ABSTRACT
Urban passenger transport is one of the most significant sources of fossil energy consumption and greenhouse gas emission, especially in developing countries. The rapid growth of urban transport makes it a critical target for carbon reduction. This paper establishes a method for calculating carbon emission from urban passenger transport including ground buses, private cars, cruising taxis, online-hailing taxis, and rail transit. The scope of the study is determined according to the transportation mode and energy type, and the carbon emission factor of each energy source is also determined according to the local energy structure, etc. Taking into consideration the development trend of new energy vehicles, a combination of “top-down” and “bottom-up” approaches is used to estimate the carbon dioxide emission of each transportation mode. The results reveal that carbon emission from Qingdao’s passenger transport in 2020 was 8.15 million tons, of which 84.31% came from private cars, while the share of private cars of total travel was only 45.66%. Ground buses are the most efficient mode of transport. Fossil fuels emit more greenhouse gases than other clean energy sources. The emission intensity of hydrogen fuel cell buses is better than that of other fuel type vehicles. Battery electric buses have the largest sensitivity coefficient, therefore the carbon emission reduction potentially achieved by developing battery electric buses is most significant.
ABSTRACT
Coronavirus disease 2019 (COVID-19) is a recently emerged disease with formidable infectivity and high mortality. Emerging data suggest that diabetes is one of the most prevalent comorbidities in patients with COVID-19. Although their causal relationship has not yet been investigated, preexisting diabetes can be considered as a risk factor for the adverse outcomes of COVID-19. Proinflammatory state, attenuation of the innate immune response, possibly increased level of ACE2, along with vascular dysfunction, and prothrombotic state in people with diabetes probably contribute to higher susceptibility for SARS-CoV-2 infection and worsened prognosis. On the other hand, activated inflammation, islet damage induced by virus infection, and treatment with glucocorticoids could, in turn, result in impaired glucose regulation in people with diabetes, thus working as an amplification loop to aggravate the disease. Therefore, glycemic management in people with COVID-19, especially in those with severe illness, is of considerable importance. The insights may help to reduce the fatality in the effort against COVID-19.