Env Health Ch 8, 11, 13, 15

Question 1

What are the health effects of NO₂?

Answer 1

NO₂ exposure is associated with eye, nose, and throat irritation, and short-term decreases in lung function. But, NO₂ is a precursor to ozone and PM, so it is hard to separate the effects of NO₂ from the effects of other pollutants.

Question 2

Define TDM.

Answer 2

Transportation Demand Management = strategies to reduce traffic congestion, such as:

1. Ride-sharing incentives.
2. HOV lanes.
3. Promotion of telecommuting.

Question 3

Describe NAAQS.

Answer 3

National Ambient Air Quality Standards. Under the Clean Air Act, the EPA has set NAAQS for 6 major pollutants. The standards include primary standards (designed to protect human health) and secondary standards (designed to protect public welfare, such as soil, water, crops, livestock, transportation, visibility, etc).

Question 4

Define cumulative exposure.

Answer 4

This is defined as aggregate exposure to a series of compounds that affect health through similar mechanisms.

Example = organophosphates (all grouped together, because they have the same mechanism of toxicity).

Question 5

What are the health effects of PM?

Answer 5

Increased hospital and ER visits, respiratory symptoms, decline in lung function, exacerbation of chronic respiratory and cardiovascular diseases, and premature death.

Question 6

Explain direct reading devices vs sample collection devices.

Answer 6

Direct reading devices provide real-time measurements of the exposure of interest.

Sample collection devices store or trap samples for later analysis.

Question 7

Name the 4 stages of urban development, and the diseases associated with each stage.

Answer 7

1. Poverty (infectious diseases).
2. Industrial (respiratory problems).
3. High-consumption (obesity and heart disease).
4. Healthy eco-city (maximum health potential).

Question 8

Define PM₁₀ and Coarse PM.

Answer 8

PM₁₀ = particles with an aerodynamic diameter of 10 µm or less.

Coarse PM = particles with an aerodynamic diameter between 2.5 µm and 10 µm.

Question 9

Describe how NO₂ is absorbed into the body.

Answer 9

NO₂ is nearly insoluble in water, so it easily reaches the lower respiratory tract.

Question 10

Describe patch sampling.

Answer 10

It is a direct assessment technique, in which an absorbent patch of material is placed on someone’s skin or outer clothing. The subject then goes about their work. Then, the patch is collected and analyzed. The amount of contaminant collected is calculated, and extrapolated to the whole body, based on how much skin area the patch covered.

Question 11

Name 4 examples of naturally-occurring air pollutants.

Answer 11

1. VOCs from vegetation
2. Pollen
3. Volcanic gases
4. Dust from deserts

Question 12

What are the health effects of SO₂?

Answer 12

SO₂ exposure is associated with reduced lung function, bronchoconstriction, hospitalizations, and more. But, SO₂ is a precursor to PM and usually exists as a complex mixture of pollutants, so it is hard to attribute these effects specifically to SO₂.

Question 13

Explain how water-soluble vs water-insoluble gaseous pollutants penetrate the respiratory system. Name an example of each.

Answer 13

Water-soluble gases are largely removed by the upper airway (example = SO₂).

Water-insoluble gases penetrate deeper into the lungs (example = ozone).

Question 14

Describe the fluorescent tracer method.

Answer 14

It is used in pesticide sampling. A nontoxic fluorescent tracer is added to the pesticide spray mix. Then, the worker goes about their work. Later, the worker is video-imaged under UV light. This helps visualize where the worker was exposed to the pesticide.

Question 15

Explain what photochemical smog is, and how it is formed.

Answer 15

When VOCs react with NO_x in the presence of sunlight, tropospheric ozone is formed. The resulting mixture is called photochemical smog.

Question 16

Describe criteria pollutants. Name all of them.

Answer 16

They are a group of key outdoor air pollutants defined by the Clean Air Act. The EPA sets standards for these pollutants. They are: CO, lead, NO₂, ozone, particulates, and SO₂.

Question 17

What is the name given to areas that fail to meet the national air quality standards?

Explain how this can be fixed. In other words, who is normally responsible for maintaining air quality?

Answer 17

Nonattainment areas.

States have a major role in achieving acceptable air quality. They develop state implementation plans (SIPs), which may limit emissions from power plants, factories, and mobile sources. If the EPA does not approve of a SIP, the federal government may withhold highway funding.

