air quality1

Definitions Unit Measurement Source of Pollutants Classification of Pollutants

Particulates Hydrocarbons CO Oxides of Sulfur Oxides of Nitrogen Photochemical Oxidants Indoor Air Pollution

Global Implications of Air Pollution

AIR POLLUTIONPresence in the outdoor atmosphere of one

or more air contaminant (i.e dust, fumes, gas, mist, odor, smoke or vapor) in sufficient quantities, of such characteristics and of such duration as to be or to threaten to be injuries to human, plant or animal life or to property or which reasonably interferes the comfortable enjoyment of life or property

Suspended particulates- mass per unit volume basis (μg/m3)

Gaseous contaminants – ppm/ppb For gases, ppm convert to μg/m3

molLxmassgmolxppm

mg

/103

3

Standard condition for many chemical reaction:•T1 = 273 K (0°C)•P1 = 1 atm (760 mmHg)•V1 = 22.4 L/mol

While T2,P2,V2 relate to actual conditions being considered.

*But most air quality determinations are referenced at 25°C, 760 mmHg

2

22

1

11

TVP

TVP

Natural sources Fungi spores, salt spray, smoke from

contaminant, dust particles from forest fires and volcanic eruptions

CO from the breakdown of methane Hydrocarbons from pine trees H2S and CH4 from the anaerobic

decomposition of organic matter

Mobile transportation Stationary combustion Industrial processes Solid-waste disposal

Mobile transportation

Stationary combustionResidentialCommercialIndustrial power and heating including steam-powered electric power plant

Industrial ProcessesChemicalMetallurgicalPulp-paper industriesPetroleum refineries

Solid waste DisposalHouseholdCommercial refuseCoal refuseAgricultural burning

Origin Considered as primary or secondary

contaminants Primary –found in the form of which

omitted (SOx, NOx and HC) Secondary –formed in atm by

photochemical reaction or hydrolysis or oxidation (ozone & peroxyacetyl nitrate (PAN) )

Chemical composition Organic or inorganic Organic –contain C, H and other elements such

as O2, N2, Ph & S, carboxylic acids, alcohols, ethers, esters, amines etc

Inorganic –CO, CO2, carbonates, SO, NO, ozone, HF, HCl

State of matter Either particulate or gaseous Particulate –dust, fumes, smoke, fly ash Gaseous –behave much as air, CO, SO, NO, HC

Oxides of sulphur

Carbon monoxideHydrocarbon

Particulate

Indoor Air Pollution

Oxides of nitrogen

Photochemical oxidants

Identified as any dispersed matter, solid or liquid, in which the individual aggregates are <500μm but larger than small molecule

3 classification –physical, chemical or biological

Size Particle of major interest in air pollution studies range

from 0.01 to 100 micron Ex: metallurgical fumes, cement dust, fly ash, carbon

black, sulfuric acid mist, smoke Mode of formation Dust-small, solid particles-created by the breakup of larger masses through processes

such as crushing, grinding or blast-may come directly from the processing or handling or

materials such as coal, cement or grains-by product of mechanical process –sawing of wood-residue of mechanical operation –sandblasting-do not diffuse –settle by gravity-diameter range-1.0 to 10000 micron

Smoke-fine, solid particles-resulting from the incomplete combustion of organic

particles –coal, wood or tobacco-consist of mainly C & combustible materials-diameter range –0.5 to 1 micron

Fumes-Fine, solid particles-Formed by the condensation of vapors of solid

material-May come from sublimation, distillation, calcination or

molten metal processes-Diameter range –0.03 to 0.3 micron-Flocculate and coalesce –settle out

Fly ash-Finely divided, noncombustible particles-Contained in flue gases from combustion of coal-Particles range 1.0 to 1000 micron –like dust-Results from burning –like smoke-Consist of inorganic metallic or mineral substances –like

fumes

Mist-Liquid particles or droplets-Formed by the condensation of a vapor, dispersion of liq or

enactment of chemical reaction-Less than 10 micron in diameter-High conc of mist -fog

