Atmospheric
aerosols
Pavel Mikuška
Institute of analytical chemistry AS CR, Brno
mikuska@iach.cz
30.11.2017
1. Atmospheric aerosol – definition, sources, deposition
2. Effect on human health and environment
3. Characterization of aerosols (size, shape, diameters, size distribution)
4. Specific types of aerosolů (nano-, bio-, indoor-aerosol)
5. Measurement of basic parameters (shape, size, concentration, …)
6. Chemical composition of aerosols (organics, metals, ions)
7. Air pollution by PM in the CR, limits
8. Positive application of aerosols
9. Literature
Program:
Main air pollutants:
• SO2: 60.-80. of last century, power stations (brown coal)
• NOx: 60.-80. of last century, power stations (brown coal)
today – transportation (gasoline cars)
• PM: 60.-80. of last century, power stations+ industry
today – transportation (diesel car) + residential combustion
• O3: secondary pollutant, O3 + PAN main components of photochemical smog
Today: O3 + PM
Atmospheric AEROSOL
– „aerosol“ first used in 1920: "aero-" "air" + solution
– Def.: dispersed system consisting of solid and liquid particles
suspended in a gas (air)
– size range: 1 nm – 100 µm
– characterization: diameter (nm, µm)
mass concentration (µg/m3, ng/m3)
number concentration (P/cm3)
– names of aerosols in specific size range:
total suspended particles:  all particles (TSP)
coarse particles: Da > 2.5 µm
fine particles: Da < 2.5 µm (PM2.5)
submicrometer particles: Da < 1 µm (PM1)
ultrafine particles: Da < 100 nm (UFP)
nanoparticles: Da < 50 / 100 nm (NPs)
Formation and sources of aerosols:
1)  primary sources: direct emission from natural or anthropogenic sources
 secondary sources: formation in air by secondary reactions of gas precursors
(gas-to-particle conversion, secondary oxidation)
2)  natural sources: volcanic activity, sea aerosol, forest fires, mineral sources (soil erosion,
desert dust), plant products (pollen, leaf detritus), bioaerosol
 anthropogenic sources:
- combustion proceses: biomass, fossil fuels (coal, oil, …), traffic, …
- industry activity: cement production, metallurgy (smelting ores and metals), power
stations, steelworks, …
- transport particles by wind from building areas, fields, …
- agricultural activity
- mining activity (quarry, …)
3)  fine aerosol: reaction of gaseous precursors, nucleation, condensation reaction, combustion
products (coal, biomass, traffic)
 coarse aerosol: earth crust material (particles of soil, weathered rock and minerals,
resuspension, bioaerosol, emission of dust from industry and construction
(cement, conveyor, …), volcanic activity, sea salt aerosol, desert dust
Specific aerosol types:
 Bioaerosol: aerosols of biological origin (viruses, bacteria, fungi, pollen, …)
 Cloud: visible aerosol with defined boundaries
 Dust: solid particle aerosol (> 0.5 µm) formed by mechanical disintegration of parent
material (crushing, grinding)
 Fume: solid particle aerosol produced by the condensation of vapors or gaseous combustion
products. Often clusters or chains of primary particles (< 0.05 µm)
 Haze: atmospheric aerosol that affects visibility
 Mist + Fog: liquid particle aerosol formed by condensation or atomization (1-200 µm)
 Spray: droplet aerosol formed by mechanical breakup of a liquid
 Smoke: visible aerosol formed by incomplete combustion; solid / liquid particles, mostly < 1 µm
 Smog: 1. general term for visible atmospheric pollution in certain areas. Term derived from
words smoke and fog
2. London smog: winter, low temperature, fog, inversion, emissions from industry and
coal combustion (SO2, PM, …)
3. photochemical smog: aerosol containig photochemical reaction products formed in
atmosphere by action of sunlight on CHx and NOx (< 1 µm)
 Droplets – liquid particles
 Particulate Matter (PM) – solid particles or liquid droplets
Dry deposition:
Effect of aerosols on environment:
• global climate  change in radiation balance of atmosphere
• visibility decrease
• acidification and eutrophication of soil and water resources
• surface for chemical reaction in atmosphere
• destruction of stratospheric ozone
• smog production
Effect of aerosols on the Earth's climate:
 change in the radiation balance of atmosphere
1) Direct Aerosol Effect: aerosol particles scatter radiation back to space or absorb
sunlight, altering the amount of the sun’s energy that enters the Earth’s climate
system, which has a cooling effect on the Earth’s energy balance (chemical
composition vs size, larger particles scatter more light than smaller aerosol particles)
2) Indirect Aerosol Effect: aerosols acting as cloud droplet seeds influences both
reflectivity of cloud (albedo) and its ability to produce precipitation
Scattering, absorption = ∫ particle size, concentration,
chemical composition
direct + indirect effect  Earth cooling („whitehouse effect“)
Contribution to total atmospheric absorption by aerosols (warming effect):
o brown carbon 19%
o black carbon 72%
Visibility reduction:
 visibility = ability of eye to distinguish the subject from surrounding background
 limited by dispersion of sun light on aerosol particles and molecules of air
 theoretically (PM  0 µg/m3)  340 km (→ dispersion of light by molecules of air)
 PM  10 µg/m3  visibility 30 - 40 km
Krkonoše from Hradec Králové (7.3.2011 after crossing the queue, 63 km, J. Strouhal)
Effect of aerosols on human health:
 wide range of health effects: increased mortality, cardiovascular, respiratory (astma), cancer, ...
 harmfulness of aerosols: deposition in organism (lung)
 health effect = ∫ aerosol properties (size, shape, concentration, composition, ….)
