Exam 2 Flashcards
What is the 1970 U.S. Clean Air Act?
Air quality criteria documents (books) that provide a summary of what is known about:
1. Sulfur oxides
2. Particulates
3. Oxidants
4. Carbon monoxide
5. Hydrocarbons (VOCs)
6. Nitrogen oxides
What was Einstein’s involvement with nuclear weapons?
Albert Einstein signed a letter to President Roosevelt alerting him to the terrible potential of weaponizing nuclear reactions
What was the Manhattan Project?
Located in Los Alamos, NM, confidential U.S. project aimed at developing an atomic bomb; most funding went to build factories that could produce the materials needed to make the bombs
Why is an atomic bomb so much more powerful than a TNT bomb?
- The amount of heat and light released is 1000 times greater
- Invisible, penetrating and harmful radiation
- Radioactive fallout remains and continues to damage living things for a long period of time
4 types of radiation that typically accompany nuclear weapon detonation
- Alpha particles
- Beta particles
- Gamma rays
- Neutrons
What is nuclear fallout, and how long does it take to exert its effects?
radioactive fragments which stick to air particles or dirt that is sucked up mushroom stem
- 80% falls back down in first day
- 90% falls back down in first week
- 10% lasts weeks to years
How is the electromagnetic pulse of nuclear weapons generated, and what are its effects?
How it works: Gamma rays ionize air, creating electrons, and electrons create large currents in the air
Effects: Currents are picked up by power lines, and power surges shut down grid and destroy attached electrical devices; e.g., 1.4Mton airburst in 1962 knocked out lights in Hawaii over 1000 miles away
What are the general effects of nuclear weapons on health?
- Most of the lasting effects are due to radiation, so are odorless and colorless
- Cancers can take 20 or more years to develop
- A single bomb can kill 100,000 people and destroy an entire city
What are fission weapons, and how do they work?
Fission releases energy in elements heavier than Iron. Bombarding U or Pu with neutrons, they split into fragments, releasing energy.
These are traditional “A” bombs.
How does critical mass lead to nuclear chain reactions?
When a large enough mass of either U or Pu is assembled, a self-sustaining chain reaction results after the first fission is produced; “critical” mass = minimum mass
What was the first detonation of an “A” bomb?
Trinity - Gadget (7/16/1945) at the Alamagordo test range in New Mexico
What are the characteristics of an “A” bomb?
Fission bomb that uses >90% Uranium; neutrons are reflected back into Uranium
Uses initial explosive device to trigger
What was the “Fat Man” style of A-bomb?
High explosives arranged to form an imploding shock wave which compresses the fissile material to supercriticality; burst of neutrons from generator is timed for moment of maximum compression
What are fusion weapons?
Elements lighter than Iron release energy when combined, such as Hydrogen, Deuterium, Tritium, and Lithium; these are thermonuclear reactions that also occur inside the sun
What is the “secret” of the H-bomb?
At the high temperatures of the fission bomb, 80% or more of the energy exists as soft x-rays…the x-rays heat a polystyrene channel, causing plasma which can compress and ignite the second (fusion) stage before the expanding primary stage disrupts it
How do hydrogen bombs work?
They typically use two stages, a fission stage and a fusion stage; more or less, it is a fission bomb that is “boosted” by hydrogen gas, making the fission more powerful
How big are nuclear weapons?
1 kTon = 2,000,000 pounds of TNT equivalent; today’s warhead is 100-200 kTons, and 2 pounds of U makes 20 kTons
Largest underground burst = 4.5 Mtons
Largest airburst = 58 Mtons
Who has nuclear weapons?
Many countries, but the US and Russia have the most by far
Is EMF from cellphones harmful?
Truly uncertain as to health effects; Cheshire Cat Effect - often symbolizes the idea of something being present yet intangible or elusive
However, there is considerable evidence concerning EMF (in general) and childhood leukemia
electric fields vs. magnetic fields
Electric fields:
1. Measured in volts per meter
2. Easily shielded
3. Charges moving from positive to negative terminal (produced by voltage)
Magnetic fields:
1. Measured in gauss (G) or tesla (T)
2. Not easily shielded
3. Fields result from movement of charges; defined by frequency of charge movement (produced by current)
frequency vs. wavelength
Frequency is # of cycles/second (Hertz), and 1 cycle = 1 wavelength
As frequency increases, wavelength decreases.
