*Khan Alam & **Hussain Majid

*Department of Geography and Geology,

University of Salzburg**Department of Bio-Physics

University of Salzburg

Measurement of aerosol size distribution, PM concentration and lung deposition calculation at different cities

of Pakistan

Part 1

Measurement of aerosol size distribution, PM concentration and

calculation at different cities of Pakistan

The part will cover

Introduction Instrumentation and Techniques Aerosol volume size distribution Aerosol mass size distribution Variability in particulate matter Conclusion

Introduction

• Pollution can be defined as an undesirable change in the physical, chemical or biological characteristics of the air, water or land that can affect health, survival or activities of humans or other organisms.

• Air pollution is a serious problem in many developing countries especially for those in the process of rapid industrialization, urbanization with increasing populations.

• Air pollution is a serious problem in Karachi, Lahore, Rawalpindi and Peshawar and many other cities of Pakistan, which are usually characterized with high ambient concentrations of particulate pollutants.

• Regular monitoring of ambient air quality is still not systematic in Pakistan. All the available information is based on random and short-term sampling conducted to assess the concentrations of various pollutants.

Aerosol????

Types Natural Aerosol

- Soil Dust- Soil Dust

- Sea Salt- Sea Salt

- Volcanic Dust- Volcanic Dust

- Oceanic Sulphates - Oceanic Sulphates Anthropogenic Aerosol

- Industrial Sulphates- Industrial Sulphates

- - Soot (Black carbon)Soot (Black carbon)

- Organic particles- Organic particles

•Aerosols are minute solid or liquid particles suspended in the atmosphere.

NO HC

CO

2

CO

SO2

Over 4000 species in gaseous, vapour and particle form are emitted from motor vehicle exhaust

Dust Smoke

Fume Mist

Clouds Pesticides

Effects of aerosols on climate

1. Direct effect

2. Indirect effect

3. Semi-direct effect

Direct radiative forcing by aerosols (Direct effect)

Solar radiation absorbed(Warming)

Solar radiation scattered to space (Cooling)

Absorbing aerosols

Scattering aerosols

e.g. Black carbon, mineral dust e.g. Sulphates, nitrates, organics

Most aerosols both absorb and scatter!

Indirect aerosol effect (I)

Few aerosolsLow droplet concentration

Less reflective cloud

Numerous aerosolsHigh droplet concentration

More reflective cloud(Cooler climate)

Indirect aerosol effect (II)

Smaller droplets Lower Precipitation rate

Clouds are longer lived and retain higher liquid water content

The semi-direct aerosol effect

Aerosols absorb solar

radiation

Evaporation of the cloud!

Absorbing aerosols in and around a cloud

• Absorbing aerosols

may reduce low cloud

cover

• This would warm the

climate as low clouds

scatter solar radiation

back to space.

Classification of Particle Sizes

• Generally, the sizes of aerosols are in the range from 0.001 to 100m

Fine particles < 2.5 m• ultra fine particles < 0.1m• submicrometer particles < 1 m

Coarse particles > 2.5m

Formation mechanisms of Aerosol particles

• Primary particles: emitted directly from sources– Example: nitric oxide and hydrocarbons

• Secondary particles: formed in the atmosphere by chemical interactions among primary aerosol particles and normal atmospheric constituents– Example: ozone, photochemical aerosol

Standards for particulate matter

• TSP

Total Suspended Particles

• PM10

Mass concentration of particles with aerodynamic diameter < 10 m

• PM2.5

Mass concentration of particles with aerodynamic diameter < 2.5 m

• PM2.5 often called fine particles

Sampling sites

• In order to analyze the aerosol concentration in term of size distribution and mass distribution mode

• We selected 4 big cities of Pakistan, namely Peshawar, Rawalpindi, Lahore and Karachi

• These cities are highly populated and industrialized.

Instrumentation • Grimm 1.109, Aerosol

spectrometer (Ainring, Germany) was used.

• It is portable optical particle counter, which uses light scattering technology for single particle counts.

• Flow rate 1.2 Litre/mint• The instrument collects sample

in 31 different size channels (0.25 to 32 μm)

• Operate in 4 mode (Environmental, occupational health, mass distribution and count distribution)

Method• The data used in this study was collected in count

distribution mode to obtain aerosol number concentration

• We convert the number concentration to mass concentration using mathematical expression

Where i is the channel number; dpi is the arithmetic diameter of upper and lower boundaries for channel i; M(dpi) is the mass concentration; N(dpi) is the no. concentration and CF is the correction factor.

)(6

)( 3pipiFpi dNdCdM

Cont. Method

• The PM10 and PM2.5 also calculated with the following • expression

Where f(dpi) is the fraction of PM10 or PM2.5 at dpi.

Results

Particle number and mass size distributions

)(6

)( 3pipiFpi dNdCdM

0

200

400

600

800

1000

Dp(um)

Mas

s co

nc

(ug

/m3 )

Morning

Afternoon

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

0.27

0.43

0.68

1.45

3.25

7.00

13.75

27.50

Dp(um)

Co

nc.

