AIRAIR

Necessary for the survival of all higher forms of life

Human can survive 5 minutes without airSeems to be vast in volumeEarth = an appleAtmosphere = apple's skin

ATMOSPHEREATMOSPHERE

•mixture of gases, liquid and solid aerosols•small concentrations•concentration and density decreases with the increase of altitude•energy of Sun photochemical reactions•presence of oxygen oxidation

Kº

11-12T

220 284

troposphere (cloud-belt)•11-12 km (poles: 8 km; Equator: 18 km) •T decreases

•1 ºC /100 m for dry air•0.65 ºC /100 m under natural conditions

•Air receives heat energy from the Earth•clouds, weather patterns, air pollution

• T increases• upward to an altitude of 50 km• most of the ozone can be found here• part of the UV radiation of the Sun is adsorbed here• contains only a small fraction of the total air mass (lower air density)

ATMOSPHEREATMOSPHERE

220 284

180

80M

50ST

Kº = C + 273

11-12T

stratosphere

mesosphere

• T decreases• up to 80 km

CONCENTRATIONCONCENTRATION

solid, liquid and gas pollutantsvolume/volume, mass/mass, mass/volume µg/m3, depends on T and p

- air m

pollutant cm = ppm 3

3

constant

3

33-

m

cm 10 = ppb

- conversion

ppm VM

= c

V [cm3/mmol] molar volume of ideal gas

(1 atm 101.3 kPa, 20 °C 22.4 l)

M [mg/mmol] molar mass

COMPOSITION OF THE ATMOSPHERECOMPOSITION OF THE ATMOSPHERE

concentration residence time effect

(2) variable

N2 78 % 108 year greenhouse

O2 21 % 5000 year

Ar 0.93 %

(1) constant

CO2 320 ppm 10 year greenhouse

CH4 1 ppm 5 year greenhouse

H2 0.5 ppm 7 year

N2O 0.3 ppm 8 year

O3 (tr./str.) 10 ppb/1 ppm 2 year smog/filter

COMPOSITION OF THE ATMOSPHERECOMPOSITION OF THE ATMOSPHERE

concentration residence time effect

(3) Significantly variable

CO 0.1 ppm 0.3 year toxic

NO2 1 ppb 10 day acidification

SO2 1 ppb 3 day acidification

Water vapour (0.4-400)102 ppm 10 day (greenhouse)

Freon (hal. hydrocarbons, pl. CF2Cl2) 100 year ozone depletion

GAS Anthropogenic Natural Anthropogenic %

CO2-C 7 000 100 000 7

CO-C 505 75 87

CH4-C 270 120 69

SO2-S 70 35 67

NO-N 20 10 67

N2O-N 1 10 9

NH3-N 20 20 50

VOC 75 750 9

Freon 1 0 100

GAS EMMISION [Tg/year]

HISTORY OF AIR POLLUTIONHISTORY OF AIR POLLUTION• II. Edward (end of 13th c.): prohibits heating with coal

• III. Richard (14-15th c.): smoke-tax

• 17th c. London: move industrial areas, have green areas (proposal)

• 1948 Donora (14 000 people), steel industry Pennsylvania) serious pollution

• 1952 London smog

• 1962 Los Angeles: photochemical smog

• 1972 research on acid rain

• DIURNAL CHANGE OF TEMPERATURE

• ATMOSPHERIC STABILITY (INVERSION)

• PLUME (convection and diffusion – wind speed and direction)

• LAMINAR AND TURBULENT FLOW

• MASS BALANCE (emission, reactions etc.)

AIR POLLUTIONAIR POLLUTIONContributing issuesContributing issues

ADIABATIC LAPSE RATEADIABATIC LAPSE RATE

Atmospheric stability depends on the relationship between air temperature and altitude

Troposphere: T decreases with increasing altitude

Adiabatic lapse rate: boundary between stable and unstable atmosphere (-0.65ºC /100 m)

UNSTABLE

STABLE

SUPERADIABATICSUPERADIABATIC

SUBADIABATIC

The environment is in superadiabatic condition. If a volume of adiabatic gas is released into the air, it will behave in an unstable way. The gas will elevate or move to the ground depending on the relation between the air and the gas temperature.

