UNIT KEJURUTERAAN ALAM SEKITAR UNIT KEJURUTERAAN ALAM SEKITAR JABATAN KEJURUTERAAN AWAM JABATAN KEJURUTERAAN AWAM

POLITEKNIK SULTAN IDRIS SHAH

CHAPTER 1CHAPTER 1INTRODUCTION OF AIR INTRODUCTION OF AIR

POLLUTIONPOLLUTION

2

Understand the scope and perspective of air pollution

State the composition of air in atmosphere Define the air pollution. Explain the perspectives of air pollution

What is Air?Air is defined as the tasteless, odorless,

and invisible mixture of gases that surrounds the earth.

78% Nitrogen 21% Oxygen 0.03% Carbon Dioxide <1% Argon (inert) Water Vapor

Composition and structure of the atmosphere

The air in the troposphere, which we breath, consist by volume of about 78% nitrogen(N2), 21% oxygen (O2),

1% Argon (Ar), and 0.03% carbon dioxide (CO2).Other inert gases are in small percentage.

Gas % by volume Gas % by volumeNitrogen 78.09 Dinitrogen oxide 0.00002Oxygen 20.95 Carbon monoxide 0.00001Argon 0.93 Zenon (Xe) 0.000008CO2 0.032 Ammonia (NH3) 0.0000006Neon 0.0018 Nitrogen oxide (NO2) 0.0000001Helium 0.00052 Nitric oxide (NO) 0.00000006Methane (CH4) 0.00015 Sulfur dioxide (SO2) 0.00000002Krypton (Kr) 0.0001 Hydrogen sulfide (H2S) 0.00000002Hydrogen 0.00005

Structure of AtmosphereThe Atmosphere is really a thin envelope

surrounding the earth• 99% of atmosphere is in lowest 30 km• the atmospheric depth is 30 km/6400 km=

0.5% of earth's radius

The elevation of Everest?

Vertical temperature profile of the atmosphere

10

100

200

500

1500

Troposphere

Stratosphere

Mesosphere

0 25

Height (km)

Normal TemperatureProfile

Inversion TemperatureProfile

Temperature (C)

The Atmosphere

TroposphereTroposphere

Stratosphere

78% N, 21% O78% N, 21% O

Ozone layerOzone layer

Structure of AtmosphereTroposphere: Innermost layer 75-80% of air mass 11-5 miles thick Earth Apple, Skin

Troposphere All weather found

here 78% N, 21% O,

others water vapor, CO2, Ar

Structure of Atmosphere

Stratosphere Second layer Filters UV rays Much less air

mass and water vapor, much more O3 than troposphere.

Blocks 95% UV radiation

“Good Ozone vs. Bad Ozone”

ATMOSPHERIC CHEMISTRY

GasGas FormulaFormula % vol/vol% vol/vol ppmppm g Nmg Nm-3-3 Quasi-fixedQuasi-fixedOxygenOxygenNitrogenNitrogenArgonArgonNeonNeonHeliumHeliumKryptonKryptonXenonXenon

O2N2ArNeHeKrXe

20.94620.94678.08478.084

18.1818.185.245.241.141.140.0870.087

5x103 yr~ 106 yr

107 yr

VariableVariableCarbon Carbon dioxidedioxideMethaneMethaneHydrogenHydrogenNitrogen Nitrogen oxideoxideOzoneOzone

CO2

CH4

H2N2OO3

~ 3.301.3 – 1.6~ 0.50.25-0.35( 1-5)x10-2

5-6 yr4-7 yr6-8 yr~ 25 yr~ 2 yr

ATMOSPHERIC CHEMISTRY

GasGas FormulFormulaa

ppmppm g Nmg Nm-3-3

Very variableVery variableWaterWaterCarbon Carbon monoxidemonoxideNitrogen Nitrogen dioxidedioxideAmmoniaAmmoniaSulfur dioxideSulfur dioxideHydrogen Hydrogen sulfidesulfideOrganic CarbonOrganic Carbon

H2OCON2ONH3

SO2

H2S

(0.4-400)x102

0.05-0.25~(0.1-5)x10-3

~(0.1-10)x10-3

~(0.03-30)x10-3

~(<0.006-0.6)x10-3

0.2-100.1-100.1-10<0.01-15-50

10 dy0.2-0.5 yr8-10 dy~ 5 dy~ 2 dy~ 0.5 dy~ 2 dy

particles per cubic meter of gas or particles per cubic meter of gas or million particles per cubic metermillion particles per cubic meter (10(1066/m/m33))

mass per unit volumemass per unit volume basis, such as basis, such as micrograms per cubic meter (micrograms per cubic meter (μμg/mg/m33).).

