Cooling and Warming Effects of a Grass Covered Area and Adjacent Asphalt Area in a Hot Day

• Main Authors: Sarmad Ghader, A. A. Bidokhti, Faramarz Madjidi, N. Mansori
• Format: Article
• Language: English
• Published: Tehran University of Medical Sciences 2013-04-01
• Series: International Journal of Occupational Hygiene
• Subjects: http://ijoh.tums.ac.ir/index.php/ijoh/article/view/120/106
• Online Access: http://Cooling Effect ; Warming Effect ; Grass ; Asphalt ;Temperature
• ISSN: 2008-5109; 2008-5435

Knowledge of the warming or cooling effects induced by asphalt or grasscovered areas, may improve our understanding of how thermal stress or thermalcomfort is created for workers who have to work outdoors for long hours in warmseasons. For this purpose a field measurements were carried out to know the cooling and warming effects of two adjacentareas, one covered with grass and the otherwith asphalt. These two adjacent coverages were located in an open area, inZanjan, a city in the north west of Iran. A calm and sunny day in June wasselected to perform measurements. The temperature and relative humidity, on the grassand asphalt surfaces and also ata heights of 1.2 m above themwere measured at 2 hours intervalfrom 6 a.m. to 12 p.m. Results showed that in the measurement day, the grass surfacetemperature was less than asphalt surface temperature in the afternoon and inthe before noon there was no significant difference between temperatures.Whereas, the temperature measurementsat the height of 1.2 m above asphalt andgrass, showed that the air temperature above grass wasless than the air above asphalt during the measurements period, but in the afternoon, thedifference between these temperatures was less thanthat of before noon. Both grass and asphalt surfaces, showed the cooling and warmingeffects, which are impressed on the air above them, dueto thermal convection.