Mathematical model of NOx production and effect of underpressure on their production.

A large number of the studies have indicated that chemical indoor air pollution has become an important environmental factor which influences the population's health. Nitrogenmonoxide and nitrogen dioxide are mainly produced by combustion at high temperatures and are formed by reactions between nitrogen and oxygen. Both nitrogen in the fuel and nitrogen in the air participate in reaction, NO is further oxidized and transferred into N02 in the atmosphere. Nitrogen dioxide is the most toxic of the nitrogen oxides and is the most important from view-point of health. In Slovakia it is possible to assess that about 40% of the emissions of nitrogen oxides originate from road traffic, about 50% from combustion and about 10% come from industrial processes. During several last years the emissions of nitrogen oxides have increased. There are great differences between annual average value of nitrogen in the countryside and in the big cities. Outdoor average concentration level of nitrogen oxides are presented. People are mainly exposed to indoor nitrogen oxides. Indoor air can be contaminated from the use of gas for heating and cooking appliances. The most important indoor source of nitrogen oxides is gas burning in the kitchen. Finally concerning the indoor environment, indoor air can be contaminated by using gas for heating and cooking and this probably involves a certain health hazard. Indoor average concentrations level of nitrogen oxides are also presented. In order to improve the chemical indoor air quality we need to estimate the indoor sources NOx production. The aims of this paper are to survey the occurrence of nitrogen oxides exposure in the building environment and to estimate the indoor NOx production on the base of the mathematical model using the dimensional analysis, The own model of NOx production in steam boilers based on supporting characteristic variables, which are connected with the combustion process is presented by authors. As well the comparison of results obtained from direct measurements with the results obtained from the created mathematical model has been accomplished.