Measures against the heat of the Tokyo Olympics and Para The possibility of adverse effects is also on August 9 at 0:09

The research results show that measures against heat for the Tokyo Olympics and Paralympics may have a “counter-effect”.

Experts verified the effect of `` heat-shielding pavement '', which is being developed to lower the surface temperature of the road, and found that there were cases where the temperature at which people stand was higher than normal pavement It was. Experts say that “the risk of heat stroke among athletes and spectators may increase”.

The “heat-shielded pavement” of the road is a measure that suppresses the rise in surface temperature by applying white paint on the road surface and reflecting sunlight, and Tokyo and the country are over 100 km including the Olympic marathon course We are proceeding with maintenance.

Research group of Prof. Nobuo Tsujimura of Tokyo University of Agriculture, who is familiar with measures against heat stroke, surveys the difference in temperature on the road surface of "heat-shielded pavement" and "ordinary pavement" during the day of a sunny day last month and this month. The we.

As a result, the surface temperature after applying "heat-shielded pavement" was about 10 degrees lower than that of "normal pavement", which was the same trend as in previous countries.

However, as a result of measuring the temperature in a space of 50 centimeters in height, 50 centimeters in 1 meter, and 2 meters, it was found that the average temperature was higher in both “heat-shielding pavements”.

The space above “heat-shielded pavement” has an average temperature of around 1.5 degrees, especially on days with strong solar radiation, and has a time zone that is at least 3 degrees higher, as well as an index to prevent heat stroke. The “heat index” becomes higher.

Prof. Kashimura analyzes that “thermal barrier pavement” is easy to reflect sunlight, so the surface temperature decreases, but the reflected heat increases the temperature at the height where people stand.

On top of that, “Thermic pavement has been said to reduce the risk of heat stroke, but it is counterproductive when there is daytime solar radiation, and at the Olympics, it can be considered to increase the risk of athletes and spectators. Wants to take this data, verify the effectiveness of thermal barrier pavement, and take measures. "

On the other hand, the Ministry of Land, Infrastructure, Transport and Tourism has published the results of a survey of the “heat index” of the space on each road in 2016, comparing the differences between “thermal barrier pavement” and “normal pavement”. .

In the published heat index graph, although “thermal barrier pavement” is higher depending on the time of day, errors are likely to occur in the survey, and it is generally within a difference of 1 degree. I can't say. "

In addition, the Ministry of Land, Infrastructure, Transport and Tourism believes that heat-shielding pavement has the effect of reducing heat, based on various surveys, such as athletes actually evaluating running and feeling low in temperature. I am commenting.