Prediction of Indoor Nitrogen Oxides Concentration

Indoor air is mostly contaminated from the use of gas for heating and cooking appliances. It is well known that the oxide of nitrogen production in the combustion products is the process that not been exactly described so far on all variables which are connected with its production. The comprehensive analysis of indoor air nitrogen oxides pollution show that extent of indoor air level exposure varies with many factor mainly with different distribution conditions and burning activity. It seems to be necessary study and formulate mathematical model for indoor nitrogen oxides production. A mathematical model has been developed to describe the physical processes determining indoor nitrogen oxides concentration as a function of outdoor concentration, indoor emission rates and building characteristic. The model has been parameterized for typical Slovak residences. The base of this activities is presented in the paper with belief in the next continue future work. INDEX TERMS Indoor environment, Nitrogen oxides concentration, Mathematical modeling INTRODUCTION Nitrogen monoxide 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 NO2 in the atmosphere. Nitrogen dioxide is from the toxicology point of view the most important. During several last years the emissions of nitrogen oxides have increased. The mean daily outdoor nitrogen oxides concentrations achieve value 107,1 μg.m in the winter and 35,2 μg.m in the summer. The mean daily indoor nitrogen oxides concentrations achieve value 125,3 μg.m in the winter and 48,5 μg.m in the summer (Senitkova, 1999). The most important indoor source of nitrogen oxides is gas burning in the kitchen. Finally concerning to indoor environment, indoor air can be contaminated by using gas for heating and cooking and this probably involves a certain health hazard. Practical experiences show, that range of indoor nitrogen oxides concentration depends on energy conservation tendency interpret with ventilate level decrease. The highest nitrogen oxides concentrations are achieved during gas burning in the kitchen in dependence on intensity of gas burning, amount of gas burned and on room disposition (Senitkova, 2000). The indoor NOx concentrations were measured in order to understand the contribution of indoor sources to human exposure. The models and modeling substantially contribute to problem solution and to obtaining new cognition concerning system behavior respectively to air component dynamic changes. The mathematical description of the processes can generalize the achieved results and their interpretation on other various processes physically similar to introduced model. * Contact author email: [email protected] Proceedings: Indoor Air 2002