Question 18

Define temperature inversion. How does it affect air quality?

Answer 18

Temperature inversion = when there is a layer of warm air above a layer of cooler air at the earth’s surface.

This causes air pollutants to be trapped near the ground.

Question 19

Define dose.

Answer 19

Dose refers to the mass of contaminant that crosses the tissue barrier and enters the body.

Question 20

Explain the temporal and spatial variation in ozone levels.

Answer 20

[O₃] is higher in summer.

Ozone problems tend to be regional, not localized.

Question 21

What are the 2 “types” of ozone?

Answer 21

1. Stratospheric ozone (forms the ozone layer that protects us from UV rays).
2. Tropospheric ozone (ground-level ozone, a harmful pollutant).

Question 22

Define job-exposure matrix.

Answer 22

It is a method used to estimate indirect exposure to a contaminant.

It is a carefully-constructed table, which assigns each worker to an exposure level, based on his job assignment and work zone location.

It is usually the only way to assess exposures in a retrospective study.

Question 23

Define potential dose.

Answer 23

The potential dose is what the dose would be, assuming that all the material crosses the tissue boundary and enters the body.

Question 24

How are sulfur oxides formed? What is the main source of SO₂ emissions?

Answer 24

They are formed from the combustion of sulfur-containing fuels and materials, such as coal and metal ores.

Main source of SO₂ emissions = Power plants.

Question 25

Explain active sampling.

Answer 25

Active sampling devices draw air through an absorbing medium, using an electric pump. Active sampling is highly versatile, sensitive, and specific to the contaminant of interest, due to the existence of specific lab methods such as mass spectrometry. However, they are bulky and noisy, so are sometimes not suitable for personal sampling.

Question 26

Define NO_x-limited and VOC-limited.

Answer 26

Due to the complex chemistry of ozone formation, decreased emissions of either NO_x or VOCs could change ozone levels. For NO_x-limited locations, reduction of NO_x levels may be the best way to reduce ozone levels. For VOC-limited locations, reduction of VOC levels may be the best way to reduce ozone levels.

Question 27

Name 3 reasons why unequal societies may be more likely to pollute or degrade their environment.

Answer 27

1. Power asymmetry - The wealthy accrue more of the economic benefits of polluting activities, both as producers (shareholders) and consumers (consumption increases with wealth). But, the wealthy are better able to avoid the effects of pollution. 2. Inequality leads people to consume more, due to a desire to emulate the privileged. 3. Inequality erodes social cohesion and trust. This increases competition and insecurity about the future, which in turn decreases investment in public services which would lessen environmental impact.

Question 28

Describe brownfield redevelopment.

Answer 28

Brownfield = Land that was previously used for industrial or commercial purposes, which now has suspected or known pollution / contaminants. Brownfield redevelopment = when this land is re-purposed and used again for something else.

Question 29

What is the difference between primary and secondary pollutants? Name an example of each.

Answer 29

Primary pollutants are directly emitted from a source (example = CO₂ from cars). Secondary pollutants are formed in the atmosphere through physical and chemical conversion of precursors (example = ozone is formed when sunlight chemically converts other precursors into ozone).

Question 30

How is mercury released into the environment?

Answer 30

Mercury is naturally found in fossil fuels, especially coal. When these are burned, mercury is released into the air.

Question 31

Name 4 disadvantages of / problems with biomarkers.

Answer 31

1. The timing can be tricky to understand (some biomarkers last a long time, others are gone within minutes). 2. There are usually multiple metabolic pathways that influence biomarkers, and they may behave similarly for related compounds. 3. Biomarkers integrate over all routes and pathways. This is good, but also bad because the route of exposure cannot be identified. 4. Different people can metabolize contaminants at different rates.

Question 32

What are the primary causes of acid precipitation?

Answer 32

NO_x and SO_x.

Question 33

Name one way to overcome the limitations of biomarkers.

Answer 33

Use a panel of biomarkers (measure multiple markers at once).

Question 34

How are nitrogen oxides formed?

Answer 34

They are formed through combustion, when the nitrogen in the air becomes oxidized.

Question 35

Define PM.

Answer 35

PM = particulate matter (solid or liquid particles suspended in air).

Question 36

Describe stratified sampling.

