Browsing by Author "Almeida, G."
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- Air Quality in a children Day Care Centres - Pilot StudyPublication . Cano, M.; Aguiar, F.; Almeida, G.; Proença, C.The negative impact of a poor indoor air quality in children’s health is well recognized and the establishment of a relation between air quality, ventilation and children’s health is crucial to correct the actual situation. Levels of carbon dioxide usually exceed recommended values and are often associated with the raise of many other indoor pollutants accumulated in consequence of poor ventilation rates. This paper describes field measurements of chemical and biological indoor contaminants in order to investigate indoor air quality in a children day care center (CDCC). Objective The aim of this pilot study was to point out the need for indoor air quality investigations in CDCC in order to control ventilation rates and prevent children respiratory diseases. Material and Methods The monitoring tasks were carried out in a CDCC in Lisbon with the evaluation of suspended particulate matter, carbon dioxide, carbon monoxide, total volatile organic compounds (TVOC’s), bacteria and fungi. Relevant measurements of chemical and biological parameters were also conducted outdoors. The studied CDCC had mixed ventilation with extraction in toilets and openable windows. Carbon monoxide, carbon dioxide and TVOC’s were monitored using a Photoacoustic Multigas Monitor Type 1312, INNOVA, Air Tech Instruments. Particulate matter was collected by active sampling into PVC filters using pumps operating at 2 L/min airflow, followed by gravimetric analysis. Samples of viable microorganisms were collected using the MAS-100 sampler with Malt Extract Agar (MEA) plates supplemented with chloranphenicol, Trypticase Soy Agar (TSA) and MacConkey agar as collecting media for fungi, total bacteria and gram-negative bacteria respectively. Field campaign was conducted in March 2008, during routine school activities (10:00-17:00). Results TVOC’s concentrations exceed recommended limits in one of the ten studied rooms, being also one of the rooms with CO2 concentration above the recommended value (2200 mg/m3). CO concentrations ranged from 0,064 mg/m3 to 0,361 mg/m3 never exceeding 12,5 mg/m3. The mean CO2 concentration indoors exceeds 1800 mg/m3 in 7 of the 10 studied rooms, with a maximum concentration of 3750 mg/m3, a minimum of 1630 mg/m3 and an outdoor level of 773 mg/m3. The results obtained show a relation between CO2 and bacterial concentrations, being also observed a predominance of gram-positive bacteria. Fungal spore concentrations ranged from 116 to 476 ufc/m3 and the outdoor level (582 ufc/m3) was never exceeded. The maximum total suspended particulate matter concentration obtained was 0,162 mg/m3 with an outdoor level of 0,062 mg/m3, the minimum level was obtained in the nursery (0,051 mg/m3). Conclusion This pilot study provides evidence that ventilation in the monitored CDCC is clearly insufficient to maintain an acceptable indoor air quality. Being the human occupancy the major source of CO2 and bacteria, it is possible to predict the accumulation of other infectious agents, such as human origin viruses and also of chemical contaminants from indoor sources, as a consequence of poor ventilation. These results are in accordance with previous studies that report an increased risk of infectious diseases of children attending day care centers compared with those cared for at home. Further research is needed with an enlarged number of CDCC in order to develop guidelines to create healthy environments for children.
- Preliminary results on indoor environmental quality in day care centers located in LisbonPublication . Cano, M.; Azevedo, S.; Aguiar, F.; Almeida, G.; Brás, C.; Pinhal, H.; Nogueira, A.; Proença, M.C.The growing concern about indoor air quality results from the knowledge that exposure to indoor air pollutants may be higher than the exposure to outdoor air pollutants and from the evidence that in most developed countries day care centers are places where children spend most of their time. How environmental factors affect children respiratory health is still controversial and unclear. This paper describes the results from field measurements of physical parameters, chemical and biological indoor contaminants, to investigate indoor environmental quality, in 70 classrooms of 10 Children Day Care Centers (CDCC), located in Lisbon. Objective The aim of this study is to gather information on indoor environment of CDCC in order to correlate it with both ventilation and children’s health. Material and Methods Chemical contaminants (carbon dioxide, carbon monoxide, formaldehyde, total volatile organic compounds and PM10), biological contaminants (bacteria, fungi and house-dust mites) and thermal comfort parameters were monitored. Formaldehyde was analyzed according to NIOSH 3500 method using a visible absorption spectrometry with air samples taken on impingers by active sampling. Total volatile organic compounds were analyzed by gas chromatography according to the ISO 16000, part 6, with air samples taken on Tenax TA sorbent by active sampling. Carbon monoxide and carbon dioxide measurements were made using a Photoacoustic Multi- Gas Monitor INNOVA. Samples of viable microorganisms were collected using a MAS-100 sampler with Malt Extract Agar plates, Trypticase Soy Agar and MacConkey agar as collecting media for fungi, total bacteria and gram-negative bacteria. Dust samples were collected on filters using a vacuum cleaner with a DustreamTM collector and determined using an ELISA test to quantify mite antigens. PM10 were collected using PTFE filters on Personal Environmental Monitors attached to personal pumps and the filters were analyzed gravimetrically for particle mass. Thermal comfort was evaluated according to the ISO 7730 International Standard using a 1213 Bruel & Kjaer analyzer. Results The reported preliminary results only represent a small part of a larger study under development in 20 CDCC located on Lisbon and Porto. The mean CO2 concentration indoors exceeded the recommended level of 1800 mg/m3 in 54% of the 70 studied rooms, with a maximum concentration of 5630 mg/m3 and an outdoor average of 839 mg/m3. The majority of the studied rooms had suspended particulate matter, TVOC’s and formaldehyde concentrations under the recommended limits. In 51% of the rooms the bacterial concentrations exceed 500 ufc/m3 (recommended limit), being also observed predominance gram-positive bacteria. In 50% of the studied rooms fungal concentrations were above 500 ufc/m3, however the mean outdoor concentration was 560 ufc/m3. Conclusion The preliminary results provide evidence that ventilation is insufficient, resulting in the accumulation of human source contaminants, such as bacteria and CO2. Taking into consideration that the results correspond to the Spring period, when occupants maintain windows and doors open, we expect worse results in the Winter period.