Indoorairquality in Portugueseschools: levels and sources of pollutants
Abstract Indoorairquality (IAQ) parameters in 73 primary classrooms in Porto were examined for the purpose of assessing levels of volatile organic compounds (VOCs), aldehydes, particulate matter, ventilation rates and bioaerosols within and between schools, and potential sources. Levels of VOCs, aldehydes, PM 2.5 , PM 10 , bacteria and fungi, carbon dioxide (CO 2 ), carbon monoxide, temperature and relative humidity were measured indoors and outdoors and a walkthrough survey was performed concurrently. Ventilation rates were derived from CO 2 and occupancy data. Concentrations of CO 2 exceeding 1000 ppm were often encountered, indicating poor ventilation. Most VOCs had low concentrations (median of individual species <5 lg/m 3 ) and were below the respective WHO guidelines. Concentrations of particulate matter and culturable bacteria were frequently higher than guidelines/reference values. The variability of VOCs, aldehydes, bioaerosol concentrations, and CO 2 levels between schools exceeded the variability within schools. These ﬁndings indicate that IAQ problems may persist in classrooms where pollutant sources exist and classrooms are poorly ventilated; source control strategies (related to building location, occupant behavior, maintenance/cleaning activities) are deemed to be the most reliable for the prevention of adverse health consequences in children in schools.
During the study period fourteen helicopter flights were recorded (see Table S8 for an overview). The peaks in PM concentrations coinciding with helicopter flights measured indoor in the rooftop service building suggest that emissions originating from the helicopter landings and take-offs can lead to penetration of PM into the indoor environment (Figure 3 ). However, the measurements with the optical instrument used in these measurements only provide information on particle concentrations, as such, there is no information on the particle composition. These particles could have originated from the turbo engines but also from resuspending (coarse) particles from other outdoor sources. It is likely that the fine particles were derived from both the turbo engines and from the surges of coarse particles caused by turbulence from the helicopter rotor. In the second week the week-average B(a)P level of the PM-4.0 captured on the filters in the roof top service building was higher than for the reference locations, suggesting a combustion source as the most plausible origin of the particles. This is suggested to be attributable to the helicopter because of the orientation of the top roof service building relative to the prevailing wind direction in week 1 (Southwest) and week 2 (Northeast). However, as this change is to some extent also observed at other outdoor sampling locations, it must be assumed that this increase might in part be caused by a change in overall general airquality that depends on wind direction. An occasional moderate rise in the PM levels at times when no helicopter landed is explained by indoor activity related to inspections or cleaning in close range to the sampling equipment.
This study provides information on airquality in indoor environments for sport practise. Across four health clubs, concentrations of gaseous (TVOCs, O3, CO2) and particulate pollutants (PM4 and PM1) exhibited large temporal spatial variations. TVOCs highly exceeded limit of 600 μg/m3 designated by Portuguese legislation in all health clubs , even when these were unoccupied, thus indicating magnitude of potential risks for the respective occupants. The highest levels of all gaseous pollutants were observed in HC3, where CO2 levels exceeding the given standard of 1800 μg/m3 (even when the club was empty) indicate insufficient ventilation. In all analyzed clubs, CO2 was well correlated with relative humidity (rs 0.534 – 0.625) and its daily profiles well agreed with occupancies, thus suggesting contribution of human activities (due exhalation during exercising). Overall, levels of gaseous and particulate pollutants were higher when clubs were occupied (p < 0.05) than for vacant periods, with larger medians observed in main workout areas rather than in spaces/studios for group exercise. Regarding PM, higher (∼2 times) concentrations were observed at clubs with natural ventilations. PM1 accounted approximately for 93–96% of PM4; both PM were highly correlated (rs 0.936–0.995) pointing towards originating from the same emission sources.
