Because formaldehyde can contribute to the risk of getting cancer, and,
like other carcinogens, has no level that is known to be risk free, the
ARB recommends that you reduce indoor formaldehyde concentrations
as much as possible. This also will reduce the likelihood of irritant effects
that can develop from long-term exposures to low levels of formaldehyde.
Current outdoor levels average about 3 ppb in California and can range to
about 10-12 ppb in some locales. It is desirable to reduce indoor levels to as
near to outdoor levels as possible; however, it is generally not possible to
reduce indoor levels below nearby outdoor levels.