What is stray voltage?
Improper grounding causing currents to flow through metal objects in house or barn; not an electric or magnetic field
How does increasing distance from source affect electric and magnetic field strength?
Increasing distance from source = decreasing EF and MF levels
4 primary sources of electric and magnetic fields
- Household appliances/in-home wiring
- Power lines
- Radio/TV transmitters/cell phones
- Earth
What did the childhood cancer residential studies of EMF reveal?
Early Studies (1979, 1988):
- In Denver, increased leukemia, brain cancer, and lymphoma associated with EMFs
More Recent Studies (1996-2006):
- 16 NA, Europe, Australia, and Japan studies found increase in leukemia only
However, there are many issues with these studies, such as weak correlations, correlation between other variables, inadequate controls, etc.
How have electrical blankets changed?
They used to have significantly higher magnetic field levels than they do now; new blankets are “low magnetic field”
What did the adult cancer residential studies of EMF reveal?
- 4 leukemia studies, only 1 showed small risk
- 4 brain tumor studies, none showed association
- 9 breast cancer studies, only 1 showed small risk
What did the adult occupational studies of EMF reveal?
- 50/50 results on whether electrical occupations exhibit association with leukemia and brain tumors
- 19 male breast cancer studies, 4 showed significantly increased risk
- 16 female breast cancer studies, 3 showed significantly increased risk
What are the adverse effects of radiofrequency (RF) exposure?
Known:
- whole or partial body heating
Suspected:
- cancer
- cardiovascular disease
- adverse reproductive outcomes
- cataracts
Is radiofrequency (RF) exposure linked to cancer in occupational studies?
Results inconsistent, the few excesses are linked with exposures other than RF and/or methodological shortcomings
Is exposure to Wi-Fi associated with negative health effects?
No, conclusion was that RF exposures were well below recommended maximum levels and that there was “no reason why Wi-Fi should not continue to be used in schools and in other places”
What is the common factor of illnesses associated with EMFs?
Disruption of melatonin
What are the effects of EMFs on animals?
Generally no effects observed across a variety of studies; all published studies negative for cancer association
What was the IARC evaluation of Extremely Low Frequencies (ELFs)?
ELF magnetic fields classified as Group 2B “Possibly Carcinogenic” based on limited human data and inadequate animal data
What are the effects of reduced levels of melatonin, and why is this important with regard to EMF?
Reduced levels of melatonin are associated with (i) increased cancer risk in animals and in humans, (ii) with depression and possibly miscarriage.
This is significant because disruption (reduction) of melatonin is the common factor of illnesses associated with EMFs.
What is the Melatonin Hypothesis?
Exposure to light at night or MFs suppresses nocturnal melatonin leading to increased risk of breast cancer.
For EMFs, the Melatonin Hypothesis has been extended to Childhood Leukemia - melatonin is highly protective of oxidative damage to the human haemopoietic system.
What is the most significant health concern of EMF?
There is considerable evidence concerning EMF and childhood leukemia, and perhaps other endpoints in children and adults
Why is there a concern about cell phones and brain cancer?
Interest in the media and potential exposure to RF; some studies report association between brain tumors and heavy (not regular) cell phone use
What is a glioma?
a general term for a group of tumors that start in glial cells; about 4 in 10 of all brain tumors are gliomas, and 8 in 10 of malignant brain tumors are gliomas
What is the chance of someone developing a malignant tumor of the brain or spinal cord?
Less than 1%
5 risk factors for primary brain tumors
- Genetic risk
- Radiation to the head
- HIV
- Smoking
- Toxins
Where are cell phones on the electromagnetic spectrum?
- Digital phones are microwaves (up to 1900 MHz)
- Early analog phones are radiowaves (800-900 MHz)
3 reasons we should not be concerned about biological effects of radiofrequency radiation from cell phones?
