HS345 Final Exam

"environment" in the context of environmental health

The complex of physical, chemical, biotic(living), and social factors that surround an organism

definition of healthy

State of complete physical, mental, and social well-being and not just the absence of disease or infirmity

how biomagnification is harmful to human health

harmful because it's just the toxins building up as you go higher and higher up the trophic levels, concentrations of toxins in organisms at higher trophic levels of the food chain, meaning humans are consuming higher levels of pollutants

biodiversity

variation of life, genetic variation, greater biodiversity equals healthier ecosystems, think MORE DIVERSE the better

ecosystem services

Benefits and value provided to humans for free by nature

Clean air, infectious disease, food and water, jobs, and the economy

Ex: mangroves protect against storm surges and erosion, bees pollinate crops, and wild plants

nested model of sustainability and how environmental protection and economic growth are not mutually exclusive

Starts with an economy that is focused on economic development and making sure people have the resources to live and thrive

To have a healthy economy, you need a healthy and just society treated fairly and equitably.

Cannot have this without a healthy environment, so they need each other

Environment, equity, and economy are all interconnected and need one another

exposure

can be good or bad

environmental exposures

Air pollution, water pollution, and soil pollution

Hill's Criteria for causality

Guidelines for epidemiologists to make a connection

1. Temporal relationship(did the exposure happen before the outcome

2. Biological plausibility

3. Consistency

4. Effect size

5. Dose-response

A continuous relationship between exposure and outcome (or dose and response)

More exposure=more risk

TBCED

necessary causes

definite cause of the disease because every person who got the disease had this specific cause (the cause is needed to get the disease)

Ex: a person must have been living with HIV before they can develop AIDS

sufficient causes

things that could have led to the disease, but didn't necessarily lead to it

GIS

A system that creates, manages, analyzes, and maps all types of data. GIS connects data to a map, integrating location data with all types of descriptive information

Applications:

Geolocation, optimizing routes, and measuring distances

Tracking disease prevalence

Visualizing population characteristics

Visualizing overlapping spatial information

examples of research questions that would require geospatial analyses to answer

How far do rural populations have to travel to reach the nearest emergency care facility?

Are cancer clusters associated with industrial waste sites?

How does proximity to highways affect asthma rates in children?

points on a map based on latitude and longitude

Latitude: horizontal lines around the world starting at the equator, 0 degrees north, and increasing in both directions towards the poles

Longitude: vertical lines that go around the world, starting at the prime meridian at 0 degrees east

exposure assessor

Determines how, when, and to what extent people come into contact with environmental hazards.

Measure levels of contaminants in air, water, soil, food, or consumer products.

Estimate human exposure through different pathways (inhalation, ingestion, dermal contact).

environmental epidemiologist

Studies the relationship between environmental exposures and health outcomes in populations.

Design and conduct studies (e.g., cohort, case-control) to investigate links between exposures (e.g., air pollution, lead) and disease (e.g., asthma, cancer).

Analyze data to identify trends, associations, or causal links.

toxicologist

Studies the harmful effects of chemicals and other agents on living organisms.

Determines dose response relationships

Assist in hazard identification and risk assessment

industrial hygiene

anticipating, recognizing, evaluating,

controlling

what industrial hygienist does

Anticipation – Identifying potential health hazards before they become a problem (e.g., during the design of a new process).

Recognition – Understanding what types of chemical, physical, biological, or ergonomic hazards exist in a workplace.

Evaluation – Measuring the extent of exposure using monitoring and analytical methods (e.g., air sampling for airborne contaminants).

Control – Implementing strategies to reduce or eliminate hazards (e.g., ventilation systems, personal protective equipment, process changes)

acute exposures

short term (seconds to days)

rapid impacts at high dose: poisoning death

chronic exposures

long term(months to decades)

delayed impacts at low doses: cancer, chronic organ damage

utilitarianism

maximize wellbeing and minimizing suffering

ends justify means: actions do not have inherent morality

motive is irrelevant

deontology

appeals to authority or laws "duty"

ends do NOT justify the means: actions have morality regardless of outcome; this morality is often informed by laws or rules

vulnerability

characteristics or conditions that make individuals or communities more likely to be exposed to environmental hazards and/or suffer more severe health impacts from these exposures.

social factors that limit the ability to prevent, prepare for, or recover from such exposures.

