Speciating volatile organic compounds in indoor air: using GC to interpret real-time PTR-MS signals.

Proton transfer reaction mass spectrometry (PTR-MS) is often employed to characterize gas-phase compounds in both indoor and outdoor environments. PTR-MS measurements are usually made without upstream chromatographic separation, so it can be challenging to differentiate between an ion of interest, its isomers, and fragmentation products from other species all detected at the same mass-to-charge ratio. These isomeric contributions and fragmentation interferences can confound the determination of accurate compound mixing ratios, the assignment of accurate chemical properties, and corresponding analyses of chemical fate.

Ultrafine Particle Generation from Ozone Oxidation of Cannabis Smoke.

Cannabis smoke is a complex aerosol mixture, featuring characteristic monoterpenes and sesquiterpenes which are susceptible to reaction with ozone and other oxidants. These reactions form less-volatile species which can contribute to secondary organic aerosol (SOA) and ultrafine particle (UFP) formation. In this work, the reaction of ozone with cannabis smoke was observed in an environmental chamber.

Modelling indoor radical chemistry during the HOMEChem campaign.

In the indoor environment, occupants are exposed to air pollutants originating from continuous indoor sources and exchange with the outdoor air, with the highest concentration episodes dominated by activities performed indoors such as cooking and cleaning. Here we use the INdoor CHEMical model in Python (INCHEM-Py) constrained by measurements from the House Observations of Microbial and Environmental Chemistry (HOMEChem) campaign, to investigate the impact of a bleach cleaning event and cooking on indoor air chemistry. Measurements of the concentrations of longer-lived organic and inorganic compounds, as well as measured photolysis rates, have been used as input for the model, and the modelled hydroxyl (OH) radicals, hydroperoxyl radicals, and nitrous acid (HONO) concentrations compared to the measured values.

Structurally Selective Ozonolysis of -Phenylenediamines and Toxicity in Coho Salmon and Rainbow Trout.

The tire-rubber-derived ozonation product of -(1,3-dimethylbutyl)-'-phenyl--phenylenediamine (6PPD), -(1,3-dimethylbutyl)-'-phenyl--phenylenediamine-quinone (6PPD-Q), was recently discovered to cause acute mortality in coho salmon (). -Phenylenediamines (PPDs) with variable side chains distinct from 6PPD have been identified as potential replacement antioxidants, but their toxicities remain unclear under environmentally relevant ozone conditions. We herein tested the multiphase gas-surface ozone reactivity of four select PPDs [6PPD, -isopropyl-'-phenyl--phenylenediamine (IPPD), ,'-diphenyl--phenylenediamine (DPPD), and -phenyl-'-cyclohexyl--phenylenediamine (CPPD)] and evaluated the toxicity of their reaction mixtures in coho salmon, rainbow trout (), and fathead minnow ().

Commercial kitchen operations produce a diverse range of gas-phase reactive nitrogen species.

Gas-phase reactive nitrogen species (N) are important drivers of indoor air quality. Cooking and cleaning are significant direct sources indoors, whose emissions will vary depending on activity and materials used. Commercial kitchens experience regular high volumes of both cooking and cleaning, making them ideal study locations for exploring emission factors from these sources.