Source apportionment of PM2.5 emissions in Makkah, Saudi Arabia : using a positive matrix factorization model

Abstract EN

In this paper, the sources of PM2.5 are quantified in the Holy City of Makkah, applying a Positive Matrix Factorisation (PMF) Model.

High Volume System (HVS) samplers for Particulate Matter (PM) were used to collect PM2.5 24 hour (10 am - 10 am) samples at two locations from September 2013 to August 2014 in Makkah.

IC technique (model: 850 Professional IC_ Metrohm USA) was used to detect the concentrations of water soluble cations and anions, such as sulphate (SO42-), phosphate (PO43-), nitrate (NO3-), ammonium (NH4+), chloride (Cl-), and fluoride (F-).

ICP technique (model : 700 series ICP, OES spectrometers Agilent) was used to detect the concentrations of K, Al, Ba, Co, Cr, Cu, As, Mn, Cd, Ni, Pb, Se, Mo, Si, and Zn.

Four main sources of PM2.5 were identified: (1) Fossil-fuel Combustion - generated by burning of petrol, diesel, and coal in vehicles, factories, houses and restaurants.

This group includes directly emitted pollutants like Pb, Ni, Cd, Cl-, F- and secondary pollutants which are formed from the conversion of gaseous pollutants, such as SO2 and NOx to secondary aerosols like SO42- and NO3- particles.

This source contributed about 60 % of PM2.5 in Makkah.

(2) Industrial emissions - mainly industrial dusts generated by various industrial processes.

These sources contributed 27 % of PM2.5.

The dominant species were As, K, Se and Si.

(3) Soil particles - mainly generated by large scale digging of mountains, construction - demolition and wind.

Soil particles contribute about 12 % of PM2.5 and the main species were Cd, Cr and MO.

(4) Miscellaneous – water-spray in the Holy Mosque and resuspension of roadside dust.

Miscellaneous contribute about 2 % of PM2.5 in Makkah and are dominated by Mn and Zn.

These results are mostly in agreement with previous studies carried out in other cities of Saudi Arabia.