Seasonal variation of volatile polyaromatic hydrocarbons (pa hs

Seasonal Variation of Volatile
Polyaromatic Hydrocarbons
(PAHs) Released from Different
Sources

Outline:
 Introduction
 Methodology
 Results & Discussion
 Conclusion

1.1. What are PAHs
 Polycyclic aromatic hydrocarbons (PAHs) a very large group of
several hundered ubiquitous persistent semi-volatile organic
compounds (SVOCs).
 They are comprised of two or more fused aromatic (benzene)
rings arranged in various configurations generally exist as complex
mixtures rather than single compounds.
 Some PAHs are manufactured. These pure PAHs usually exist as
colorless, white, or pale yellow-green solids.
 PAHs are found in coal tar, crude oil, creosote, and roofing tar, but a
few are used in medicines or to make dyes, plastics, and pesticides.

Naphthalene (NAP) Acenaphthylene (ACY) Acenaphthene (ACE) Fluorene (FLO)
Phenanthrene (PHE) Anthracene (ANT) Fluoranthene (FLA) Pyrene (PYR)
1.1. What are PAHs (16 USEPA priority PAHs)

Chrysene (CHR) Benz(a)anthracene (BaA)
Benzo(k)fluoranthene (BkF)Benzo(b)fluoranthene (BbF)

Benzo(a)pyrene (BaP) Indeno(l,2,3-cd)pyrene (IcdP)
Dibenz(a,h)anthracene (DahA) Benzo(g,h,i)perylene (BghiP)

 The properties and environmental fate of PAHs are dependent on the number of rings and molecular
weight.
− The Light Molecular Weight (LMW) PAHs (consist of two to three fused benzene rings) are:
 Less persistent, Highly volatile, Slightly soluble in water
 less carcinogenic but are toxic to fish and other marine organisms since they accumulate in their
tissues (i.e. bioaccumulation) and are able to move up the food chain (biomagnification) and adversely
affect humans upon consumption.
 Undergo photo-degradation (i.e. photo-chemically decomposed) under strong ultraviolet light or
sunlight and thus are able to react with other pollutants, such as sulfur dioxide, nitrogen oxides and
ozone yielding sulfonic acids, nitro- and dinitro-PAHs, and diones, respectively of which toxicity may
be more signiﬁcant.
 Found most exclusively in the gas phase.
1.2. Physical and chemical characteristics of PAHs

− The High Molecular Weight (HMW) PAHs (have four or more fused benzene rings) are:
 Persistent, less volatile, more resistant to oxidation
 More insoluble when alkyl substituent groups are attached to one or more rings.
 The substitution of an alkyl or chlorine group to PAHs make them more reactive and
potentially more toxic than the parent PAHs.
 Included in a class of persistent organic pollutants (POPs) where their persistence in the
environment is linked to their low water solubility and high thermal and chemical
stability.
 Emitted in the particulate phase (totally adsorbed onto airborne particles)

 Gas to Particle Distribution of PAHs in the Atmosphere
− the vapor pressure of a PAH molecule determines to a large extent, the phase (particulate or
vapor) in which the chemical will be found.
− It was showed that compounds with vapor pressures above 1 × 10-5 kPa should occur almost
entirely in the gas phase, whereas compounds with vapor pressures less than 1×10-9 exist
predominantly in the particulate phase. Any compound with a vapor pressure between these
approximate limits would be expected to occur in both the vapor and particle phase.
− The ambient temperature will also effect on adsorption of PAHs onto particulate phase.
− The particulate form of PAHs are initially in the gaseous phase at high combustion temperature,
however when the temperature decreases, gaseous phase PAHs adsorb or deposit on fly ash
particles. The smaller the particle size, the greater the surface area for the adsorption of PAHs.

Gas to particulate partitioning data
PAH
Molecular Weight
(g/mole)
Vapor Pressure
(kPa)
% of total found in
particulate phase
Naphthalene 128.18 1.1×10-2 2%
Fluorene 166.23 8.7×10-5 5%
Acenaphtene 154.20 2.1×10-3 4%
Acenaphtylene 152.20 3.9×10-3 11%
Phenanthrene 178.24 2.3×10-5 9%
Anthracene 178.24 36×10-6 8%
Fluoroanthene 202.26 6.5×10-7 16%
Pyrene 202.26 3.1×10-6 55%
Benzo[a]anthracene 228.30 1.5×10-8 78%
Chrysene 228.30 5.7×10-10 89%
Benzo[b]ﬂuoroanthene 252.32 6.7×10-8 91%
Benzo[a]pyrene 252.32 7.3×10-10 89%
Benzo(ghi)perylene 276.34 1.3×10-11 83%
Indeno[1,2,3-cd]pyrene 276.34 - 100%

1.3. Formation of PAHs
 PAHs can be formed during any incomplete combustion or high
temperature pyrolytic process involving fossil fuels like coal, oil and gas,
garbage, or other organic materials containing C and H like tobacco.
 PAH may be synthesized from saturated hydrocarbons under oxygen-
deficient conditions.

 The mechanism of formation of PAHs in any fuel combustion system can be
classified into two processes, pyrolysis and pyrosynthesis.
 Pyrolysis (at ~ 500-800°C) of fuel hydrocarbons involves the production of the
smaller and unstable fragments from an organic compound upon heating.
 Fragments are the highly reactive free radicals with a very short average life time.
 The C2 and C1 fragments, as well as higher radicals, recombine rapidly in the
reducing atmosphere to form partially condensed aromatic molecules which
then lead to form more thermal stable PAHs and this process is called
pyrosynthesis
1.3. Formation of PAHs

1.4. Sources of PAHs
 Natural Sources of PAHs:
Biosynthesis by bacteria and aquatic microorganisms, volcanic eruptions,
forest fires and low to moderate temperature diagenesis of sedimentary organic material
to form fossil fuel.
 The anthropogenic sources of PAHs:
pyrolytic processes especially the incomplete combustion of organic material (i.e. the temperature of
combustion is low and there is no access of air) in the coal, petroleum as well as the metal smelting
industries. They also include urban runoffs, vehicle traffic, tobacco smoking and deterioration of asphalt
pavement surfaces and car tyres. Other industrial activities like petroleum production and spillage,
cement, bitumen and asphalt production, municipal and medical solid waste incineration, wood
preservation products, commercial heating and power production stations through combustion of natural
gas.

