ENVI Chapter 18 Air Pollution

Levels of both pollutants stabilized after the

1970s

The Atmosphere

is the whole mass of air surrounding the earth.

The Troposphere

is the innermost layer of the atmosphere. It contains about 95% of the earth's air and extends about 11 miles above the earth's surface.

nitrogen in air

78%

oxygen in air

21%

argon in air

less than 1 %

Water vapor in the air

varies

ozone (O3)

(between 11 & 16 miles), which filters out about 95% of the incoming harmful ultraviolet radiation

UV radiation causes

sunburn, skin cancer, cataracts, damage to plants, etc.

Ozone in the stratosphere is considered

good

Air Pollution

occurs when the concentration of a normal component of the air or a new chemical added to or formed in the air builds up to the point of causing harm to humans, plants, animals, and materials.

The major types of outdoor air pollutants are:

CARBON MONOXIDE (CO) NITROGEN DIOXIDE (NO2) SULFUR DIOXIDE (SO2) SUSPENDED PARTICULATE MATTER OZONE (O3) LEAD •Volatile organic compounds• Radioactive Substances• Heat• Noise

Sulfur oxides

Sulfur dioxide (SO2) and sulfur trioxide (SO3)

Photochemical oxidants

Ozone (O3), peroxyacyl nitrates (PANs), hydrogen peroxide(H2O2), aldehydes

Hazardous air pollutants (HAPs), which cause health effects such as cancer, birth defects, and nervous system problems

Carbon tetrachloride (CCl4), methyl chloride (CH3Cl),chloroform (CHCl3), benzene (C6H6), ethylene dibromide(C2H2Br2), formaldehyde (CH2O2)

CARBON MONOXIDE (CO)

Colorless, odorless gas that is poisonous to air-breathing animals.

CARBON MONOXIDE (CO) Major human sources

Cigarette smoking, burning of fossil fuels. About77% (95% in cities)comes from motor vehicle exhaust.

NITROGEN DIOXIDE (NO2)

Reddish-brown irritating gas that gives photochemical smog its brownish color; in the atmosphere can be converted to nitric acid (HNO3), a major component of acid deposition.

NITROGEN DIOXIDE (NO2) Major human sources:

Fossil fuel burning in motor vehicles (49%) and power and industrial plants (49%).

NITROGEN DIOXIDE (NO2) Health effects:

Lung irritation and damage; aggravates asthma and chronic bronchitis; increases susceptibility to respiratory infections such as the flu and common colds (especially in young children and older adults).

NITROGEN DIOXIDE (NO2) Environmental effects:

Reduces visibility; acid deposition of HNO3 can damage trees, soils, and aquatic life in lakes.

NITROGEN DIOXIDE (NO2) Property damage:

HNO3 can corrode metals and eat away stone on buildings, statues, and monuments; NO2 can damage fabrics.

SULFUR DIOXIDE (SO2) Major human sources:

Coal burning in power plants and refineries.(10%).

SULFUR DIOXIDE (SO2) Health effects:

Breathing problems for healthy people; restriction of airways in people with asthma; chronic exposure can cause a permanent condition similar to bronchitis. According to the WHO, at least 625 million people are exposed to unsafe levels of sulfur dioxide from fossil fuel burning.

SULFUR DIOXIDE (SO2) Environmental effects:

Reduces visibility; acid deposition of H2SO4 can damage trees, soils, and aquatic life in lakes.

SULFUR DIOXIDE (SO2) Property damage:

SO2 and H2SO4 can corrode metals and eat away stone on buildings, statues, and monuments; SO2 can damage paint, paper, and leather.

SUSPENDED PARTICULATE MATTER

Variety of particles and droplets small and light enough to remain suspended in atmosphere for short periods (large particles) to long periods(small particles; cause smoke, dust, and haze.

SUSPENDED PARTICULATE MATTER Major human sources:

Burning coal in power and industrial plants, burning diesel and other fuels in vehicles, agriculture (plowing, burning off fields), unpaved roads, construction.

SUSPENDED PARTICULATE MATTER Environmental effects:

Reduces visibility; acid deposition of H2SO4 droplets can damage trees, soils, and aquatic life in lakes.

SUSPENDED PARTICULATE MATTER Property damage:

Corrodes metal; soils and discolors buildings, clothes, fabrics, and paints.

OZONE (O3)

Highly reactive, irritating gas with an unpleasant odor that forms in the troposphere as a major component of photochemical smog .