 „All particles are equal but some particles are more equal“ (Brunekreef, EAC, Zurich 2017)
all particles are toxic but some particle are more toxic !
 size: toxicity increases with decreasing size, … UFP the most toxic
 shape: sphere, fibre, irregular, amorphous
 concentration: mass × number Cd, Pb, Ni, Tl, Hg, Ba, .., As
 composition: BC, organic compounds (carcinogens), SOA, heavy metals
 bioavailibility PAHs, N-PAHs, PCBs, dioxines, …
 2 different approaches:
o epidemiological: exposure level (= delivered concentration), large populations
o toxicological: mechanism of reaction, dose (delivered concentration retained in
the tissue), mass conc. not useful, surface drives particle toxicity
 Europe in 2000: ≈ 370 000 inhabitants died due to air pollution by aerosols
(= about 10times more than deaths due to traffic accidents)
1) Meuse valley: 1.-5.12.1930
 5-day fog, T-inversion
 high conc. SO2 (coal combustion)
 high conc. PM (H2SO4, …)
 63 deads, 6 000 patients
2) Donora (Pennsylvania): 26.-31.10.1948
 fog, T-inversion
 high conc SO2 and HF (steelworks, ceramic industry)
 high conc. PM (H2SO4, F-, …)
 20 deads, 7 000 patients
3) London: December 1952
 fog, low temperature (cca 0°C)
 T-inversion (from 5.11.)
 PM accumulation (coal
combustion – industry, households)
 7 December: visibility  0.5 m !
 > 12 000 deads !
 Los Angeles, 50- 60s of 20th century
- photochemical smog
 Today: Peking, Delhi, Indonesia
Athens, Po Valley, Ostrava + South Silesia
cathedral St. Paul, 1903
London smog 1952
Particle deposition in respiratory tract:
• Human respiratory tract is divided into 3 main regions:
head airways, tracheobronchial region and alveolar region (pulmonary; gas-exchange)
• Particles must generally become deposited in respiratory tract to exert biological effects
• Particle separated according to penetration into respiratory regions:
 Inhalable fraction: mass fraction of total airborne particles that enters body through nose
and/or mouth during breathing
 Thoracic fraction: mass fraction of inhaled particles penetrating beyond larynx
(Da  10 µm, PM10)
 Respirable fraction: mass fraction of inhaled particles penetrating into alveolar region of lungs
(Da  4 µm, PM4): PM2.5 – particle penetration into bronchi
PM1 – particle penetration into pulmonary cells
NPs – particle penetration into blood
Particle deposition mechanisms in respiratory tract:
 Impaction: large particles at large velocity in curved
pathway (bronchial region)
 Interception: long fibers in narrow airways
 Gravitational settling: large particles at low flow velocity
and small airway dimension
 Diffusion (Brown): small particles ( 0.5 µm) in small
airways and long residence time
(alveolar region)
Nanoparticles (NPs): Da  50 / 100 nm
 nanomaterials – at least 1 external dimension smaller than 100 nm
 nanoparticles – objects with all 3 external dimensions at the nanoscale ( 100 nm)
 nanoclusters – at least one external dimension smaller than 10 nm
• NPs sources:
o natural (volcanic dusta, forest fires, …)
o incidental byproducts of combustion processes (e.g., welding, diesel engines)
o engineered nanoparticles: intentionally produced and designed with very specific properties
(shape, size, surface properties and chemistry)
• different properties in comparison with the same material of large diameter (surface)
• surface area - biologically most relevant dose metric for NPs
• pathways of NPs entry into the body:
o inhalation (mouth/nose lungs, main route)
o along olfactory nerv (directly to brain)
o ingestion
o skin (damaged)
o food (gastrointestinal tract)
• serious health effects:
o penetration through intercellular space into body blood transport accumulation in
organs (brain, kidney, liver, … )
o cardiovascular, neurodegenerative and carcinogenic effects
o chronic breathing problems
Gehr, BB workshop, Praha 2013
Bioaerosols: = aerosol of biological origin
 viruses
 viable organisms (they are reproduced): bacteria, fungi, mold, algae, yeast, …
 non-viable organisms (no reproduction): product of organisms (fungal spores, pollen), body
parts of animals (hairs, skin, feathers), insects and plants
• size: 0.02 – 100 µm
• characteristic properties: size, viability, infectivity, allergenicity, toxicity,
pharmacological activity
• importance: adverse health effects (allergy, illnesses, …, deaths)
adverse social impacts (harvest damage, damage to cattle)
Radioaerosols:
• measurement of natural radioactivity: radiation protection
mechanism of transport
distribution of radionuclides in environment
• natural radioactivity: mainly Rn (220Rn, 222Rn) – gas ()
short-term products of Rn transformation bound to PM
• collection of air at filter, measurement of activity:
220Rn 212Pb, 212Bi
222Rn 218Po, 214Pb, 214Bi
• different half-lives of individual transformation products
Indoor aerosols:
- 68 % time spent in indoor space
 Indoor sources of aerosols:
• cooking (main): 90% particles < 10 nm
• combustion: gas stove, fireplace, candles, aromatic sticks, …
• electrical equipments: stoves, tools, kitchen appliances, hair dryer
• smoking: cigarettes, pipes
• Laser / 3D printers
• home animal, plants
• building material: asbestos
• kitchen degreaser + cleaners
(MEA, limonen, …)
 Outdoor sources : inward infiltration (penetration through window, door)
Gas stove
Characterization of atmospheric aerosols:
• size (diameter)  determines behaviour and properties
• shape
• density
• concentration: mass  number
integral  size-resolved
• chemical composition
• toxicology analysis
• refractive index
• surface
size + concentration  size distribution
evaluation / estimation of health risk / effects
Particle shape:
• spherical, fibrous, irregular, …
• collection PM on filters (polycarbonate filter)
• analysis individual particles with electron microscope 
simultaneously size, shape, chemical composition
• use: identification of emission sources
estimation of health risk (fibres)
particles of biological origin
ash (Ostrava) agreggates from traffic
Particle diameter (Dp)  particle size
• unambiguous definition Dp: spherical particle
• particle with irregular shape diameter of equivalent sphere
• equivalent diameter: dimeter of sphere with the same physical property as measured
particle of irregular shape
• particle Ø defined according to measurement method  aerodynamic, optical, electromobility,
Stokes, volume, geometric, …
• Aerodynamic diameter (Da): diameter of sphere with unit density (1000 kg/m3) and the same
settling velocity as the irregular particle. Da determines particle
behaviour in air (sedimentation, deposition in lungs, …)
• Stokes diameter (Ds): diameter of sphere with the same density and the same
settling velocity as the irregular particle.
• Volume equivalent diameter: diameter of spherical particles with the same volume and with
the same settling velocity as the irregular particle.
Corrections for other shapes:  (dynamic shape factor): sphere 1.00; cube
1.08; quartz 1.6; fibre: 1.35 (5:1); 1.68 (10:1)
• Equivalent mobility diameter: diameter of spherical particles with the same mobility …
Important equivalent diameters of irregular particles:
Size distribution of aerosol:
• simultaneous characterization of size and concentration of individual aerosol particles
• real aerosols: high concentration of particles
impossible to characterize each particle separately
• size distribution (curve)  particle concentration as a function of particle diameter
o concentration (number, mass, volume, surface) of particles in selected size interval
o distribution is characterized by location and width of distribution
Locations of distribution curve:
• Mode: particle diameter (Dp) with the highest frequency
• Median: Dp that divides frequency curve into equal areas
• Mean (arithmetic average, ): Dp with arithmetic mean value
• Geometric mean (Dg): mean diameter on log-normal distribution curve
• mode < median < mean
F = count number
(mass, volume)
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1) linear scale of sizes  Normal distribution
- unsymmetrical
2) logaritmic scale  Log-normal distribution
- normal distribution for log D (symmetrical shape)
- CMD = Dg
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CMD = Dg
Polydisperse aerosol: wide range of particle sizes
 - standard deviation
g - geometric standard deviation
 monodisperse aerosol: g ≤ 1.25
 polydisperse aerosol: g ≥ 1.25
Monodisperse aerosol: very narrow range of particle sizes (mean = mode = median)
Log-normal distribution curves of ambient aerosol:
- weighted by N, S, M / V
• Number distribution
• Surface area distribution
• Volume / Mass distribution
→ different sources and composition particles
• Nucleation mode: Dp < 20 nm, „lifespan“ ≈ 1 hod
- origin: nucleation of gases → formation of new particles
- composition: ions, organic compounds
• Aitken mode: 0.02 < Dp < 0.1 µm (UFP)
- origin: emission from combustion processes,
condensation of cooled gases after emission,
coagulation of particles of nucleation mode
- composition: EC, organic compounds, ions, metals
• Accumulation mode: 0.1 < Dp < 2.5 µm, „lifespan“ ≈ weeks
- origin: coagulation of smaller particles, condensation of volatile
compounds, reaction of gases
- composition: sulphates, nitrates, NH4
+, organic compounds, EC, metals
• Coarse mode: Dp > 2.5 µm, „lifespan“ ≈ hours - days
- origin: resuspension, mechanic decomposition/erosion of material of earth's surface, emission
from traffic and building, sea aerosol, …
- composition: earth crust material (particles of soil, weathered rocks and minerals), bioaerosol,
products of mechanic operation (milling, quarries, …) and traffic (abrasions of tires, cars,
pavements, …), desert sand, sea aerosol, …
Fine aerosol = Nucleation + Aitken + Accumulation modes
Atmospheric aerosol: 4 - modal number size distribution
