Indoor Air Quality And Ventilation Essay In Sydney Buildings.

The Sydney CBD experiences heavy traffic and high population density relative to other parts of Australia, and as a result experiences high ambient concentrations of air pollution. Both, residents within the CBD and workers that commute to the CBD have raised concerns about air pollutant concentrations, specifically indoor environmental quality, where these people spend most of their time.

The ambient indoor air quality across Sydney is relatively unknown, as is the contribution of outdoor air pollutants to indoor environments.The concentration and composition of indoor air pollutants is determined by a multitude of variables,building ventilation type likely to be the most predominant factors in most scenarios.In 2012, work was commissioned by the City of Sydney, to assess whether building ventilation type has an impact on prevalence and concentrations of indoor air pollutants.

Eleven buildings across the CBD were assessed. These buildings were selected for assessment of the occurrence and composition of air pollutants. Buildings were selected due to their use in a commercial capacity, proximity to central Sydney and their spatial distribution. Buildings with building ventilation types were classified as natural, mechanical and mixed-type ventilation.Additional to ventilation type, building conditions were documented to assess their potential impact on indoor air quality; including the age of construction and design (between the years 1891 and 1993),renovations performed, local history and surrounding industry, building entrance orientation, and roof
type. 

The indoor air conditions of a building in terms of pollutant concentration and prevalence is a function of different factors (Hodas et al, 2016). These include the indoor air condition, outdoor air conditions and also how the indoor and the interaction between the indoor and the outdoor air conditions (Liu et al, 2016). Poor indoor air quality may have negative health implications to humans and therefore knowledge about it helps in its control (Tham, 2016). One of the causes of the interaction between the indoor and the outdoor air condition is due to the ventilation of the building (Carrer et al, 2015).

General question

• Does the ventilation type of the buildings in the CBD of the city of Sydney have an effect on the indoor air pollution?

Specific questions

• How does the outdoor air pollutants for Sydney Australia compare to the indoor air pollutants.
• What is the general indoor air quality of a typical building in Sydney Australia?
• Are there other factors that contribute to the indoor air quality of the buildings in Sydney Australia?
• Are there seasonal variations of the indoor/outdoor ratios of air pollutants in the buildings in Sydney Australia?

This project aims at determining whether the ventilation type in a building in the central business district of Sydney city contributes to the indoor air condition in terms of pollution, whether it affects the prevalence and the concentration of the indoor air pollutants in relation to the outdoor air conditions. This will be done by comparing the indoor/outdoor ratios of air pollutants across buildings of different ventilation types. Other factors that also contribute to the indoor air pollution in the buildings in the city of Sydney Australia will also be determined by comparing the indoor air pollutant prevalence and concentration across different buildings and in different locations.

Materials and methods

There were different air quality parameters measured in order to determine the quality of the indoor air in the buildings in the city of Sydney Australia. Each of these parameters and the devices used for each are shown in the table below

In this project, eleven buildings were selected and used. There were different factors considered in the selection of the buildings to be used in for the experiment in order to ensure good results were obtained. These factors were the use of the building, the spatial distribution and the proximity to the Central Business District of the city of Sydney. The commercial use buildings located in the CBD of Sydney that were well spaced from each other were chosen to be used for this research project.

Their type of ventilations were then determined before checking the air quality inside the building. The ventilation types were mechanical ventilations, natural ventilation and the mixed type of ventilation. Other physical factors of the buildings that were assessed to be used as research parameters in this project were the physical condition of the building, the building age and design, the local history of the building, the renovations performed on the building, the surrounding environment such as the surrounding industry, the type of roof of the building and the orientation of the building entrance.

Materials and Methods

Results and discussion

 The results of this project will be aimed at answering the general and specific questions that of the research. Therefore, the results will be analyzed and discussed to suit and answer a specific question.

1. General quality of indoor air in a typical building in Sydney Australia

Table 1

The table above shows annual average indoor air quality parameters that were measured for different buildings located in different locations in Sydney Australia. These parameters informs a lot on the indoor air quality of buildings in Sydney (Liu et al, 2018).

Generally, the quality of indoor air in a typical house in Sydney is poor. This is because it does not meet the threshold of the generally acceptable standards of the indoor air (Persily, 2015). This is because most of the air quality parameters are beyond the recommended limits as shown by the table below

Ventilation type and air and the indoor air quality.

All the eleven houses that were used in the research project had different types of the ventilation. These include the combine natural and mechanical type, the natural ventilation type and the Heating Ventilation and Air Conditioning (HVAC) air conditioning. This project aims at establishing whether the type of ventilation has any significant influence on the indoor air quality. This will be done by taking a representative of one building with the each of the three types of ventilation and comparing the relationship between indoor and the outdoor air conditions.

Table 2

The above results shows that the type of the ventilation affects the quality of the indoor air. Different parameters of the air quality depend on the type of ventilation. For instance, in the table above, the colony forming units in a building depends are more in the naturally ventilated buildings, followed by the combined natural and mechanical type of ventilation. The heated ventilation and air conditioned houses has little colony forming units of the fungal spores. This shows that it has a better air flow as compared to the others. This is because poorly ventilated houses gives a good environment for development of spores (Zamora et al, 2017)

The amount of the carbon dioxide inside the houses also depends on the type of ventilation. The heated ventilation and air conditioned houses has high amounts of carbon dioxide because of the carbon dioxide produced during heating (Chau, Leung, & Ng, 2015). However, the ventilated house that are without heating has lower amount of carbon dioxide.

