Recently, summer high temperature events caused by climate change and urban heat island phenomenon have become a serious social problem around the world. Urban areas have low albedo and huge heat storage, resulting in higher temperatures and longer lasting characteristics. To effectively consider the urban heat island measures, it is important to quantitatively grasp the impact of urban high temperatures on the society. Until now, the study of urban heat island phenomenon had been carried out focusing only on the effects of urban high temperature on human health (such as heat stroke and sleep disturbance). In this study, we focus on the effect of urban heat island phenomenon on air pollution. In particular, the relationship between high temperature phenomena in urban areas during summer and the concentration of photochemical oxidant is investigated. High concentrations of ozone during summer are confirmed to coincide with a day when the causative substances (NO2,VOCs) are high in urban areas during the early morning hours. Further, it is noted that the night urban heat island intensity is large.. Finally, although the concentration of other air pollutants has been decreasing in the long term, the concentration of photochemical oxidant gradually increases in Daegu.

Abstract
1. Introduction
2. Materials and Methods
3. Results and Discussion
    3.1. Annual change trends of ozone concentration
    3.2. Relationship between ozone concentrationincrease in summer and urban hightemperature
    3.3. Correlation between ozone concentration andtemperature
4. Conclusions
References

• Eun-Ji An(Department of Global Environment, Keimyung University)
• Hae-Dong Kim(Department of Global Environment, Keimyung University) Corresponding author