Profile and Source Identification of Polycyclic Aromatic Hydrocarbons in Dust Deposited on Leaves of Street Trees as Indicators of Air Pollution Sources in Cairo

Mamdouh Ibraheim Khoder

Air Pollution Research Department, National Research Centre, Dokki, Giza, Egypt

Corresponding author: Mamdouh I. Khoder
    Department of Air Pollution Research, National Research Centre
    Dokki, Giza, Egypt
    Telephone: +202 3371433/1402
    Fax number: +202 3370931
    E-mail: khoder_55@yahoo.com

CEJOEM 2007, Vol.13. No.1.: 71–90

Key words:
Polycyclic aromatic hydrocarbons (PAHs), profile, source identification, carcinogenic compounds, street dust, dust on leaves, urban areas, greater Cairo

Abbreviations:
PAHs
NA
ACY
ACE
FLU
PHE
ANT
FLT		 = polycyclic aromatic hydrocarbons
= naphthalene
= acenaphthylene
= acenaphthene
= fluorene
= phenanthrene
= anthracene
= fluoranthene		 PYR
BaA
CRY
BbF
BaP
DBA
IND
BGP		 = pyrene
= benz(a)anthracene
= chrysene
= benzo(b)fluoranthene
= benzo(a)pyrene
= dibenzo(a,h)anthracene
= indeno(1,2,3,–cd)pyrene
= benzo(ghi)perylene

Abstract:
Polycyclic aromatic hydrocarbons (PAHs) were determined in paved street dust and dust deposited on leaves of street trees (leaves dust) in two urban areas in greater Cairo (Ramsis in the city centre of Cairo and Haram). The concentrations of the individual PAH compounds in paved street dust and leaves dust in Ramsis area were higher than those found in Haram area. The total PAH concentrations were: 92.32 and 40.41 µg/g in paved street dust and 337.81 and 175.51 µg/g in leaves dust in Ramsis and Haram areas, respectively. The concentrations of total and individual PAH compounds in the main street were higher than those found in the substreets in both study areas. The main street/substreet concentration ratios of the total PAHs were 2.29 and 4.01 for paved street dust and 2.22 and 2.27 for leaves dust in Ramsis and Haram areas, respectively. The total carcinogenic PAH compounds represented 55.10% and 54.12% of the total concentration of PAHs in paved street dust and 54.79% and 53.17% of that in leaves dust in Ramsis and Haram areas, respectively. The profile of the individual PAH compounds and the distribution of PAHs with different ring numbers in the paved street dust and leaves dust in both study areas indicate that the heavy PAH compounds (four to six aromatic rings) were the predominant compounds. Moreover, the light molecular weight/high molecular weight PAH concentration ratios and the ratios of the sum of major combustion specific compounds (ΣCOMB) to the sum of PAHs (ΣCOMB/ΣPAHs) in paved street dust and leaves dust indicate that combustion activities greatly affected the PAH concentration in the paved street dust and leaves dust in both study areas. In addition, the phenanthrene/anthracene (PHE/ANT) and fluoranthene/pyrene (FLT/PYR) concentration ratios indicate that pyrogenic sources were the predominant sources of PAHs in paved street dust and leaves dust in both urban areas in Cairo. The benzo(a)pyrene/benzo(ghi)perylene (BaP/BGP), benz(a)anthracene/chrysene (BaA/CRY) and indeno(1,2,3,–cd)pyrene/benzo(ghi)perylene (IND/BGP) concentration ratios indicate that PAHs in Ramsis and Haram areas were more influenced by vehicular exhaust emissions than other sources. Diesel vehicles were the dominant sources of PAHs in Ramsis area, whereas gasoline vehicles were the dominant sources in Haram area.

Received: 12 May 2007
Accepted: 21 August 2007
| Back |