Gas contaminants were usually Gas contaminants were usually given in parts per million (ppm), part given in parts per million (ppm), part

per billion (ppb), by volumeper billion (ppb), by volume

Units of measurementUnits of measurement

What is Air Pollution?The presence of

chemicals in the atmosphere high enough to affect climate and harm organisms and materials.

Natural vs. Human Made

What is Air Pollution?Is the presence of undesirable material in air, in a

quantities large enough to produce harmful effects. The undesirable materials may damage human health, vegetation, human property, or the global environment as well as create aesthetic insults in the form of brow or haze air or unpleasant smells.

Many of these harmful materials enter the atmosphere from sources currently beyond human control such as volcanic eruption and pollution from natural source. This by itself dose not pose severe enough to danger life and property.

Human activity are to be blame for pollution problems that problems threaten to make portions of the earth’s atmosphere an inhospitable environment.

Gaseous or particulate substances released into the atmosphere in sufficient quantities or concentrations to cause injury to plants, animals, or humans.

Typically emitted into the atmosphere and transported from the source to the affected organism.

Air is said to be “Polluted” when it is no longer tasteless, odorless, colorless

Main pollutants

There are five materials classified as a main pollutants:

Sulfur oxides, nitrogen oxides, carbon monoxide, hydrocarbons, and particulate.

History of Air Pollution in the United States Late 1800’s: Industrial revolution in the

U.S. caused a major increase in air pollution emissions

1943: First recognized episodes of smog occurred in Los Angeles

1948: The first known air pollution disaster in the U.S. occurred in Donora, PA

History of Smog

1943: First recognized episodes of smog occurred in Los Angeles. Visibility was only three blocks and people suffered from itchy eyes, respiratory discomfort, nausea, and vomiting. The phenomenon was termed a"gas attack“ and blamed on a nearby butadiene plant.

History of Air Pollution: Regulations

1955 Air Pollution Control Act1963 Clean Air Act of 19631967 The Air Quality Act of 1967 (Precursor to the 1970

Clean Air Act)1970 A turning point…

• National Environmental Policy Act (January 1) • First Earth Day (April 22) • Formation of Environmental Protection Agency

(July 9) • Clean Air Act of 1970

– National Air Quality Standards1987 Standards strengthened for particulate matter

(PM10)1990 Clean Air Act of 19902002 New PM standards (PM2.5)

The Clean Air Act of 1970

The primary goal of the Clean Air Act (CAA) legislation was to

achieve safe and acceptable air quality through the attainment and maintenance of national

ambient air quality standards.

The Clean Air Act of 1970 Required U.S. Environmental Protection

Agency (EPA) to set National Ambient Air Quality Standards (NAAQS) for six common air pollutants:

ozone leadcarbon monoxidesulfur dioxidenitrogen dioxideparticulate matter

Air Pollution SourcesPoint Sources – Generally a major facility emitting pollutants from identifiable sources (pipe or smoke stack). Facilities are typically permitted.

Sources Cont.Area – Any low-level source of air pollution released over a diffuse area (not a point) such as consumer products, architectural coatings, waste treatment facilities, animal feeding operations, construction, open burning, residential wood burning, swimming pools, and char broilers

Sources Cont.Mobile Sources

• On-road includes any moving source of air pollution such as cars, trucks, motorcycles, and buses

• Non-road sources include pollutants emitted by combustion engines on farm and construction equipment, locomotives, commercial marine vessels, recreational watercraft, airplanes, snow mobiles, agricultural equipment, and lawn and garden equipment

Sources Cont.Natural Sources – Biogenic and geogenic emissions from wildfires, wind blown dust, plants, trees, grasses, volcanoes, geysers, seeps, soil, and lightning

Sources of all air pollutantsmeasured in California*

(Hydrocarbons, Carbon Monoxide, Oxides of Nitrogen, Oxides of Sulfur and Particulate Matter)

Source: California Department of Consumer Affairs, Bureau of Automotive Repair

Residential fuel combustion, farming operations, construction, road dust, wind-blown dust,

Major Sources of Air Pollution

Types of Pollutants

Primary: pollutants directly emitted into the air from stacks or other sources, with effects directly caused by the emitted pollutant.Ex. SO2 and CO2