Source of emission Estimated Emission Levels
Coal Coking PAHs: 15.2 mg/kg coal charged (general for most countries)
Coal Conversion PAHs: 1500 µg/g burnt coal (general for most countries)
Petroleum Refining PAHs:0.1tpa (Canada), 11 tpa (Germany)
Power plants using fossil fuel
PAHs: 0.15 tpa (Germany), PAHs: 0.1 tpa Norway , PAHs: 11 tpa
Canada
Incinerators PAHs: 50 tpa (USA), PAHs: 2.4 tpa (Canada)
Aluminium Production PAHs:1000 tpa (USA) , 930 tpa (Canada)
Iron & steel production PAHs: 34 tpa (Norway) , PAHs: 19 tpa (Canada)
Foundries PAHs: 1.3 tpa (Netherlands)
Sinter Process PAHs:1.3 tpa (Netherlands)
Phosphorous Production PAHs: 0.2 tpa (Netherlands)
PAH emission from industrial processes for some countries
* (tpa: tones per annum)

Flow chart showing short and long term health effects of exposure to PAHs
1.5. Toxicity and Health Impact of PAHs

 PAH Carcinogenic Potencies:
− Benzo[a]pyrene (BaP) has the highest carcinogenic potency with long-
term persistency in the environment.
− Both the World Health Organization (WHO) and the UK Expert Panel on
Air Quality Standards (EPAQS) and others have considered (BaP) as a
marker or indicator of the carcinogenic potency of the polycyclic
aromatic hydrocarbons (PAH) mixture.

PAH Carcinogenic Potency
Naphthalene NA
Acenaphthylene NA
Acenapthene NA
Fluorene NA
Phenanthrene 3
Anthracene 3
Fluoranthene 3
Pyrene 3
Benz[a]anthracene 3
Chrysene 3/B2
Benzo[b]fluoranthene 2B/B2
Benzo[k]fluoranthene 2B
Benzo[a]pyrene 2A/B2
Indeno[1,2,3-cd]pyrene 2B/B2
Dibenz[a,h]anthracene 2A/B2
Benzo[ghi]perylene 3
− NA: No available evidence
for human carcinogenicity;
− 2A/B2: Probably
carcinogenic to
humans/Probable human
carcinogen;
− 2B: Possibly carcinogenic
to humans;
− 3: Not classified as to
human carcinogen.
PAHs carcinogenic potency classification of the sixteen USEPA priority
PAH pollutants

How Are We Exposed?
 Inhalation of air releases
 Contact with contaminated soil
 Ingestion of contaminated
water or cow’s milk

 Contaminated Foods
− Charred or smoked meat and fish
− Cereals
− Flour
− Vegetables
− Fruits
− Marine life in contaminated waters
− Exposed indoors mostly through
second hand smoke
How Are We Exposed?

PAH4 is the sum of
benzo[a]pyrene,
benz[a]anthracene,
benzo[b]fluoranthene
and chrysene
Total dietary exposure to (BaP) and PAH4 (ng/day) for average European
consumers Country BaP (ng/day) PAH4 (ng/day)
Belgium
Denmark
Finland
France
Germany
Hungary
Iceland
Ireland
Italy
Netherlands
Norway
Slovakia
Sweden
United Kingdom
232
223
185
245
255
231
205
238
255
239
252
244
230
188
1158
1135
978
1220
1258
1168
1039
1188
1332
1197
1449
1158
1168
936
Median EU 235 1168

Consumer exposure to Benzo(a)pyrene (BaP) and PAH4 for
different food categories
Category
BaP
(ng/day)
PAH4
(ng/day)
Cereals and cereals products
Sugar and sugar products, including chocolate
Fats (vegetable and animal)
Vegetable, nuts and pulses
Fruits
Coffee, tea, cocoa (expressed liquid)
Alcoholic beverages
Meat and meta products and substitutes
Seafood and seafood products
Fish and fisheries products
Cheese
67
5
26
50
5
21
4
42
36
21
6
257
25
177
221
75
106
25
195
289
170
20

The federal government recommendations to protect human health:
 The Occupational Safety and Health Administration (OSHA) has set a limit of 0.2
milligrams of PAHs per cubic meter of air (0.2 mg/m3).
 The OSHA Permissible Exposure Limit (PEL) for mineral oil mist that contains PAHs is
5 mg/m3 averaged over an 8-hour exposure period.
 The National Institute for Occupational Safety and Health (NIOSH) recommends that
the average workplace air levels for coal tar products not exceed 0.1 mg/m3 for a 10-
hour workday, within a 40-hour workweek.

Standards and regulation covering Polycyclic Aromatic Hydrocarbons
(PAHs) in environmental media
Agency Medium Level Comments References
American Conference of
Governmental Industrial
Hygienists
Air 0.2 mg m−3 Threshold limit value (TLV) for benzene-
soluble coal tar pitch fraction
ACGIH (2005)
National Institute for
Occupational Safety and Health
Administration
Air
0.1 mg m−3 Recommended exposure limit (REL) for coal
tar pitch volatile agents
NIOSH (2010)
0.2 mg m−3 Permissible exposure limit (PEL) for benzene
soluble fraction of coal tar volatiles
Canadian Council of Ministers of
the Environment
Soil 0.6 mg m−3 Total potency equivalents for soil contaminated
with coal tar or creosote mixtures
CCME (2010)
U.S. Environmental Protection
Agency
Water
0.0001 mg L−3 Maximum contaminant level (MCL) for
benz(a)anthracene
USEPA (2000)
0.0002 mg L−3
MCL for benzo(a)pyrene,
benzo(b)fluoranthene, benzo(k)fluoranthene,
chrysene
0.0003 mg L−3 MCL for dibenz(a,h)anthracene
0.0004 mg L−3 MCL for indenol(1,2,3-c,d)pyrene
0.0002 mg L−3
MCL for benzo(a)pyrene,
benzo(b)fluoranthene, benzo(k)fluoranthene,
chrysene

1.6. Objectives
1. Measuring the concentration levels of ambient PAHs in gaseous and particulate
phases.
2. Study the spatial and temporal variations of ambient PAH levels and their
possible relationships with meteorological parameters.
3. Identify and allocate possible sources of PAHs using diagnostic ratio.
4. Assess the health risk of PAHs in the atmosphere of this city.