[dN

/dln

(dp

)] (

cou

nt/

litr

e)

Morning

Afternoon

Mass variation in different cities

0200400600800

10001200140016001800

Dp(um)

Mass C

on

cen

(ug

/m3 ) Karachi

LahorePeshaw arPindi

PM concentrations

0

100

200

300

400

500

600

700

Sample site

PM

10 (u

g/m

3 )

1 hour average24 hour average

Particulate matter concentration

Min.= minimum, Max.= maximum, Avg.= average

No Site TSP(µg/m3 ) PM10(µg/m3 ) PM2.5(µg/m3 ) PM1.0(µg/m3 )

Min. Max. Avg. Min. Max. Avg. Min Max. Avg. Min. Max. Avg.

1. Peshawar 3467 92399 21924 119 1751 618 38 337 189 28 281 129

2. Rawalpindi 6907 82461 27131 216 1037 489 70 300 159 45 261 121

3 Lahore 3482 23896 6759 146 284 204 64 98 76 47 60 52

4. Karachi Suparco 2372 11508 5941 126 399 270 51 289 151 32 216 114

Saddar 5522 38765 14438 284 860 462 115 320 197 79 267 155

Sea View

794 11223 2308 74 127 93 51 84 64 33 48 38

Chemical Analysis

Site Al Ca Cu Fe K Mg Na S Si Zn B Ba Cr Mn Ni P Sr Ti Zr

Peshawar 7385 34569 688 8650 2676 4044 5314 2650 3062 1454 20 48 556 199 561 365 110 205 75

Pindi 10766 74955 4984 15026 7437 5981 13249 4413 21809 5032 155 152 787 375 1475

958 296 580 93

Lahore 9521 20675 657 8244 2866 3233 5531 5420 3323 1637 50 100 218 205 360 414 72 207 32

Karachi Suparco 4188 13442 273 3390 1211 1241 2384 2683 1486 757 7 27 156 96 230 133 47 75 11

Saddar 19916 74385 1146 16867 8574 7299 17839 9045 7547 2834 78 180 501 471 545 1557 243 527 42

Sea View 5571 17954 938 7344 1995 2589 11252 5469 1022 1638 21 79 616 162 474 248 58 103 23

WHO AIR QUALITY GUIDELINES 2000

Compound Guideline [ug m-3] Averaging Time

Carbon monoxide 100 000 15 min 60 000 30 min 30 000 1 hour 10 000 8 hours

Nitrogen dioxide 200 1 hour

40 1 year

Ozone 120 8 hours

Sulphur dioxide 500 10 min

125 24 hours

50 1 year

LeadLead 0.5 0.5 1 year1 year

2006

100

20

EFFECTS OF AIRBORNE POLLUTANTS

• Effects on atmospheric properties– Visibility reduction– Fog formation and precipitation– Solar radiation reduction– Temperature and wind distribution alteration

• Effects on materials• Effects on vegetation • Effects on health

Health effects of airborne pollutants

Allergy and other effects on the immune system

Cancer and effects on reproduction Respiratory effects Irritative effects on skin and mucous

membranes of eyes, nose and throat Sensory effects on nervous system Effects on cardiovascular system

Health effects of selected contaminants

• Carbon monoxide: ranging from fatigue to death

• Nitrogen oxides: trigger of asthma attacks and long term effects on respiratory system

• Lead: mental retardation• Ozone: eye irritation, damage to sensitive

tissue and exacerbates asthma• Radon: increased risk of lung cancer

Conclusion The current study analyzed findings on TSP, PM10, PM2.5 and

PM1 loading in the ambient air of four major cities in Pakistan

(Karachi, Lahore, Rawalpindi and Peshawar). Data were collected at three points in Karachi, one point each in

Lahore, Rawalpindi, and Peshawar. Highest average mass concentrations were observed all the cities

investigated. Highest mean TSP, PM10,PM2.5 and PM1 values were recorded

for Peshawar followed by Rawalpindi, Karachi and Lahore. The current air pollution problems in Pakistan are challenging for

local and state authorities to take timely action and develop a control strategy that is enforced and implemented.

Part 2

Particle lung deposition Particle lung deposition calculations and its importancecalculations and its importance

The part will cover

Why deposition calculation is important Human lung structure Lung deposition mechanisms Particle clearance from the lung Stochastic lung deposition model Lung deposition calculations Conclusions

Why is this important?

• Evaluating efficiency of dose deliverance i.e. how much and how long particles will remain in the lung.

• Pulmonary drug delivery

• Assessing toxic effects of airborne pollutant depositing in certain region of the lung.

• Estimation for the location of probable induced cancer due to exposure in radiation environment.

