PERSISTENT ORGANIC POLLUTANTS (POPS)
POPs are organic compounds that are resistant to environmental degradation.
Many POPs are currently or were previously used as pesticides (e.g., DDT),
solvents, pharmaceuticals, and industrial chemicals (e.g., polychorinated
biphenyls [PCBs] used as heat transfer fluids and in electrical transformers and
dioxin—an unintentional by-product of high-temperature processes, such as
incomplete combustion and pesticide production). Dioxins are typically emitted
from the burning of hospital waste, municipal waste, and hazardous waste, along
with automobile emissions and burning coal and wood. POPs exert their
negative effects on the environment through two processes: (1) long-range
transport, which allows them to travel far from their source, and (2)
bioaccumulation, which concentrates these chemical compounds (generally in
fatty tissues) to dangerous levels. Recent studies of indoor dust and air have
implicated indoor environments as a major source for human exposure to POPs
via inhalation and ingestion.
RADON
Radon is an invisible, radioactive gas that results from the radioactive decay of
radium, which can be found in rock formations (typically granite containing
uranium) beneath buildings or in certain building materials. Radon is probably
the most pervasive serious hazard for indoor air in the United States and Europe.
It is responsible for tens of thousands of deaths from lung cancer each year.
Radon is a heavy gas and thus will tend to accumulate at the floor level. Radon
accumulation is greatest for well-insulated homes. In areas where natural radon
levels occur, mitigation methods include:
■ Sealing concrete slab floors
■ Sealing basement foundations
■ Increasing indoor ventilation with outdoor air