Determination of fluxes and mass transfer coefficients of polychlorinated biphenyls (PCBs)

This study evaluated a modified water surface sampler (MWSS) in terms of deposition characteristics of atmospheric polychlorinated biphenyls (PCBs). Water was employed as a collection surface for the atmospheric PCBs. The main difference between the MWSS and previous WSSs was its cover which prevented the deposition of particles and minimized wind effects. Therefore, lower particle-phase deposition fluxes were observed. Moreover, preventing wind from the water surface, which was the collection surface, caused lower dissolved phase fluxes and mass transfer coefficients (MTCs). Forty-eight flux and ambient air samples were taken by using an MWSS and a high volume air sampler (HVAS), respectively. The average dissolved phase PCB fluxes were 5.92 +/- 5.37 ng/m(2)-day. Particle phase PCB fluxes were also determined by attaching a filter to the sampler. The particle phase flux ratio was 14% of the total flux, which was much smaller than previously reported ones. This difference was mainly due to the cover layer which minimized the wind effects. 4- CBs and lower chlorinated PCBs were dominant in the samples. Homolog groups obtained from both the MWSS and HVAS were highly correlated. This result indicated that both samplers collected similar atmospheric PCBs. Then, MTCs were calculated for each PCB congener. To calculate the MTCs, dissolved phase PCB fluxes were divided by gas-phase PCB concentration. The average MTC was determined to be 0.25 +/- 0.23 cm/s which was smaller than the previously reported MTCs. This result illustrated that the MWSS configuration allowed us to determine the minimum MTCs and gas transfers to the water

Existence of SARS-CoV-2 RNA on ambient particulate matter samples: A nationwide study in Turkey

Coronavirus disease 2019 (COVID-19) is caused by the SARS-CoV-2 virus and has been affecting the world since the end of 2019. The disease led to significant mortality and morbidity in Turkey, since the first case was reported on March 11th, 2020. Studies suggest a positive association between air pollution and SARS-CoV-2 infection. The aim of the present study was to investigate the role of ambient particulate matters (PM), as potential carriers for SARS-CoV-2. Ambient PM samples in various size ranges were collected from 13 sites including urban and urban-background locations and hospital gardens in 10 cities across Turkey between 13th of May and 14th of June 2020 to investigate the possible presence of SARS-CoV-2 RNA on ambient PM. A total of 203 daily samples (TSP, n = 80; PM2.5, n = 33; PM2.5-10, n = 23: PM10 mu m, n = 19; and 6 size segregated PM, n = 48) were collected using various samplers. The N1 gene and RdRP gene expressions were analyzed for the presence of SARS-CoV-2, as suggested by the Centers for Disease Control and Prevention (CDC). According to real time (RT)-PCR and three-dimensional (3D) digital (d) PCR analysis, dual RdRP and NI gene positivity were detected in 20 (9.8%) samples. Ambient PM-bound SARS-CoV-2 was analyzed quantitatively and the air concentrations of the virus ranged from 0.1 copies/m(3) to 23 copies/m(3). The highest percentages of virus detection on PM samples were from hospital gardens in Tekirdag, Zonguldak, and Istanbul, especially in PM2.5 mode. Findings of this study have suggested that SARS-CoV-2 may be transported by ambient partides, especially at sites close to the infection hot-spots. However. whether this has an impact on the spread of the virus infection remains to be determined. (C) 2021 Elsevier B.V. All rights reserved