Bernard Polednik

Particulate matter and student exposure in school classrooms in Lublin, Poland

This study reports particle mass (PM) and number (PN) concentrations and student exposure in classrooms in three secondary schools in Lublin, Poland, during the winter (February-March) and summer (May-June) season measurements. The emissions from residential coal combustion and particle generating didactic experiments carried out in the classrooms significantly influenced the particle concentrations. In the winter season the average student exposure to PM and PN was respectively 2.1±0.4 (mean±standard deviation) and 1.5±0.5 times higher than outdoors.

Particle exposure in a baroque church during Sunday Masses.

Particle concentrations were measured in a Baroque church during five Sunday Masses. The highest particle number and mass concentrations were observed when both candles and the incense were burned. They were respectively 16.8 and 14.3 times higher than outdoors for submicron particles. The exposure to particles experienced by the churchgoers, especially priests and church workers who participated in several Masses on that day, was considerably higher than the exposure experienced at the same time outdoors.

Aerosol and bioaerosol particles in a dental office.

This study reports comprehensive aerosol and bioaerosol measurements in a dental office. The highest submicrometer particle concentrations were observed during dental grinding and they were on average 16 times higher than the indoor background. Certain metallic trace elements and total carbon concentrations were significantly elevated (>10 times) in the particles deposited in the operating room. Dental procedures also contributed to increased bacterial contamination that may pose a health risk both for dental personnel and patients.

Radon and its decay products in an air-conditioned auditorium in correlation with indoor air parameters

The measurements of radon and its attached decay product activity concentrations were carried out in an occupied and unoccupied auditorium during three air-conditioning modes i.e. air-conditioning system switched off (air-conditioning off), air-conditioning system switched off during the night and switched on during the day (air-conditioning on/off) and air-conditioning system switched on (air-conditioning on). Higher average concentrations of radon and its decay products were recorded in the auditorium when the air-conditioning system was switched off. The average particle mass and CO2 concentrations and indoor air thermal parameters were elevated during the air-conditioning on/off mode. A statistically significant (p < 0.001) positive correlation between the decay product concentrations and the particle number and average particle mass concentrations has been observed in the air-conditioning off mode (r = 0.55 and r = 0.68) and in the air-conditioning on/off mode (r = 0.54 and r = 0.62, respectively). A significant negative correlation has been observed between the decay product concentrations and the indoor air temperature and CO2 concentrations in the air-conditioning off mode (r = −0.86 and r = −0.47, respectively). The obtained results confirmed the impact of the air-conditioning system operation on the decrease of health risks related to the presence of radon and its decay products in air conditioned premises.

Radon Hazards in Relation to Elemental and Isotope Composition of the Geological Structures in the Lubelskie Voivodeship

The study involved investigation of the relationship between the radon concentrations in the ground air – and thus in the indoor air – and the geological structure of the Lubelskie Voivodeship (eastern Poland). Both passive and active methods were used for measuring the radon concentrations in coal, phosphate and chalk mines, caves, wells as well as indoor environments. The study also included elemental, uranium and lead isotope analyses of rocks. The performed research showed that Paleogene and Mesozoic sedimentary rocks rich in radionuclides are the sources of radon in the Lubelskie Voivodeship. In the case of the buildings located in proximity to such rocks, characterized by relatively high radon exhalations, radon remediation methods are recommended. Already at the designing stage of buildings, the measures which protect against the hazardous radon gas should be applied.

Comparison of interpretation methods of thermocouple psychrometer readouts

Thermocouple psychrometers allow to determine the water potential, which can be easily recalculated into relative humidity of air in cavity of porous materials. The available typical measuring range of probe is very narrow. The lower limit of water potential measurements is about −200 kPa. On the other hand, the upper limit is approximately equal to −7000 kPa and depends on many factors. These paper presents a comparison of two interpretation methods of thermocouple microvolt output regarding: i) amplitude of voltage during wet-bulb temperature depression, ii) field under microvolt output curve. Previous results of experiments indicate that there is a robust correlation between water potential and field under microvolt output curve. In order to obtain correct results of water potential, each probe should be calibrated. The range of NaCl salt solutions with molality from 0.75M to 2.25M was used for calibration, which enable to obtain the osmotic potential from −3377 kPa to −10865 kPa. During measurements w...

Is the perception of clean, humid air indeed affected by cooling the respiratory tract?

