This paper presents a comparison of Indoor Air Quality in several buildings constructed prior to the implementation of the new Spanish regulation on thermal installations (RITE, 2007 modified on 2013) and some new ones that fully accomplish the requirements of this new regulation. The objective is to confirm whether new regulation had a positive impact on the indoor air quality. The month of April 2014 marked a year since the publication of the amendment of RITE (RD 238/2013 of April 5, 2013 Spanish Regulation on Thermal Installations), among the changes that were included, we highlight two that had a great relevance in terms of Indoor Air Quality. Within the document in the section IT 3.3 describing maintenance programs to be implemented in facilities subject to RITE (> 70kW), two maintenance items where added:
- 38. Review of the ductwork and AHU hygiene according to the UNE 100012: t.
- 39. Revision of indoor environmental quality according to the UNE 171330: t.
This is accomplished by two types of reviews including several analysis and visual inspections, first ensure that HVAC systems are in good hygienic conditions (UNE 100012) and secondly that the quality of the air users breathe is satisfactory (UNE 171330). On the other hand since 2007 RITE makes compulsory to install high quality filters according to outdoor air quality. In order to estimate the positive impact of such measure we have analyzed Indoor Air Quality according to RITE requirements in 38 buildings half of them with low quality filtration (projects made before 2007) and the other half buildings projected and executed according to new RITE. The summary of findings indicates an overall positive effect in all indicators related to pollution mainly found outdoor as particulates and fungi, but not so relevant in airborne bacteria since those are produced indoor by the occupants mainly. Building projected, executed and maintained according to new RITE 2013 requirements offer in average 60% more reduction of pollution than old ones. It must be taken into account that new buildings are also tighter than the old ones. Carbon dioxide have been used as and indicator of tightness being the Indoor-Outdoor relative CO2 concentration higher in new buildings (indoor minus outdoor concentration of CO2). That means new buildings have higher CO2 readings but that does not mean worst Indoor Air Quality since filtration has been enhanced.