Answer 36

This is when a population is divided into subgroups (strata), and each individual that is monitored represents a known number of individuals in the subgroup. This is an efficient way to estimate exposures, when there is a large group of people with different exposure levels.

Question 37

Explain how SO₂ emissions are regulated by the federal government.

Answer 37

Under the Clean Air Act, the EPA created a cap and trade system for SO₂. This began in the 1990s.

Question 38

Define "windows of vulnerability". Explain the effects that can occur.

Answer 38

This refers to the times during fetal development, childhood, and adolescence, when the human body is extra sensitive to chemical exposure. Prenatal chemical exposure has been linked to adverse health effects, both at birth (low birth weight and birth defects) and later in life (cancer and cardiovascular disease).

Question 39

Describe the Global Warming Solutions Act.

Answer 39

This is a California law that passed in 2006. AKA Assembly Bill 32 (AB 32). This requires that GHG emissions be reduced to 1990 levels by 2020, and to **80% below 1990 levels by 2050.**

Question 40

Define biomarkers.

Answer 40

Biomarkers are used to assess an individual's exposure to a contaminant. They are collected by sampling body fluids or tissues.

Question 41

Define exposome.

Answer 41

The totality of exposure events that affect a person.

Question 42

Describe universal design.

Answer 42

The designing of products and environments so they are usable by all people, to the greatest extent possible, without the need for adaptation or specialized design.

Question 43

Describe tape stripping.

Answer 43

A special tape is applied to the skin, and then stripped away. This removes a single layer of exposed skin cells. The tape is then analyzed. The amount of contaminant collected is calculated, and extrapolated to the whole body, based on how much skin area the tape covered.

Question 44

Define TSP.

Answer 44

Total Suspended Particles = refers to almost all particles suspended in the air. Typically, it is measured as particles up to about 45 µm in aerodynamic diameter.

Question 45

Explain how different exposure profiles may have different health effects, even with equivalent total exposures.

Answer 45

Some contaminants are easily cleared by the body at low exposure levels, but toxic at higher levels.

Question 46

Explain why environmental justice benefits everyone, not just the marginalized groups.

Answer 46

Social inequality is linked to greater environmental degradation, such as air pollution and water contamination (these issues affect everyone).

Question 47

Define environmental justice.

Answer 47

It is the principle that all people and all communities are entitled to equal protection of environmental and public health laws and regulations.

Question 48

Define HIA.

Answer 48

Health Impact Assessment. It is a method for assessing the health impacts of proposed policies and projects. It explicitly addresses socially excluded or vulnerable people. It focuses on the health impacts of decisions made in non-health sectors, such as community design. It can make recommendations to increase positive and minimize negative health outcomes.

Question 49

Define VOCs.

Answer 49

Volatile organic compounds = they have a high vapor pressure, so they evaporate easily. Examples: Benzene, chloroform, formaldehyde, isoprene, methanol, and monoterpenes.

Question 50

Define aggregate exposure.

Answer 50

This refers to the practice of simultaneously assessing all routes and exposure pathways (dermal, inhalation, etc) for a single compound.

Question 51

Describe the Clean Air Act.

Answer 51

Originally passed in 1963. Greatly expanded in 1970 (EPA was created this same year). It is the major piece of legislation that addresses air quality in the USA.

Question 52

Describe HAPs.

Answer 52

Hazardous Air Pollutants - established by the Clean Air Act Amendments of 1990. This regulatory category includes a number of VOCs, pesticides, herbicides, and radionuclides.

Question 53

Name 4 sources of PM.

Answer 53

1. Burning of fuel 2. Driving on unpaved roads 3. Industrial activity 4. Natural sources (pollen, dust, salt spray, etc)

Question 54

Define absorbed dose. How is it calculated? What are the units?

Answer 54

The absorbed dose is the amount of contaminant that actually enters the body. Absorbed dose = (Potential dose) x (Absorption factor) The units are expressed in grams or micrograms (there is no time component)

Question 55

Define duplicate diet study. How does it work?

Answer 55

It is a direct approach to assessing ingestion exposure. Duplicate portions of the food eaten by test subjects are collected and analyzed for contaminant levels.

Question 56

Describe LEED.

Answer 56

Leadership in Energy and Environmental Design. This is a certification program managed by the US Green Building Council.

Question 57

Name 3 facts about lead toxicity.

