In its first report on the urban heat island effect, released Monday, the government outlined a list of potential measures to help city centers beat the heat and called for an evaluation to determine which are most effective.
Drawing on domestic and foreign research, the Environment Agency report lists steps cities can take to stem the heat island phenomenon, which is created when natural settings are transformed into urban areas, with heat-soaking asphalt and buildings replacing greenery.
Officials say a copy of the report is to be sent to cities to use as a resource.
Measures advocated to cut urban temperatures include:
* using lighter colors for buildings and roads to cut down on glare; * increasing water surface area; * increasing vegetation; * reducing emissions from vehicles and buildings; * planning cities so that buildings do not obstruct the path of wind, which helps flush out hot air.
The urban heat island effect has been known for more than a century, and aside from raising temperatures has been implicated in affecting the weather, wind, human health and air pollution.
Sweltering city centers are known to alter weather patterns in surrounding suburbs as well.
Hot air blown inland from Tokyo has been shown to raise temperatures in places such as as Maebashi, Gunma Prefecture, and Kumagaya, Saitama Prefecture, government officials said.
Next year, officials said they plan to try to test heat island measures, possibly in Sendai.
A committee will then review the program to try to evaluate the effectiveness of the measures, as well as the merits of combining various measures.