We know surprisingly little about oxidizing capacity in occupied residences. While numerous measurements of oxidants have been performed indoors, most have taken place in non-residential buildings. Lower air-exchange rates and different sources (e.g. cooking) in residences may lead to different oxidizing conditions. The proposed project combines field, laboratory, and chamber studies to determine what controls indoor oxidant levels in residences. It consists of two research questions:
- What are the concentrations of oxidant precursors and oxidants indoors?
- Is photochemistry an important source of indoor oxidants?
What are the concentrations of oxidant precursors and oxidants indoors?
Time-resolved concentrations of oxidants and oxidant precursors will be measured in occupied residences and in an indoor simulation chamber using a Mobile Indoor Laboratory for Oxidative Species (MILOS). MILOS will measure O3, NO, NO2, HONO, H2O2, CO, CO2, relative humidity, and temperature. Additional instrumentation to measure reactive chlorine, HCl, and VOCs will be included for some studies. These measurements will provide real-time information about oxidant levels in occupied residences, and the data will enable radical budgets to be calculated under a variety of conditions (e.g. night time, during cooking events, and when doors or windows are open).
Is photochemistry an important source of indoor oxidants?
Photochemistry can be an important indoor oxidant source under some conditions. In order to accurately predict photochemical oxidant formation rates, photon fluxes must be better characterized indoors. The Research Team will characterize the emission of common lightbulbs and the transmittance of common window materials in the UV, and will measure wavelength-and spatially-resolved photon fluxes in residences. Steady-state indoor oxidant concentrations will be calculated based on these measurements. Measurements in residences and in chambers will also be performed to better constrain the role of photochemistry on indoor oxidant concentrations.
PI: Tara Kahan (University of Saskatchewan)
Co-PIs: Trevor VandenBoer (York University), Cora Young (York University), Jianshun Zhang (Syracuse University)