Source Apportionment of PM10 at an Urban Site of a South Asian Mega City

Imran Shahid; Muhammad Usman Alvi; Muhammad Zeeshaan Shahid; Khan Alam; Farrukh Chishtie

doi:10.4209/aaqr.2017.07.0237

Source Apportionment of PM10 at an Urban Site of a South Asian Mega City

Imran Shahid ¹, Muhammad Usman Alvi²^,3, Muhammad Zeeshaan Shahid⁴, Khan Alam⁵, Farrukh Chishtie⁶

¹Institute of Space Technology, Islamabad 44000, Pakistan
²Institute of Chemistry, University of the Punjab, Lahore 54590, Pakistan
³University of Education, Okara Campus, Okara 57000, Pakistan
⁴King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
⁵Department of Physics, University of Peshawar, Peshawar 25120, Pakistan
⁶SERVIR-Mekong, Asian Disaster Preparedness Center, Bangkok 10400, Thailand

Received: July 24, 2017
Revised: October 24, 2017
Accepted: October 26, 2017
Download Citation: ||https://doi.org/10.4209/aaqr.2017.07.0237

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Cite this article:
Shahid, I., Alvi, M.U., Shahid, M.Z., Alam, K. and Chishtie, F. (2018). Source Apportionment of PM10 at an Urban Site of a South Asian Mega City. Aerosol Air Qual. Res. 18: 2498-2509. https://doi.org/10.4209/aaqr.2017.07.0237

HIGHLIGHTS

A very high PM₁₀ concentration was observed during the study period i.e., 793 µg m^–3.
Backward trajectory analysis exhibited local contribution and long range transport.
Maximum contribution of Ca, Al and Fe was found in PM₁₀ concentrations.
PMF used for the source apportionment of PM₁₀ at Karachi.
A strong correlation was observed between the observed and predicted PM₁₀ mass.

ABSTRACT

In the present study, elemental composition of PM₁₀ and source apportionment was conducted in the urban atmosphere of Karachi. Trace elements such as Ni, Ba, Cd, Ca, Mg, Cr, Mn, Fe, Co, Cu, Sr and Ti were measured. The PM₁₀ concentration ranged from 255 µg m^–3 to 793 µg m^–3 with an average of 438 ± 161 µg m^–3. Among the various elements analyzed, concentrations of Ca, Al and Fe were highest (> 10 000 ng m^–3), followed by Mg and S (> 1000 ng m^–3). Elements like Zn, P, Cu, Pb, Mn, Ti, Sr and Ba demonstrated medium concentrations (> 100 ng m^–3), whereas lowest concentrations were measured for elements like Cr, Ni and Se (> 10 ng m^–3). The Positive Matrix Factorization (PMF) model identified five possible factors contributing towards PM₁₀, including biomass burning, coal combustion, re-suspended road/soil dust, vehicular emission and industrial dust. Industrial dust as major contributor (23.2%) to PM₁₀ followed by Biomass burning (23%), Vehicular emissions (22.2%), Coal combustion (21.7%) and Re-suspended dust (9.9%). A strong positive correlation (R² = 0.98) was observed between the model predicted PM₁₀ mass and gravimetrically measured mass collected on filters.