Week 6: Air Pollution Flashcards
What are 4 details about air pollution?
Air pollution is a major contributor to adverse human health conditions, from asthma to cardiovascular disease to premature death.
Air pollution is not just a modern phenomenon; it has been
recognized as a problem for thousands of years.
Air pollution is not a single entity; it consists of distinct, identifiable components such as ozone and particulate matter, each with its own sources, chemistry, and toxic effects.
The ambient concentration of an air pollutant in a particular location depends on many factors, including emissions sources, weather, and
land patterns
What are 3 details about the history of air pollution
Historical recognition of connection to health:
Hippocrates (2,500 years ago) noted that health affected by air, and air quality differs by area
13th century London air so bad, abatement plans
developed
Modern recognition – extreme episodes
Meuse Valley, Belgium (1930), > 60 deaths
Donora, Pennsylvania (1948), 20 deaths
London, England (1952), 10,000-20,000 deaths
2010 Global Burden of Disease Study attributed >3.2 million deaths and 3.1% of global morbidity (i.e., disability-adjusted life years) to ambient particulate air pollution
What are 3 details about air pollution in the world’s dirtiest cities?
Air pollution levels in the fast-growing cities of low-and middle-income countries can be extreme
In China, where air quality can be poor, urban air pollution levels routinely exceed World Health Organization (WHO)
standards by an order of magnitude.
The Chinese government launched a “war on pollution” in 2013, and in 2014, the Chinese
Environmental Protection Ministry announced that only eight of the nation’s seventy-four large cities had met official air quality standards (up from
three the previous year); 471
“environmental emergencies” in 2014, due to especially high air pollution levels
What are 5 natural sources of air pollution?
Wind storms that spread dust clouds
Salt evaporation along the earth’s coasts
Production of materials that have a biologic origin (e.g., mold spores, pollen, and organic material from plants and animals)
Forest fires
Volcanic eruptions
Explain anthropogenic sources of air pollution.
Stationary sources:
Mobile sources:
What are 8 details about the different types of ambient air pollution?
- Pollutant concentration depends on emissions,
weather, land patterns, other factors - Highest during stagnant winds and temperature inversions
- Can vary by season and day depending on weather and
sources (e.g., traffic, wood burning) - Some pollutants (e.g., ozone) travel large distances
- Categorized by source, physical and chemical
characteristics, or regulatory approach - Primary pollutants, emitted directly; secondary, from
physical, chemical conversion of precursors - Biogenic, natural sources; anthropogenic
- Criteria air pollutants (CO, lead, nitrogen dioxide, ozone,
particulates, SO2)– U.S. NAAQS [national ambient air quality
standards]; hazardous air pollutants, no NAAQS
List 3 major ambient air pollutants. Give their source types, major sources, and health effects.
Lead:
Source type: primary
Major sources: anthropogenic (leaded fuel (phased out in some locations such as the United States), lead batteries, metal processing)
Health effects: accumulates in organs and tissues; learning disabilities, cancer, damage to the nervous system
Sulfur dioxide:
Source type: primary
Major sources: anthropogenic (combustion of fossil fuel (power plants), industrial boilers, household coal use, oil refineries); biogenic (decomposition of organic matter, sea spray, volcanic eruptions)
Health effects: lung impairment,
respiratory symptoms; precursor to PM; contributes to acid precipitation
Carbon monoxide:
Source type: primary
Major sources: anthropogenic (combustion of fossil fuels (motor vehicles, boilers, furnace)); biogenic (forest fires)
Health effects: interferes with delivery of oxygen; fatigue, headache, neurological damage,
dizziness
List 3 additional major ambient air pollutants. Give their source types, major sources, and health effects.
Particulate matter:
Source types: primary and secondary
Major sources: anthropogenic (burning of fossil fuel, wood burning, natural sources (for example, pollen), conversion of precursors (NOx, SOx, VOCs); biogenic (dust storms, forest fires, and dirt roads)
Health effects: Respiratory symptoms, decline in lung function, exacerbation of
respiratory and cardiovascular disease (for example, asthma),
mortality; effects can vary by particle size and composition
Nitrogen oxides:
Source types: primary and secondary
Major sources: anthropogenic (fossil fuel combustion (vehicles,
electric utilities, industry), kerosene heaters); biologic (biological processes in soil, lightning)
Health effects: decreased lung
function, increased respiratory infection; precursor to ozone; contributes to PM and acid precipitation
Tropospheric ozone:
Source types: secondary
Major sources: formed through chemical reactions of
anthropogenic and biogenic precursors (VOCs and NOx) in the presence of sunlight
Health effects: decreased lung
function, increased respiratory symptoms, eye irritation, bronchoconstriction
Define particular matter. List 3 sources.
Particulate matter: a major pollutant for which concentrations are anticipated to be affected by climate change, and is therefore emphasized for public health impacts.
Particulate matter comes in different sizes (coarse and
fine) from a number of sources including:
▪ Dust and other small particles from construction,
mining and agriculture
▪ Pollen
▪ Fine particles from burning fossil fuels in factories,
power plants, and diesel- and gasoline-powered
motor vehicles
What affects a pollutant’s respiratory penetration? Give 1 detail and list the effects of acute and long term exposure.
Respiratory penetration: affected by a pollutant’s physical form and chemical properties, ambient concentration, ventilation rate
Very large particles are stopped at the nose while very small particles reach the alveoli and deposit there
Acute exposure: short-term decrease in lung function, exacerbation of respiratory and
cardiovascular diseases, and hospitalizations and deaths
Long term exposure: respiratory and cardiovascular diseases and cardiopulmonary and lung cancer deaths
List the populations of people who are at risk due to exposure of particulate matter and the populations of people who are at risk due to sensitivity.