Answer 57

1. Children are more susceptible than adults. 2. Most of the effects of lead toxicity are due to effects on the nervous system. 3. There is no threshold for lead toxicity (health effects can occur at levels below US regulatory standards).

Question 58

Name 3 reasons why children are more susceptible to lead poisoning than adults are.

Answer 58

1. They eat more dust and soil, which may be contaminated with lead. 2. The blood-brain barrier in young children is not fully developed. 3. Children absorb lead from their GI tracts more efficiently than adults do.

Question 59

Describe how ozone is absorbed into the body, and what effects it has.

Answer 59

Ozone is not very soluble in water, so it can reach the lower respiratory tract. It can break molecular bonds and rapidly damage tissue. Short-term exposure causes temporarily decreased lung function, increased airway resistance, and increased coughing and wheezing. Long-term exposure may cause chronic lung diseases.

Question 60

Explain passive sampling.

Answer 60

Passive sampling devices use diffusion to collect an air sample. They require an absorbing medium that removes the compound of interest from the air (by reaction or absorption at the surface of the medium). The concentration gradient formed causes the compound to absorb. The compound is then analyzed in a lab.

Question 61

Define absorption factor.

Answer 61

It is the percentage of a contaminant that actually crosses the tissue barrier and enters the body.

Question 62

Describe worst-case sampling.

Answer 62

This is when the highest-risk workers are selected for an exposure study, or when measuring is conducted during the time of highest exposure. The assumption is that if these workers are not being overexposed, then no one else is, either.

Question 63

Define climate gap.

Answer 63

This refers to the disproportionate impact that climate change has on certain social groups. Specific impacts: sea level rise, hurricanes, floods, heat waves, air pollution, and infectious diseases.

Question 64

What are the units that are used for expressing exposure?

Answer 64

(units of concentration) x (time)

Question 65

Explain the difference between urbanization and urbanism.

Answer 65

Urbanization = the dynamic process of growth and change in cities. Urbanism = how urban residents interact with the built environment.

Question 66

Define exposure profile, and total exposure.

Answer 66

It is a graph of the concentration of a chemical present in someone's breathing zone (or drinking water) over time. Total exposure = the area under the curve.

Question 67

What are the health effects of VOCs?

Answer 67

Irritation of the respiratory tract, headaches, and carcinogenicity.

Question 68

Describe how SO₂ is absorbed into the body.

Answer 68

SO₂ is very water-soluble, so when inhaled, it is mostly absorbed by the mucous membranes of the upper airways. However, increased breathing rate and oral breathing can increase the dose delivered to the lung.

Question 69

Define aerosol.

Answer 69

Small, solid or liquid particles suspended in air.

Question 70

Name 3 advantages of biomarkers.

Answer 70

1. They can prove that an individual has absorbed a compound into his body. 2. They account for bioavailability (how readily a compound can cross the tissue barrier and enter the body). 3. They integrate across all routes of exposure, so they are useful to assess aggregate exposure.

Question 71

How are VOCs formed?

Answer 71

They are formed from natural sources (vegetation), industrial processes, and motor vehicles. In many places, biogenic sources contribute more to VOCs than anthropogenic sources do.

Question 72

Define MPOs.

Answer 72

Metropolitan Planning Organizations. They are groups of local and state officials, who are responsible for planning the use of transportation funds in their metro areas.

Question 73

Define aerodynamic diameter.

Answer 73

It is defined as the diameter of the spherical particle with a density of 1000 kg/m³ and the same settling velocity as the particle you are measuring. In other words, it allows you to compare particles that have irregular shapes and densities. It is used to classify particulate matter. It can be used to predict where in the respiratory tract a particle will deposit (smaller particles penetrate more deeply).

Question 74

Name 3 things that determine the ability of a pollutant to penetrate the respiratory system.

Answer 74

1. The physical form and chemical composition of the pollutant (example = solubility, if it is a gas). 2. The concentration of the pollutant. 3. The individual's ventilation rate (breathing rate).

Question 75

How are people exposed to mercury?

Answer 75

Oral, inhalation, and dermal exposure. Oral is the most common, through ingesting contaminated food (when airborne mercury is deposited in water and on farmland).

Question 76

How is CO formed?

Answer 76

By the incomplete combustion of carbon-containing molecules.

Question 77

Why are low-income communities particularly vulnerable to heat waves?

Answer 77

Because they often live in inner-city neighborhoods (heat islands).