• The ratio of Indoor/Outdoor air pollutants.

The air pollutants inside the buildings differs from that of the outside in Sydney Australia.

Results and Discussion

Table 3

The above table shows Indoor/Outdoor ratios of different air quality parameters in Sydney.

These values have different meanings. If the I/O ratio greater than 1.2, this means that there is a higher indoor concentration than the outdoor concentration and this is caused by the indoor sources (Rivas et al, 2015). If the I/O ratio ranges between 0.8 and 1.2, it means an equilibrium between indoor and the outdoor conditions will be arrived at while an I/O ratio below 0.8 shows a higher concentration in the outdoor than in the indoor hence a possible influence (Sajani et al, 2015).

1. Seasonal variation of I/O ratio

Table 4

The above table show the Indoor/Outdoor ratios for the total suspended particles in buildings with different types of ventilation for the months of January and September. This parameter and the two months has been used as a representative dataset and shows that there is a seasonal variation of the Input/output ratios of pollutants across buildings of  different ventilation types in Sydney Australia

1. Contribution of other factors to the air pollutants concentration

The research in this project involved not the type of ventilation the building had to determine the relation with the indoor pollutants but also other factors such as the age of the building, population density, size of the building and the building material. This is because of the seasonal variation of the activities (Zhu et al, 2015).

Figure one shows the correlation that exists between the concentration indoor pollutants and the age of the building while figure two shows the correlation between the population density and the concentration of pollutants. These two parameters has been used as a representative data. There is no any significant correlation in the two figures. This show that there is no significant correlation and hence no significant relationship (Cohen, West, & Aiken, 2014) between the concentration of pollutants in the buildings in Sydney and these factors.

References

Carrer, P., Wargocki, P., Fanetti, A., Bischof, W., Fernandes, E.D.O., Hartmann, T.,

Kephalopoulos, S., Palkonen, S. and Seppänen, O., 2015. What does the scientific literature tell us about the ventilation–health relationship in public and residential buildings?. Building and Environment, 94, pp.273-286.

Chau, C.K., Leung, T.M. and Ng, W.Y., 2015. A review on life cycle assessment, life cycle

energy assessment and life cycle carbon emissions assessment on buildings. Applied Energy, 143, pp.395-413.

Cohen, P., West, S.G. and Aiken, L.S., 2014. Applied multiple regression/correlation analysis

            for the behavioral sciences. Psychology Press.

Hodas, N., Loh, M., Shin, H.M., Li, D., Bennett, D., McKone, T.E., Jolliet, O., Weschler, C.J.,

Jantunen, M., Lioy, P. and Fantke, P., 2016. Indoor inhalation intake fractions of fine particulate matter: review of influencing factors. Indoor Air, 26(6), pp.836-856.

Liu, S., Li, R., Wild, R.J., Warneke, C., de Gouw, J.A., Brown, S.S., Miller, S.L., Luongo, J.C.,

Jimenez, J.L. and Ziemann, P.J., 2016. Contribution of human?related sources to indoor volatile organic compounds in a university classroom. Indoor air, 26(6), pp.925-938.

Liu, Z., Cheng, K., Li, H., Cao, G., Wu, D. and Shi, Y., 2018. Exploring the potential

relationship between indoor air quality and the concentration of airborne culturable fungi: a combined experimental and neural network modeling study. Environmental Science and Pollution Research, 25(4), pp.3510-3517.

Persily, A., 2015. Challenges in developing ventilation and indoor air quality standards: The

            story of ASHRAE Standard 62. Building and Environment, 91, pp.61-69.

Rivas, I., Viana, M., Moreno, T., Bouso, L., Pandolfi, M., Alvarez-Pedrerol, M., Forns, J.,

Alastuey, A., Sunyer, J. and Querol, X., 2015. Outdoor infiltration and indoor contribution of UFP and BC, OC, secondary inorganic ions and metals in PM2. 5 in schools. Atmospheric Environment, 106, pp.129-138.

Sajani, S.Z., Ricciardelli, I., Trentini, A., Bacco, D., Maccone, C., Castellazzi, S.,

Lauriola, P., Poluzzi, V. and Harrison, R.M., 2015. Spatial and indoor/outdoor gradients in urban concentrations of ultrafine particles and PM2. 5 mass and chemical components. Atmospheric Environment, 103, pp.307-320.

Tham, K.W., 2016. Indoor air quality and its effects on humans—A review of challenges and

            developments in the last 30 years. Energy and Buildings, 130, pp.637-650.

Zamora, P., Casas, A.G., Dueñas, M., San Martin, R. and Diez, J.J., 2017. Factors influencing

growth, sporulation and virus transfer in Cryphonectria parasitica isolates from Castilla and León (Spain). European journal of plant pathology, 148(1), pp.65-73.

Zhu, Y., Yang, L., Meng, C., Yuan, Q., Yan, C., Dong, C., Sui, X., Yao, L., Yang, F., Lu, Y. and

Wang, W., 2015. Indoor/outdoor relationships and diurnal/nocturnal variations in water-soluble ion and PAH concentrations in the atmospheric PM2. 5 of a business office area in Jinan, a heavily polluted city in China. Atmospheric Research, 153, pp.276-285.