4  3 - modal particle size distribution:
Σ Aitken + nucleation
mode
nucleaction mode
3-modal distribution
Particle size: dependence of particle Ø on measurement method
• wide range (5 orders): 1 nm – 100 µm
• no universal method for all size range
• different measurement principles  different sizes pro the same particle
Diameter Dependence on: Instrumentation
aerodynamic
mobility
optical
geometric
…
size, shape, density
size, shape
size, shape, refractive index
size
APS, impactor
SMPS, FMPS, EEPS
OPC
electron microscopy
APS, SMPS, OPC: size + number concentration simultaneously
 number size distribution
SMPS Spectrometer = Scanning Mobility Particle Sizer
SMPS = impactor + neutralizer + DMA + CPC
1) Impactor: removal of particles Dp > 1 µm
2) Neutralizer: redistribution of electric charge of particles
according to Boltzmann (85Kr, 210Po, 241Am)
3) DMA – Differential Mobility Analyser
- classification of particles according to electric mobility (Z)
into narrow size intervals depending on voltage difference
between inner/outer electrodes → monodisperse aerosol
at DMA output
- DEM =  (shape, geometric size)
4) CPC – Condensation Particle Counter
- detection of classified monodisperse particles
- saturation of air by vapor of n-BuOH (H2O, isoPrOH)
at increased T, condensation on particles after cooling,
increase of particle size above 1 µm, optical detection
(scattering of laser light)
 
Mobility diameter (DEM):
p
c
D
Cen
Z
3

SMPS = Scanning Mobility Particle Sizer
- size range: 2.5 - 1000 nm
- concentration range: max. 2×108 P/cm3
- resolution: max 167 size channels
- CPC: n-BuOH, isopropanol, H2O
- electrometer: CPC alternative
lower sensitivity
Aerodynamic diameter (Da):
APS Spectrometer = Aerodynamic Particle Sizer
- measurement of flight time between 2 laser beams
- Da =  (density, shape, size)
1 g/cm3 sphere
- study of deposition (lungs) and behaviour of particles in
air (sedimentation)
- „single-particle“ detection
- size range Da: 0.5 - 20 µm
- concentration range: max. 1×103 P/cm3
- resolution: 52 size channels
Optical diameter:
OPC = Optical Particle Counter
- light scattering on particle
- „single particle“ detection
- D =  (size, shape, refractive index)
- scatter angle → particle size
- intensity of scatter puls → concentration
- source: laser, white light (Palas)
- size range: 0.1 - 40 µm
- concentration range: max. 1×105 P/cm3
- resolution: 52 size channels
iyx
v
v
m
P
air
P 
x – scatter, y - absorption
Refractive index:
Number concentration of aerosols: P/cm3
- measurement method determines:
o measured size range
o concentration range
o particle diameter
Method Size range: Concentration range
(P/cm3)
Particle diameter
SMPS
APS
OPC
1 – 1000 nm
0.5 – 20 µm
0.1- 40 µm
1 – 2×108
1 – 1×103
1 – 1×105
mobility
aerodynamic
optical
Mass concentration of aerosols: ng/m3, µg/m3
- measured mostly in defined size fraction (TSP, PM10, PM2.5, PM1)
1) discontinuous: sampling on filters (foils in impactors)
- integral method
- weighing filters or foils
- difference in mass of filters/foils before and after exposition
- filters  1-2 days equilibration in special weighing room (50%, 20°C)
- static charge on filter/PM  charge removal
- weighing filters on special microbalance ( 1 µg)
- reference method (nitrocellulose filters)
- low time resolution (~ 2 – 24 h)
2) continuous: on-line instrumentation
- high time resolution (1-min and less)
- oscilation microbalance (TEOM)
- radiometric method
- optical spectrometer → parallel 3 size fraction (PM10, PM2.5, PM1)
only 1 size fraction
TEOM = Tapered Element Oscillating Microbalance
- continuous on-line measurement of mass concentration
- collection of PM on filter placed on oscillating tube  oscillation frequences decreases with
increasing mass of filter
- selection of analysed PM fraction according to inlet separator
- mass resolution: 0.1 µg/m3 (5 min)
Radiometric method of mass concentration measurement:
„beta attenuation“
- semi-continuous measurement of mass concentration (time resolution 1 h)
- collection of aerosols on filters  measurement of β-radiation (14C, 85Kr) attenuation with
Geiger-Müller counter
- selection of analysed PM fraction according to inlet separator
- mass resolution: 1 µg/m3 (24 h)
5 µg/m3 (1 h)
- measurement of PM10 and PM2.5 in CHMI
• Radiometric method („beta attenuation“)
• Daily limit PM10: 50 µg/m3
- measurement PM10 - from 1996
- measurement PM2.5 – from 2005
AIM – automatic immision monitoring network (CHMI):
Váňa M., conference CAS 2013, Nový Smokovec
Station classification according to type: traffic, urban, rural, background
PM10 PM2.5
Aerosol toxicity:
Deposition of PM in lungs and subsequent release of bound harmful compounds
 particle size: Dp  10 µm  enter into respiratory tract
 particle shape: fibrous × spherical
fibrous particles (asbestos) – cancerogenic effects
 particle components:
o several compounds bound to PM toxic for body/organs  metals, organic compounds
o solubility / bioavailability of components
a) organic compounds:
- PAHs: BaP – carcinogenic/mutagenic (WHO), estimation of health risk (cPAHs)
cPAHs = 7 carcinogenic PAHs: benz[a]anthracene, chrysene, benzo[b]fluoranthene,
benzo[k]fluoranthene, benzo[a]pyrene,
dibenz[a,h]anthracene, indeno[1,2,3-cd]pyrene
- nitroPAHs
- PCBs
- PCDD/PCDFs, …
b) metals: Pb, Ni, CrVI, As, Cd, Hg (Be, Tl, Ba, Pt, …)
Analysis of chemical composition:
1. Aerosol sampling: continuous, semi-continuous, discontinuous
2. Sample treatment: extraction, derivatization, preconcentration
3. Sample analysis: organic compounds - GC, LC, IC, MALDI, …, AMS
metals – PIXE, RTG, NAA, ICP, AAS, …
ions - IC, CZE, FIA, AMS, …
 continuous methods:
- time resolution: seconds - min
- in-situ
- Aerosol Mass Spectrometer)
 semi-continuous methods:
- time resolution: min - hod
- continuous sampling
- on-line analysis (in-situ)
- limited mostly to water-soluble compounds (ions, DCA, NH4
+, metals)
 discontinuous methods:
- time resolution: 2-24 hod
- aerosol collection on suitable medium (filters, foils)
- off-line analysis in laboratory
Aerosol sampling:
 obtaining representative sample of aerosol
- no change in chemical composition (elimination losses and deposition of PM)
- no change in particle distribution
 Isokinetic sampling:
- Uinlet = Ustreamline
- same velocity of aerosol sample and air
 Superisokinetic sampling: losses:
Uinlet > Ustreamline deposition,
turbulence,
 Subisokinetic sampling: coagulation,
Uinlet < Ustreamline …….
Size selective inlets:
 selection of sampled particle fraction
 removing of particles with Dp > Dp50 from sampled air stream
 PMX  X = „cut-point“ diameter (Dp50)  PM10, PM2.5, PM1, …)
 X (Dp50) determines size fraction sampled with 50% efficiency (PMX)
Dp > X  particle removal (collection in inlet)
Dp  X  particle penetration through inlet
into sampler
 PMx =  (sample flow rate) from sampled air stream
 principle inertial classification:
 impactor
 cyclone
50%
designed for specific cut-point
diameter and sample flow rate
Size selective inlet: 1. cyclone
- particle separation based on principle of inertia
- larger particles with a higher inertia cannot follow the path and impact on the cyclone wall while
gases and lighter particles have less inertia and exit cyclone through outlet tube
- no reliable theory for cut-off point calculation
- cut-off are not as sharp as in impactors
- long-term operation without maintenance
- collection of much larger quantity of particles than impactor
Size selective inlet: 2. impactor
- particle separation based on principle of impaction of PM on impaction plate in front of jet nozzle
- calculation of collection efficiency → Stk (Stokes number)
- cut-off (dp50) =
Stk50 = 0.24 (circular nozzle)
= 0.59 (rectangular nozzle)
- particles with Stk > Stk50 are collected
actual and ideal impactor cutoff curves
W
S
W
UCd
Stk
cpp



9
2 S – stopping distance
Cc – slip correction factor
W – nozzle diameter (width)
U – velocity
W
S
Stk
Impaction plate
inlet PM2.5 + PM10
Continuous analysis of chemical composition of aerosols:
 Aerosol Mass Spectrometer
 continuous sampling + on-line MS analysis of particles in real time
Aerosol Time of Flight Mass Spectrometer:
 continuous sampling + on-line analysis in real time
- size and chemical composition of individual particles in real time
- size range: 30 – 1000 (3000) nm
- qualitative analysis:
 sufficient for inorganic ions, metals
 insufficient for identification of organic compounds
- quantitative analysis: questionable
- problematic field application (high weight)
- Aerodyne AMS (Aerodyne)
- ATOFMS = Aerosol Time of Flight Mass Spectrometer (TSI, model 3800)
Commercial AMSs comparison:
Black – Brown – Elemental – Soot – Organic – Inorganic Carbon
 Soot: A black, blackish or brown substance formed by combustion, present in atmosphere as
fine particles, or adhering to sides of chimney or pipe conveying smoke
 Soot carbon (Csoot): carbon particles with morphological and chemical properties typical
of soot particles from combustion: aggregates of spherules made of graphene layers,
consisting almost purely of carbon, with minor amounts of bound heteroelements (H, O)
 Black carbon (BC) originates from combustion processes (coal, wood, traffic), responsible for
absorption of visible sunlight and warms atmosphere. BC is generally used when optical
methods are applied for its determination
 Elemental carbon (EC): fraction of carbon oxidized in combustion analysis above a certain
temperature threshold, and only in presence of oxygen-containing atmosphere
 “BC” and “EC” are used as synonyms for Csoot
BC × EC: different measurement methods
 Brown carbon (BrC; light-absorbing organic carbon): class of organic carbon, light brownish
color, absorbs strongly in the ultraviolet wavelengths and less significantly in VIS.