The quality of the indoor environment is a major health concern due to the fact that most of the indoorair is merely outdoor (or ambient) air with additional pollutants emitted from building materials and consumer products. The indoor environment forms the basic breathing and dermal exposure background for 90% of the lifetime of the European population. The quality of the ambient air in most cities falls far short of the World Health Organization (WHO) guidelines, and most of the indoorair interacts directly with the ambient air through openings that can be controlled to some extent (windows, doors and air-specific uptakes and exhausts) as well as some unwanted openings (leaks, cracks, etc.). The outdoor air is therefore one of the major sources of pollution indoors . To address this problem, the use of mechanical systems equipped with filtering and, more rarely, cleaning capabilities, has been presented as a panacea to reduce both outdoor and indoorair pollution. However, such means are not necessary if local authorities can develop policies and measures on clean ambient air in general, and specifically in schools surroundings. Appropriate rules can be adopted regarding the location, design and management of school buildings, taking into account geographical and current climatic specificities and future climate change scenarios. The SINPHONIE project aimed to gather new, more and better indoorairquality (IAQ) and associated health data from schools across as many European countries as possible. The ultimate goal was to compile a number of recommendations to inform existing and future policies and to propose a set of guidelines towards a healthy school environment in Europe. This approach was linked to the European Environment and Health Action Plan 2004-2010  and the Environment and Health Strategy of the EU.
an indicator of indoorairquality (Twardella et al., 2012). CO 2 concentrations levels are
associated to ventilation rates and since ventilation plays a key role in maintaining IAQ, CO 2
measurements are always crucial. Studies conducted in Greek schools have found that CO 2
concentrations levels frequently exceed their recommended limit values (Synnefa et al, 2003, Santamouris et al., 2008). According to the international literature, the indoor environment of school classrooms is encumbered by airpollutants due to insufficient ventilation, inadequate maintenance and also due to lack of the necessary funding (Mendell and Health, 2005). Thus, the understanding in details of the existing situation of airpollutants in classrooms is essential in order to come up with certain proposals to improve the indoorairquality.
DST, S.A., Braga, Portugal
Since the implementation of the Energy Performance of Building Directive, EPBD, in general, and the entrance into force of the respective Portuguese codes, in particular, buildings are requested to have better energy performances. However, during the buildings performance evaluation, energy issues should not be the only concerns since the indoor environmental quality is also as important. Thus, in this paper it is presented an “in-situ” evaluation of the Portuguese building stock regarding several parameters related to indoor environmental quality (IEQ), envelope thermal quality and operating conditions, natural illumination levels, thermal and acoustic comfort and indoorairquality. During the measurement campaign were evaluated several buildings that encompass different types of construction solutions, climatic zones and construction periods. One of the major objectives of this study was to support the development of building solutions that can optimize all the relevant parameters to the IEQ. Another important objective is the dissemination of the results through public entities, such as construction companies and design teams in order to influence the buildings projects to include other parameters than energy during the design process. Even though the measuring campaign is still in progress, there are already some preliminary results that show that, in average, the Portuguese buildings have a poor envelope thermal resistance, untreated thermal bridges, unsuitable natural illumination levels, several problems regarding high concentration of some pollutants like CO2 or VOC and also problems with acoustic discomfort due to an inadequate sound insulation.
Figure 4 shows the ventilation ductwork connected to the fresh air, exhaust air, supply air, and return air duct systems. The balanced ventilation system consists of two “duct” fans with a flow of 100 L/s (210 cfm) that provides fresh air to the house for one hour out of every three hours. The fans require 70 W each, with the energy from one fan added to the supply airstream and the energy from the other fan exhausted to the outside. The additional two hours of the duty cycle can be used for house conditioning when required, with the ventilation system in a “recirculation” mode rather than fresh air mode. When outside air is “nicer” than inside air, the system oper- ates in “free” conditioning mode, leaving the heat pump off while bringing in fresh air to condition the house; equivalent to opening the windows in the house. The two additional hours also allow for increased fresh air ventilation during periods of high occupancy levels.
