First Principles - Sustainable Design: The Science of Sustainability and Green Engineering - page 50

Health Organization (WHO) is addressing the health concerns raised about ex-
posure to radio-frequency (RF) and microwave fields, intermediate frequencies
(IFs), extremely low frequency fields, and static electric and magnetic fields.
Intermediate and radio-frequency fields produce heating and the induction of
electrical currents, so it is highly plausible that this is occurring to some extent
in cells exposed to IF and RF fields. Fields at frequencies above about 1 MHz
primarily cause heating by transporting ions and water molecules through a
medium. Even very low energy levels generate a small amount of heat, but
this heat is carried away by the body's normal thermoregulatory processes.
However, some studies indicate that exposure to fields too weak to cause
heating may still produce adverse health consequences, including cancer and
neurological disorders (e.g., memory loss).

HEAT ISLANDS

At the building and community scale, sites are developed and paved. This
changes the color and absorbing behavior of a surface, inducing a heat island ,
which results from the thermal gradient between the developed (warmer)
and undeveloped (cooler) areas (see Fig. S2.2). The surface changes increase

92°

85°

Rural Suburban

residential

Commercial Downtown Urban

residential

Park Suburban

residential

Rural
farmland

Figure S2.2 Heat island effect.
Courtesy of Heat Island Group, Lawrence Berkeley National Laboratory.