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Cancer Health Risks. In each IAQ Zone, provide mitigation for any formaldehyde exposure <br />risk as determined in Step 6, that exceeds the CEQA cancer risk of 10 per million or the <br />CEQA non -cancer Hazard Quotient of 1.0. <br />Provide the source and/or ventilation mitigation required in all IAQ Zones to reduce the <br />health risks of the chemical exposures below the CEQA cancer and non -cancer health risks. <br />Source mitigation for formaldehyde may include: <br />1.) reducing the amount materials and/or furnishings that emit formaldehyde <br />2.) substituting a different material with a lower area -specific emission rate of <br />formaldehyde <br />Ventilation mitigation for formaldehyde emitted from building materials and/or <br />furnishings may include: <br />1.) increasing the design minimum outdoor air ventilation rate to the IAQ Zone. <br />NOTE: Mitigating the formaldehyde emissions through use of less material/furnishings, or <br />use of lower emitting materials/furnishings, is the preferred mitigation option, as mitigation <br />with increased outdoor air ventilation increases initial and operating costs associated with <br />the heating/cooling systems. <br />Outdoor Air Ventilation hnpact. Another important finding of the CNHS, was that the <br />outdoor air ventilation rates in the homes were very low. Outdoor air ventilation is a very <br />important factor influencing the indoor concentrations of air contaminants, as it is the <br />primary removal mechanism of all indoor air generated air contaminants. Lower outdoor air <br />exchange rates cause indoor generated air contaminants to accumulate to higher indoor air <br />concentrations. Many homeowners rarely open their windows or doors for ventilation as a <br />result of their concerns for security/safety, noise, dust, and odor concerns (Price, 2007). In <br />the CNHS field study, 32% of the homes did not use their windows during the 24- hour <br />Test Day, and 15% of the homes did not use their windows during the entire preceding <br />week. Most of the homes with no window usage were homes in the winter field session. <br />Thus, a substantial percentage of homeowners never open their windows, especially in the <br />01 <br />