The Helsinki Office Environment Study: Air Change in Mechanically Ventilated Buildings

Abstract The objective of this study was to assess the magnitude and balance of mechanical ventilation in the rooms of Helsinki metropolitan office buildings with different types of ventilation systems. A random sample of 50 office buildings was selected from the Building Registry. Of these buildings, the 33 that have a mechanical ventilation system were included in this study. Most office buildings in the Helsinki metropolitan area have a ducted supply and exhaust system and hot water radiator heating. Air recirculation is used in about half of the buildings which have a mechanical supply and exhaust system. The average exhaust airflow was 1.2 L/s, m² (SD 0.73) or 17.2 L/s per person (SD 11.6). The variation of the airflows was found to be very high among the buildings, and among the rooms within the buildings. Therefore, even though the ventilation rates on average comply with the Finnish building code, it was found that many people were working in offices with airflows which were either too low or unnecessarily high.     

Information technology and changes in industry

Because of its generic character, information technology (IT) is a key technology in changing the industrial structure and daily routines of companies. The diffusion process of new technologies, including information technology, is a complicated process and difficult to manage. Increasing understanding of this process means increasing management of the technology and its use. The diffusion process of a technology can be described by the form of a S-shaped curve. Such a curve is a function of time giving the penetration level of the particular technology. Because the function itself is dependent on so many variables and arguments, the only way to increase understanding of the existing status and the future improvements is to use modularisation (i.e. finding components whose behaviour can be managed) and thereby achieve an incremental increase in our knowledge of the continuing process. This investigation includes state-of-the-art studies, case-studies and analyses on the diffusion process of specific products. Each of these provides both quantitative and qualitative data to produce a synthesis giving a clear view of the diffusion process. This paper reviews some of the results of two studies (Jaakkola & Mertanen, 1990; Latvala et al., 1990) on the diffusion of information technology in Finnish industry. The experiences and results of a national microelectronics program are reported. Basic principles and the character of the diffusion process are discussed, and in conclusion, certain details of the diffusion process of IT are discussed.     

Significance of humidity and temperature on skin and upper airway symptoms

The objective of the present study was to assess the effect of absolute and relative humidity, temperature and humidification on workers' skin and upper airway symptoms, and perceptions in the office environment. Associations between physical factors, and symptoms and perceptions were assessed in logistic regression models. At temperatures between 18 and 26 degrees C, relative humidity of 17-40%, and absolute humidity of 3.3-5.6 g H2O/kg air, skin symptoms and nasal dryness and congestion were alleviated by both kinds of humidity. Pharyngeal dryness increased when temperatures rose and was alleviated with a rise in relative humidity. Eye symptoms showed no dependence on humidity. Any kind of humidity increased odor sensation. Stuffiness increased when the air was humidified. In non-humidified conditions (21.3-22.7 degrees C, 20.0-31.7%, 3.3-5.6 g H2O/kg air), skin and nasal symptoms showed no association with humidity or temperature. Pharyngeal dryness diminished when humidity rose. In addition, the association between humidity and odor disappeared. In humidified conditions (21.5-23.7 degrees C, 26.6-41.2%, 4.2-7.0 g H2O/kg air), nasal dryness and congestion were alleviated by both absolute and relative humidity, and odor perception increased. Skin dryness and rash, pharyngeal dryness, and nasal dryness and congestion are alleviated in higher humidity. Steam humidification results in a risk for increased perception of odor and stuffiness.     

Effect of industrial pollution on soil-to-plant transfer of plutonium in a Boreal forest.

Plutonium in a forest ecosystem was studied at different distances from the copper and nickel smelter at Monchegorsk, Kola Peninsula, Russia. Soil and plant samples were collected 7 (site A), 16 (B), 21 (C) and 28 (D) km from the smelter and at a reference site situated in Finland, 152 km from Monchegorsk. The deposition of Cu in litter and in the organic layer decreased from 10700 mg/m2 at site A to 33 mg/m2 at the reference site, the deposition of Ni from 14300 to 29 mg/m2. From the reference site to site A, the volume of the litter layer increased almost five-fold. Most of the 239,241Pu in soil was found in the organic layer and in the litter layer. When industrial pollution increased, the content of 239,240Pu in the litter layer increased (from approx. 0.5 at site D to 15 Bq/m2 at site A) whereas, that in the organic layer decreased (from approx. 20 at site D to 5 Bq/m2 at site A). Four different plant species typical for the subarctic environment were collected at each sampling site: Deschampsia flexuosa (forest hair grass); Empetrum nigrum (crowberry); Vaccinium myrtillus (blueberry); and Vaccinium citis idaea (lingonberry). The concentration of 239,241Pu increased with pollution in Deschampsia flexuosa (from approx. 2 at site D to 7 mBq/kg at site A), Empetrum nigrum (from approx. 3 at site D to 14 mBq/kg at site A) and Vaccinium myrtillus (from approx. 1 at site D to 8 mBq/kg at site A). In Vaccinium vitis idaea, the Pu concentration did not have any clear trend of association with pollution. With the exception of Vaccinium vitis idaea, the aggregated transfer factors of plutonium (m2/kg) for the plants studied increased almost ten-fold from site D to site A, the range being 3 x 10(-5)-3 x 10(-4) m2/kg for Deschampsia flexuosa, 7 x 10(-5)-5 x 10(-4) m2/kg for Empetrum nigrum and 3 x 10(-5)-3 x 10(-4) m2/kg for Vaccinium myrtillus. The most likely explanation for the higher transfer factors of plutonium near the smelter is contamination of the plants by litter rather than root uptake.     