Spray -Liquid particles -Formed by the atomization of parent liquids, such as

pesticides and herbicides-Particle range 10 to 1000 micron in diameter

Settling properties Is the major natural self-cleansing

process Suspended particulates –size less than

1 to 20 micron Settleable particulates –larger than 10

micron

18)( 2

pwpt

dgv

Optical qualities Cause reduction in visibility Affected by particles in range of visible light

(0.38 to 0.76 micron) Affected by particle shape, surface

characteristics, distribution of particlesChemical characteristics Contain both organic and inorganic

components Organic –phenols, organic acids, alcohols Inorganic –nitrates, sulfates, metals (iron,

lead, manganese, zinc and vanadium)

Biological characteristics Include protozoa, bacteria, viruses,

fungi, spores, pollens and algae Microorganisms survive for short time

in atm –lack of nutrients and ultraviolet radiation from sun

Certain bacteria and fungi –can survive for long periods

Effect of particulates

On human health At high conc, poses hazards to those

susceptible to respiratory illness Human respiratory system defend itself

against invasion of foreign substances as indicated in Table 7-8 pg 437

The success or failure of respiratory defense system depends on size of particulates inhaled and depth of penetration

40% of 1 - 2 micron particles retain in bronchioles and alveoli

0.25 to 1 micron –breathed in and out Particles below 0.25 micron –results in

impingement

Lead Human exposure originate from inhalation and

ingestion of lead containing particulates Affect reproductive, endocrine, hepatic etc Acute lead poisoning-vomiting, colic, insomnia,

irritability Chronic lead poisoning –headache, weakness

Aeroallergens -Refer to airborne substances causing allergies -Common allergens –pollen and spores -Others of biological origin –yeasts, molds, animal

fur, feathers and hair

Effects on Plants and animals Little damage if deposited on a leaf surface Reduce photosynthesis, hence plant growth

Effects on Materials Soiling clothing and textiles Corroding metals (at RH above 75%) Eroding building surfaces Discoloring and destroying painted surfaces

Organic compounds containing C and H only Aliphatic hydrocarbon:

Alkanes: saturated HC ( ex: methane), generally not active in atmospheric photochemical reaction

Alkenes/olefins : unsaturated, highly reactive in atmospheric photochemistry

Alkynes : highly reactive, rare, not major concern

Aromatic HC Biochemically and biologically active Some are potentially carcinogenic Concern ~ polynuclear group of aromatic HC because some of these

compounds have been shown to be carcinogenic ~ lung cancer Sources-Natural

Biological sourcesGeothermal areasCoal fieldsNG from petroleum fieldsNatural firesPlants & trees

-Anthropogenic Industrial sourcesTransportationSolid waste disposalForest firesetc

Colourless, tasteless, odourless If high concentration ~ affect human,

vegetation & material Refer to table 7.11 page 445 Sources

Natural ~ vegetation decay ~ human metabolism ( a resting

person- 1 ppm CO) Anthropogenic ~ transportation

~ fuel combustion in stationary sources

~ industrial processes~solid waste disposal

6 gaseous compounds Sulphur monoxide (SO) Sulphur dioxide (SO2) Sulphur trioxide (SO3) Sulphur tetraoxide (SO4) Sulphur sesquioxide (S2O3) Sulphur heptoxide (S2O7)

SO2 Colourless, nonflammable, nonexplosive, suffocating

odour, stable in athmosphere, highly soluble in water Source: Oil & gas industry, energy production, coal

burning, industrial combustion & industrial processes

Effect : Human: aggravates asthmatic & bronchitis Plants: damage vegetation

Transport~1000 km

6 gaseous compounds Nitric oxide ( NO) Nitrogen dioxide ( NO2) Nitrous oxide ( N2O) Nitrogen sesquioxide ( N2O3) Nitrogen tetroxide ( N2O4) Nitrogen pentoxide ( N2O5)

NO2 Cause respiratory illness Source Transport, power generation &

industrial combustion Readily soluble in water~ nitrous acid or nitric

oxide

Photochemical oxidants indicate the net oxidizing ability of ambient air

03, 0, 02, PAN, PPN, H2O2 eg f oxidants Effects of Oxidants

On human health – coughing, shortness of breath, airway constriction, heachace etc, exposure to high level of ozone result to damage chromosomes