2.1. Summary of method
 The selected sites for sampling will be located and defined with their
coordinate parameters on the sampling site map.
 The meteorological parameters during the sampling time, including
ambient temperature, relative humidity, wind speed/direction, and
precipitation, were recorded.
 The applied methodology in this study is originated from US-EPA Method
TO-13A (Compendium Method for determination of PAHs in ambient air).

 The method is based on using a High-Volume Air Sampler for collection of
PAHs from ambient air onto the sampling module that consists of particle
filter and high volume collection tube containing adsorbent media (i.e.
sorbent cartridge).
 This method is applicable for collecting and trapping gaseous as well as
particulate phases of PAHs.
 After sampling, PAHs accumulated on filters and sorbent materials are
returned to the laboratory for analysis.

 The filter and cartridge are combined for PAHs extraction using Soxhlet
system containing mixtures of organic solvents such as mixtures of n-
hexane, diethylether and dichloromethane.
 The extracted PAHs solutions were concentrated by rotary evaporator
system because PAHs are not as easily detected at low concentrations.
 For qualitative and quantitative analysis, the extracted PAHs is analyzed
using Gas Chromatography-Mass Spectrometry (GC-MS). The minimum
detection limits for PAHs using this method are in the range of 1 nanogram
to 10 picogram

2.2. Sampling Site Description
 The study area is located in the south of El Tabbin city with geographical coordinates of
29°44'59.92" N to 29°47'35.12" N latitude and 31°17'35.45" E to 31°20'12.13" E
longitude, and total area of 25 km2.
 The study area represents a large urban industrialized area in El Tabbin city and even in
Helwan Governorate where it has the largest factories for the heavy industries such as
“Egyptian Iron and Steel company”, “National Cement company”, “Helwan Cement
company”, “Nasr Company for Coke and Basic Chemicals”, “Egyptian company for
Metallurgical Industries” and “Helwan Fertilizers Company” as well as many bricks
plants. Furthermore, it is bordered by two heavy trafficked highways, Nile Cornish and Al
Tabbin Autostrad.
 The population in the residential area is about 100,000 according to the population count
in 2014.

 Four sampling sites were chosen:
1. Tabbin Institute for Metallurgical Studies (TIMS):
− This site is considered the center between other sampling sites as it is in vicinity and downwind of
most of industrial plants in study area such as:
(i) cement plants e.g. National Cement Company (NCC) and Italcementi Group,
(ii) foundry bricks
(iii) power plant
(iv) Egyptian iron & steel plant
− The fuel type used for these plants are raw coal and/or heavy oil.
− This site is also close to streets characterized by heavy traffic such as Al Masanea Road and El Tabbin
Autostrad and facing the main road which leads to police station, car licensing department.

2. The residential area (RA):
− As the traffic density inside this area is moderate but it is close to Nile Courniche
highway that is characterized by high motor-vehicle traffic density.
− The presence of a numerous industrial activities near to this area produce critical
situations for the urban environment.
3. Coke Factory (CK):
Sampling at the border of Al Nasr Coke factory where the sampling process was performed
above the administrative building near the south borders of the plant.
4. Arab Abu Said area (AAS):
Sampling site in vicinity to the large number of bricks plants (~ 250 plants used heavy oil as
fuel) and El Tabbin Autostrad high way.

Description of sampling sites and their GPS coordinates
Site Location Mnemonic Latitude (N) Longitude (E) Site Activity Description
Tabbin Institute TIMS 29°46'54.57" 31°18'47.45" Traffic and Industrial area
Residential Area RA 29°46'37.85" 31°17'41.11" Residential and Traffic area
Coke Factory CK 29°45'54.70" 31°18'52.44" Industrial area
Arab Abu Said AAS 29°45'46.62" 31°21'36.93" Traffic and Industrial area

Map shows the location of four sampling sites in the south of El Tabbin area

Map of the study area where the red spots indicate sampling sites and the
yellow lines indicate national ways

2.3. Air Sampling Methodology
Air Sampling System:
 The High-Volume Air Sampler (Andersen Instruments Inc., 500 Technology Ct.,
Smyrna, GA) system is used to acquire sufficient sample for analysis.
 This system is capable of pulling ambient air through the filter/sorbent cartridge at a
flow rate of approximately 225 L/min (i.e. 0.225 m3/min) to obtain a total sample
volume of greater than 300 m3 over a 24-hour period.
 The sampling system is equipped with a valve to control sample flow rate where it is
designed to operate at a standardized volumetric flow rate of 8 ft3/min (0.225
m3/min), with a maximum acceptable flow rate fluctuation range of ± 10% of this
value (i.e. between 0.202 to 0.248 m3 /min).

Air Sampling System:
 The assembly of venturi and Magnehelic gauge is used for monitoring the airflow
through the sampling system.
 By fully open the flow control valve and adjusting the voltage variator, the sample flow
rate will correspond to the desired flow rate (typically 0.225 m3 /min) which will be
indicated on the Magnehelic gauge reading of approximately 70 inches H2O.
 Sampling times are restricted to 25 h to minimize degradation and loss (volatilization)
of collected PAHs.

