Personal exposure to ambient pollutants in the indoor
environment is complicated by indoor air chemistry,
through which some ambient pollutants are degraded (e.g.,
O3 and nitrate particles) and other new air pollutants are
formed (e.g., aldehydes and ammonia) (8). Concentrations
of ozone indoors have been found to range widely from 10%
to 80% of outdoor concentrations, with means of 40-50%,
due to loss of ozone by chemical reactions that occur
primarily on interior surfaces (9). The effectiveness of
staying indoors to reduce exposure to outdoor-source PM
is more limited due to typical penetration factors which
can approach unity in the absence of air conditioning (10),
and relatively little loss of particles to surface deposition.
Evidence that closing windows reduces penetration of PM
and associated cardiovascular health risk came from a recent
study of 300 healthy adults in Taipei who alternately opened
and closed windows at home for 2-week periods. Lin et al.
[2013] found associations between PM levels and adverse
changes in markers of cardiovascular disease risk (increased
plasma CRP and fibrinogen, and decreased heart rate
variability) after periods with windows open, but no changes
with windows closed (11).
Personal exposure to ambient pollutants in the indoorenvironment is complicated by indoor air chemistry,through which some ambient pollutants are degraded (e.g.,O3 and nitrate particles) and other new air pollutants areformed (e.g., aldehydes and ammonia) (8). Concentrationsof ozone indoors have been found to range widely from 10%to 80% of outdoor concentrations, with means of 40-50%,due to loss of ozone by chemical reactions that occurprimarily on interior surfaces (9). The effectiveness ofstaying indoors to reduce exposure to outdoor-source PMis more limited due to typical penetration factors whichcan approach unity in the absence of air conditioning (10),and relatively little loss of particles to surface deposition.Evidence that closing windows reduces penetration of PMand associated cardiovascular health risk came from a recentstudy of 300 healthy adults in Taipei who alternately openedand closed windows at home for 2-week periods. Lin et al.[2013] found associations between PM levels and adversechanges in markers of cardiovascular disease risk (increasedplasma CRP and fibrinogen, and decreased heart ratevariability) after periods with windows open, but no changeswith windows closed (11).
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