Comparison Between Oxidative Potentials Measured of Water-Soluble Components in Ambient Air Pm1 and Pm2.5 of Tehran, Iran Publisher



Khoshnamvand N¹ ; Nodehi RN¹ ; Hassanvand MS^{1, 2} ; Naddafi K^{1, 2}
Source: Air Quality# Atmosphere and Health Published:2023

Abstract

Abstract: Epidemiological studies suggest that measuring the oxidation potential of particles is more appropriate than measuring PM mass concentration. For the quantification of oxidation potential (OP) associated with ambient particulate matter (PM), two cell-based and cell-free methods are commonly used. One of the most widely used cell-free methods for particle oxidation potential is the dithiothreitol (DTT, HSCH2 (CH (OH))2 CH2SH)), which requires less controlled environments and offers faster readout of PM oxidative potential. In the present study, to observe the seasonal variations of the OP of the particulate matter of different sizes (PM1, PM2.5), using a DTT assay water-based, the OP was measured during spring, summer, and autumn in the ambient air of Tehran city, the capital of Iran from 2021/4/17 to 2021/12/6. PM1 samples were collected with Sioutas cascade impactor using low-volume air samplers operating at a flow rate of 9 L/min, with high-volume air samplers (operating at a flow rate of 1.415 m3/min) used for PM2.5. PM1 and PM2.5 mass concentrations in ambient air were within (13.8–111.2) and (18.4–148.2) μg/m3 respectively. The results of the present study revealed that generally, OP of PM1 was higher than OP of PM2.5, and this value was larger in autumn than in spring and in spring higher than in summer. The correlation between the mass concentration of PM2.5 and oxidative potential mass normalized (OPDTTm) for total and spring was significant with R2 equal to 0.64 and 0.81, respectively, while a significant correlation was observed between oxidative potential volume normalized (OPDTTv) and PM2.5 mass concentration in summer with R2 of 0.63. It is expected that the existence of these studies can lead to measuring oxidative potential with the direct reading approach in the future. Highlights: • The ability of particles to generate reactive oxygen species (ROS) was measured for the first time in Iran. • Acellular assay dithiothreitol was used for oxidative potential (OP) in ambient air PM1 and PM2.5 of Tehran, Iran. • OP of PM1 was higher than the OP of PM2.5 • The value OP of PM1 and PM2.5 was higher in autumn > spring > summer. Graphical Abstract: [Figure not available: see fulltext.] © 2023, The Author(s), under exclusive licence to Springer Nature B.V.