Typical high volume air sampler for PAHs collection with its internal
components

Sampling collection materials
 The applied method in this study provides efficient collection of most PAHs
involving two member rings or higher either in a particulate phase or in a
gaseous phase through utilization of quartz fiber filter with adsorbent
cartridge consists of both PUF and XAD-2® resin as a sorbent media where
XAD-2® is intermediated between two layers of polyurethane foam (PUF) in
sandwiching configuration in order to minimize breakthrough of highly
volatile PAHs.

 Particulate Filter:
The used filter is binder-less high purity Quartz (SiO2) Microfiber Filter that can be used for air
sampling in acidic gases, stacks flues and aerosols particularly at high temperatures up to 500°C,
Grade QM-A with Diameter: 10.2 cm, Pore Size: 2.2µm, Whatman™, Maidstone, UK.
Quartz Fiber Filter used for
collection of Particulate PAHs

 Sorbent Cartridge Assembly (Adsorbent tube):
− The sorbent cartridge is Large PUF/XAD Cartridge (65mm OD x 125mm length, 25mm
thick PUF/200g XAD-2/50mm PUF) provided from Restek Corporation, Bellefonte, PA, U.S.,
− This type of cartridge is rigorously cleaned and baked prior for being supplied. and tested
by capillary GC/flame ionization detector from side of the supplier (i.e. ready to be used
directly for sampling collection).
− The adsorbent media is ultra-clean resin of a combination of Styrene/divinylbenzene
(SDVB) resin equivalent to XAD-2® resin that is sandwiched between layers of
polyurethane foam (PUF).

− The Polyurethane foam (PUF) plugs are 65mm diameter cylindrical plugs with density of
0.22 g/cm3 from polyether type used for furniture upholstery, pillows, and mattresses.
− The large glass sampling cartridge or holder is fitted with double stainless steel screens
(mesh size 200/200) for supporting small diameter PUF plug (50 mm diameter).
− 200 g of XAD-2® resin is placed on the top of small diameter PUF plug.
− The large PUF plug (25 mm thick by 65 mm diameter) will be fitted with slight
compression, in the glass cartridge, on the top of XAD-2® resin layer.
− The commercial sampling cartridge is wrapped with a cleaned aluminum foil cap with the
Teflon end caps and placed in a cleaned labeled aluminum container (Aluminium Canister)
and sealed with Teflon tape.
 Sorbent Cartridge Assembly (Adsorbent tube):

The main constituents of the sampling sorbent cartridge

Typical Assembled Sampling Module for holding particle filter and
absorbent cartridge (PUF/XAD)

 Sampling collection Procedure
− The high volume air sampler is located in an unobstructed area from any obstacle to air
flow where it is usually placed on a rooftop of buildings at least 5 meters above the ground.
− With the sample cartridge removed from the sampling head and the flow control valve fully
open, the pump is turned on and allowed to warm-up for approximately 5 minutes.
− Attach a "dummy" sampling cartridge loaded with the exact same type of filter and sorbent
media to be used for sample collection.
− Turn the sampler on and adjust the flow control valve to the desired flow as indicated by the
Magnehelic gauge reading (i.e. 70 inches H2O).
− Once the flow is properly adjusted, take extreme care not to inadvertently alter its setting.

High Volume Air Sampling locations for each sampling site (a) Residential
site, (b) Arab Abu Said site, (c) Coke factory site and (d) Al Tabbin Institute
site

− Turn the sampler off and remove the "dummy" module. The sampler is now ready for field
use. Check the zero reading of the sampler Magnehelic gauge. Attach the loaded sampler
cartridge assembly to the sampler.
− Detach the lower chamber of the cleaned sample head and remove a clean glass sorbent
module (i.e. cartridge assembly) from its shipping container.
− Insert the glass module into the lower chamber and tightly reattach the lower chambers to
the module.
− Place a clean conditioned fiber filter at the top the filter holder and secure in place by
clamping the filter holder ring over the filter.
− Place the aluminum protective cover on top of the cartridge head.

− After the sampling module has been assembled, activate the elapsed time meter and
record the start time. Turn the sampler on and the Magnehelic reading is recorded every 6
hours during the sampling period. A total sample volume is approximately 340 m3 with an
average sampling period of 25 h.
− At the end of the desired sampling period, turn the power off. Carefully remove the
sampling head containing the filter and sorbent cartridge. Place the protective "plate" over
the filter to protect the cartridge during transport to a clean recovery area. Also, place a
piece of aluminum foil around the bottom of the sampler cartridge assembly.
− When the sampler cartridge assembly is transported to a clean recovery area, remove the
sorbent glass cartridge from the lower module chamber and lay it on the retained
aluminum foil in which the sample was originally wrapped.

− After that, carefully the quartz fiber filter is removed from the upper chamber. The
filter is folded in half twice (sample side inward) and placed in the glass cartridge at
the top of PUF.
− The combined samples (i.e. filter/sorbent cartridge) are wrapped in the original
hexane-rinsed aluminum foil, and placed in their original aluminum shipping
container to prevent possibly photo-decomposition. The containers is stored under
blue ice or dry ice to refrigerate samples under 4 °C until transported to the laboratory
for extraction and analysis.
− Chain-of-custody for sampling is maintained for all samples.
− All samples are extracted within less than a week (Approx. 4 days) after sampling
where they are stored frozen (at -20°C) until required for extraction.

− Four High-Volume Air Samplers were used, one at each site. Based on one year round
monitoring, the sampling campaign was conducted over 10 months from January 20,
2014 to November 04, 2014 in order to cover the four seasons of year.
− A total of 48 samples were intermittently collected during this period where 3 samples
were taken in 3 consecutive weeks (i.e. samples were collected every 7 days from 10:00
am to 10:00 am on the next day) for each site and for each represented season in order
to include high-temperature period sampling (i.e. heating season sampling starting from
middle of June to end of October) and low-temperature period sampling (i.e. non-heating
season sampling starting from middle of January to middle of April).

