an infectious agent is called a pathogen.

Seven deadliest infectious diseases

1. Flu and Pneumonia

2. HIV/AIDs

3. Diarrheal diseases

4. tuberculosis

5. Malaria

6. Hepatitis B

7. Measles

Zika Virus

First identified in Africa, is spread through mosquitoes. Zika can cause birth defects and has no cure, though only on in 5 infected people die. It has been spreading faster in recent years(notable outbreak in 2016), in part to global warming

CoronaVirus

originated from a live animal market in Wuhan, China in december of 2019 and was declared an outbreak of international concern by WHO in january of 2020. Spreading very easily, Covid-19 has infected more than 77 million people, killing more than 1.2 million in the U.S. and 7 million worldwide(as of 2025)

Leading causes of Death in the US

1. heart disease

2. cancer

3. covid

4. accidents

5. respiratory disease

Epidemiological transition

As a country industrializes, it usually makes an epidemiological transition, where chronic diseases overtake childhood infectious diseases in mortality.

Phase one of epidemiological transition

Characterized by extremely high death rates with peaks due to epidemics, famines, and wars

Phase two of epidemioligcal transition

characterized by less frequecnt epidemic peaks and a dropping death rate due to medical advances

phase three of epidemiological transition

characterized by a leveling off of death rate with most death occurring from non-transmissible diseases associated with aging.

Phase 4 of epidemiological transition

continues with a level death rate and shows an increasing average lifespan due to medical advances.

Phase 5 of epidemiological transition

shows an increase in death rate due to the re-emergence of new infectious disease due to urbanization and the overuse of antibiotics and pesticides.

Atmosphere

is the thin layer of gases that surround the earth.

Composition of gases in the atmopshere.

78% Nitrogen

21% oxygen

0.9% argon

0.1%. water vapor, carbon dioxide, neon, helium, and other trace gases

Troposphere

extends from the earth’s surface up to about 10 km. It contain 75-80% of the atmosphere’s gases. Layer where weather occurs

Stratosphere

Extends from 10 km to 50 km above the earth. Contains the Ozone layer which absorbs the majority of the UV radiation from the sun. 

Mesosphere

extends from 50km to about 80km above the earth. Coldest layer, dropping as low as -90 C

Thermosphere

Lower layer of the thermospheres is the ionosphere- which can reflect radio waves back to earth. It cannot reflect television waves, which have a shorter wavelength.

The upper layer of the thermosphere is the exosphere which extends for thousands of kilometers above the earth, blending into the vacuum of interplanetary space.

Air pollution

the presence of one of more chemicals in the atmosphere in quantities and duration that cause harm to humans, other forms of life, and materials.

Primary pollutants

products of natural events and human activites

Secondary pollutants

Happens when primary pollutants may react with one another or with basic components of air to form new pollutants

Major classes of Air pollutants

Carbon Oxides (CO, CO2)

Sulfur Oxide(SO2, SO3)

Nitrogen Oxide (NO, N2O)

Volatile Organic Compounds (VOCs such as CH4, CFC’s)

Suspended organic particles(Dust, Soot, Pesticides)

photochemical oxidants (O3, H2O2)

Radioactive substances(Radon-222, Plutonium-239)

Toxic compounds (mostly carcinogens)

Photochemical smog

formed when NO’s and VOC’s react with heat and sunlight to produce a variety of pollutants

industrial smog

consists mostly of sulfur dioxide formed from burning of coal and heavy oil.

Catalytic converters

used in automobiles to convert CO, NOx, and hydrocarbons to less harmful gases( like CO2)

Wet and drug scrubbers

gases in smoke stakes are passed through CaO(lime) or CaCo3(Calcium carbonate) to remove S02 accumulating in a sludge

Electrostatic percipitators

removes particles using an induced electrical charge

vapor recover nozzle

on a gasoline pump minimized gas fumes from escaping

Afterburners

an additional combustion process

Acid deposition

the mixture of acidic rain, fog, snow, cloud vapor, and particles that reach the earth’s surface.

Effects are:

• direct damage to plant foliage, bark, and roots

• Soil acidification and death of microorganisms

• lake acidification and stress of aquatic life

Indoor air pollution

Air pollution is not limited to the outdoors. Building with particularly poor air quality are said to have sick building syndrome. The EPA estimates 17% of U.S. commercial buildings are sick.

Causes of sick-building syndrome include the presence of tobacco smoke, formaldehyde, gasoline, radon gas, asbestos, carbon monoxide, VOCs, and some species of fungi and bacteria.

Human Health

Exposure to air pollutants, particularly cigarette smoke may lead to several human health issues

• lung cancer

• asthma- muscle spasms in the bronchial walls

• Chronic bronchitis- inflammation of cells lining the bronchi and bronchioles

• emphysema- damage to the air sacs in the lungs

Radon

Radon 222 is a colorless, odorless, and radioactive gas that is produced by the decay of uranium-238 in rocks and soil. the gas can seep upward through soil and accumulate in unventilated lower levels in buildings.

Clean air acts

the U.S. congress clean air acts in 1970,1977,1990, and impose the following strategies

• EPA establishment of national ambient air quality standards(NAAQS)

• EPA establishment of national emission standards for toxic air pollutants

• Recent legislation, such as the “Clear Skies Initiative” (2003) have actually reduced the effectiveness of the clean air act. 

Deficiencies of the Clean Air Act

Continues reliance on pollution clean up rather than prevention

failure of sharply increase fuel efficiency standards for cars and light trucks

no requirement for stricter emission standards for fine particulates

giving municipal trash incinerators 30-year permits

weak standards for incinerators

weak standards for emissions of CO2 and other greenhouse gases.

