The chemical assessment of surfaces and air (CASA) study: using chemical and physical perturbations in a test house to investigate indoor processes.

The Chemical Assessment of Surfaces and Air (CASA) study aimed to understand how chemicals transform in the indoor environment using perturbations (, cooking, cleaning) or additions of indoor and outdoor pollutants in a well-controlled test house. Chemical additions ranged from individual compounds (, gaseous ammonia or ozone) to more complex mixtures (, a wildfire smoke proxy and a commercial pesticide). Physical perturbations included varying temperature, ventilation rates, and relative humidity.

Ventilation in a Residential Building Brings Outdoor NO Indoors with Limited Implications for VOC Oxidation from NO Radicals.

Energy-efficient residential building standards require the use of mechanical ventilation systems that replace indoor air with outdoor air. Transient outdoor pollution events can be transported indoors via the mechanical ventilation system and other outdoor air entry pathways and impact indoor air chemistry. In the spring of 2022, we observed elevated levels of NO (NO + NO) that originated outdoors, entering the National Institute of Standards and Technology (NIST) Net-Zero Energy Residential Test Facility through the mechanical ventilation system.

The persistence of smoke VOCs indoors: Partitioning, surface cleaning, and air cleaning in a smoke-contaminated house.

Wildfires are increasing in frequency, raising concerns that smoke can permeate indoor environments and expose people to chemical air contaminants. To study smoke transformations in indoor environments and evaluate mitigation strategies, we added smoke to a test house. Many volatile organic compounds (VOCs) persisted days following the smoke injection, providing a longer-term exposure pathway for humans.

Quantitative, traceable determination of cell viability using absorbance microscopy.

Cell viability, an essential measurement for cell therapy products, lacks traceability. One of the most common cell viability tests is trypan blue dye exclusion where blue-stained cells are counted via brightfield imaging. Typically, live and dead cells are classified based on their pixel intensities which may vary arbitrarily making it difficult to compare results.

Applicability of Spray Polyurethane Foam Ventilation Guideline for Do-It-Yourself Application Events.

Small two-component spray polyurethane foam (SPF) application kits are often applied by Do-It-Yourself (DIY) consumers. The United States Environmental Protection Agency (EPA) publishes a guideline for ventilating a space where SPF is being applied to minimize exposure to mists, vapors, particles and dust. This study sought to assess the applicability of the EPA ventilation guideline in protecting non-application areas of a house from exposure to SPF-associated emissions during a DIY application.