Sampling parameters during sampling days for each sampling site
Sampling Date Average Temperature (°C) Relative Humidity (%)
Wind Speed
(km/h)
Predominant wind
direction
20 Jan. 2014 18 43 5 N-NW
27 Jan. 2014 15 42 20 N-NW
3 Feb. 2014 16 67 12 NW
7 Apr. 2014 22 47 13 W
14 Apr. 2014 22 38 15 N
21 Apr. 2014 20 54 18 NW
20 Jun. 2014 31 37 13 N-NW
27 Jun. 2014 31 38 14 W
4 Jul. 2014 29 57 13 NW
21 Oct. 2014 22 44 4 N-NW

Wind rose for Al Tabbin sampling area

2.4. Sample Extraction, Concentration, and Cleanup
 The applied method calls for extraction of the filter and sorbent
together to permit accurate measurement of total PAH air
concentrations, to reach required detection limits, to minimize cost
and to prevent misinterpretation of the data

 Soxhlet extraction is performed with 700 ml of 20:80 dichloromethane
(DCM): Petroleum Ether (PE) solution that reflux for 24 hours at a rate of
3 cycles per hour.
 The extract from the Soxhlet extraction is dried by passing it though a
drying column containing about 10 grams of anhydrous sodium sulfate.
 The extracts were concentrated by rotary evaporation to approximately 5
mL.
 Solvent was exchanged for hexane by adding 15 mL hexane and
evaporating the mixture again to 5 mL, and finally, the extracts were
reduced to 2 mL by blowing a stream of ultra-pure nitrogen gas above the
extract.

 The purification of extracts was carried out with (1 cm-i.d. x 15-cm-
hieght) 2:1 silica–alumina glass chromatography column containing
anhydrous sodium sulfate.
2 mL of the sample extract is transferred to the column, and washed on
with 2 mL of n-hexane to complete the transfer.
At the rate of 2 mL/minute, PAHs were eluted with a mixture of 100 mL of
DCM and hexane (1:1 v/v).
After that, the column is further eluted with 25 mL of diethyl ether.
The solution was rotary-evaporated and concentrated to 5 mL. Solvent-
exchanged into hexane by adding 15 mL hexane and evaporating and
reducing the mixture again to 5 mL and the ﬁnal sample volume was
reduced to 1 mL with hexane under a gentle stream of pure nitrogen.

2.5. Sample Analysis using Gas Chromatography with
Mass Spectrometry Detection (GC/MS)

3.1. Atmospheric mass concentrations of PAHs
 The total amounts of analyzed PAHs (i.e. Total ∑16 PAHs) in the
area under study varied from 76.48 ± 19.44 µg/m3 in RA site to
26995.86 ± 2835.91 µg/m3 in the CK site with a mean
concentration of 7085.08 ± 773.98 µg/m3
 The total ∑16 PAHs concentrations as well as the average
concentrations of ∑16 PAHs over the seasonal sampling period in
the different functional zones of the study area can be ordered as
follow:
CK site > TIMS site > AAS site > RA site

Total PAHs Concentrations (Total ∑16 PAHs) over the
seasonal sampling period for the different sampling sites:
26995.86
901.34 366.64 76.48
CK TIMS AAS RA
0
7000
14000
21000
28000
35000
TotalPAHsConcentrations(g/m
3
)
Sampling Site

Total of the individual PAH concentrations (∑i PAHs)
over the seasonal sampling period for each sampling site:
NAP
ACE
ACY
FLO
PHE
ANT
FLA
PYR
BaA
CHR
BbF
BkF
BaP
IcdP
DBahA
BghiP
0 5 10 15
(RA site)
PAH Concentration (g/m3
)
PAHs
NAP
ACE
ACY
FLO
PHE
ANT
FLA
PYR
BaA
CHR
BbF
BkF
BaP
IcdP
DBahA
BghiP
0 20 40 60 80
(AAS site)
)
PAHs
NAP
ACE
ACY
FLO
PHE
ANT
FLA
PYR
BaA
CHR
BbF
BkF
BaP
IcdP
DBahA
BghiP
0 50 100 150 200
(TIMS site)
)
PAHs
NAP
ACE
ACY
FLO
PHE
ANT
FLA
PYR
BaA
CHR
BbF
BkF
BaP
IcdP
DBahA
BghiP
0 1000 2000 3000 4000 5000 6000
)
PAHs
(CK site)

 The total concentrations of COMPAHs (the combustion derived
PAHs including FLA, PYR, CHR, BbF, BkF, BaA, BaP, IcdP, BghiP)
for the different sampling sites are ranged from 63.24 ± 17.35
µg/m3 to 17546.97 ± 1848.55 µg/m3 accounting for 65 % − 83
% of total PAHs with the highest mass percentages occurred in
RA.
 The calculated COMPAH/ΣPAH ratio for different sampling sites
are 0.65, 0.61, 0.75 and 0.83 for CK, TIMS, AAS and RA,
respectively.

 The total mass concentrations of the carcinogenic PAHs (∑C-PAHs
including BaA, CHR, BbF, BkF, BaP, IcdP, DBahA) over the seasonal
sampling period were in the range of 32 ± 7 µg/m3 in RA samples
to 9213 ± 1279 µg/m3 in CK samples with the average
concentrations of 2429 ± 344 µg/m3, accounting for 34 – 42 % of
total PAHs.

 The content of BaP (the most carcinogenic PAH) over the
seasonal sampling period was varied from 5.7 ± 1.4 µg/m3 in
RA samples to 1657 ± 252 µg/m3 in CK samples, hold a mean
value of 430 ± 66 µg/m3, accounting for ~ 4% in TIMS to ~ 8%
in RA of total PAHs concentrations.

 PAHs can be classiﬁed into:
- Lower molecular weight (LMW) containing 2 (Nap) and 3-ring
PAHs (ACE, ACY, FLO, PHE and ANT)
- Middle molecular weight (MMW) containing 4-ring PAHs
(FLA, PYR, BaA and CHR).
- Higher molecular weight PAHs (HMW) containing 5 (BbF, BkF
and BaP) and 6-ring (DBahA, IcdP and BghiP ) PAHs.

