Simultaneous measurements of the indoor and outdoor particle mass (PM) and particle number (PN) concentrations as well as the air temperature, relative humidity (RH), and CO2 concentrations have been conducted in 6 occupied (L) and unoccupied (V) classrooms in 3 secondary schools in Lublin, Poland, in the heating (H) and summer (S) seasons. The schools were located in residential areas where the majority of private houses are heated by means of coal-burning stoves. The ratios of the average particle concentrations in occupied and unoccupied classrooms (L/V) were higher during the heating season measurements. The ratios of the average particle concentrations during the measurements in the heating and summer seasons (H/S) were higher in occupied classrooms. In both seasons the average PM and PN concentrations amounted to 239 μg/m3 and 7.4×103/cm3 in the occupied classrooms, and to 76 μg/m3 and 5.4×103/cm3 in the unoccupied classrooms, respectively. The particle exposures experienced by students were higher in the monitored classrooms than outdoors and were on average about 50% higher in the heating than in the summer season. A positive correlation between mass concentrations of coarse particles and indoor air temperature, RH and CO2 concentrations in both seasons was observed. The concentrations of fine particles were negatively correlated with the indoor air parameters in the heating season, and positively correlated in the summer season.

The nature and concentration of aerosol particles affect the classroom indoor air quality and have a significant impact on children's and youth's health. The results of investigation of trace elements concentrations, grain size and mineral distribution of aerosol particles and precipitation inside one of the classrooms in Lublin University of Technology have been presented. They were compared with the results of investigation of outdoor aerosols and precipitation. A significant difference between the indoor and outdoor particulate matter was shown. The indoor aerosols contained more Ca and K, while Fe and Pb predominated in outdoor aerosols. The attempt to identify sources of pollution in the classroom indoor air was undertaken on the basis of these results. It was emphasized that quantitative data from studies of aerosol particles in classrooms could play an important role in determination of students' exposure to specific contaminants connected with inhaled aerosols. Utility of such investigations for activities which eliminate sources of hazardous aerosols in schools was also pointed out.

The theoretical dependence between flocculated suspension settling time and mass floe size has been presented. The good agreement with the experimental relation between settling time of 80% of suspension and mass median floe size was showed, which indicates the possibility of developing a new method for clarification efficiency estimation.

One of the concepts of the ventilation rate control in buildings with dense and unpredictable occupancies is based on the CO2 measurements. There are many limitations regarding the validity of CO2 measurement inputs as suitable to the ventilation rate control. Verifying research has been conducted in an air-conditioned auditorium, in the real conditions at altered ventilation air thermal parameters and variable occupancy. The CO2 and the number concentrations of the fine and coarse aerosol particles(> 0.3 μm) and bioaerosol particles (bacteria and staphylococci) as well as the indoor air thermal parameters were measured in the individual sectors of the occupied area. The sensory assessments and instrumental determinations of the acceptability of indoor air quality (ACC) were also performed. The ventilation control strategy based, apart from the CO2 measurements, on the continuous monitoring of the perceived air quality (PAQ) in the auditorium sectors has been suggested. The PAQ monitoring could be accomplished by aerosol concentration measurements and the ACC instrumental determinations. This strategy should ensure a desired PAQ in sectors which benefit the occupants' comfort, health and productivity as well as energy savings not only in the case of its implementation in the considered auditorium.

The indoor aerosols that arc. among others, generated by air-conditioning systems arc especially significant in school facilities. The measurements carried out in the new, air-conditioned auditorium have shown that the aerosol concentrations arc strongly dependent on the operation or the air-conditioning system and the presence of students. The aerosol concentration was approximately 5 times higher when the air-conditioning (AC) system was switched on. An increased air movement inside the auditorium and the connected with it rcsusperuion of the particles settled on the indoor surfaces could be responsible for this fact. It could also result from the ineffective operation ofthe AC filters. The presence of students in the auditorium caused an increase of the coarse aerosol particles irrespectively of the AC system operation. The results of aerosol particle monitoring should be taken into consideration while controlling the AC processes in order to ensure the desired indoor air quality in this type or facilities.

This paper deals with the acceptability (AKC) and perceived concentration of pollutants (D) emitted by occupants in relation to the specific enthalpy (h) and relative humidity (qi) of indoor air. Measurements of AKC/D/, described by semilogarithmic function depend significantly on both In h and In (jl. The equation fits to the data published in the literature in a reasonably good way. Therefore, it indicates that the linear function between AKC and h which is commonly used in literature yields rough approximations. The proposed equation allows for the validation of the indoor mieroclimatc and brings an idea how to make measurements of the perceived air quality instrumentally and how to control the air conditioning process.

Levels and distribution of selected polybrorninated diphenyl ether congeners in dust samples taken from different indoor environments in Lublin, South-Eastern Poland, are reported. The most abundant congeners, found in the majority of sampling sites, were BOE 47, 100 and 28, respectively. The highest levels of examined congeners were observed in dust samples taken from a computer repair facility and labs. BOE 47, 99 and 100, occurring at highest levels and having the greatest contribution confirm that in Polish indoor environments polymer products contain Penta - BOE technical mixture.