Lead

Solid toxic metal and its compounds, emitted into the atmosphere as particulate matter

Lead Poisoning control

Replace lead pipes and plumbing fixtures containing lead solder, remove lead paint and lead dust from older houses and apartments, sharply reduce lead emissions from incinerators, remove lead from TV sets and computer monitors before incineration or land disposal, Test for lead in existing ceramicware use to serve food, test existing candles for lead, wash fresh fruits and vegetables

Air Pollution from Natural Sources

Dust blown by wind Pollutants from wildfires and volcanoes Volatile organics released by plants

Photochemical Smog

is a complex mixture of air pollutants produced in the atmosphere by the reaction of hydrocarbons and nitrogen oxides under the influence of sunlight(example: Los Angeles). from burning fossil fuels

Normally, warm air near the ground is able to

escape into the atmosphere(warm air rises), and carry with it air pollutants such as smog and soot).

The Donora Fluoride Fog of 1948 caused

Emissions of sulfur dioxide, nitrogen dioxide, and fluoride from the zinc smelting plant began to accumulate. The smog became so thick that driving was impossible. The plant itself did not cease operations until 4 days later. The smog finally broke up as a rainstorm entered the area after 5 days.

how many people became sick after the The Donora Fluoride Fog of 1948

14,000

Acid Deposition This problem begins with

tall smokestacks, which smokestacks, which reduce local pollution, yet cause pollution downwind, long distances away.

Wet Deposition

are the liquid acid droplets

Dry Deposition

-are solid acid-forming particles.

Lakes in deep soil high in limestone are

buffered

Windborne ammonia gas and some soil particles partially

neutralize acids and form dry sulfate and nitrate salts

Normal rain has a pH of

5.0-5.6,

Countries like Canada receive tremendous amounts of acid from the United States because of

prevailing winds

Harmful Effects of Acid Deposition

Damage to buildings, statues, and monuments Leaching of soil nutrients Lower crop yields

HC=

hydrocarbons

mobile sources of air pollution

motor vehicles

the indoor air in many homes, schools, etc. is more polluted and and dangerous

than outdoor air on a smoggy day.

Trees at high elevations have

long life spans plus needles year round, which are exposed year round

Acid deposition kills lakes when the

surrounding soils cannot buffer the rain or snow

Acid Shock -

occurs when large amounts of acid rain or snow runoff into lakes.

EPA: proposed stricter emission standards for

diesel-powered vehicles

Even though new cars emit much less pollution, these high levels have been due to more

automobiles, relaxed fuel efficiency standards, and less money for enforcement. The problem is our laws are based on cleanup rather than on prevention.

carbon dioxide in air

0.035%

The Stratosphere

is the second layer of the atmosphere, extending from 11 miles to 30 miles. It contains the ozone layer (O3)

zone in the troposphere is

bad

Carbon oxides

Carbon monoxide (CO) and carbon dioxide (CO2)

Nitrogen oxides

Nitric oxide (NO), nitrogen dioxide (NO2), nitrous oxide(N2O) (NO and NO2 often are lumped together and labeled NOx)

Volatile organic compounds (VOCs)

Methane (CH4), propane (C3H8), chlorofluorocarbons(CFCs)

Suspended particulate matter (SPM)

Solid particles (dust, soot, asbestos, lead, nitrate, and sulfate salts), liquid droplets (sulfuric acid, PCBs, dioxins, and pesticides)

Radioactive substances

Radon-222, iodine-131, strontium-90, plutonium-239(Table 3-1, p. 49)

CARBON MONOXIDE (CO) Health effects:

Reacts with hemoglobin in red blood cells and reduces the ability of blood to bring oxygen to body cells and tissues. This impairs perception and thinking; slows reflexes; causes headaches, drowsiness, dizziness, and nausea; can trigger heart attacks and angina; damages the development of fetuses and young children; and aggravates chronic bronchitis, emphysema, and anemia. At high levels, it causes collapse, coma, irreversible brain cell damage, and death.