The study aims at determining exposure-response relationships after short exposure to clean air and long exposure to air polluted by people. The impact of water vapor content in the indoor air on its acceptability (ACC) was assessed by the occupants after a short exposure to clean air and an hour-long exposure to increasingly polluted air. The study presents a critical analysis pertaining to the stimulation of olfactory sensations by the air enthalpy suggested in previous models and proposes a new model based on the Weber-Fechner law. Our assumption was that water vapor is the stimulus of olfactory sensations. The model was calibrated and verified in field conditions, in a mechanically ventilated and air conditioned auditorium. Measurements of the air temperature, relative humidity, velocity and CO2 content were carried out; the acceptability of air quality was assessed by 162 untrained students. The subjective assessments and the measurements of the environmental qualities allowed for determining the Web...

Thermal conditions and perceived air quality in an air-conditioned auditorium

The study reports measurements of indoor air temperature (T) and relative humidity (RH), perceived air quality (PAQ) and CO2, fine aerosol particle number (PN) and mass (PM1) concentrations in an air conditioned auditorium. The measurements of these air physical parameters have been carried out in the unoccupied auditorium with the air conditioning system switched off (AC off mode) and in the unoccupied and occupied auditorium with the air conditioning system switched off during the night and switched on during the day (AC on/off mode). The average indoor air thermal parameters, CO2 concentration and the PAQ value (in decipols) were elevated, while average PM1 concentration was lower in the AC on/off mode. A statistically significant (p < 0.001) positive correlation has been observed between T and PAQ values and CO2 concentrations (r = 0.66 and r = 0.59, respectively) in that AC mode. A significant negative correlation has been observed between T and PN and PM1 concentrations (r = −0.38 and r = −0.49, res...

The influence of air conditioning changes on the effective dose due to radon and its short-lived decay products

Abstract Most people spend the majority of their time in indoor environments where the level of harmful pollutants is often significantly higher than outdoors. Radon (222Rn) and its decay products are the example of radioactive pollutants. These radioisotopes are the main source of ionizing radiation in non-industrial buildings. The aim of the study was to determine the impact of air-conditioning system on radon and its progeny concentrations and thus on the effective dose. The measurements were carried out in the auditorium at the Environmental Engineering Faculty (Lublin University of Technology, Poland). Measurements of radon and its progeny (in attached and unattached fractions) as well as measurements of the following indoor air parameters were performed in two air-conditioning (AC) operation modes: AC ON and AC ON/OFF. The air supply rate and air recirculation were taken into consideration. The separation of radon progeny into attached and unattached fractions allowed for determining, respectively, the dose conversion factor (DCF) and the inhalation dose for teachers and students in the auditorium. A considerable increase of the mean radon progeny concentrations from 1.2 Bq/m3 to 5.0 Bq/m3 was observed in the AC ON/OFF mode compared to the AC ON mode. This also resulted in the increase of the inhalation dose from 0.005 mSv/y to 0.016 mSv/y (for 200 h/year). Furthermore, the change of the air recirculation rate from 0% to 80% resulted in a decrease of the mean radon concentration from 30 Bq/m3 to 12 Bq/m3 and the reduction of the mean radon progeny concentration from 1.4 Bq/m3 to 0.8 Bq/m3. This resulted in the reduction of the inhalation dose from 0.006 mSv/y to 0.003 mSv/y.

PARTICLE CONCENTRATIONS IN A CHURCH DURING DIFFERENT WEATHER CONDITIONS – A CASE STUDY

The purpose of this study is to report particle number (PN) and particle mass (PM) concentration changes in the church during three 60-minute Masses held on a cloudy, sunny and rainy day. At each Mass with a similar number of participants the same number of candles was lit and incense was burned. The highest average PN1 and PM1 concentrations of submicrometer particles which respectively amounted to 23.9 pt/cm3 and 241.1 μg/m3 were obtained for the Mass held on a rainy day. During that Mass the maximum PN1 and PM1 concentrations (amounting to 59.4·10 3 pt/cm3 and 632 μg/m3) were respectively about 15 and 39 times higher than the church background levels. The greatest number of submicrometer particles (about 18.5·109) was inhaled by an average participant of the Mass held on a sunny day and it was approximately 7 times higher than the number that would have been inhaled at the same time outdoors. The greatest mass of such particles (about 195.4 μg) was inhaled by an average participant of the Mass held on a rainy day and it was approximately 8 times higher than the mass of particles that would have been inhaled outdoors during the same time.