Tracheaobronchial (TB)

Trachea direct air into the lung Bronchial tree is the first part of the lung. This part directs air in the lung Each branch in the tree split into 2 part

Bronchial tree can be divide into 5 segment that use to characterize the lung airway

Parent Branch

Major daughter

Minor daughter

Bifurcation

Head airway (HA)

Air and aerosol enter from here and used to remove dust and other particles from entering the respiratory Humidify the air before entering the lung Separate out food to digestive system

Trachea

Bronchial Tree

Mouth

Pharynx

Larynx

NoseHuman lung structure

Alveolar or Pulmonary (AV)

Alveoli are located at the end of the bronchial tree

Gas exchange occur at the Alveoli

If particle deposit in this region it can directly enter the blood stream

Alveoli

alveoli Alveolar duct Alveolar entrance rings

100µm

100µm

Airway Generation Lung is made up of airway call

generation. Trachea is generation 0 (G0), this is a straight duct with ring structure

The upper bronchial consist of generations 1 to 16. This is a series of branching “smooth” tube. High flow in this region with large airway.

Alveoli start appearing at generation 17. Airways are much smaller and the wall with alveoli is no longer smooth. This is a region of low flow and high residence time

Modelling and Simulation of Particle Deposition in the Human Lung

Deposition Mechanisms Involved

Major:

Minor:

DiffusionSedimentationImpaction

InterceptionElectrostatic

Naso-pharyngeal: impaction, sedimentation, electrostatic (particles > 1 μm)Tracheo-bronchial: impaction, sedimentation, diffusion (particles < 1 μm)Pulmonary:sedimentation, diffusion (particles < 0.1 μm)

Diffusion

Cause by Brownian motion

Diffusion is the deposition mechanism for small particles. Diffusion depends increases with decreasing particle size and flow rate. More deposition occurs in the alveoli region because longer residence time and smaller airway.

Sedimentation

• When gravitational force act on the particle

• Particles will settle to the lower surface of the airway. This occur more in the lower generation where the velocity is much lower and the airway is smaller

• Lung airways have different orientation so deposition of particle will be different depending on the direction of the particle flow and direction of gravitational force

ForceForce

Impaction

Particle cannot follow the trajectory due to its inertia and hit the wall called impaction. Impaction increases with particle size and flow rate. This type of deposition occur through out the lung. This is important, especially in the head airway where most of the large particles are screened out

Impaction occurs mostly in the upper generation airways due to high velocity

Factors that Effect Deposition

1. Aerosol property

2. Air Flow property

3. Respiratory tract

Size distribution (MMD, AMD. Etc)ConcentrationParticle hygroscopicityGas particle interactionChemical reactionParticle surface charge

Lung structure and morphologyModel uses: Weibel, Raabe, and Horsfield

Lung capacityBreathing frequencyTidal Volume

Particle Clearance

• Getting rid of deposited particles from the lung is called clearance

• The muco-ciliary escalator operates in the tracheobronchial region for clearance predominantly up to generation 12 and fading out at generation 16

Particle Clearance mechanisms:The Naso-pharyngeal Compartment:• mucociliary clearance (transport back to nasopharynx )• mechanical clearance (sneezing, coughing, swallowing)• absorption into circulation (soluble particles).The Tracheo-bronchial Compartment:• mucociliary clearance (transport to oropharynx)• endocytosis into peribronchial region (insoluble particles)• absorption into circulation (soluble particles)The Pulmonary Compartment:• alveolar macrophage mediated clearance• endocytosis by lung epithelial cells into interstitum• absorption into circulation (soluble particles)

Stochastic Lung Model

• Deposition fraction and distribution within airways generations are found by stochastice lung mod

• Particle inhalled follow random path in the lung– Random selection of actual path out of millions of possible pathway by

tracing histories of large number of smiulated particles

• The model uses asymmetric nature of branching pattern of the lung. – Variability of lenghts and diameter of airways are described by log-

normal frequency distribution

• Analytical (deterministic) formulas are used for computing deposition by diffusion, sedimentation and impaction

• Monte Carlo process continues even after depsition of particle within airway by decreasing statistical weights of particles

Deposition patterns of 0.25-10 µm particles under light exercise breathing condition (VT = 500 mL, t = 4s) for three different days at Karachi, Sadar near a road crossing

Deposition is normalized to the number of particles

entering the trachea.

Particle deposition in lung

Deposition patterns of 0.25-10 µm particles under light exercise breathing condition (VT = 500 mL, t = 4s) for two different days at Rawalpindi, near a road crossing

Deposition is normalized to the number of particles

entering the trachea.

Particle deposition in lung (cont..)

Conclusions• Estimation of aerosle deposition patteren in the lung play

key role for dose assesment.• Intersubject variability of lung morphometry, breathing

patterens, local inhomogeneties of particle deposition and muco-ciliary clearance are the critical paramenters in lung dosimetry for the inhaled particles.

• Calculation of aerosol deposition fraction can help to find the particulate mass enhaled by the workers in a particular environment and its ultimate effects on their health.