Secondary: pollutants which result from transformations of primary pollutants into other chemical species, which then cause direct and indirect effects.Ex. Photochemical pollutants (ozone), acid rain, smog

Some air pollution is not regulated

Wishful

thinking

Photo by R. Grippo

More unregulated air pollution - burning rice stubble in Poinsett Co., Arkansas

Major Air Pollutants- mostly coal-plant generated

A. Suspended particulates - Most common, oldest problem addressed

1. Trace rock from burning pulverized coal (unburnable residues)

2. Fly ash from coal (contains Cd, Cu, Pb, Se, As, Hg) has high volume control by electrostatic precipitators

3. Carbon/soot from dieselB. Gasses

1. SO2- respiratory inhibitor- plant leaf injury- decreases N fixation in bacteria- oxidizes to SO3 (sulfur trioxide) H2SO4

B. Gasses (con’t)

2. Oxidants (O3 )- in atmosphere not enough- at ground level too much

comes from hydrocarbons (gasoline) + O2 = O3

- also a respiratory aggravator- leaches nutrients from soil

lower primary productivity less carbon fixed increase greenhouse effect

3. Nitrogen oxides (NOx ) - N2O nitric acid – comes from

atm N (atm = 80% nitrogen) - NO2 nitrous oxide (ha, ha!)

- respiratory aggravator - decreases soil pH reduces

soil micronutrient availability to plants

- NO2 + H2O = HNO3 = brown haze = smog

Photo courtesy U.S. EPA

B. Gasses (con’t)4. Carbon oxides

- CO monox competes with O2 binding on hemoglobin (affinity is 200X O2 )- CO2 dioxide = greenhouse effect

Minor Gaseous Air PollutantsMinor Gaseous Air PollutantsLow in direct effects, high in indirect effects1. CFC’s (Freon)

Principal refrigerant (a/c, refrigerators) Catalyze destruction of ozone Ozone forms protective layer around earth partially blocks UV Montreal Accord (1990) – supposed to phase out CFC’s by 2000 (not completely done yet)

2. Halon Related to CFC Used in fire extinguishers

3. Carbon tetrachloride and Methychloroform Dry cleaner solvents Manufacturing processes

All above compounds catalyze the destruction of ozoneRecall: catalyzers participate in a reaction but are not consumed hang around a long time (1/2 life of several years) and continue to reduce ozone Therefore, if stopped using now good effects would take many years to appear

Activity: Discuss about air pollution composition

and types of pollutant from oil palm industry ?

Explain about history of air pollution in Malaysia ?

QUIZWhat can be done to prevent pollution?

A: Did you know that your home and office contribute to the greenhouse effect? Energy used in our everyday activities -- turning on electrical appliances, driving cars, and heating and cooling our homes -- is responsible for air pollution that contributes to climate change. Technologies are available today that can cut this energy use significantly and, at the same time, improve our quality of life

QUIZ What pollutants affect air quality?

A: A few air pollutants, called criteria air pollutants, are common throughout the United States. These pollutants can injure health, harm the environment and cause property damage. The current criteria pollutants are: Carbon Monoxide (CO), Lead (Pb), Nitrogen Dioxide (NO2), Ozone (O3), Particulate matter with aerodynamic size less than or equal to 10 micrometers (PM-10), and Sulfur Dioxide (SO2).

QUIZ What kinds of air pollution are produced by mobile sources?

Combustion of fuels can cause the release of hydrocarbons (HC), carbon monoxide (CO), oxides of nitrogen (NOx), particulate matter (PM), toxics, sulfur dioxide (SO2), and greenhouse gases such as carbon dioxide (CO2) and nitrous oxide (N2O). Mobile sources produce air pollution from exhaust emissions, as well as evaporative emissions and refueling losses from gasoline engines. The type and amount of pollution depends on many factors: the type of engine or vehicle (e.g., passenger car, heavy-duty truck, lawn mower, locomotive, etc.); the type of fuel used (e.g., gasoline, diesel, or alternative fuels); the type and condition of emission control devices (e.g., catalytic converters); and how the engine is used/run. For example, diesel engines used in trucks, buses, locomotives, and ships tend to emit more NOx and PM than gasoline engines. Engines with catalytic converters (e.g., passenger cars) emit much less HC, CO, NOx, and toxics than similar engines without catalysts (i.e., the catalytic converter is an important pollution control device to reduce exhaust emissions).

Thank

you!