Evaporative Cooling of 3He-4He Mixture Films

Heat transport by saturated ³ He- ⁴ He films has been studied at temperatures 50..350 mK and the bulk concentration of ³ He ranging from 0.1 ppm to 5%. The cooling of the film, when locally heated above 160 mK, is mainly via 2D flow of surface ³ He from colder area followed by evaporation of ³ He. At certain heating power the 2D flow becomes a bottleneck, the heated spot runs out of ³ He and its temperature abruptly increases. The critical power is nearly proportional to the surface density of ³ He. For higher ³ He concentrations another distinct step in temperature has been observed at a lower heating power. It is attributed to the existence of an excited ³ He surface state whose population starts at ³ He surface density of 3.5×10 ¹⁴ cm^–2 . The second state is located about 1.2 K higher in energy than the ground state and provides an additional channel for the 2D flow of ³ He.     

Simple active method for reducing magnetic interference in a thermoelectrically cooled photomultiplier tube

We present a simple modification for thermoelectrically cooled photomultiplier tube (PMT) assemblies that eliminates the magnetic interference between the peltier element and the PMT. An active compensation is accomplished by forming current loops of the wires of the peltier element and placing them in such a way that they eliminate the interfering magnetic field. It is demonstrated that the improved system reduces measurement errors of the order of 1% to statistical noise at the level of 0.07%.     

Bayesian methods for elucidating genetic regulatory networks

Bayesian network methods are useful for elucidating genetic regulatory networks because they can represent more than pair-wise relationships between variables, are resistant to overfitting, and remain robust in the face of noisy data.     

Hygroscopic properties of mixed ammonium sulfate and carboxylic acids particles

The hygroscopic growth of internally mixed ammonium sulfate and carboxylic acid particles was measured as a function of relative humidity by using a tandem differential mobility analyzer (TDMA). In TDMA experiments the organic compounds with different solubilities act in several ways, ranging from the behavior of totally insoluble substance to that of soluble compounds. The hygroscopic properties for mixtures containing either adipic acid or phthalic acid together with ammonium sulfate indicate that the organic fraction of the particles behaves as an inert mass and does not contribute to water uptake. The mixtures involving malonic acid or succinic acid increased the water uptake of the ammonium sulfate part only. The results indicate that the solubility of the organic fraction in individual aerosol particles clearly influences the aerosol–water interaction.     

Elemental and organic carbon exposure in highway tollbooths: a study of Taiwanese toll station workers

The carbon composition of fine particles (PM(2.5)) from traffic exhausts may play a role in adverse health effects. The objective of this study was to assess the concentrations of elemental and organic carbon in PM(2.5) in traffic exhausts from different types of vehicles in the booths of Taiwanese toll station workers and estimate the relations between traffic density and carbon concentrations. Tollbooth indoor monitoring samples were collected for 10 days to assess the 8 h integrated PM(2.5) concentration. Particle samples were analyzed for the content of total carbon, and elemental, and organic carbon. The mean carbon concentrations in the bus and truck lanes were [total: 167.7 microg/m(3) (SD 79.8 microg/m(3)); elemental: 131.7 (66.2); organic: 36.0 (25.8)], substantially higher compared with the car lanes with cash payment [39.2 (29.5); 20.2 (19.5); 19.2 (14.6)] and the car lanes with ticket payment [34.1 (26.1); 15.8 (17.6); 18.5 (12.2)]. The increase in elemental carbon concentration per vehicle in the bus and truck lane was 14 and 9 times greater than that of car lanes of ticket payment and car lanes of cash payment. The mass fraction of carbonaceous species in PM(2.5) accounted for 54% in bus and truck lanes, whereas the corresponding figure was 30-31% for car lanes. Elemental carbon is an important component of diesel exhaust. Workers in toll stations are exposed to high levels of both elemental and organic carbon.