Includes tar materials from smoldering fires or coal combustion or biomass burning
 Organic carbon (OC): carbon in organic compounds (primary emissions from sources)
 Secondary organic carbon (SOC): C in organic compounds formed secondary in atmosphere
 Total carbon (TC): TC = OC + EC
 Inorganic carbon (IC): carbon in inorganic carbonates
Aethalometer
- optical method of continuous detection of BC and BrC concentration
- BC = Black Carbon , BrC = Brown Carbon
- principle:
o continuous collection PM on qurtz filter
o attenuation of IR (880 nm) across filter is proportional to BC concentration
o attenuation of VIS (520 nm) is proportional to BrC concentration
o attenuation of UV (370 nm) is proportional to aromatic compounds
f. Magee Scientific
Model AE33:
• attenuation of transmitted light at wavelengths of 370, 470, 520, 590, 660, 880 and 950 nm
• detection limit (1 hour): <0.005 μg/m3
• range: <0.01 to >100 μg/m3 BC
• resolution: 0.001 μg/m3
EC-OC analyser: thermal-optical transmission method (TOT)
• direct analysis without derivatization
• collection PM on quartz filters
• laboratory version: off-line filter treatment
EC-OC → CO2 → CH4 → FID
• field version: on-line filter treatment
EC-OC → CO2 → IR
laboratory version:
„field“ version:
CC – carbonate
PC – pyrolytic carbon
f. SunSet Laboratory
Semi-continuous analysis of chemical composition:
 continuous collection of PM into liquid and subsequent on-line analysis (FIA, LC, IC, …)
 advantages:
- collection of PM from air directly into liquid (H2O)
- elimination of errors resulting from manual treatment of filters
- quick detection (FIA – CL / FL) → short time resolutiom (s – min)
 disadvantages:
- size of small particles has to be first increased to be collected
- limited only to water–soluble aerosol components: ions, NH4
+, metals, several
organic compounds (DCA, saccharides)
- interference: positive  collection gaseous pollutants into water (HNO3, NO2, NH3, PAHs, …)
→ eliminated by diffusion denuder
negative  losses of volatile compounds by evaporation in oversaturated
environment (PAHs, NH4NO3)
- on-line detection requires fast and sensitive instrumentation
 continuous collectors → 2 different principles:
- condensation of supersaturated water steam on particles
- Venturi scrubber
SJAC: Steam-Jet Aerosol Collector PILS: Particle-Into-Liquid Sampler
Continuous collectors: 1) condensation type
 condensation of supersaturated water steam on aerosol particles
 turbulent mixing of analysed air with water steam (100° C) → adiabatic cooling → water
steam supersaturation → steam condensation → particle size increase → collection of
enlarged particles into H20
 100 % CE for Dp > 10 nm
 disadvantages: SVOC losses, NO2 interference
VPC: Venturi Particle Collector
ACTJU: Aerosol Counterflow Two-Jets Unit
Continuous collector: 2) Venturi scrubber
 Venturi scrubber: efficient way for removing of particles from air stream
 turbulent mixing of air and absorption liquid in Venturi throat, increased
velocity of air, atomisation of water, mutual collisions of particles and
water droplets, particles are collected into water droplets
 100 % CE for Dp > 0.3 µm
PP - peristaltic pump, D - detector, W - waste,
V - injection valve, HP - high-pressure pump,
DB - debubbler, PC - preconcentration column,
AC - analytical column, R1, R2 - reagents
Semi-continuous determination of metals in PM:
Cu
Co
Fe
Absorption liquid – H2O
CL detection: luminol + H2O2
Time resolution - 30 min
1 – cyclone inlet, 2 – annular diffusion
denuder, 3 – Condensation Growth Unit,
4 – ACTJU, 5 – piston pump, 6 – 10-way
injection valve, 7 – preconcentration
column No. 1, 8 – preconcentration
column No. 2, 9 – IC, 10 – computer
Semi-continuous determination of ions and DCAs in PM:
Absorption liquid – H2O
Time resolution - 60 min
Discontinuous analysis of chemical composition:
 sampling aerosols on filters / foils + off-line analysis in laboratory
 the most frequent method for determination of chemical composition
 sampling medium:
 filters → only 1 size fraction of aerosols (PM1, PM2.5, PM10, TSP)
→ size selective inlets: impactor, cyclone
 foils in cascade impactors → several size fraction simultaneously  size resolved
chemical composition
 advantages:
 collection of sufficient amount of sample → analysis of different groups of compounds
 disadvantages:
 off-line analysis of aerosol components in laboratory
 long time of sampling
 results averaged over time
 sampling artefacts (over-/under- estimation of aerosol component concentration):
1. positive (adsorption of gases, organic vapors or SVOC on collected particles/filter)
2. negative (losses due to volatility of compounds bound to collected particles (NH4NO3,
PAHs, …)
3. change in composition of collected particles (reaction with NO2 or oxidants (O3, OH, …)
 possible contamination during manual processing or transport
 particle size distortion (particle losses in inlet or between plates of cascade impactor)
Sampling PM on cascade impactors:
 classification of particles into several sizes according to
aerodynamic diameter
 collection of particles on principle of inertial impaction:
 mass concentration and chemical composition in several
size fraction simultaneously (size resolved composition)
 number concentration PM → „electrical“ impactor
 cascade impactor: 3 - 13 plates + „back-up“filter
 separation particles in size range 10 nm - 18 µm
 low plates – small amount of samples
 sampling medium: 1. foils (Al, Tedlar)
2. filter (Nucleopore, Zefluor)
 foils covered with inert grease (Apiezon, silicone) to
prevent particle bouncing and transfers to next plate
Gradual decrease of W, S and Dp50:
W
S
Cascade impactors used for mass + chemical composition:
 Berner low pressure: 10 plates, 25 LPM, 26 nm – 6.8 µm
 Moudi (rotating): 13 plates, 30 LPM, 10 nm - 18 µm
 Dekati low pressure: 13 plates, 30 LPM, 30 nm – 10 µm
 Andersen: 8 plates
 Sioutas personal: 3 plates, 9 LPM
Moudi:
Parameters of Berner LPI:
Electrical Low Pressure Impactor (ELPI, Dekati)
 measurement of real-time particle size distribution and number concentration (7 nm – 10 μm)
 principle:
o particle charging in a unipolar corona charger
o size classification of particles in a cascade impactor according to aerodynamic diameter
o electrical detection of electric charge carried by particles into each impactor stage
Virtual Impactor
 impaction plate is replaced with collection probe
 particles with sufficient inertia are thrown into collection probe. These particles remain
airborne and are carried by minor air flow into filter.
