TY - JOUR TI - Ozone-particle associations for public primary school classrooms with mechanical ventilation systems DO - https://doi.org/doi:10.7282/t3-bery-xs85 PY - 2018 AB - The 2001-2002 Lawrence Berkeley National Laboratory (LBNL) nested, crossover-design study explored the operating profiles of two HVAC systems alternated over a period of approximately nine weeks, including during 2001 Fall school semester, in two pairs of classrooms sited adjacent to one another and equipped with either standard or alternate (low-emissivity) interior finish materials. The present study, a retrospective analysis, included inferring estimated indoor ozone concentrations. Because ozone can react with certain indoor pollutants to generate secondary organic aerosols, a mass-balanced based indoor/outdoor ratio expression was used to model indoor ozone to subsequently model indoor particles from possible ozone-initiated chemistry. When the advanced HVAC system, called IDEC, was running, surface (especially ceiling) reactions dominated ozone loss processes. When either of the standard HVAC systems, or Bard (different percentages of outdoor air intake) was running, damper setting and ventilation and/or gas phase reactions accounted for the majority of the indoor-outdoor ozone difference. In this study, statistical analysis indicated classroom B-A containing carpet (with polypropylene/polyolefin backing) and teaching materials (with bare surfaces) had higher fine particle number counts (PNC; PM0.3-0.5/PM0.5-0.7) than in the other study classrooms. Additionally, elevated humidity coupled with elevated estimated ozone at school A-B yielded comparatively elevated PNC. Mixed models demonstrated IDEC system use (100% outdoor air intake) at SDB-A, especially during weeks 7-9, yielded significantly greater indoor PNC (PM0.3-0.5/PM0.5-0.7) values than in the other study classrooms. Bard (50% outdoor air intake) use in both SDA classrooms (A, B) yielded comparatively greater PNC than IDEC. KW - Public Health KW - Ventilation KW - Ozone LA - eng ER -