The greenhouse effect

the process in which greenhouse gas prevent the radiation of heat into space by trapping it in the troposphere. More greenhouse gases in the atmosphere create higher temperature near the earth. 

The atmosphere allows UV rays to strike the earth, heating it up. The earth then radiates infrared rays( heat) back outward. The ability of the earth’s surface to reflect light is called albedo

Major greenhouse gases

Water vapor(H2O)- naturally occurring, #1 greenhouse gas

carbon dioxide (CO2) burning of fossil fuels

nitrous oxide (N2O)-burning of fossil fuels, fertilizers.

methane (CH4)- burning of fossil fuels, wetlands, livestock

chloroflourocarbons(CFCs)- aerosols, refigerants

Global warming

as result of the greenhouse effect, the average temperature of the earth will rise at least 2˚ celsius by 2050. This predicted increase in temperature is called global warming.

• The effects of this seemingly small increase in temperature is called global warming.

The effects of this seemingly small increase in temperature could include: weather change, stronger storms, more flooding, in some areas, more drought in other areas, the best farming areas would move northward and a rise in sea level.

Global warming in naturally occuring

Layers of antarctic ice provide the data for the past 900,000 years, and it is found that cycles of heating and cooling have occured on a global basis

Each ice age lasts approximately 100,000 years and is followed by a period of warming that lasts 10,000 to 12,500 years.

The warming period during the last 10,000 years has been a major factor in the development of agriculture, human civilizations, and population growth. 

Global warming is caused by human activity

The past 100 years have seen a significant increase in global mean temperature caused by rapid increase in major classes in air pollutants/greenhouse gases. The primary source of these pollutants is the burning of fossil fuels. The 2nd leading source is deforestation(slash and burn). 

The biggest greenhouse gases are: 

CO2- Carbon dioxide not as potent of a GHG, but lots of it. The good news: half of man-made CO2 would be reabsorbed by plants and the ocean within 30 years if we stopped excess production

CH4- methane- 20 times as potent as CO2 over a 100 year period. The good news: we can capture CH4 and use it as fuel. 

Particulate(AKA soot aka black carbon)- the good news: it is washed out of the atmosphere by rain relatively quickly'

Water vapor

Water vapor is the gas most responsible for the greenhouse effect, accounting for 60-70%. It is the most prevalent greenhouse gas by mass and volume.

• The amount of water vapor the atmosphere can hold is almost entirely a function of temperature. as temperature rises, more evaporation, more water.

• Emissions of excess GHGs leads to warmer temperatures, which leads to more water vapor, which leads to warmer temperatures. it is a positive feedback loop.

Things that can be done to decrease greenhouse gases

• reduce air pollution, which will reduce negative effects to human health including asthma, lung cancer, bronchitis, and emphysema. 

• Reduce dependence on foreign energy sources

• reduces environmental effect such as habitat destruction from mining and acid rain. 

• Renewable energy sources save mining in the long term. 

Bad news: it will cost money in the short term and political will for the long term. 

IPCC

Intergovernmental panel on climate change was established in 1988 to provide decision makers with an objective source of information on climate change. It was set by the world meteorological organization and the united nations environmental programme and consists of hundreds of scientists from around the world.

The most recent report from the IPCC stated that “human interference with the climate system in occuring, and climate change poses risks for human and natural systems” and that during this century, temperatures will rise between 1.1 and 6.4˚ C.

The kyoto treaty

The kyoto treaty was the first major international agreement on greenhouse gas emissions. In december of 1997, the treaty was designed and agreed on by the major countries involved in 1992 U.N. earth summit. This treaty would reduce emission by 5% from 1990 levels 2012.

Copenhagen

The 15th United nations climate change conference took place in Copenhagen, Denmark in December 2001. The conference ended with an agreement by the 194 countries to “cap temperature rise, reduce emissions, and raise finance to kick start action in the developing world to deal with climate change”. The emissions targets are meant to keep temperature from rising more than 2˚ C. 

Paris

The 2015 UN climate change conference, known as COP21, was heald in paris france.. This conference was of particular importance because of significant contributions by the two largest carbon emitters— china and US. In april of 2016, 174 countries signed the agreement and begun implementing plants to limit global warming to 1.5˚ C. This will require a target of zero emissions by sometime between 2030 and 2050.

Ozone

the form of oxygen with molecules of three oxygen atoms. It is colorless and has a strong odor. It is good in the stratosphere and absorbs most of the UV radiation hitting the earth. In the troposphere, ozone contributes to air pollution.

Ozone destroyers

CFCs destroy ozone in the stratosphere, and have created a thinning (hole is an incorrect term) in the ozone shield above the south pole. 

The burning of fossil fuels increases ozone in the troposphere. 

Why is ozone thinning seasonal?

Each sunless antarctic winter, ice crystal in the air collect CFCs and catalyze the reaction that releases Cl atoms and ClO. Without the sunlight to catalyze ozone destruction, the ClO combine to form Cl2O, which accumulates in the atmosphere.

When sunlight and spring return the light breaks up the stored molecules, releasing large numbers of Cl atoms. This leads to loss of 40-50% of the ozone in most areas- 100% in some

Montreal Protocol

CFC’s(Chlorofluorocarbons), a type of halocarbons, were manufactured in the 1930’s as a refrigerant and spray can propellant

CFC’s were found to destroy stratospheric ozone in the 1970’s, which lead to the montreal protocol(1987). This international agreement phased out a series of substances, including CFC’s, responsible for ozone depletion. 

As a result, stratospheric chlorine levels in polar regions should return to 1980 levels by 2065. This is often cited as the largest global environmental success story.