Accumulation and coarse mode aerosol concentrations and carbonaceous contents in the urban background atmosphere in Amman, Jordan

Abstract

In this study, we analyzed the concentrations of accumulation and coarse modes measured during November 2013-July 2017 at an urban background site in Amman, Jordan. The concentrations showed distinct seasonal variations with high concentrations with a monthly average higher than 100 cm −3 and 1.5 cm −3 , respectively, for accumulation and coarse modes during the winter and low concentrations with a monthly average less than 40 cm −3 and 1-1.5 cm −3 , respectively, for accumulation and coarse modes during the summer. Sand and dust storms (SDS) affected the coarse mode during the early spring whereas local dust resuspension affected them during the autumn. The gravimetric analysis confirmed the seasonal variation of the calculated particulate mass concentration but suggested that the assumption of spherical particles and unit density is not always proper. The ATR-FTIR analysis of selected filters revealed that aerosols in the background atmosphere of Amman are a mixture of locally emitted (fossil fuel combustion) and local/regional dust. Based on the 24-h average of the calculated PM 10 , the pollution standard index (PSI) revealed that about 81% of the days were either good or moderate air quality conditions. About 71% of the days were below the 24-h PM 10 limit value according to the Jordanian air quality standards (120 μg m −3).

Urban Aerosol Particle Size Characterization in Eastern Mediterranean Conditions

“…During March and April, the monthly PN Coarse was about 3.3 cm −3 . As previously reported about this particle size fraction in Amman [19], it had a clear seasonal pattern linked to the sand and dust storms, which are often occurring in the spring season, and local dust resuspension, which are usually dominant in the autumn season. In general, the dust episodes lasted from a few hours to several days.…”

“…During March and April, the monthly PNCoarse was about 3.3 cm −3 . As previously reported about this particle size fraction in Amman [19], it had a clear seasonal pattern linked to the sand and dust storms, which are often occurring in the spring season, and local carbon (PNBC). As expected, this size fraction had temporal variations (Figure 4c) very close to those of the total number concentrations but with lower concentrations (Figure 3a).…”

“…It is important to mention here that what we presented here as PNBC should not be understood as the concentration of black carbon; we only wanted to have an insight into the temporal variation of the black carbon fraction. Except for Amman [17][18][19][20][21][38][39][40], particle number concentrations and size distributions has never been reported before in urban areas in the Middle East. The previous studies were mainly about some gaseous pollutants; PM mass concentrations, and chemical composition [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56].…”

“…Indeed, the complexity of urban aerosols lies in the fact that several sources can contribute in the same particle size range, making it difficult to entangle [9,10]. Although, some studies focusing on the particle number size distribution have been conducted around the East Mediterranean region at both urban and remote sites [11][12][13][14], very few studies can be found regarding the Middle East [15][16][17][18][19][20][21]. In fact, the Middle East and North Africa (MENA) is of extreme interest as it serves as a compilation of aerosol particle sources including natural dust, anthropogenic pollution from petrochemical industry and urbanization, as well as new particle formation.…”

Regional Inhaled Deposited Dose of Urban Aerosols in an Eastern Mediterranean City

“…Urban air pollution has been reported extensively in some parts of the world. However, air pollution data is severely limited in Eastern Mediterranean conditions [45][46][47][48][49]. It can be suggested that the main sources were secondary sulfates from coal burning (local and long-range transportation), traffic, crustal and construction dust, and biomass burning.…”