- Energy of a RF wave from a phone is billions of times lower than the energy of an x-ray photon
- RF radiation is insufficiently energetic to break molecular bonds
- No consistent experimental evidence of carcinogenicity or genotoxicity
Should only be concerned with heavy use, according to the CERENAT, Interphone, and Million Women Studies.
What was the CERENAT 2013 study of cell phones and tumors?
Case-control study that found no association between regular mobile phone use and gliomas and meningiomas, but positive association with heavy users and gliomas
What was the Interphone Study?
Decade-long study overseen by the WHO that “appears” to have found a link between heavy usage of cellphones and brain cancer
What is conventional vs. unconventional natural gas?
Formed by organic matter (marine organisms) trapped in sedimentary rocks.
“Conventional” natural gas collects in porous rock (sandstone) domes.
“Unconventional” natural gas remains trapped in pores in tighter rocks (shale).
What is fracking?
Short for “hydrofracturing,” technique for increasing oil production from worked-out oil wells, but a new technique for obtaining methane (natural gas)
What is hydraulic fracturing?
Fracking technique for extracting natural gas from “tight” rock structures deep below the surface. Involves:
- Drilling a well deep into the earth
- Injecting 500,000 gallons of fluid (99% water plus sand and chemicals) to fracture shale and extract natural gas
How does fracking work?
A well is drilled (can be bored vertically or horizontally) and water laced with chemicals is pumped down to fracture the shale and release gas, which can be pumped back up
What is shale?
Tight rocks that contain natural gas; targeted in fracking
What are the environmental problems with fracking?
- Lengthy, extensive, lots of equipment/fluid necessary
- Methane releases major problem - tap water lighting on fire
What is the primary health concern of fracking workers?
Aside from “typical” industrial injuries, silica sand
How does fracking affect water?
Surface water:
1. Exposure: fish/game consumption, air, and farm animals
2. Fracking chemicals/flowback water
3. Potential for spills
4. Waste water disposal
Ground water:
1. Exposure: Private drinking water wells
2. Fracking chemicals
3. NORM (Naturally Occurring Radioactive Materials) and heavy metals
4. Chemical interactions
What is the relationship between fracking and earthquakes?
A study found that wastewater from gas wells caused earthquakes
What Wisconsin lacks in shale, is compensated by…
Frack sand (silica sand); commonly mined in Wisconsin
2 mechanisms of silica toxicity
- Obstructive airway disease
- Generation of ROS (causes cancer)
What is silicosis?
chronic, progressive inflammatory disease that causes scarring of the lung as a result of silica exposure
Silicosis is the most important occupational disease.
How much silica are frac workers exposed to?
NIOSH study found that 47% showed exposures greater than the calculated OSHA PEL, and 79% showed exposures greater than the NIOSH REL.
Some samples were 10 or more times the PEL and REL.
Why is air quality a concern with fracking?
- Exposure: inhaled by workers, neighbors, and regional communities
- Diesel engines from vehicles and equipment
- Emissions from wells
- Evaporations from storage ponds
3 disasters/accidents associated with fracking
- Flooding may wash chemicals into water/soil
- Earthquakes from injection wells
- Explosions/spills may cause injury or contaminate environment
5 effects of fracking on community health
- Noise/light pollution
- Stress and mental health
- Population change (workers)
- Impacts on health services (disaster response, etc.)
- Increased housing costs/demand
5 challenges of discussing fracking
- Polarized
- Cost/benefit ratio
- Multidisciplinary
- Uncertainty and conflicting information
- “People listen to people who agree with them”
5 motor vehicle pollutants of concern
- Ultrafine Particles (UFP)
- Black carbon (BC)
- Nitrogen oxides (NOx)
- Carbon monoxide (CO)
- Particle-bound polycyclic aromatic hydrocarbons (PPAH)
What are ultrafine particles (UFP), and how are they formed?
Particles with a diameter of 0.005 to 0.1 microns, formed by the condensation of hot vapors in tailpipe emission; can grow/shrink in size
What is the “spectrum of concern” with regard to particles?
Smaller particles have greatest health impacts, and the number of particles appears to be more important than mass
What is black carbon or “soot carbon,” and how is it formed?