The environment is in subadiabatic condition. If a volume of adiabatic gas is released into the air, it will behave in an stable way. The gas will gather in a small zone of height.

INVERSIONINVERSION

Increase in temperature with altitude

Most undesirable condition with respect to air quality

Colder air is trapped below the warmer air – vertical movement of air masses is restricted

No mixing or dispersion of air pollutants in an upward direction

INVERSION (sunny, clear sky)

Pollutants in the plume are mixed in the thin, unstable layer near ground, causing a condition of fumigation

EFFECT OF WARM INVERSION LAYEREFFECT OF WARM INVERSION LAYER

SHAPE OF THE PLUME

SUPERADIABATICgood mixing

ADIABATIC

INVERSION 1.little dispersion

INVERSION 2.Inversion begins at a certain elevation – relatively thin layer of unstable air below – plume stop rising when reaching inversion layer

100 m chimney, 20 °CExample:

Dust doom

Wind condition is the most important factor in the horizontal dispersion

WIND CONDITION

MIXING

- LAMINAR AND TURBULENT FLOW

- MIXING AND DIFFUSION DEPENDS ON THE METEOROLOGICAL CONDITIONS

Chimney sizing : Gaussian distribution and method

222),,( //5.0exp2

zy

zy

zyx Hzyu

QC

222),,( //5.0exp2

zy

zy

zyx Hzyu

QC

value: - diagram- calculation

sizing:

Q, u known parameters

aim: in x, y, z given limit

Hight of the chimney?

TYPES AND SOURCES OF AIR POLLUTIONTYPES AND SOURCES OF AIR POLLUTION

air pollution presence of „foreign” substances in the atmosphere in high enough concentration, and for long enough duration to cause undesirable effects

natural air pollutioneruption of volcanoessmoke and gases from forest fireswindblown dust from desertssalt sea spraypollen grains

pollution caused by industry, transportation and other human activities

TYPES AND SOURCES OF AIR POLLUTIONTYPES AND SOURCES OF AIR POLLUTION

• Primary pollutants:• released directly into the air in a harmful form

• Secondary pollutants: • modified to a hazardous form after they enter the air

or are formed by chemical reactions as components of the air mix and interact

TYPES AND SOURCES OF AIR POLLUTIONTYPES AND SOURCES OF AIR POLLUTION

Mobile source automobiles, air plains

Stationary source coal fired electrical power stations

Different dispersion patterns

Different pollution control strategies

TYPES AND SOURCES OF AIR POLLUTIONTYPES AND SOURCES OF AIR POLLUTION

• Particulates

• Sulfur dioxide

• Nitrogen dioxide

• Carbon monoxide

• Hydrocarbons

• Ozone

• Lead

PARTICULATESPARTICULATES

Small suspended fragments of solids or liquid droplets

0,1 – 100 µm

< 1 µm particles tend to remain suspended in the air (smoke)

> 1 µm particles tend to settle (dust, mist)

Total suspended particulates > 10 million ton/year in USA

CARBON MONOXIDECARBON MONOXIDE

incomplete combustion of fuels (automobiles)if the oxygen supply is insufficient,residence time is too short,temperature is too low

2 C + O2 2 CO

Colorless and odorless gas100 million tons annually in the USA70% from transportation

CARBON OXIDESCARBON OXIDES

predominant form is CO2

non-toxicincreasing (0.4 % / year)global warming

NITROGEN OXIDESNITROGEN OXIDES

highly reactive gases

during the combustion of fuels – reaction between atmospheric N2 and O2

N2 + O2 NO, NO2, NOx

Red-brown toxic gas with sharp odor

20 million tons/year

with water they form nitric acid (HNO3) - acidification

NITROGEN OXIDESNITROGEN OXIDES

45% of the emission is anthropogenic

95% comes from fuel combustion in transportation and electric power generation

ammonia from fertilizer and decaying matter is

oxidized to NOx

HYDROCARBONSCARBONS

Compounds that consist of only H and C

Natural sources (85%) – forests, decomposition of organic material

Incomplete combustion, evaporation of gasoline from automobiles, industrial and chemical manufacturing processes