Caution must be used in directly extending the ACGIH TLVs ® or other workplace guidelines to spaces covered by this standard and to population groups other than workers. Indus- trial health practice attempts to limit worker exposure to inju- rious substances at levels that do not interfere with the industrial work process and do not risk the workers' health and safety. There is not an intention to eliminate all effects, such as unpleasant smells or mild irritation. Further, the health criteria are not uniformly derived for all contaminants. Irrita- tion, narcosis, and nuisance or other forms of stress are not uniformly considered as the basis for the concentration limits. This is because different organizations use different end points and different contaminants have more or less information available on diverse end points of interest. The target popula- tion is also different from the occupants found in the spaces covered by this standard. Healthy industrial workers tend to change jobs or occupations if an exposure is becomes intoler- able. In contrast, workers in commercial environments such as offices often do not expect to have elevated concentrations of potentially harmful substances in their work environments., nor are Also, monitoring programs are unlikely to be in place, as may be the case with industrial workplaces contaminants. In addition, the general population may have less choice about where they spend most of their time and includes those who may be more sensitive, such as children, asthmatics, allergic individuals, the sick, and the elderly.
(c) Select louvers that restrict wind-driven rain penetration to less than 2.36 oz/ft2•hr (721 g/ m2•hr) when subjected to a simulated rainfall of 3 in. (75 mm) per hour and a 29 mph (13 m/ s) wind velocity at the design outdoor air intake rate with the air velocity calculated based on the louver face area. Note: This performance corresponds to Class A (99% effectiveness) when rated according to AMCA 511-99 AA-9 and tested per AMCA 500-L-99. AA-8
Pollutant Pathways and Driving Forces
Airflow patterns in buildings are determined by the combined forces of mechanical ventilation systems, human activity, and natural effects. Air pressure differences created by these forces move airborne pollutants from areas of higher pressure to areas of lower pressure through any available openings in building walls, ceilings, floors, doors, windows, and HVAC systems.
From a logic perspective, if the VAC system is design properly, the recirculat- ing STC unit operates dry, providing sensible cooling only. Thus, at this unit, there should be no danger and thus no concern for creating an environment that encourages microbial growth. This then becomes a simple, inexpensive air handling unit with no problems of freeze protection or damper interlocks. Furthermore, if the VAC unit discharge air is ducted directly to the space, the STC unit is smaller by the amount of air provided by the VAC unit. Also, the STC unit has a much lower pressure drop than a more “conventional” unit because it doesn’t require pressure losses through the mixing dampers, preheat coil, eliminators, wet cooling coils, and filters designed to remove atmospheric impurities. Being able to reset the sup-
According to ISO 7730 , and ASHRAE Standard 55 , the sensation of thermal comfort can be defined as “that condition of mind that expresses satisfaction with the thermal environment”, that is, the person is thermally comfortable in a certain indoor environment when he or she does not feel cold or hot. This definition assumes a certain degree of individual subjectivity, associated with the physical aspects (thermal environment) and the subjective intrinsic physiological and psychological aspects of the occupant . Thus, it is difficult to achieve thermal comfort conditions in a space that satisfies all its occupants. Moreover, one must take into account the adaptation that a person experiences when entering a space from another with different thermal comfort requirements .
Regarding some situations, measurements of indoor CO 2 concentrations can be used to assess indoorairquality and ventilation performance [ 44 , 46 , 47 ]. The relationship between CO 2 concentration and the ventilation rate, under steady-state conditions, is presented in ASHRAE Standard 62.1 [ 48 ], which also provides an equation that allows us to estimate the CO 2 generation rates in L/s per person. This is dependent on the metabolic rate, the respiratory level, the height and body mass of the person, as shown by Persily and de Jonge [ 49 ]. Normally, an indicator of an acceptable indoorairquality is a CO 2 concentration below 1000 ppm [ 48 ]. However, associations between CO 2 concentrations and occupant perceptions of the indoor environment are more complex because they combine several issues including the comfort impacts of CO 2 itself, associations between the CO 2 concentrations and other contaminants, and the relationship between CO 2 and ventilation [ 50 ].
