Date

2023-1-25

Author

Aydın, Neşe

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Urban environment characteristics have a crucial role in air quality. The geographic location of the city, the natural features and factors brought by this location, and different solid/void relationships, building densities, levels of greenery, street connectivities, land-use mixes and traffic densities affect air quality. Some urban environment characteristics can cause more air pollution than the others. Current research shows that children are more affected by air pollution than adults because they breathe more often. This is also why respiratory diseases become chronic during childhood. Asthma is one of the chronic diseases that has been seen as very common in children over the past few decades. The dynamics of this occurrence indicate that it is the effect of changes in the environment rather than the influence of, for example, age, gender and heredity. Evidence shows that asthma starts in childhood and mostly persists into old age, which explains the importance of focusing on children to decrease the prevalence of asthma in the general public. Understanding the factors that explain mesoscale urban characteristics that affect outdoor air pollution is essential for planners and designers to develop effective mitigation measures and prevent children's exposure to air pollution. Regarding this, the thesis asked three main research questions: (1) What is the relationship between mesoscale urban environment characteristics and outdoor air quality? (2) Is there a relationship between urban environment-caused outdoor air pollution and childhood asthma? And, (3) What are the physical characteristics of the areas where children are more prone to asthma? In order to respond these questions, four regions with different urban environment characteristics have been selected in Ankara, Turkey. Next, 800 m radius circles are drawn around each public primary and secondary school, located inside these four regions, to determine the range of children’s neighborhoods. The natural environmental characteristics (altitude, temperature, relative humidity, wind speed) and built environmental characteristics (figure-ground, building density, land-use mix, greenness, street connectivity, traffic volume and proximity to industrial areas) of the chosen neighborhoods were analyzed in ArcGIS. Afterward, the streets in these four regions were classified based on their typologies. Air quality measurements in terms of particulate matter (PM10 and PM2.5) were made in the selected streets from each region three times (two on weekdays and one at weekends at peak hours). PM10 and PM2.5 measurements were made with 2 DustTrak II 8530 devices mounted on the hood of the car while traveling by car at min 5 to max 20 speed and stopping for 2-5 minutes at the specified points. Finally, doctor-diagnosed children data of the regions that are registered in Family Public Health Centers was collected from the Ministry of Health. The research questions of the thesis were addressed using all of these data sets. A variety of statistical analysis techniques were used to respond each research question, including pearson correlation and regression. This thesis contributes to the existing literature by finding the different urban environment characteristics that affect outdoor air quality, the effect of outdoor air pollution on childhood asthma and lastly, the effect of different urban environment characteristics on childhood asthma. The results of the thesis show that the urban environments where children live significantly affect outdoor air quality and childhood asthma. The thesis revealed a significant link between altitude, temperature, and relative humidity from natural environmental characteristics, and PM10 and PM2.5 concentrations. The built environment characteristics that affect PM concentrations vary depending on different buffer and PM sizes. A positive correlation was found between the number of children with asthma and PM concentrations. As for the urban environment features, it was determined that figure-ground, building density and APOGR (Active-Passive Open Green Ratio) were associated with asthma prevalence. The study's findings led to the conclusion that, in the absence of air quality measures, comparing urban environmental characteristics with data on childhood asthma would not produce reliable results.

Subject Keywords

Urban Environment, Outdoor Air Quality, Childhood Asthma

URI

https://hdl.handle.net/11511/102564

Collections

Graduate School of Natural and Applied Sciences, Thesis