Sources and Temporal Variations of Coarse Particulate Matter (PM) in Central Tehran, Iran

Abstract

In this study, we used the positive matrix factorization (PMF) model to evaluate the sources of ambient coarse particulate matter (PM) and their temporal variations in two sampling sites, i.e., a school dormitory and a retirement home, located in central Tehran. 24-h ambient PM samples were collected using low-volume air samplers from May 2012 to June 2013. The collected filters were analyzed for their chemical components, including water-soluble ions, metals, and trace elements, which were used as the input to the PMF model. Our results indicated annual averages of 45.7 ± 3.8 µg/m 3 and 36.2. ± 4.0 µg/m 3 for coarse PM at the School dormitory and Tohid retirement home, respectively. Moreover, higher ambient coarse PM mass concentrations were observed in the warm season (53.3 ± 5.8 µg/m 3 for school dormitory and 43.1 ± 6.1 µg/m 3 for Tohid retirement home) as opposed to the cold season (41.4 ± 4.7 µg/m 3 for school dormitory and 28.7 ± 4.6 µg/m 3 for Tohid retirement home). Our PMF analysis also identified road dust, soil, and industry, and atmospherically processed coarse PM as the three sources of ambient coarse PM in central Tehran. Road dust, soil, and industry were the major sources of ambient coarse PM, contributing respectively to 74 ± 9% and 19 ± 2% of the total coarse PM mass concentration, while atmospherically aged aerosols had a rather minimal contribution of 7 ± 1% to total coarse PM mass concentration. The temporal trends of the resolved factors also revealed higher contributions of road dust to total ambient coarse PM during warm season as opposed to cold season, due to the increased resuspension rate from road surfaces as a result of higher wind speeds, and temperatures, combined with lower relative humidity. Similarly, higher resuspension rate of mechanically originated particulates resulted in higher warm-season time contributions of the soil factor. Results of this study clearly revealed the key role of road dust and non-tail pipe emissions on ambient coarse PM mass concentrations in crowded areas of central Tehran, and have important implications on the potential health impacts that can be caused by these difficult to mitigate sources of coarse PM.

The impact of stay-home policies during Coronavirus-19 pandemic on the chemical and toxicological characteristics of ambient PM2.5 in the metropolitan area of Milan, Italy

“…8 shows the concentration of selected metals and trace elements, including titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), and cupper (Cu) during the investigation period. These metals, characterized as redox-active ones responsible for PM oxidative potential ( Decesari et al, 2017 ; Lai et al, 2016 ; Ntziachristos et al, 2007 ; Yuan et al, 2001 ), are well-known tracers of re-suspended road dust particles originating from soil, tire and brake wear, and road abrasion ( Adamiec et al, 2016 ; Al-Shidi et al, 2020 ; Dall'Osto et al, 2008 ; Godri et al, 2011 ; Harrison et al, 2012 ; Soleimanian et al, 2019b ). In addition, Ni can be emitted as a result of fuel combustion in industrial sectors, power plants, vehicles engines, and to some extent residential heating ( Masiol et al, 2020 ; Moreno et al, 2010 ; Zhang et al, 2014 ).…”

Variability of airborne microbiome at different urban sites across seasons: a case study in Rome

“…Finally, it's worth noticing that, coupled with the most prevalence of soil-inhabiting bacteria and fungi, a marked increment of insoluble fractions of allumium (Al_Ins), rubidium (Rb_Ins), lithium (Li_Ins), cesium (Cs_Ins), tallium (Tl_Ins) and titanium (Ti_Ins) has been also recorded in two different seasons, winter and summer. These elements are considered reliable tracers for soil resuspension, which can be favored, as in this specific case, by the passage of vehicles, particularly during warm and/or dry periods (Soleimanian et al, 2019). As proved by Pollegioni et al (2022), road dust can be a primary local source of out-door air bacteria and fungi in urban environments of Rome.…”

Industrial Co-Agglomeration and Air Pollution Reduction: An Empirical Evidence Based on Provincial Panel Data

“…Therefore, improving and accelerating the coordinated development of the two industries will have a significant effect on air pollution reduction. On the other hand, natural weather conditions, such as humidity saturation, static weather, and radiation temperature inversion, in the south will also lead to aggravated air pollution [40,41]. Therefore, the improvement of industrial co-agglomeration will help to reduce sulfur dioxide emissions, thus making a more significant improvement in air quality.…”