PAH-Homologue concentrations of samples from
different sampling sites:
RA AAS TIMS CK
0
10
20
30
40
50
60
70
80
90
100
LMW-PAH
MMW-PAH
PAH-homologueconcentration(%)
Sampling site
6-Ring
5-Ring
4-Ring
3-Ring
2-Ring
HMW-PAH

Correlation among total PAHs and LMW-PAHs, MMW-
PAHs, HMW-PAHs, C-PAHs and COMPAHs
0 5000 10000 15000 20000 25000 30000
0
3000
6000
9000
12000
15000
18000
y = 0.64 x + 14.95 (r = 0.998)
y = 0.35 x + 5.83 (r = 0.999)
y = 0.27 x + 10.04 (r = 0.978)
y = 0.36 x + 6.48 (r = 0.998)
LMW-PAHs
MMW-PAHs
HMW-PAHs
C-PAHs
COMPAHs
MassConcentrations(g/m3
)
(g/m
3
)
y = 0.33 x -12.70 (r = 0.990)
16
PAHsTotal

Comparison of mean PAHs concentrations between RA site and other
urban sites
Sampling site
Mean concentration
(ng/m3)
Literature
RA, El Tabbin city, Egypt 19000 This study
Los Angeles, USA 27 Gordon (1976)
Essen, Germany 1411 Grimmer et al. (1981).
Brisbane, Australia 152 Muller et al. (1998)
Birmingham, UK 151 Harrison et al. (1996).
Chicago, USA 574 Vardar et al. (2004)
Athens, Greece 1420 Valavanidis et al. (2006).
Bursa, Turkey 1410 Esen et al. (2008)
Delhi, India 1782 Sharma et al. (2007)
Seoul, Korea 89 Park et al. (2002)
Shanghai, China 216 Chen et al. (2011)
Beijing, China 116 Zhou et al. (2005)

3.2. Characteristic of PAHs Profiles for
different function sites
The majority PAHs for each functional site during the seasonal
sampling period:
 For CK: Naphthalene (~19%), Fluoranthene (~15%), Pyrene (~12%)
and Phenanthrene (~10%).
 For TIMS: Phenanthrene (~18%), Fluoranthene (~12%), Naphthalene
(~11%) and Chrysene (~10%).
 For AAS: Phenanthrene (~18%), Fluoranthene (~16%), Pyrene (~14%)
and Benzo(b)Fluoranthene (~11%).
 For RA: Pyrene (~16%), Fluoranthene (~15%), Benzo(b)Fluoranthene
(~12%), Benzo(g,h,i)Perylene (~10%).

PAHs profiles for the different function sites over the
seasonal sampling period
NAP
ACE
ACY
FLO
PHE
ANT
FLA
PYR
BaA
CHR
BbF
BkF
BaP
IcdP
DBahA
BghiP
0
3
6
9
12
15
18
21
MassPercentage(%)
CK
TIMS
AAS
RA

Coefﬁcient of Divergence (CDjk):
Identifying the differences or similarities between the
PAH composition profiles in different function zones
𝑪𝑫𝒋𝒌 =
𝟏
𝑷
𝒊=𝟏
𝒑
𝑿𝒊𝒋 − 𝑿𝒊𝒌
𝑿𝒊𝒋 + 𝑿𝒊𝒌
𝟐
Where :
 j and k stand for the two proﬁles for sampling sites,
 p is the number of investigated components,
 Xij and Xik represent the average mass concentrations of chemical
component i for j and k.
 If CDjk approaches zero, PAH composition profiles j and k are similar, and
if it approaches one, they are significantly different.

0 5 10 15 20
0
5
10
15
20
PYR
ACY
DBahA
ACE
FLO
ANT
IcdP
BghiP
BaP
BbF
BkF
BaA
CHR
PHE
FLA
PAHsmasspercentage(%)forCK
PAH mass percentage (%) for TIMS
NAP
CDCK &TIMS= 0.90
Comparison of PAHs mass percentage profiles for the
different function zones with CDjk values

0 5 10 15 20
0
5
10
15
20
CDCK & AAS= 0.97
IcdP
BaA
CHR
BkF
ANT
ACY
FLO
DBahA
ACE
BaP
BghiP
PYR PHE
BbF
FLA
NAP
PAH mass percentage (%) for AAS

0 3 6 9 12 15 18
0
5
10
15
20
CDCK & RA= 0.25
BaA
IcdP
BkF
CHR
ANT
FLO
ACE
DBahA
ACY
BaP
BghiP
FLA
PYR
BbF
PHE
NAP
PAH mass percentage (%) for RA

0 5 10 15 20
0
5
10
15
20
CDTIMS & AAS= 0.54
BkF
DBahA
ACE
ACY
FLO ANT
IcdP BaP BghiP
BbF
PHE
FLA
PYR
BaA
CHRNAP
PAHsmasspercentage(%)forTIMS
PAH mass percentage (%) for AAS

0 3 6 9 12 15 18
0
5
10
15
20
CDTIMS & RA= 0.82
CHR
BaA
BkF
DBahAACY
ACE
FLO ANT
IcdP BaP BghiP
BbF
PYR
FLA
PHE
NAP
PAHsmasspercentage(%)forTIMS

0 3 6 9 12 15 18
0
5
10
15
20
CDAAS & RA= 0.62
BaA
IcdP
BkF
CHR
NAPDBahA
ACY
FLO
ACEANT
BaP
BghiP
BbF
PYR
FLA
PHEPAHsmasspercentage(%)forAAS

3.3. Seasonal variability of PAHs
concentrations
Summation of 16 PAHs concentrations (∑16 PAHS) for
each sampling season at different function sites
Winter Spring Summer Autumn
0
2000
4000
6000
8000
AAS RA
CK TIMS
Concentrations(g/m
3
)Concentrations(g/m
3
)
0
50
100
150
200
250
300
350
Concentrations(g/m
3
)Concentrations(g/m
3
)
0
40
80
120
0
5
10
15
20
25
30