SDOH

environmental justice

The principle that environmental hazards must not be disproportionately burdened on communities by race, income, or any other characteristic

stipulates that all communities should have equal access to a healthy environment

Requires recognizing the causes and consequences of these systemic inequities and actively working to undo them

examples of environmental injustices

Environmental health hazards imposed on vulnerable communities

ex: The placement of toxic waste sites in low-income, minority neighborhoods, or a community that suffers from disproportionate exposure to harmful air pollutants while lacking the resources to mitigate or adapt to these risks.

Temperature and total energy

Warmer objects emit more total energy. This is a result of the Stefan-Boltzmann law, which states that the total energy radiated by an object is proportional to the fourth power of its absolute temperature (T⁴).

peak wavelength

Wien's Law explains that hotter objects emit radiation at shorter wavelengths. As the temperature increases, the peak wavelength of emitted radiation shifts to shorter wavelengths, meaning hotter objects emit more high-energy radiation (e.g., blue light or ultraviolet).

property of a molecule for it to be considered a greenhouse gas

molecules in the atmosphere that absorb thermal infrared(longwave) radiation(heat) emitted by the Earth

major greenhouse gases

water vapor, carbon dioxide, methane, nitrous oxide, and fluorinated gases

global warming potential (GWP)

measures how much energy a molecule can absorb and contribute to warming, relative to carbon dioxide (CO2). It differs depending on the timeframe considered (e.g., 100 years).

residence time

length of time a molecule spends in the atmosphere before it is removed (e.g., through precipitation or chemical reactions). How long an emission of a molecule influence global temperatures

Water Vapor Residence Time

7-10 days(least RT)/ NO GWP

CO2 Residence Time

hundreds to thousands of years/ GWP = 1 (relative)

methane residence time and GWP

10 years / GWP = 30-80 x CO2

nitrogen oxide residence time and GWP

110 years / GWP = 273x CO2

residence times in order from shortest to longest

water vapor, ozone, methane, nitrous oxide, carbon dioxide, fluorinated gasses

GWP shortest to longest

carbon dioxide (relative), methane, nitrous oxide

the basic principle of Clausius-Clapeyron relation with respect to global warming

describes the relationship between the vapor pressure of a substance and its temperature. It shows that as temperature increases, the amount of water vapor in the air (its vapor pressure) increases exponentially.

Why global warming leads to more moisture in the atmosphere.

Mechanisms through which climate change can affect air pollution

Temperature-dependent: Warmer temperatures can lead to more ground-level ozone (O₃) formation(pollution)

Inversion layers: Warmer air can trap cooler air underneath, keeping pollutants closer to the ground.

Wildfires and droughts: Warmer, drier conditions contribute to larger wildfires, which emit pollutants like PM2.5 and ozone precursors, worsening air quality.

vector-borne illnesses

diseases transmitted to humans (or animals) through the bites of infected arthropods, such as mosquitoes, ticks, fleas, or sandflies. These vectors carry pathogens like viruses, bacteria, or parasites from one host to another.

how climate change can affect vector borne illnesses

Warmer temperatures increase the range of mosquito and tick habitats

Mosquitos lay eggs in stagnant water: more rainfall, more breeding grounds

Habitable areas expanding

Cooler places become warmer, and wet places become wetter, which can facilitate greater areas in which mosquitoes and ticks can thrive

Longer warm season

Earlier spring onset and later fall offset mean more time spent outdoors and hence a greater risk of exposure to Lyme-carrying ticks

Warmer temperatures accelerate the mosquito life cycle and the incubation period for malaria

where in the atmosphere it is "good" or "bad" to have ozone in terms of human health

Good up high but bad nearby

good ozone

found in the stratosphere high above earth and protects us from the Sun's harmful ultraviolet rays

bad ozone

found in the troposphere near the Earth and makes up most of the air pollution we call "smog"

water insoluble so respiratory irritant

ingredients for forming ozone

from complex chemical reactions that require: precursors(NOx and VOCs) and UV radiation

