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Table 1: Relationships between thermal comfort and urban heat islands
Thermal comfort parameter	Relationship to the urban heat island
Air temperature	Reducing the UHI increases thermal comfort in summer
Radiant temperature field	Reducing surface temperatures reduces the UHI and increases thermal comfort
Solar radiation	Reduced solar penetration limits the UHI and improves thermal comfort
Air speed	Increased air speed removes heat from the urban environment and improves thermal comfort
Humidity	Use of evaporative cooling from lakes may increase humidity and decrease thermal comfort

Table 2: Categories of urban geometry and greenness for London
Category	Height/width ratio of street, x	Surface	Description
1	x%3D0	Grass, etc	Rural fields, large park or trees
2	x%3D0	Hard and grass	Housing near park or field
3	x%3D0	Hard	Urban derelict or unbuilt area or car park
4	0%3C%3Dx%3C0.3	Hard, very wide gorge	Low-density residential area
5	0.3%3C%3Dx%3C0.5	Hard, wide gorge	Medium-density urban area
6	0.5%3C%3Dx%3C1	Hard, wide gorge	High-density urban area, around focus
7	1%3C%3Dx%3C2	Hard, medium gorge	City centre with tall buildings
8	x%3E%3D2	Hard, narrow gorge	Narrow “back streets” with medium-tall (six storey) buildings