Type of PM, impure form of elemental carbon with graphite-like structure; product of incomplete combustion of fossil fuels, biofuels, and biomass
Black carbon is the “runner-up” to CO2 in emissions resulting in global climate change
What are nitrogen oxides (NOx), and how are they formed?
Compounds containing nitrogen and oxygen; result of combustion processes, particularly at high heat
Contributor to ozone air pollution
What are particle-bound polycyclic aromatic hydrocarbons (PPAH), and how are they formed?
Compounds made up of 3 or more benzene rings; formed by incomplete combustion of organic materials, such as wood or fossil fuels
Benzene is a known human carcinogen and benzo-a-pyrene most studied
What is carbon monoxide, how is it formed, and why is it dangerous?
Colorless, tasteless, odorless, nonirritating, flammable, and poisonous gas; forms as a result of incomplete combustion of fuel
Dangerous because it is a silent killer, and because it enters bloodstream through lungs and forms carboxyhemoglobin, which inhibits the blood’s capacity to carry oxygen
Why do we not need to measure EVERY motor vehicle pollutant?
Because of their common source - vehicle emissions - UFP, NOx, black carbon, and CO are highly correlated
4 adverse birth outcomes that are associated with roadway pollution
- Low birth weight and reduced head circumference
- Increased risk of wheeze and probable asthma
- Elevated stable chromosomal aberrations in umbilical cord blood lymphocytes, predictive of long-term cancer
- Lower mental development scores
What are the cardiovascular effects of roadway pollution?
Heart attack and 85% increase in prevalence of coronary heart disease associated with increased traffic near home and proximity to roadways
What is the key point with regard to roadway pollutants?
Proximity is key: Much higher exposures to traffic-related air pollutants occur within 30 meters as compared to >200 meters
2 pollutants of concern NOT influenced by roadway proximity
- PM2.5 and PM10
- Benzene
5 variables to consider in studying near-highway pollutants
- Type of highway
- Types and amounts of vehicles using highways
- Driving conditions
- Fuel chemistry
- Meteorology (rain)
What are the health effects of road traffic noise?
Air pollution and road traffic noise can increase the risk of heart failure, and former smokers or those with hypertension may be most suceptible to the adverse effects
What is the relationship between air pollution exposure and autism?
There is an association between air pollution exposure, cognitive and adaptive function, and ASD severity among children with autism.
Also, might be a tie between in-utero exposure to near-roadway air pollution and ASD in children.
What is the relationship between air pollution and obesity?
Air pollution might be an “obesogen,” meaning it is associated with obesity
What is the relationship between traffic-related air pollution and neurodegenerative disorders?
Traffic-related air pollution is neurotoxic and may be linked to neurodegenerative diseases
How has the acreage burned in wildfires trended over time?
There has been a substantial increase in the yearly quantity of acres burned in wildfires since 1985
What are the predictions for future wildfire risk?
- Up to 55% increase by 2050
- Up to 128% increase by 2099, with estimated burned area increase of 59% to 169%
How does climate change contribute to wildfire risk?
- Landscape is drier
- Temperatures increase
- Snow melts sooner
- More extreme weather patterns
What percentage of wildfires are manmade?
Over 90%, and many are preventable
5 primary and 2 secondary air pollutants of wildfires
Primary air pollutants:
1. PM
2. CO
3. NO2
4. Polycyclic aromatic hydrocarbons (PAHs)
5. VOCs
Secondary air pollutants:
1. PM
2. Ozone
7 pollutants of concern when vehicles and buildings burn
- HCN
- HCl
- Phosgene
- Metals
- Toluene
- Styrene
- Dioxins
What dictates the composition of wildfire smoke?
Composition of smoke depends on the fuel type (e.g., type of tree), the temperature of the fire, and the wind conditions
Why is wood smoke (from wildfires) so dangerous?
Contains many of the same toxic and carcinogenic substances as cigarette smoke, including benzene, benzo(a)pyrene, and dibenz(a,h)anthracene
How does smoking equate to air quality index (AQI)?
3 cigarettes/day is about equivalent to an AQI of 200
What type of PM is in wildfire smoke?