NOx

class of nitrogen- and oxygen- containing molecules

reaches LRT, precursor to ozone formation

VOCs

organic chemicals that evaporate at typical temperatures and pressures

characteristics of air pollutants that make them more hazardous to health

size, solubility, chemical composition

water insoluble can make it to the lower respiratory tract(more dangerous)

water soluble are mostly removed in the upper respiratory tract

general trend of criteria air pollutants in the US over the past several decades

Air pollution is among the leading risk factors for premature death globally

The Global South has higher health burdens from air pollution

Reductions in indoor air pollution mostly drive improvements in global air pollution-related deaths, but there has been little progress globally on outdoor air pollution

Only about half of the countries, mainly in the Global North, have seen reductions in outdoor air pollution deaths since 1990

Over the past several decades, the general trend of criteria air pollutants in the United States has been a significant decline, despite increases in population, energy use, and vehicle miles traveled.

mostly driven by reductions in indoor air pollution

inflammation

The body's immune response to pathogens and toxins

inflammation's relationship to long term air pollution exposure

Fine, water-insoluble pollutants cause inflammation

Chronic inflammation is associated with a wide range of noncommunicable diseases, including autoimmune disorders, heart disease, asthma, mental health conditions, and Alzheimer

characteristics of sulfur dioxide as an air pollutant

Strong odor

Reaches the upper respiratory tract but its is water soluble so has more difficulty reaching lower respiratory tract

emissions creates acid rain

slight cooling impact on global temperature(forms sulfate aerosols)

serious health and environmental harms far outweigh any benefits.

acid rain

Rain that has a slightly lower pH than normal rain

hurts infrastructure and agriculture.

ways to reduce indoor air pollution from cooking with a gas stove

HEPA filter in the kitchen,

turn on exhaust hood while cooking or crack the window

Use the microwave, a toaster oven, or an electric kettle instead

consider electric induction

approximate % of Earth’s water that is liquid freshwater

<0.1%

67% is locked in glaciers

surface water

Water in contact with the atmosphere(oceans, lakes, rivers)

Source water for 1/2 Americans

"Checking account"

Groundwater under direct influence of surface water (GWUDI)

Groundwater that either:

1. Contains organisms

2. Has changing characteristics in response to surface water or meteorological conditions

Must be saturated with water and no air pockets

Source water for 1/2 Americans

"Savings account"

"true" ground water

Underground freshwater is stored in aquifers that are not affected by surface waters

considered the cleanest source water

simply water that fills the cracks and spaces in underground soil and rock layers

confined aquifer

an aquifer surrounded by a layer of impermeable rock or clay that impedes water flow

land subsidence

If groundwater is withdrawn faster than it can be replenished, the land can sink

benefits of wastewater treatment

Removes pathogens that can cause waterborne illnesses like cholera, dysentery, and hepatitis.

Prevents contamination

There would be a huge amount of toxins and nutrient loading that would mess up the marine ecosystems(biodiversity loss)

ways to reduce your personal PFAS exposure

filtering your drinking water, choosing PFAS-free alternatives for food packaging and cookware, and avoiding stain-resistant or water-resistant products in your home and clothing

urban heat island effect

phenomenon in which cities (or parts of cities) are warmer than surrounding suburbs and rural areas

Caused by…

1. lower albedo(reflectivity) from darker surfaces + heat-absorbing building materials to asphalt roads and dark roofs absorb a substantial amount of solar radiation

2. Tall compact buildings trap heat and create “canyons” that allow radiation to bounce back and forth rather than being emitted outward

3. Anthropogenic sources of heat(cars, air conditioners)

4. Lack of trees and plants, which cool the surrounding air via evapotranspiration(an endothermic process, which cools the surrounding environment)

Benefits of planting trees in urban areas

1. Reduces the urban heat island effect

2. Improves air quality(gaseous pollutant are absorbed through stomata)

3. Reduces runoff and flooding because trees, root systems, and soil absorb it

3. improves water quality while also reducing localized flooding

how to promote environmental justice when planting trees in a city

focus on equitable distribution of benefits and resources, ensuring all communities, especially those most vulnerable, have access to the positive impacts of urban forests

environmental gentrification

The displacement of lower-income residents from neighborhoods due to environmental improvements or climate-related interventions

