Fine particulate matter from brick kilns site and roadside in Lahore, Pakistan: Insight into chemical composition, oxidative potential, and health risk assessment

Mushtaq Ahmad; Jing Chen; Sirima Panyametheekul; Qing Yu; Asim Nawab; Muhammad Tariq Khan; Yuepeng Zhang; Syed Weqas Ali; Worradorn Phairuang

doi:10.1016/j.heliyon.2024.e25884

Fine particulate matter from brick kilns site and roadside in Lahore, Pakistan: Insight into chemical composition, oxidative potential, and health risk assessment

Heliyon. 2024 Feb 10;10(4):e25884. doi: 10.1016/j.heliyon.2024.e25884. eCollection 2024 Feb 29.

Authors

Mushtaq Ahmad¹, Jing Chen², Sirima Panyametheekul^{1

3}, Qing Yu², Asim Nawab⁴, Muhammad Tariq Khan⁵, Yuepeng Zhang², Syed Weqas Ali⁶, Worradorn Phairuang⁷

Affiliations

¹ Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University Bangkok, 10330, Thailand.
² State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing, 100875, China.
³ Thailand network centre on Air Quality Management: TAQM and Research Unit: HAUS IAQ, Bangkok, Thailand.
⁴ Department of Environmental Sciences, University of Peshawar, Peshawar, 25120, Pakistan.
⁵ Department of Science and Environmental Studies, The Education University of Hong Kong, Taipo, New Territories, Hong Kong, China.
⁶ Department of Environmental Sciences, Abdul Wali Khan University, Mardan, 23200, Pakistan.
⁷ Faculty of Geosciences and Civil Engineering, Institute of Science and Engineering, Kanazawa University, Kanazawa, 920-1192, Ishikawa, Japan.

Abstract

Background: Human health is seriously threatened by particulate matter (PM) pollution, which is a major environmental problem. A better indicator of biological responses to PM exposure than its mass alone is the PM "oxidative potential (OP)," or ability to oxidize target molecules. When reactive oxygen species (ROS) are generated in the OP in excess of the antioxidant capacity of body due to PM components such metals and organic species, it causes inflammation, deoxyribonucleic acid (DNA), proteins, and lipids damage.

Method: The samples of fine particulate matter (PM_2.5) are collected from the brick kiln site and the roadside in Lahore, Pakistan. The organic carbon (OC) and elemental carbon (EC) were estimated by carbon analyzer (DRI 2001A) using the thermal/optical transmittance (TOT) protocol. The water-soluble organic carbon (WSOC) concentration was determined using a total organic carbon analyzer (Shimadzu TOC-L CPN). Ion chromatography (Dionex ICS-900) with a conductivity detector was used to analyze the water-soluble anions (Cl^-, NO₃^-, and SO₄^2-) and cations (NH₄⁺, Na⁺, K⁺, Mg²⁺, and Ca²⁺). Inductively coupled plasma-mass spectrometry (iCAP TQ ICP-MS, Thermo Scientific) was used to determine the concentrations of metals in the solution. The dithiothreitol (DTT) consumption rate was calculated using a spectrophotometer at a wavelength of 412 nm.

Results: The mean concentrations of PM_2.5 at the brick kiln site and roadside reported are 509.3 ± 32.3 μg/m³ and 467.5 ± 24.9 μg/m³, and the average OC/EC ratio is 1.9 ± 0.4 and 2.1 ± 0.1. primary organic carbon (POC) contributed more to OC than secondary organic carbon (SOC), which indicated the dominance of primary combustion sources. The anion equivalent (AE) to cation equivalent (CE) ratio indicated that PM_2.5 is acidic at both sites due to the dominance of NO₃^- and SO₄^2-. The DTT consumption rate normalized by PM_2.5 mass (DTT_m) and DTT consumption rate normalized by air volume (DTT_v) of PM_2.5 at the roadside samples are higher than at the brick kiln site due to the higher contribution of ionic species to the mass of PM_2.5. Carbonaceous species of PM_2.5 at both sampling sites are significantly correlated with DTTv of PM_2.5, while metallic species behaved differently. The incremental lifetime cancer risk (ILCR) values (lung cancer) of As and Cr at both sampling sites, while the ILCR value of Cd at the roadside samples is exceeding the permissible limits for adults and children. The lifetime average daily dose (LADD) value for adults is higher than that for children, indicating that children are less vulnerable to metals.

Conclusion: The concentration of PM_2.5 at both sampling sites were exceeding the permissible limits of Pakistan' National Environmental Quality Standard (NEQS) and posing risk to the health of the local population. The POC and SOC contribution to OC at the brick kiln site and roadside in Lahore were 84.6%, 15.4% and 84.4%, 15.6%. POC at both sampling sites were the dominant carbon species indicating the dominance of primary combustion sources. The residence of Lahore poses the lung cancer risk due to Cr, As, and Cd at both sampling sites. The results of this study provide important data and evidence for further evaluation of the potential health risks of PM_2.5 from brick kiln site and road side in Pakistan and formulation of efficient air-pollution control measures.

Keywords: Aerosol acidity; Air pollution; Cancer risk; Carbonaceous species; Oxidative stress.