 smaller particles are carried radially away from jet axis by major air flow, avoid collection
probe and are collected on another filter
 particles larger than and smaller than cut-off diameter are collected on separate filters
Sampling on filters:
Samplers:
 high-volume (30-60 m3/h: Digitel (filters 150 mm), …
 medium-volume (3-6 m3/h): Leckel, Derenda
 low-volume (1 m3/h): Leckel, home-made
filters 47 mm
inlet
PM2.5
PM1 inlet
NILU filter (47 mm) holder
Digitel DHA-80 inlet PM2.5
quartz and membrane filter under microscope
Filters:
 100 % collection efficiency (Dp  0.3 µm)
 choice of filter type according to analysed compounds:
 fibrous (quartz, QMA) - porosity 70-99%, low flow resistance, Ø fibre 1-100 µm
- analysis of organic compounds (ions, metals) bound to PM
 membrane: porosity 50-90%, higher flow resistance
- cellulose esters (nitrate/acetate-cellulose) → analysis of metals
- Teflon (Zefluor, Teflo) → analysis of ions
- polycarbonate → determination of particle shape (SEM, TEM)
 shape and size of filters: circular (Ø 25; 37; 47; 150 mm)
rectangular (250 × 200 mm)
 dependence on air humidity → equilibration at const t/RH before weighing (24-48 hod)
clean and exposed QMA (PM2.5, 24 h, 720 m3)
Efficiency of PM collection on filters:
Mechanisms of PM collection on filters / deposition in lungs:
• inertial impaction
• interception
• diffusion (Brown)
• electrostatic deposition
• gravitational settling
Efficiency of filters:
 :  filter type (filter thickness, diameter of pores/fibres, …)
 particle diameter
 flow rate of sample through filter
 filtration mechanism
 minimum filtration efficiency for particles with Da ≈ 0.3 µm
(the most penetrating particle size !)
Discontinuous analysis of chemical composition:
1. collection of PM on filters or foils
2. direct on-line filter analysis: OC/EC: field analyser
BC: aethalometer
metals: RTG, NAA, PIXE, …, LAS, LIBS, …
3. off-line filter/foils analysis:
 filter treatment:
 before sampling: - filter cleaning – only for QMA (500°C, min. 10 h)
- equilibration at constant T/RH (20°C / 50%)
- removal of static charge
- weighing of filter on sensitive microbalance ( 1 µg)
 after sampling: - equilibration, removal static charge, weighing
- extraction: water – ultrasonic extraction
organic solvents: MeOH, DCM, acetone, hexane, …
ultrasonic / Soxhlet / ASE / PSE
- decomposition: HNO3, HF, …
 extract treatment: extract preconcentration: solvent evaporation
extract fractionation: silicagel/alumina + solvents with increased polarity
extract derivatization: low volatility or thermally unstable compounds
 extract analysis: organic compounds: GC-MS/FID, LC-MS, HPLC, IC, MALDI, …
OC/EC: laboratory analyser
metals: ICP-MS, AAS, RTG, OES, …
ions: IC, CZE, FIA, LC, ….