Summation of PAHs concentrations for different
function sites at the sampling dates:
20Jan
27Jan
3Feb
7Apr
14Apr
21Apr
20Jun
27Jun
3Jul
21Oct
28Oct
4Nov
5000
5500
6000
6500
7000
7500
8000
8500
9000
9500
CK
TIMS
AAS
RA
100
150
200
250
300
350
70
80
90
100
110
120
130
12
14
16
18
20
22
24
26
28PAHsConcentrations(g/m3
)

Correlations of Total PAHs concentrations and
atmospheric temperatures during the sampling dates
14 16 18 20 22 24 26 28 30 32
5000
6000
7000
8000
9000
10000
TotalPAHsconcentrations(g/m3
)
Ambient Temperature (o
C)
y = -194 x + 11413.6
r = - 0.84

Seasonal variations of estimated atmospheric outflow of the
south of El Tabbin city
20Jan
27Jan
3Feb
7Apr
14Apr
21Apr
20Jun
27Jun
3Jul
21Oct
28Oct
4Nov
PAHs outflow (g/(m
2
.S) (magnitude multiplier is 0.005 )

3.4. Diagnostic ratio analysis for PAHs Source identification
Diagnostic ratios of PAHs attributed to specific sources compiled from different references:

Diagnostic ratios of PAHs in the south of El-Tabbin city

For CK site, (sampling was occurring at the border of Coke production plant)
the values of diagnostic ratios for PAH isomers are comparable to the
reported values for coke and coal combustion:
 The values of PHE/(PHE+ANT) for different seasons are in the range of
0.80 ± 0.13 to 0.85 ± 0.03 that are close to the value of coal combustion
(i.e. 0.85 ± 0.11).
 The averaged values of FLA/(FLA+PYR), BaA/(BaA+CHR),
IcdP/(IcdP+BghiP) and BaP/BghiP over the sampling period are 0.55 ±
0.06, 0.45 ± 0.10, 0.48 ± 0.17 and 1.24 ± 0.32, respectively, which are
consistent with reported values (i.e. 0.58 ± 0.02, 0.45 ± 0.15, 0.62 ± 0.02
and 1.32 ± 0.64, respectively)

For TIMS site, (sampling was occurring at the prevailing wind directions
carried the combustion emissions coming from stationary sources of
several industrial complexes),
 The averaged values of PHE/(PHE+ANT), FLA/(FLA+PYR),
BaA/(BaA+CHR), IcdP/(IcdP+BghiP) and BaP/BghiP over sampling
seasons are 0.84 ± 0.26, 0.55 ± 0.21, 0.47 ± 0.19, 0.48 ± 0.32 and 0.94 ±
0.48, respectively.
 It can be inferred from the ratio analysis that, within uncertainties, the
influence of pyrogenic sources (either coal, oil and natural gas
combustions or coal burning during industrial processes) for producing
PAHs in TIMS site is dominated.

For AAS site, (sampling was occurring at ≤ 1 Km northwest of the
stationary exhausts of more than 250 bricks plants using heavy oil as fuel),
the averaged values of PHE/(PHE+ANT), FLA/(FLA+PYR),
BaA/(BaA+CHR), IcdP/(IcdP+BghiP) and BaP/BghiP over sampling
seasons are 0.88 ± 0.33, 0.52 ± 0.11, 0.50 ± 0.29, 0.36 ± 0.22 and 0.75 ±
0.51, respectively.
It can be concluded that, the PAHs were originated from mixture of sources
including petrogenic sources (diesel and gasoline vehicle exhaust
emissions) and pyrogenic sources (oil and coal combustion – dominating
source for PAHs).

 For RA site (sampling was occurring in vicinity to a heavy traffic area), the
averaged values of PHE/(PHE+ANT), FLA/(FLA+PYR), BaA/(BaA+CHR),
IcdP/(IcdP+BghiP) and BaP/BghiP over sampling seasons are 0.78 ± 0.28,
0.48 ± 0.21, 0.53 ± 0.29, 0.36 ± 0.25, 0.75 ± 0.57, respectively. These
values implying the dominance of the vehicle exhaust emissions (either
diesel or gasoline – petrogenic sources).
 Within uncertainties, the values of diagnostic ratios are ranged within 0.5
– 1.06, 0.27 – 0.69, 0.24 – 0.82, 0.11 – 0.61 and 0.18 – 1.32, respectively,
which suggests that the PAHs are released from mixture of sources
including vehicle exhaust and pyrogenic sources (i.e. oil and coal
combustions) (i.e. dual impacts from the vicinity to industrial complexes
and vehicle emissions.

Diagnostic ratios for different function sites between
FLA/(FLA+PYR) and PHE/(PHE+ANT)
0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3
0.2
0.3
0.4
0.5
0.6
0.7
0.8
CK
AAS
TIMS
Pyrogenic
sources
FLA/(FLA+PYR)
PHE / (PHE+ANT)
Diesel/Gasoline vehicle, Coal combustion
Petrogenic
sources
RA

Diagnostic ratios for different function sites between
FLA/(FLA+PYR) and IcdP/(IcdP+BghiP)
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Liquid fossile fuel combustion
CK &TIMS
AAS
Pyrogenic
sources
FLA/(FLA+PYR)
IcdP / (IcdP+BghiP)
Coal combustion
Petrogenic
sources
RA

 In conclusion, the results obtained with diagnostic ratio analysis for
different functional sites reinforce that the coal combustion, vehicle
emission and industrial processes are principle sources for PAHs in
this heavy industrial city with dominancy of coal combustion.
 This is not too unexpected in view of the fact that recently, coal is
widely used to meet energy requirements in Egypt.