Over 80% is less than 2.5, making it especially dangerous
Where in the body is PM deposited based on size?
> 10 microns: nose and mouth (removed)
5-10 microns: upper respiratory tract
1-5 microns: deeper in the lungs, lower respiratory tract
How does PM2.5 exposure compare to smoking cigarettes?
One cigarette/day is the rough equivalent of a PM2.5 level of 22 micrograms/cubic meter
Does PM2.5 cause death?
Yes, PM2.5 causes 4.2 million premature deaths worldwide/year.
Air pollution as a whole causes 9 million premature deaths worldwide/year.
What country faces the highest loss in life expectancy as a result of PM2.5?
Bangladesh, 1.87 years of life lost due to PM2.5
However, due to population, China’s air quality effects the most people in any single country
3 primary respiratory effects of wildfires
Due to PM2.5 from wildfire smoke:
1. Asthma exacerbations
2. COPD
3. Bronchitis and pneumonia
All inflammation-related effects
What is the cardiovascular effect of wildfires?
Due to PM2.5 from wildfire smoke, increased cardiovascular (ischemic heart disease, heart failure, etc.) and cerebrovascular (stroke) ER visits
These are inflammation-related effects
What is the mechanism of the cardiovascular effects of wildfires?
Increased systemic inflammation, oxidative stress and coagulation through PM2.5 mediated changes in ANS
How much did the California wildfires impact the risk of heart problems?
Risk of heart problems increased by 42%, with the greatest risk among adults aged >65 years
What populations are at risk due to wildfires?
- Young children
- Elderly
- Those with pre-existing respiratory and cardiovascular disorders
What are the effects of wildfires on asthma?
Wildfires can severely exacerbate existing asthma, noted by an increase in asthma-related ER visits
How do wildfires impact the health of firefighters?
Respiratory function is impacted, and biomarkers show measures of oxidative stress
3 studies of the health impacts of wildfires on animals
- Orangutans exposed to wildfire has increased rest, decreased travel and ketones that suggested an altered energy expenditure related to the immune system
- Rhesus Monkeys exposed to wildfires as babies showed immune dysregulation and decreased lung function
- Mice were exposed to coarse or fine wildfire PM, showing neutrophilic inflammation and decreased macrophages in bronchial lavage
Is there a safe distance from a wildfire?
No…
- Closing windows or using filters does not help
- N95 protects against PM but not hazardous gases
What is the “goalpost” of climate change?
+1.5 degrees C, but we are headed towards +2.7
What percentage of people globally breathe unhealthy air?
90-95% of people, as there is no safe level of air pollution
How many deaths/year is indoor and outdoor air pollution responsible for?
7 million deaths/year
How does temperature affect the formation of ozone?
Higher temperatures favor the chemical formation of ground-level ozone, and natural emissions of precursors are elevated in warmer weather
What conditions lead to higher concentrations of PM2.5?
stagnant air + less frequent precipitation = increased PM2.5
How is ozone formed?
UV + NOx + VOCs = Ozone
Higher temperatures favor the formation of ground-level ozone
How does seasonality affect ground-level ozone?
Ground-level ozone is much higher in the summer due to increased temperatures; e.g., little to no ozone in February but a substantial amount in June
Why are smaller particles more dangerous to human health?
- Smaller particles penetrate deeper in the lungs
- The body’s defense mechanisms are inept against smaller particles
What is the relationship between electricity use during summer and air pollution?
Increased demand for electricity during warmer summers worsens air pollution; cooling contributes to air pollution
Where has wildfire smoke pollution most significantly increased in the U.S. over the past decade?
California
How do wildfires contribute to lead exposure?
Toxic metals such as lead are also released by wildfires, as fire burns things that emit these metals
Why is PM2.5 from fires more dangerous than PM2.5 from other sources?
Wildfire-specific PM2.5 was found to be ~10 times more harmful to children’s respiratory health than PM2.5 from other sources.
This is likely due to the burning of other toxic metals by wildfires.
Are wildfires just a Western U.S. problem?
No, although the majority of large fires occur in the western U.S., we find the majority of mortality and asthma morbidity attributable to smoke PM2.5 occurs outside the West
Has the Clean Air Act been successful?