Chemical composition of aerosols:
 variable
 dependent on particle size, time and place of sampling (different emission sources)
 use: identification of emission sources of PM
estimation/evaluation of health risk PM
 fine × coarse aerosol
 PM10, PM2.5, PM1, UFP
 water-soluble × water-insoluble
 primary PM components: compounds emitted directly from source
secondary PM components: compounds formed secondary in atmosphere
o reaction of gaseous precursors (SO2, NO2, … → H2SO4, HNO3)
o oxidation of VOCs, reaction with NO2, …
o photolysis of organic compounds, …
Chemical composition of atmospheric aerosols:
1) inorganic compounds:  primary emission: metals, insoluble minerals, …
 secondary formation: nitrates, sulphates, NH4
+, …
2) organic compounds:
 primary: EC, polar (acids, saccharides,...) and nonpolar (PAHs, alkanes, …)
 secondary: oxo-, nitro-, … derivates, dicarboxylic acids, …
 HULIS (HUmic-LIke Substances)
3) water: mainly PM2.5 particles are mostly hygroscopic, water content increases with RH
(RH > 80%: H20 usually forms more than ½ PM2.5 mass)
 SIA: NH4NO3, (NH4)2SO4, NH4Cl, …
SOA: secondary organic aerosol (DCAs, oxo/nitro-derivates, …)
 carbon in PM: „carbonaceous fraction of aerosols“: EC + OC (+ carbonates)
- EC: elementary carbon ( BC, soot)
- OC: organic carbon, ∑ C in organic compounds in PM
- WSOC: water soluble organic compounds
- WNSOC: water non-soluble organic compounds
 HULIS: group of WSOC with high molecular weight (200-600 Da) accounting up to 72% of
WSOC mass. HULIS are comprised of hydrophobic aliphatic and aromatic compounds
containing different polar functional groups (hydroxyl, carboxyl and carbonyl). Due to
complexity and chemical diversity (hundreds of individual substances), chemical
characterization is still relatively poor. Primary and secondary origin.
OC + EC form 25-75% PM mass,
OC + EC = TC, TC - total carbon
• Unresolved (UCM): rozvětvené cyklické a nenasycené CHx (emise z dopravy)
• Non-Extractable/Non-Elutable: HULIS, …
Organic compounds analysed in PM collected on filters
+ indicated sources:
 compounds important due to health effects  evaluation of health risk
(PAHs, nitroPAHs, PCBs, dioxines, …)
 molecular markers  unique identification of emission sources
 monosaccharide anhydrides: biomass combustion
 resin acids + retene: softwood combustion
 methoxyphenols: wood combustion (soft- and hard-wood)
 saccharides: monosaccharides: wood combustion, plant
disaccharides: plant (pollen, …), microorganisms
polyols: fingal spores, bacteria, soil microorganisms
 alkanes: traffic, coal combustion, biological sources (plant metabolites)
 acyclic isoprenoids: traffic, biogenic sources
 hopanes: coal combustion, traffic
 steranes: traffic
 picene: coal combustion
 triphenylbenzene: plastic material combustion
 1-nitropyrene: diesel
 oxo/nitro-PAHs: SOA
 dicarboxylic acids: traffic, SOA
 higher monocarboxylic acids (C16, C18) + cholesterol: cooking
 other: OC-EC, HULIS, …
1. Naphthalene
2. Acenaphthylene
3. Acenaphthene
4. Fluorene
5. Phenanthrene
6. Anthracene
7. Fluoranthene
8. Pyrene
9. Benz[a]anthracene
10. Chrysene
11. Benzo[b]fluoranthene
12. Benzo[k]fluoranthene
13. Benzo[a]pyrene
14. Indeno[1,2,3-cd]pyrene
15. Dibenzo[a,h]anthracene
16. Benzo[ghi]perylene
Coronene
Perylene
Retene
Picene
Benzo[e]pyrene Triphenylbenzene
Polycyclic aromatic hydrocarbons: 16 priority PAHs
carcinogenic PAHs
Pristane: C19H40 , Phytane: C20H42
Levoglucosan
Mannosan
Galactosan
BaP BeP
triphenylbenzenepicene
EEA report 2012
PM10 in Europe
EEA report
2016
EEA report 2012
PM2.5 in Europe
EEA report
2016
TSP concentration + dust emission: trend in CR
Váňa (CHMI),
ČAS 2013,
Nový Smokovec
Main sources of PM:
 coal combustion
 biomass (wood) burning
 traffic
 industry
 agricultural
residential heating
Annual average concentration of benzo(a)pyrene in 2007
Field of 36. highest 24-hod concentration PM10 in CR (CHMI):
 effect of meteorological situation on PM10
2005 2007
2009
Positive use of aerosols:
 Speleotherapy  inhalation of speleoaerosols (cave aerosols) in selected caves
(Sloupsko-Šošůvské caves), specific clima with constant temperature and high
humidity, metals in aerosols: Ca, Mg, K, Na, Cl, Fe, … → treatment of asthma
 Inhalation aerosols:
- application of therapeutic aerosols for targeted dosing of aerosols into patient
lungs → aerosols as carrier of drug → treatment of allergy
- treatment of cystic fibrosis (disruption of chloride cellular transport): transport of
genetically modified virus to lungs
 Elimination of CO2 increase in atmosphere: transport sulphate aerosols into low
stratosphere (5% contribution of sulphur into aircraft fuel)
Literature:
1) W.C. Hinds: Aerosol Technology. Properties, Behaviour, and Measurement of Airborne
Particles (Wiley, 1982)
2) K. Willeke, P.A. Baron: Aerosol Measurement. Principles, Techniques, and Applications
(Nostrand Reinhold, 1993)
3) P.C. Reist: Aerosol Science and Technology (McGraw-Hill, 1993)
4) C.N. Davies: Aerosol Science (Academic Press, 1966)
5) I. Colbeck: Environmental Chemistry of Aerosols (Blackwell Publishing, 2008)
6) K.R. Spurný: Analytical Chemistry of Aerosols (CRC Pres, 1999)