Sources, variability, long-term trends, and radiative forcing of aerosols in the Arctic: implications for Arctic amplification.

Atmospheric pollution in the Arctic has been an important driver for the ongoing climate change there. Increase in the Arctic aerosols causes the phenomena of Arctic haze and Arctic amplification. Our analysis of aerosol optical depth (AOD), black carbon (BC), and dust using ground-based, satellite, and reanalysis data in the Arctic for the period 2003-2019 shows that the lowest amount of all these is found in Greenland and Central Arctic. There is high AOD, BC, and dust in the northern Eurasia and parts of North America. All aerosols show their highest values in spring. Significant positive trends in AOD (> 0.003 year-1) and BC (0.0002-0.0003 year-1) are found in the northwestern America and northern Asia. Significant negative trends are observed for dust (- 0.0001 year-1) around Central Arctic. Seasonal analysis of AOD, BC, and dust reveals an increasing trend in summer and decreasing trend in spring in the Arctic. The major sources of aerosols are the nearby Europe, Russia, and North America regions, as assessed using the potential source contribution function (PSCF). Anthropogenic emissions from the transport, energy, and household sectors along with natural sources such as wildfires contribute to the positive trends of aerosols in the Arctic. These increasing aerosols in the Arctic influence Arctic amplification through radiative effects. Here, we find that the net aerosol radiative forcing is high in Central Arctic, Greenland, Siberia, and Canadian Arctic, about 2-4 W/m2, which can influence the regional temperature. Therefore, our study can assist policy decisions for the mitigation of Arctic haze and Arctic amplification in this environmental fragile region of the Earth.

Pericardial Effusion and Tamponade Complicating Acute Pericarditis in a Human Metapneumovirus-Infected Adult: A Unique Case Report.

Acute pericarditis (AP), or pericardial sac inflammation, is a self-limited condition in healthy individuals. Viruses, including adenoviruses, enteroviruses, cytomegalovirus, and influenza virus, have been well documented to cause AP. In contrast, human metapneumovirus (hMPV), a relatively newer virus, has been described in a few cases to cause serious cardiac complications. Here we report a patient who developed an imminent cardiac tamponade associated with hMVP respiratory infection.