released by samples of four new carpets collected directly from the manufacturers' mills and packaged to preserve their chemical integrity showed that the concentrations and emission rates of most compounds decreased rapidly over the first 12 hours. This initial period, in which the decay rates were exponential, was followed by a period of slower decay and at the end of the week-long experiments, the concentrations of all but one compound were 10 parts per billion or less . For carpets, the “new odour” is largely due to 4-phenylcyclohexene (4-PC), which, because it has a very low odour threshold, even at trace levels it can still be detected by the human nose. 4-PC is a by-product formed during the polymerisation of styrene-butadiene rubber (SBR) latex used to hold the fibres to the backing, and most of it will have been evaporated away during manufacture. Toxicology studies have shown that 4-PC is not a health hazard at the levels experienced from carpet . Nevertheless, keeping rooms well ventilated during installation and for a few days after, will ensure the 4-PC odour and other VOCs will dissipate rapidly. In addition, modern adhesives have significantly lower VOC emission levels. The Carpet and Rug Institute “Green Label” certification for environmentally friendly carpet in the US, has a testing and labelling programme to certify carpets, underlays and adhesives meeting stringent VOC emission standards.
All staff and students will wash their hands before and after handling animals, cage debris, or animal supplies.
10.2 Food Services
Cooking activities generate odors, moisture, food waste, and other trash, which, if not managed carefully, can lead to IAQ problems. Lakeville Area Public Schools have assigned the following responsibilities to food service staff to assist with IAQ management:
Odours are associated with occupancy, cook ing, bathroom activities, waste etc. Odour pollu tion is more often associated with discomfort rat her than serious health effects. The human sense of smell permits perception of very low concen trations of odours (a few ppb). P.O. Fänger intro duced in 1988 two new physical units, namely olf and decipol, the airquality units which enable the evaluation of different pollutants on the same scale 141. He quantified air pollution sources by comparing them with a well-known source - a standard sedentary person in thermal comfort. One olf is defined as the emission rate of airpollutants from a standard person. The decipol unit is defined as the perceived intensity of air pollution caused by one standard person located in the room which is ventilated by 10 litres/s of
In 14 homes in the UAE, indoor and outdoor elemental composition was examined. The composition profiles for indoor and outdoor samples were similar, which suggests that ambient infiltration may play a role in indoor PM concentrations. Carbon and silicon were identified as the most abundant elements. The presence of carbon inside the home is indicative of a combustion source, possibly from indoorsources such as tobacco smoke or incense. Cooking with natural gas may also be a source for some homes, but it may not be as prominent a source as one would find in the US or Europe because the kitchens of most Emirati homes are located in a separate building (e.g. 69% of homes reported having detached kitchens in this study). Ambient sources of carbon, in- cluding automobile exhaust from traffic, may also infiltrate into homes. The higher indoor presence of carbon in urban compared with rural areas may be due to the higher density traffic and lends support to the suggestion of ambient infiltration. Conversely, silicon, which is the primary element in sand, was more abundant in rural PM samples, possibly due to less dense neighborhoods and smaller buildings that permit sand to blow more freely and infiltrate into homes. However, as noted previously, the total concentration of carbon may have been unde- restimated due to the polycarbonate-coated SEM stubs used in this study, which are less sensitive to carbona- ceous particles. This sample media bias may explain the lack of association found between activities such as smoking and burning incense indoors with indoor concentrations of PM.
elevated concentrations are a potential threat to human health, and the environment. Exposure to these pollutants can lead to various deleterious health effects like respiratory symptoms and lung disorder (USEPA, 2012). Exposures to these pollutants vary in outdoor and indoor environments, duration of stay, and involvement in particular activities. Even prolonged or continuous exposure to some daily activities can cause an increase in health risks like CO exposure due to electric and gas stoves, respiratory infections due to parental smoking and smoke due to cooking activities (A.P. jones, 1999), prevalence of cough and phlegm among women using open fire (Bruce et al. 1998). The time spent in a particular microenvironment is a major factor which governs the exposure and risk levels for an individual. A regular personal monitoring of these pollutants is required to avoid such health risks.