Impact of a green roof system on indoor fungal aerosol in a primary school in Greece.

A primary school was investigated for airborne fungi by a culture-based method, in classrooms underneath a green roof in comparison to conventional concrete roofs. A portable Burkard sampler was used for the collection of air samples onto petri dishes with 2% Malt Extract Agar. The fungal aerosol mean concentration was 71 CFU m-3 (range 17-176 CFU m-3, median 51) in the classroom directly under the green roof, significantly lower than 192-228 CFU m-3 (range 0-1090 CFU m-3, median 69) under the concrete roofs and 188-412 CFU m-3 (range 0-2183 CFU m-3, median 771) in ground floor classrooms. The Indoor/Outdoor ratio was 0.4 for total fungi and 0.2-1.1 for predominant genera underneath the green roof, whereas 1-2.1 and 0.3-3.2 respectively for the rest of classrooms. The Potential Exposure Dose (PED) for fungal particles was calculated to 4.6 CFU kg-1 and 9.3-35.3 CFU kg-1 respectively. The genera Penicillium, Cladosporium and Aspergillus prevailed indoors and in ambient air. Aspergillus concentrations indoors correlated significantly with the concentration of the coarse fraction (PM10) of particulate matter. The genus Penicillium increased indoors during late spring and summer, in temperature 20-23 °C and relative humidity 42-53% and also predominated in ambient air, both indicative of multiple anthropogenic sources of amplification. The evidence about the green roof positive effect on microbial indoor air quality (mIAQ) is a matter of concern for further investigation.

Indoor air quality assessment in the air traffic control tower of the Athens Airport, Greece.

In this study, an assessment of indoor air quality (IAQ) and thermal comfort in the Athens Traffic Control Tower (ATCT) offices of Hellinicon building complex, which is mechanically ventilated, is presented. Measurements of PM(10), PM(2.5), TVOCs and CO(2) concentrations were performed during three experimental cycles, while the Thom Discomfort Index was calculated to describe the employees' feeling of discomfort. The aim of the first cycle was to identify the IAQ status, the second to investigate the effectiveness of certain measures taken, and the third to continuously monitor and control IAQ. During the first two cycles, daily spot measurements of TVOCs and CO(2) were performed at various indoor locations and at the respective outdoor air intake positions, in addition with mean 24-h spot measurements of indoor PM(10) and PM(2.5). Results revealed that pollution levels vary according to the occupancy and the kind of activity. Following that, an automated system (IMAS) was designed and employed to continuously monitor indoor and outdoor CO(2), TVOCs, temperature and relative humidity. The ultimate scope was to control the IAQ and offer acceptable comfort conditions to the employees, whose work is of special nature and extremely demanding. Intervention scenarios were formulated and applied to the system to improve indoor conditions, when and where necessary. Regarding the third cycle, 1-year measurements collected from the system to examine its effectiveness. While it was shown that discomfort may be attributed to co-existence of unsatisfactory thermal comfort conditions and IAQ, usually the sole predominant factor of discomfort feeling is thermal comfort.

An experimental study of aerosol distribution over a Mediterranean urban area.

In this study an attempt is made to investigate the aerosol spatial and size distributions at different heights over the Greater Athens Area (GAA), Greece, under sea breeze conditions and clear sky and to further discuss possible implications for aerosol characteristics. The data used are airborne measurements of aerosol collected during two flights that were performed within the context of the 1997 STAAARTE experimental campaign. The aerosol measurements cover particle diameters from 0.1 to 45.5 microm. The horizontal and vertical distribution revealed that higher concentrations exist within or just above the atmospheric boundary layer, while greater concentrations are observed over the sea compared to land at high altitudes. At all altitudes the number size distributions show dominant diameter ranges between 0.1 and 0.3 microm at all altitudes. The volume distributions are characterised by two modes, one in the accumulation and the other in the coarse particle regime. At lower altitudes, fresh combustion emissions more likely cause the predominance of the size range 0.1-0.3 microm while enhanced physical and chemical processes that favour the growth of smaller particles to larger sizes could also act. The relative humidity does not seem to affect the observed number size distributions at low altitudes, where relative humidity is below 70% while at 4000 m the distributions seem to change over the sea where the humidity increases.

Investigating cigarette-smoke indoor pollution in a controlled environment.

The objective of this study was to investigate the evolution of pollutant concentrations generated by smoking in a controlled indoor environment. For this purpose, a small flat in the centre of Athens, Greece was equipped with NO(x), O(3) and SO(2) continuous measuring instruments and portable analysers for spot measurements of TVOCs and CO(2), while two volunteer smokers remained inside and smoked as normal inhabitants. The results indicated that when windows are kept closed and smoking takes place NO(x), CO(2) and TVOCs concentrations increase by an order of 3, 4 or 10 times, respectively, and decrease returning to initial levels after 1 or 2 h.