Effects of plants – major oxidant cause damage to plant is O3 and PAN as both enter the plan leaf thru stomata and intefere plant cell metabolism, exposure level of 0.01 – 0.15 ppm will reduce crop yeilds (soybeans, corn, radishes)

Effects on materials – O3 oxidizes paint, elastomers, textile fibres and dyes Source of oxidants

Produced in upper atmosphere by solar radiation, lightning and forest fires

Originated from building materials, furnishings, equipment and such human activities as cooking, cleaning and smoking

Pollutants Source Detections Standard & Control

Hydrocarbon :Aliphatic HC (contain alkanes, alkenes and alkynes) and Aromatic HC

-Natural source are from biological sources –plant and tree-Anthropogenic –industrial refineries, transportation

Gas chromatography

S-160 μg/m3

C-incineration,adsorption, absorption, condensation

Carbon monoxide

Decaying vegetation-oxidation of methane-human metabolism-transportation,solid-waste disposal, forest fires

Nondispersiveinfrared (NDIR), gas chromatography, catalytic conversion, flame ionization detection

S-10 mg/m3 (8 hr)and 40 mg/m3 (1 hr)C-adsorption, abs, condensation, combustion

Oxides of sulfur –SO2 and SO3

Burning of solid and fossil fuel, industrial processes

Colorimetric, conductometric, coulometric, spectroscopic

S-6 to 10 μg/m3 for 24 hr averageC-burning fuel with less sulfur, dispersion by tall stacks, remove sulfur from fuel

Pollutants Source Detections Standard & Control

Oxides of nitrogen –NO and NO2

-Natural source are solar radiation, lightning-Anthropogenic –fuel combustion, transportation

Calorimetric method, ultraviolet spectrophotometry, electrical tranducers

S-100 μg/m3

C-modification of combustion conditions, devices to remove NOX from exhaust

Photochemical oxidants –ozone, PAN, H2O2

Solar radiation, lightning

-,ultraviolet photometry-gas chromatography (PAN)

S-240 μg/m3 (1hr)and 40 mg/m3 (1 hr)

-Results – gaseous emissions of sulfur oxides (SOx) and nitrogen oxides

(NOX) + water vapour + sunlight strong acidic compounds

(i.e H2SO4 & HNO3)

- H2SO4 & HNO3 + other organic & inorganic chemicals are deposited on the earth as: i) Dry deposition : aerosol & particulates

ii)Wet deposition: raindrops, snowflakes , fog or dew-Effect of acid rain deposit vary i) sensitivity of ecosystem ii) damage to building & monuments in highly industrialized areas

O3 reduces UV radiation that reaches earth’s surface O3 layer deplete from O3 reaction with Cl2 - CFC (use as

aerosol spray propellants) Industrialized nation – banned the use of fluoroC

CO2 increase – O2 decreases Increase in CO2 :

Fossil fuel consumption Agricultural Forestry Land use practices

Continued build up – melt Artic ice pack

Cold countries ~a green house usually built a glass~ used to grow plants & flowers that require plenty of warmth

Sunshine thru glass ~ inside of the greenhouse( very warm)~ roof and walls keep heat from escaping

Earth’s T increase even 1°C experience change in : Weather patterns Flooding Rising sea-level Glaciers melt

But industrial gases i.e CO2, CH4, Nox, CFC ~ trap a certain kind of radiation ( infrared) ~ heat ~ keep it close to earth’s surface

Malaysian Air Pollution Index (MAPI) ~ measures level of criteria air pollution May occur as a result of :

Natural causes Man’s activities

• Natural pollutants: Soil dust Volcanic eruption Salt splashes from the sea

• Man made pollutants: Smoke & wastes from fuel burning Wastes from industrial processes HC from combustion processes

Normal local & foreign sources: Motor vehicles Industrial operation Open burning Land clearing & construction Deforestation Ashes from volcanic eruption