To investigate the thermal environment over the summertime asphalt pavements, an automatic weather observation system was installed at a parking lot paved with asphalt to observe various meteorological parameters and surface temperature from July 1 to September 30, 2014. Since the number of rainy days in summer of 2014 particularly after the mid July is more than that of average data, a ratio of daily peak surface temperature above 45 ℃ was 28% which was lower than the average. The observational data about hourly average surface temperature and various heat balance factors at days where daily peak surface temperature is above 45 ℃ are as follows: An hour that had the daily maximum temperature was around 15 pm and the value was 49℃ approximately. Net shortwave radiation was the highest at 12pm as 800 W/m2 and much radiation of 500 W/m2 was absorbed at the ground between 11am and 17pm. Sensible heat that was delivered from the ground to the atmosphere was evaluated as 200 W/m2 between 10am and 19pm. underground transfer heat up to 100 W/m2 was measured as negative from 19pm to the next day 8am, which indicated the lower atmosphere was heated at night.

To investigate thermal environment and effect of clean-road system over a broad way, we conducted the filed meteorological observation during 12~13 August 2014. The clean-road system was employed over a part of the broad way of Dalgubul(Dalgubul-Daero) by Daegu Metropolitan city in 2011. The clean–road system in general is operated two times(4 am, 2 pm) during summertime. In case of scorching alert, the system is operated 3 times a day(4 am, 2 pm and 4 pm). To evaluate the present thermal condition and the improvement effects due to the system, we analyzed the time variation of discomfort index and WBGT(wet-bulb and globe temperature). WBGT was more than 25 during 8 a.m. ~ 9 p.m. And discomfort index was more than 75 during 8 a.m. ~ 11 p.m. The thermal improvement effect of the clean-road system was restrictive during daytime.

To improve air quality around a broad way, Daegu Metropolitan city employed the clean-road system at a part of the broad way of Dalgubul (Daigubul-daero) in 2011. The clean–road system in general is operated two times (4 am, 2 pm) during summertime. In case of scorching alert, the system is operated 3 times a day (4 am, 2 pm and 4 pm). To evaluate the effect of air quality improvement due to the system, we analyzed the time variation of monthly mean particulate matter (PM10) concentration in recent 3 years (2011-2013). The improvement of air quality was estimated at about 5～15 % under the system.