 Toxic equivalency factors: BaP equivalent concentration (BaPeq):
3.5. Health-risk assessment
Bapeq = Ci × TEF
Where Ci is the concentration of individual PAH in the air samples,
TEF is the corresponding toxic equivalent factors of individual PAH in corresponding to
BaP
 The carcinogenic potency of the PAHs exposures will be estimated as the sum of each
individual BaPeq:
Total Bapeq = ∑i (Ci × TEF)
 Three sampling sites (TIMS, AAS, RA) that could have population exposed to the influence
of PAHs

BaPeq exposure levels for PAHs (ng/m3) in the TIMS, AAS and RA sampling
sites during the seasonal sampling period:

 For all sampling sites, the BaPeq levels for PAHs in winter and autumn are
significantly higher than corresponding BaPeq levels in spring and
summer.
 The contribution of higher molecular weight PAHs (i.e. 4-rings such as FLA and CHR, 5-
rings such as B(b,k)F and 6-rings such as DBahA, IcdP, BghiP) in the potential toxicity is
substantially.
 The averaged values of Total BaPeq over the seasonal sampling period exhibited
decreasing sequence as TIMS (16554.79 ng/m3) > AAS (9353.48 ng/m3) > RA (2183.48
ng/m3).
 The potential health risks of PAHs at the two industrial sites TIMS and AAS are ~ 7.6 and
~ 4.3 times of that for the RA.
 The averaged value of total BaPeq in the atmosphere of the south of El-Tabbin city is
9364 ng/m3 in 2014 which implies the atmospheric PAHs pollution is a serious situation

Lifetime lung cancer risk of PAHs
 The estimated lifetime lung cancer risk from PAHs in the atmosphere based on the
WHO Unit Risk (UR) is 8.7 cases per 100,000 people with chronic inhalational
exposure to 1 ng/m3 BaP over a lifetime of 70 years
 The risk of developing lung cancer can be calculated as:
Lifetime lung cancer risk = BaPeq (ng/m3) × UR
UR = 8.7 ×10-5
 The corresponding annual number of lung cancer cases in the population of the study
area that could be attributed to PAH:
𝐏𝐨𝐩𝐮𝐥𝐚𝐭𝐢𝐨𝐧 𝐞𝐱𝐩𝐨𝐬𝐞𝐝 (𝐧𝐮𝐦𝐛𝐞𝐫 𝐨𝐟 𝐢𝐧𝐡𝐚𝐛𝐢𝐭𝐚𝐧𝐭𝐬) × 𝐥𝐢𝐟𝐞𝐭𝐢𝐦𝐞 𝐥𝐮𝐧𝐠 𝐜𝐚𝐧𝐜𝐞𝐫 𝐫𝐢𝐬𝐤
𝟕𝟎 (𝐲𝐞𝐚𝐫𝐬 𝐨𝐟 𝐞𝐱𝐩𝐨𝐬𝐮𝐫𝐞)

9.00E-06
2.00E-02
4.00E-02
6.00E-02
8.00E-02
1.00E-01
1.20E-01
1.40E-01
1.60E-01
1.80E-01
FLA, 1.26E-02
CHR, 2.54E-03
BbF, 2.02E-02
BkF, 4.39E-03
BaP, 1.24E-01
IcdP, 9.34E-03
DBahA, 1.27E-02
BghiP, 3.30E-03
Excesscancerriskperpersonexposed
FLA CHR BbF BkF BaP IcdP DBahA BghiP
Average estimated lifetime lung
cancer risk expressed as excess
cancer risk per person exposed
by individual PAH over the
whole area under study and
over the seasonal sampling
period

 The highest estimated risk for the lifetime lung cancer risk is 1.8 × 10-1
(i.e. 1.8 additional cases per 10 people exposed).
 By concerning the individual toxicity of the target PAHs, the
compounds that contributed most to the total estimated risk are BaP
(65.25 %), BbF (10.65 %), similar contribution between DBahA and
FLA (~ 6.6 %) and finally IcdP (~ 5 %).
 Combined contribution of CHR, BkF and BghiP (~ 5.4 %) to the overall
risk.

 The average of the excess lifetime lung cancer risk per person exposed
over the sampling period is 1.2 × 10-2 (1.2 additional cases per 100
people exposed) for the study area as whole.
 Taking into account the calculated average lifetime risk and assuming a
homogeneous exposure of the inhabitants (i.e. 100,000) in RA, the
annual cases of lung cancer that could be attributed to this PAH
exposure is ~ 17.

 The mass concentration of PAHs ranged from 76.48 ± 19.44 µg/m3 to
26995.86 ± 2835.91 µg/m3 with a mean concentration of 7085.08 ±
773.98 µg/m3, with the highest concentrations at the industrial areas
(CK, TIMS and AAS) following by residential area (RA).
 PAHs concentrations were high in winter and autumn at the four sampling
sites. This behavior could be attributed to the meteorological factors such
as regional climatic conditions, lower atmospheric mixing height,
decreased sunlight intensity as well as frequent temperature inversion that
intensify the PAH pollution in winter.

 Among the 16 PAHs, FLA, PYR, CHR, BbF, BkF, BaA, BaP, IcdP, BghiP
(represent combustion derived PAHs) were most abundant,
accounting for 65 % − 83 % of total PAHs, which reflects the influence
of combustion processes (either coal or oil) and vehicle emission.
 Atmospheric outflow was estimated based on the concentration of
PAHs and wind velocity where the elevated transport fluxes were
found during the spring and winter seasons and southeastward
transport is dominated

 BaP concentration in the study area is extremely high where the
average BaP concentration over seasonal sampling period for the study
area as a whole is 5287 ng/m3, reflecting a serious hidden danger to
health.
 The potential health risks of PAHs at industrial sites (i.e. TIMS and AAS)
are higher than the residential area (i.e. RA).
 The average estimated lifetime lung cancer risk for this study area was
higher than the WHO and the U.S. EPA recommended values as well as
higher than the threshold value of 10-3 considered a definite risk
according to criteria used in similar risk assessment studies

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