Env Health Ch 8, 11, 13, 15 Flashcards
What are the health effects of NO2?
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.
Define TDM.
Transportation Demand Management = strategies to reduce traffic congestion, such as:
- Ride-sharing incentives.
- HOV lanes.
- Promotion of telecommuting.
Describe NAAQS.
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).
Define cumulative exposure.
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).
What are the health effects of PM?
Increased hospital and ER visits, respiratory symptoms, decline in lung function, exacerbation of chronic respiratory and cardiovascular diseases, and premature death.
Explain direct reading devices vs sample collection devices.
Direct reading devices provide real-time measurements of the exposure of interest.
Sample collection devices store or trap samples for later analysis.
Name the 4 stages of urban development, and the diseases associated with each stage.
- Poverty (infectious diseases).
- Industrial (respiratory problems).
- High-consumption (obesity and heart disease).
- Healthy eco-city (maximum health potential).
Define PM10 and Coarse PM.
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.
Describe how NO2 is absorbed into the body.
NO2 is nearly insoluble in water, so it easily reaches the lower respiratory tract.
Describe patch sampling.
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.
Name 4 examples of naturally-occurring air pollutants.
- VOCs from vegetation
- Pollen
- Volcanic gases
- Dust from deserts
What are the health effects of SO2?
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.
Explain how water-soluble vs water-insoluble gaseous pollutants penetrate the respiratory system. Name an example of each.
Water-soluble gases are largely removed by the upper airway (example = SO2).
Water-insoluble gases penetrate deeper into the lungs (example = ozone).
Describe the fluorescent tracer method.
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.
Explain what photochemical smog is, and how it is formed.
When VOCs react with NOx in the presence of sunlight, tropospheric ozone is formed. The resulting mixture is called photochemical smog.
Describe criteria pollutants. Name all of them.
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.
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?
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.
Define temperature inversion. How does it affect air quality?
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.
Define dose.
Dose refers to the mass of contaminant that crosses the tissue barrier and enters the body.
Explain the temporal and spatial variation in ozone levels.
[O3] is higher in summer.
Ozone problems tend to be regional, not localized.
What are the 2 “types” of ozone?
- Stratospheric ozone (forms the ozone layer that protects us from UV rays).
- Tropospheric ozone (ground-level ozone, a harmful pollutant).
Define job-exposure matrix.
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.
Define potential dose.
The potential dose is what the dose would be, assuming that all the material crosses the tissue boundary and enters the body.
How are sulfur oxides formed? What is the main source of SO2 emissions?
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.
Explain active sampling.
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.
Define NOx-limited and VOC-limited.
Due to the complex chemistry of ozone formation, decreased emissions of either NOx or VOCs could change ozone levels.
For NOx-limited locations, reduction of NOx 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.
Name 3 reasons why unequal societies may be more likely to pollute or degrade their environment.
- 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.
- Inequality leads people to consume more, due to a desire to emulate the privileged.
- 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.
Describe brownfield redevelopment.
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.
What is the difference between primary and secondary pollutants? Name an example of each.
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).
How is mercury released into the environment?
Mercury is naturally found in fossil fuels, especially coal. When these are burned, mercury is released into the air.