SULFUR DIOXIDE (SO2)

Colorless, irritating; forms mostly from the combustion of sulfur containing fossil fuels such as coal and oil; in the atmosphere can be converted to sulfuric acid(H2SO4), a major component of acid deposition

SUSPENDED PARTICULATE MATTER Health effects:

Nose and throat irritation, lung damage, and bronchitis; aggravates bronchitis and asthma; shortens life; toxic particulates (such as lead, cadmium, PCBs, and dioxins) can cause mutations, reproductive problems, cancer

OZONE (O3) Major human sources:

Chemical reaction with volatile organic compounds (VOCs, emitted mostly by cars and industries) and nitrogen oxides to form photochemical smog

OZONE (O3) Health effects:

Breathing problems; coughing; eye, nose, and throat irritation; aggravates chronic diseases such as asthma, bronchitis, emphysema, and heart disease; reduces resistance to colds and pneumonia; may speed up lung tissue aging.

OZONE (O3) Environmental effects:

Ozone can damage plants and trees; smog can reduce visibility.

OZONE (O3) Property damage

Damages rubber, fabrics, and paints.

Lead Major human sources:

Paint old houses), smelters (metal refineries), lead manufacture, storage batteries, leaded gasoline (being phased out in developed countries).

Lead Health effects:

Accumulates in the body; brain and other nervous system damage and mental retardation (especially in children); digestive and other health problems; some lead-containing chemicals cause cancer in test animals

Lead Environmental effects:

Can harm wildlife

Lead poisoning prevention

phase out leaded gasoline worldwide, phase out waste incineration, ban the use of lead solder, ban the use of lead in computer and TV monitors, ban lead glazing for ceramicware used to serve food, ban candles with lead cores, test blood for lead by age 1

Natural air pollutants can include

Smoke from wildfires Methane released from livestock Volcanic eruptions

air pollutions from human sources

mostly in industrialized and/or urban areas

Primary pollutants

Emitted directly into the air (SO2 for example)

Secondary pollutants

Are formed in the air (from reactions of primary pollutants)

Industrial Smog

is a mixture of sulfur dioxide and sulfuric acid (when the sulfur dioxide mixes with water), caused by industries burning coal and oil. (Formerly cities like London, and Pittsburgh, but now mostly in China and India).

The amount of smog and air pollution in an area is influenced by factors such as

local climate, winds, rain, and topography (mountains, etc.).

thermal inversion

sometimes cool air (dense air) is trapped beneath a layer of warm, stagnant trapped beneath a layer of warm, stagnant air, and pollutants build up to dangerous air, and pollutants build up to dangerous levels.

thermal inversion occurs more frequently over towns or cities located in

valleys surrounded by mountains or near a coast (Los Angeles has both!)

The Donora Fluoride Fog of 1948

In late October, the town of Donora experienced a temperature inversion. The town is located along the Monongahela River south of Pittsburgh, within a small valley. The main employer of the town was a US Steel Zinc smelting plant

how many people did the The Donora Fluoride Fog of 1948 kill

20

Donora experienced higher than normal mortality rates for

10 years afterwards

The sulfur dioxide and nitric oxide emitted by the tall smokestacks and automobile emissions form a smokestacks and automobile emissions form

variety of secondary pollutants, such as sulfuric acid or nitric acid (SO or nitric acid (SO22 + H+ H22O = HO = H22SO4 and NO + HSO4 and NO + H22O =O =HNOHNO33).).

Acid Deposition, or Acid Rain -

occurs when these liquid acid droplets return to the earth's surface.

Lakes in shallow soil low in limestone become

acidic

PH

Is a numeric value that indicates the relative acidity or alkalinity of a substance on a scale acidity or alkalinity of a substance on a scale of 0-14, with the neutral point at 7.

Acid solutions

have pH values lower than 7

basic solutions

have pH values greater than 7.

rain in the easter united states (NJ) has a PH of

4.3 (tomato juice)

Harmful Effects of Acid Deposition Human health

- respiratory disorders

Harmful Effects of Acid Deposition Forest damage -

weakening or killing trees, stunting vegetation

Harmful Effects of Acid Deposition Aquatic ecosystems affected

Lowers pH and kills fish & lakes

how many lakes in Canada are fishless because of acid Deposition

14,000

how many lakes are threatened by acid Deposition

150,000

Stationary sources of air pollution

power plants and industrial facilities industrial facilities

solutions to acid deposition prevention

reduce coal use, burn low-sulfur coal, Increase use of natural gas and renewable energy resources, Remove SO2 particulates and NOx from smokestack gases, and remove NOx from motor vehicular exhaust, Tax emissions of SO2

solutions to acid deposition cleanup

Add lime to neutralize the acidified lake, Add phosphate to neutralize acidified lakes

Prolonged exposure to multiple air pollutants such as ozone and acid rain can damage

leaves of trees and other plants.