Involved in atmospheric reactions that form secondary air pollutants

Photochemical smog

SULPHUR COMPOUNDSSULPHUR COMPOUNDS

natural sources:

• evaporation of sea spray• erosion of sulphate-containing dust from arid soils• fumes from volcanoes• biogenic emissions of hydrogen sulphide and org S

containing compounds

25% of the total flux is anthropogenicin cities: 90%

Sulfur-dioxide is the main form of anthropogenic sulphur, mainly originating from electric power generation.

SULPHUR DIOXIDESULPHUR DIOXIDE

fossil fuels (coal, oil) contain the element sulphur as impurity

when sulphur is burned oxidation

S + O2 SO2

colorless corrosive gas with sharp, choking odorprimary pollutant (directly damages plants animals and humans)27 million tons annually in the USA!China and USA are the largest sources!

WHO standard:

1 hour 0.125 ppm350 µg/m3

longterm 50 µg/m3 0.018 ppm

0.18 ppm500 µg/m310’

• 1952 – London smog

- 4000 deaths

- maximum 2 mg/m3 0.75 ppm

- SO2 (bronchitis) smoke, smog

- inversion

- synergic effects!!!

1962 Los Angeles: photochemical smog

• automobiles, sunshine, high humidity

• nitro-oxides, hydrocarbons

• catalytic effect of sunshine new substances (secondary pollutants) e.g. ozone (toxic, stifling mist attacking the eye and nose, mycoderm)

-primary and -secondary pollution

- diurnal variation

NONO22+UV+VOC+O+UV+VOC+O22

NONO22+O+O33+PAN+aldehydes+PAN+aldehydes

Electromagnetic spectra

far infrared (IR2)Ultra violet (UV) Visible (V) near infrared (IR1)

shortwave long wave

0.2 0.38 0.76 4.0 100

µm

Sun Earth

mikrowaveX-ray

GREENHOUSE EFFECTGREENHOUSE EFFECT

CO2 EMISSION: FOSSIL FUEL

CHANGE OF CO2 CONCENTRATION IN THE ATMOSPHERE (1850-1995)

GLOBAL CHANGE OF AVERAGE TEMPERATURE (1880-1994)

GREENHOUSE EFFECT - GLOBAL WARMINGGREENHOUSE EFFECT - GLOBAL WARMING

• ADSORPTION OF LONG WAVES (EARTH - 243 W/m2)

• CO2 12-17 µm, O3 9.6 µm, WATER VAPOUR 8 µm

• GASES

- CO2:-270 ppm 350 ppm (since the industrial revolution)-USA is the largest polluter, emitting 25% of the overall anthropogenic CO2-emission

- CH4 : production of rise, animal keeping (anaerobic digestion)

- N2O : combustion, fertilizers (denitrification)

• Fighting GHE – last stage: Kyoto protocol

PER CAPITA GREENHOUSE GAS EMISSIONS (WORLD MEAN 1)

OZONEOZONE

• TROPOSPHERE

- 10 %, 1 %/year increase

• STRATOSPHERE

- 80-85%, decreasing

- carcinogenic, considered as photochemical smog

• CHAPMAN MODELL (1930)

O + O2 O3 UV radiation

O + O3 2 O2 catalizator - NO, Cl, H

• “OZONE HOLE” – The decrease of the stratopheric ozone concentration over the Earth’s poles during the polar spring