At risk from exposure: persons living or working in urban areas, especially near high-traffic corridors and/or stationary sources of PM (such as factories
or power plants)
At risk from sensitivity: persons with respiratory and cardiovascular diseases, elderly and children, persons with asthma and/or allergies
How can climate change affect exposures to particulate matter?
Increasing emissions from fossil
fuel-fired power plants due to
demand for electricity for cooling
Increasing natural sources of air
pollutant emissions, such as wildfire smoke induced by
drought and heat
Increasing temperatures: higher temperatures hasten the
chemical reactions (gas to matter formation) that lead to secondary particle formation
What are 6 details about sulfur dioxide?
Sulfur dioxide, SO2, a water-soluble gas, was a primary component of the 1952 London fog
Sulfur oxides are produced from the combustion of sulfur-containing fuels and materials, such as coal and metal ores.
Power plants are the main source of SO2 emissions in the United States. Other sources are industrial boilers, trains, ships, and metal-processing facilities. Household use of coal can contribute significant amounts of SO2 as well. In some areas, such as parts of China, coal is the primary fuel for cooking and heating and causes high levels of SO2 indoors. Natural sources of SO2 include volcanoes.
SO2 can be converted to sulfuric acid and therefore contributes to acid deposition, which harms vegetation, other materials, and wildlife. SO2 also contributes to the formation of particulate
matter.
Because SO2 is highly soluble in water, most inhaled SO2 is absorbed by the mucous membranes of the upper airways with little reaching the lung; however, increased ventilation and oral breathing, such as from exercise, can raise the dose delivered to the lung.
SO2 has been associated with reduced lung function, bron
What are 5 details about nitrogen oxides?
Nitrogen oxides, NOx, make up a category of highly reactive gases
containing nitrogen and oxygen, such as nitrogen dioxide (NO2) and nitrogen oxide (NO).
NOx are produced through combustion, including fossil fuel combustion, when the nitrogen that constitutes almost 80% of air is oxidized
Sources of NOx therefore include car and truck engines, electric utilities,
and industries. Indoor sources can also contribute to NO2 through kerosene heaters, nonvented gas stoves and heaters, and tobacco smoke.
Health effects of NO2 include irritation of the eyes, nose, and throat at higher concentrations; short term decreases in lung function; and possibly
increased respiratory infections and symptoms for children.
Nitrogen oxides also have indirect but important roles as precursors of tropospheric ozone and secondary particulate matter, and play a crucial role in the formation of acid precipitation
What are 5 details about volatile organic compounds?
VOCs are organic compounds that, with high vapor pressures and low boiling points, evaporate quickly from solid or liquid forms.
Manufactured products, such as paints and solvents also contain VOCs. One of the most commonly encountered, and best-studied, VOCs is formaldehyde.
Cigarette smoke is the leading exposure source, followed by off-gassing from paints, glues, or solvents.
Similarly, construction materials release formaldehyde, making newly constructed homes a potentially hazardous source of indoor inhalation exposure to formaldehyde.
Acute exposure to formaldehyde can lead to irritation of the respiratory system, eyes, skin, nose, and throat; high acute exposure can lead to more serious health impacts, including vomiting, nausea, coma, and possibly death; formaldehyde is mutagenic, meaning it can damage DNA and lead to cancer
What are 6 details about the tropospheric ozone?
A gas, found in the lower atmosphere (troposphere),
vs. stratospheric ozone (i.e., the ozone layer)
Secondary pollutant formed by chemical reactions
among precursors (VOCs and NOx) and sunlight
Concentrations highest in hot months; diurnal fluctuations follow sunlight and traffic patterns
Levels lower indoors vs. outdoors because it adsorbs
to surfaces and breaks down
Powerful oxidant– breaks molecular bonds, can
damage lung tissue; increases respiratory symptoms
High ozone days associated with increased asthma attacks, hospitalizations, mortality
What are 5 details about mercury?
Elemental Hg inhaled as a vapor,
absorbed by lungs
Cause: vaporized mercury
Sources: coal combustion, accidental spill, mining (teeth silver fillings)
Effects: Nervous system (acute, high), respiratory system (chronic, low), kidneys,
skin, eyes, immune system; Mutagenic properties
Symptoms
Acute: chills, nausea, chest pains/tightness,
cough, gingivitis, general malaise
Chronic: weakness, fatigue, weight loss, tremor, behavioral changes
What are 3 details about -dioxins?
Generic term for several chemicals that are highly
persistent in the environment
chlorinated dibenzo-p-dioxins (CDDs)
chlorinated dibenzofurans (CDFs)
certain polychlorinated biphenyls (PCBs)
Cause: burning hydrocarbons in presence of chlorine or
chlorides
Sources: waste incinerators
What are 4 details about air pollution prevention and control?
Various approaches, from controlling emissions at the
source to controlling exposures (air quality warnings)
U.S. Clean Air Act (1963, 1990 amendments):
Primary standards (NAAQS) for 6 criteria pollutants, designed to protect public health, including sensitive subpopulations, with an adequate margin of safety;
periodically revised based on updated scientific review
Secondary standards, designed to protect, soil, crops, etc.
MACT (maximum achievable control technology) required
for hazardous air pollutants
Nonattainment areas (exceeding NAAQS) develop state implementation plans to control emissions
Power plant cap-and-trade approach used for SOx
Define the air quality index.
The Air Quality Index is used to
provide the public with an
indication of air quality in a local
area on a daily basis
It focuses on health effects you
may experience within a few
hours or days after breathing
polluted air
