This paper reports the NO reduction activity of several potassium-containing coal briquettes obtained from different coal precursors (ranging from anthracite to lignite) with the purpose of understanding the effect of coal rank. Also, two fractions of a bituminous coal, with two very distinct ash contents, were selected to determine the influence of the mineral matter content of coals in NO reduction. The catalytic effect of potassium in this reaction was evaluated in a fixedbed flow reactor at atmospheric pressure using two types of experiments: (i) temperature programmed reaction in a NO/He mixture; and (ii) isothermal reaction at 300-600 °C. The reaction products were monitored in both cases, thus allowing detailed oxygen and nitrogen balances to be determined. The effect of coal rank is manifested in two ways: larger amounts of potassium incorporated in coal briquettes and higher NO reduction activity as the coal rank precursor decreases, for all of the reaction temperatures tested. Ash contents of the coals (quartz, silicates) seem to have a negative effect in the NO-carbon reaction, acting as a sink that sinters and deactivates the potassium, forming potassium carbonate and silicates, both of them inactive for the process.

Abstract-Radon is a gas that is considered as an extremely harmful element to people's health by the World Health Organization (WHO). Radon is a type of radioactive gaseous element that is present in almost all materials with which buildings are constructed, as well as in the areas in which they are raised.

The presence of radon gas in constructions is an indicator of air quality. The study presented analyzes the amount of radon gas in the Railway Tunnel in Alicante. This infrastructure is very important for the city due to its social importance in facilitating urban mobility. radon gas is an element considered highly harmful to people by different scientific agencies in the field of medicine and health, including the World Health Organization (WHO). The main effect of the presence of radon in the environment of the human being is the risk of contracting lung cancer. This radioactive gaseous element is present in almost all building materials, and in the land in which the buildings are implanted. In this article the measurements made in the tunnel are provided and the levels obtained are analyzed according to their danger to humans. In Spain, the Technical Building Code (CTE) still does not contemplate the dose of radon that can hold a maximum of one building and how to contain it.

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