Essentially, efforts to make a neighborhood greener or more resilient can displace long-term residents who can no longer afford the rising costs.

trend of urbanization

Communities are increasingly in urban settings, which presents both challenges and opportunities for environmental health

The trend toward urbanization exists across all national income levels

higher population density

ways that urban sprawl has negative environmental impacts

expansion of cities outward to suburbs that have low-density housing, single-use zoning, and a reliance on cars for transportation

cars are prioritized, little to no public transit, greater GHG emissions because bigger houses, more land use

smart growth

Legislation and regulations to limit suburban sprawl and preserve farmland.

approach to developing communities that prioritizes environmental health, social connectedness and more livable communities

ex: mix land uses, more trees and parks, walkable neighborhoods

genetically modified organisms (GMOs)

Crop varieties are genetically modified to be more resilient. This has many benefits, such as increased yield and greater climate resistance.

Approved GMO foods currently on the market are safe to eat

There is evidence that GMOs do not pose a PH risk

Insecticides and herbicides are considered a greater public health concern

pesticides

Chemicals used to kill, repel, or alter the behavior of pests

pros of pesticides

crucial for the control of vector-borne diseases, such as malaria

help protect crops to ensure adequate yields to meet global food security needs

Prevents disease causing pests from inhabiting living spaces

cons of pesticides

can accumulate and biomagnify (DDT), causing substantial environmental and human health impacts

acute toxicity, particularly for agricultural workers and people living near farms

health risks can be minimized, but not eliminated, and there is potential for unknown impacts

clean air act

the law that defines EPA's responsibilities for protecting and improving the nation's air quality and the stratospheric ozone layer

very successful at reducing pollutants

Concentrated animal feeding operations (CAFOs)

factory farm buildings with high-density confinement of livestock without access to grass or vegetation

Still illegal in most states to keep chickens and pigs in confinement so tight that their movements are restricted

CAPO health impacts

1. Antibiotic resistance

2. Air and water pollution(hydrogen sulfide and ammonia)

3. Animal waste(filled with pathogens) spreads from farm to community via occupational exposures, runoff and food contamination, not regulated by the EPA like human waste is

main ideas of the Grummon et al. (2024) assigned reading

investigates how "natural" claims on fruit drink packaging influence parents' perceptions and purchase intentions

The study concludes that "natural" claims can mislead consumers about the nutritional quality of fruit drinks, suggesting a need for stricter regulation of such labeling to prevent consumer deception and protect public health

ways to prevent getting bed bugs

Never put your luggage on the floor or on the bed

Wash and dry your clothes in hot water and high heat

reduce clutter

mattress encasement

Inspect hotel rooms

ways to reduce your personal exposure to pesticides

Buy organic

Integrated pest management

Rinse produce before eating

solid waste

anything that is deemed to no longer have value

It does not necessarily have to be a solid at room temperature!

(ex: municipal waste, hazardous waste, special waste)

how electronic waste is hazardous to human

Electronics contain numerous chemicals, including lead and mercury

Some e waste (22%) is formally recycled, but much of it is shipped to nations in the global south, where improper handling and disposal expose workers and communities to heavy metals and air, soil, and water pollution

what happens to organic matter (such as food waste) when it is in a landfill

it undergoes anaerobic decomposition due to the lack of oxygen in the tightly packed waste. This process generates methane, a powerful greenhouse gas, and leachate, a harmful liquid.

leachate

Liquid that pools at the bottom of the landfill and needs to be pumped out and treated separately

ways you can reduce amount of waste produced

composting, dining in, cloth bags, stainless steel water bottles

description of an environmental hazard (such as PFAS) that is written in a way that would be effective for a general audience without a background in environmental health science

if it's written in simple, accessible language, avoids technical jargon, and focuses on the practical implications for everyday life

strategies for effective health communication

Simple and clear message

Repetition

Trusted messengers