Thesis on indoor air pollution

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Abstract : The main objective of this work was to investigate relationships between the schoolenvironment and asthma and asthmatic symptoms in schoolchildren. Data on symptoms werecollected through postal questionnaires answered by 1, pupils in 39 randomly selectedschools, and were related to data on exposures obtained through hygienic measurements in theschools.

Abstract : Clean air is one of the most fundamental human needs. Abstract : It has been increasingly common to design for increased ventilation rates above legislative requirements specified in building codes and other norms as the most optimum way to improve indoor air quality. However, this concept has recently been challenged, for example, by studies demonstrating that the emissions or pollution from used traditional particle filters increases proportionally with air flow through the filter.

This could be achieved by constructing airtight and energy efficient envelopes with functional building materials such as age-resistant plastic films, insulation and different sealing products. Abstract : Chemical compounds in indoor air can adversely affect our comfort and health. The participants sat still indoors for at least 30 min, and completed the questionnaire while seated. The questionnaire was compiled by the surveyor independently.

In order to show the statistic more intuitively, the number of people involved in the questionnaire survey was taken as the denominator, the number of people satisfied with the factor of indoor environment or the people with the symptom was taken as numerator.


Thereby, the result expressed as a percentage was required in following charts. C i and S i are the concentration of measurement and standard for the same air pollutant; n is the kind of measured air pollutants. IAQ according to the calculating index I can be divided into five levels [ 35 ], as shown in Table 4. Table 4. The level of indoor air quality. The gray system theory is theorized by Deng [ 54 ] and developed by Liu [ 55 ]. It focuses on the study of problems involving small samples and poor information and deals with uncertain systems with partially known information through generating, excavating and extracting useful information from what is available.

Grey incidence analysis based on the gray system theory, provides a new method to analyze which factors have primary influence, and which have less influence, on the development of the system. In this paper, the model of absolute degree of grey incidence is used for analysis. The definition of absolute degree of grey incidence is as follows. Based on the result of the Section 2. The theory is based on conservation of mass. A summary of temperature and relative humidity is shown in Table 5.

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In the nine test rooms, 3WN has the greatest temperature fluctuating ranging from Figures 3 and 4 show the number of people and indoor CO 2 concentration respectively on a typical sampling day. Table 5. Summary of the average 5-day temperature and relative humidity during the sampling campaign. CO 2 concentration variation in library rooms. According to the stable daily routine for most students, the number of people had been a gradual increase during — and reached peak at in the rooms 1EW, 1WS, 1WN, 3WS, 3WN. With the arrival of the lunch break, the number of people was falling rapidly during — and reached the lowest at Then the number increased quickly again during — and remained stable until the library closed.

As shown in Figure 4 , indoor CO 2 concentrations seem to be influenced by human occupancy. In most rooms, CO 2 was beginning to build up when the pupils start occupying the library rooms and then started declining slightly during the lunch break. The same upward trend was followed during — It was noteworthy that higher CO 2 concentration happened as the number of people declined during dinner.

This might be explained for the following reasons: one, CO 2 was accumulated constantly with the doors and windows closed during measurement; the other, the emission of CO 2 by the remainder was still greater than wind seepage. By a simple estimation, there is a balance between CO 2 concentration produced and released based on the density of 0. Figure 5 shows the concentration of indoor formaldehyde varies during the daily testing period. From the figure we can see that indoor formaldehyde concentrations were all relatively stable and had similar trends except for 1EW.

This trend can be explained by formaldehyde gathering due to the sources that are irrelevant for people. The volatile date in 1EW might be resulted by the operation. The reason might be that the placed density of books in 1CL and 1CT is almost more than twice it in other rooms and lots of old books are hold in 1CL and 1CT. The reason might be similar with the explanation of formaldehyde. It is important that both the concentrations of formaldehyde and TVOC are under the levels of Chinese standard [ 57 ]. Figure 7 shows that the concentration of indoor and outdoor PM2.

Significant strong correlation between indoor and outdoor PM2. Outdoor concentration of PM2. The concentrations of PM2. The levels indoors are all lower than found outdoors. As shown in Figure 8 , taken together, indoor PM2. For the difference of PM2. The comparison of PM2. Table 6. Data statistic of questionnaires. The results are shown in Table 7. Table 7. Simplified data statistic of questionnaires. For people in different rooms, there may be a big difference on subjective feeling of the same parameter.

A more intuitive comparison is shown in Figure 9 a. With doors and windows closed during the transition season, without air conditioning or ventilation system, the concentration of carbon dioxide is high, the ventilation rate is low, and the air is not fresh. Subjective satisfaction reported by people in the library booking rooms.

Center for the Built Environment

This might be because people in the mall had long exposure time in the library rooms and automatically to maintain a stable position. SBS were associated with odors and environmental factors. Thus, the overall odors perceptions are influenced by many kinds of individual odors, for example, the degradation of cellulose-based materials, mold of walls and emission from body [ 60 ].

The air quality levels in library rooms are calculated based on the data of field measurements, as shown in Figure It is inferred that when outdoor air quality is worse PM2. The upper limit with indoor PM2. According to the indoor air levels, 3WS and 3CT is taken as the representative of different type room respectively to determine the correlation. The satisfaction of IAQ by questionnaire and the concentrations of indoor pollutants by field measurement are shown in Tables 8 and 9.

Table 8. The data of satisfaction and measured concentrations in 3WS. After entering the data in Tables 8 and 9 into the software, we get the results. The correlations between satisfaction of IAQ and the concentrations of pollutants arranged from the largest to smallest, are in order, 0.

It can be seen that the primary indoor air pollutant is not the same in different room. In order to build a more satisfactory indoor environment, the requirements of fresh air and the functionality of the space usages should be considered in the ventilation system or central air-conditioning system design.

ResearchSpace/Manakin Repository

From Section 3. According to research [ 61 ], the plan with the theme of ventilating rapidly in a short time to decrease CO 2 concentration and purifying to eliminate PM2. While for mechanical ventilation, temperature difference between indoor and outdoor air was ignored based on the assumption that there was an electric heating or heat recovery unit at air inlet. The volume fraction of outdoor CO 2 is 0.

The function is holding-reading in 3WS, CO 2 concentration is at much higher level, so choose 3WS as an example to calculate. Because the CO 2 concentration in 3WS is much higher, the calculating results can be applied in other holding-reading rooms. The results of calculating are shown in Figure In the rooms only holding books, CO 2 concentration gets beyond the national standard until but excessive rarely, so ventilating naturally can decrease obviously CO 2 concentration. If air purifiers are no working during ventilating, so N p is 0. By calculating, indoor PM2. Indoor PM2.

The calculating results are as shown in Figure This article presents the onsite measurement of nine library rooms without central HVAC systems in the University of Science and Technology Beijing during non-heating period April in The field measurements including indoor and outdoor air temperature, relative humility and the concentrations of CO 2 , PM2.

Results show that each library room has diverse IAQ. One improving plan is made based on the results. The main findings are summarized as follows: Various indoor air pollutants with varying concentrations were detected in the library rooms in USTB, in terms of the high CO 2 concentration of — ppm, the changing PM2. CO 2 , PM2. Description: Restricted Item.

Indoor air quality and health in schools

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