• FREON

- measured since - 1970

PHOTODISSOCIATION OF FREON

CFCs (Chlorofluorocarbons) produce Cl- ion if UV radiation

Cl- + O3 ClO + O2

ClO + O3 ClO2 + O2

ClO2 Cl- + O2

1 Cl- consumes 2 O3 and again reforms to Cl-

NO + O3 NO2 + O2

NO2 + O NO + O2

CCl2F2 + UV CClF2 + Cl2

Cl2 + O3 ClO + O2

DATA FROM NASA (1987 SEPT: OZONE AND CHLORINE MONOXIDE): OZONE HOLE

DEPLETION OF THE STRATOSPHERIC OZONEDEPLETION OF THE STRATOSPHERIC OZONE

Consequences:The UV radiation reaching the Earth’s surface is increasing

→ skin cancer→ suppression of the immune system→ severe sunburn→ accelerated skin aging→ damage of the plants→ degradation of polymers, plastics

ACIDIFICATIONACIDIFICATION

SO2-2

4SO

DRY DEPOSITIONWET DEPOSITIONE

MODEL

soil

• EMISSIONS

- NOx

- SO2,

50-60 % transportation

50-60 % energy industry

- CO2 energy industry

- CH4 automobiles, combustion, stock raising

ACIDIFICATIONACIDIFICATION

effect on lakes

pH of rain: 5.5acid rain: 2-3because of H2SO4 and HNO3

acidic lakes can not support lifeeggs of many fish killed at ph = 5, also plants, insects diebelow 5 even adult fish die (due to drowning!)disrupt the food chain

consequence: very clean water without suspended solids, but also without life

ACIDIFICATIONACIDIFICATION

effect on lakes

buffering capacity of water!

ability to neutralise acid/baselots of HCO3

- in water decrease acidity or alkalinity

HCO3- + OH- = CO3

2- + H2OHCO3

- + H3O+ = H2CO3 + H2O

ACIDIFICATIONACIDIFICATION

damage to forests

- direct damage because of acidic precipitation- mobilization of heavy metals (Al) in the soil - toxic (no time for adaptation)- indirect effects (sensitive symbiotic organisms – e.g. lichen)

• SO2 emission (in Hungary)

- 1930 0.3 Mt/year

- 1965 1.7 Mt/year

- 2000 0.9 Mt/year

- causes : Economic recession

Decrease of coal heating

Increasing efficiency and pollution prevention

SO2/GDP ( 10x USA )

NOx/ GDP ( 2x USA )

DEPOSITION OF SULPHUR (gS/m2/year, 1985) EMEP monitoring net

pH OF PRECIPITATION (1980-1984) SENSIBLE AREAS

Scale of air pollution

EFFECTSEFFECTS

SO2: EYES, MUCOSAL, LÉGUTAK, LUNG

CO: TOXIC, HEADACHE, VOMIT (OXIHAEMOGLOBIN

CARBOXIHAEMOGLOBIN)

NO: NERVOUS SYSTEM + METAMOGLOBENIAE

NO2 : LUNG, EYE, RESPIRATORY TRACKS (ACID IN LUNGS)

NH4 : MUCOSAL, EYE

Cl: RESPIRATION, EYE, COUGH

FLUORIDS: EYE, SKIN, NOSE

SOLID POLLUTANTS: SILICOSIS

PAH (diesel) …. BENZOPIRENE - HEADACHE, COUGHING, EYE

LEAD: 80 % PETROL – NERVOUS SYSTEM, BLOOD PRESSURE

COMBINED EFFECTS

MEDICINES, TREATMENT, ECONOMIC LOSSES

ANIMALS

SMALL DIRECT EFFECT

PLANTS SOLID

– ASSIMILATION IMPEDED

– FODDER

GASES

– ASSIMILATION CELL SURFACE + WATER ACID DESTRUCTION

+ PHOTOSYNTHESIS IMPEDED CHANGE IN COLOR

ACIDIFICATION

– Al, MICROORGANISMS - FORESTS

– WATER

– HUMANS

INDICATOR (MOSSES)

BUILDING AND ARCHEOLOGICAL SITES

EFFECT OF INHALATION CO IN TERMS OF CONCENTRATIONEFFECT OF INHALATION CO IN TERMS OF CONCENTRATION AND EXPOSITION TIMEAND EXPOSITION TIME