Yes, it is an epidemiology success story, as it has decreased the prevalence of many pollutants
What is the “Exceptional Events Rule?”
loophole in the Clean Air Act related to wildfire emissions
Why are wildfires exceptionally concerning with regard to air pollution progress?
Wildfire smoke has been erasing years of progress toward cleaning America’s air, even reversing air quality improvements
How many people live in areas that exceed air quality standards?
Ozone: 120 million
PM2.5: 70 million
2 mechanisms of climate change impacts on health
- Direct - Poor Climate/Air Quality directly increases Health Risks
- Indirect - Poor Climate/Air Quality increases electricity demand, which in turn further worsens Climate/Air Quality, leading to health risks
How do temperature projections for 2069 compare to 2007?
The frequency of hotter summer days is expected to be substantially higher in 2069
Why is proximity to power plants important?
Proximity to power plants can influence health impacts of pollution
How is summer ozone expected to change over time?
Future summer ozone projected to be greater than current summer ozone; estimated summer ozone increase is +15.6 parts per billion
How is summer PM2.5 expected to change over time?
Future summer PM2.5 projected to be greater than current PM2.5; estimated summer PM2.5 increase is +3.8 micrograms/cubic meter daily
How does air conditioning affect PM2.5 levels?
Ambient PM2.5 has increased more due to air conditioning than to climate change alone
How does air pollution relate to COVID-19?
Increased air pollution = worsened COVID-19 severity
What are the consequences of a 3-4 degrees C rise in temperature?
- Sea levels rise
- Weather extremes
- Disease
- Reduced food/water supply
Why is climate change an economic concern?
Widespread economic burden relating to deaths, medical care, wages, medications, etc.
What is the “price tag” of climate change health effects, and who pays for these costs?
Estimated to be $10 billion; a disproportionate share of the illness-related costs are shouldered by Medicare and Medicaid patients
What is the hierarchy of risk management controls?
- Policy/Administration
- Engineering/Infrastructure
- Personal Protection
The higher in hierarchy for an intervention, the more people are generally protected.
How does air pollution contribute to DALYs?
Household air pollution from solid fuels and ambient particulate matter pollution both impact healthspan
Why is solid fuel use concerning?
In developing countries (places that aren’t electrified), majority of the population relies on solid fuels for cooking. This cooking often occurs indoors in confined spaces, exacerbating the issue.
Household air pollution from solid fuels is a major contributor to DALYs.
How do energy sources vary across incomes?
Lower incomes rely on wood burning, kerosene, etc. (“dirtier” sources), while higher incomes rely on electricity, natural gas, and renewables
Why is the time cost of collecting fuel a concern?
In developing nations, women frequently spend a significant amount of time/day gathering fuel
2 key indoor pollutants of concern
- PM
- Carbon monoxide
How does indoor PM2.5 compare to outdoor PM2.5?
Indoor PM2.5 constituted >10% of outdoor PM2.5 levels in regions housing 4.4 billion people
What is the outdoor PM burden of cooking with solid fuels?
Household cooking with solid fuels accounts for 12% of outdoor PM2.5; exposure to outdoor PM2.5 from cooking caused the loss of hundreds of thousands of lives and 10 million disability-adjusted life years globally
4 challenges in air pollution exposure assessments
- Fate of pollution - pollutants can form secondarily, making it harder to track
- Mixtures of pollutants (interactive effects) - not just PM2.5, but others
- Accumulation and removal of pollution - stagnant air = increased pollution, rain = decreased pollution
- Timing of exposure
How severe is the PM2.5 problem in developing countries?
Levels often ~1000x human limit due to “dirtier” energy sources and indoor cooking practices
Where in the world is pollution the worst?
India; it has the world’s five most populated cities, with PM2.5 and NO2 being a major concern
What is the “epicenter of the NO2 problem?”
Bangladesh, India, Nepal, Pakistan, and Sri Lanka; PM2.5 and NO2 are both extremely high in this region
What are the WHO Ambient Air Quality Guidelines?
Like NAAQS, but global guidelines (not law); guidelines and interim targets for key pollutants, limits set to protect public health and the environment