Dataset of methane pyrolysis products in a batch reactor as a function of time at high temperatures and pressures.

Methane pyrolysis is a process used to generate hydrogen gas and carbon black without the creation of carbon dioxide. Methane pyrolysis in a constant volume batch reactor was investigated at temperatures of 892, 1093, and 1292 K with reaction times of 15, 30, 60, 180, and 300 s at an initial pressure of 399 kPa. A quartz vessel (32 mL) was placed inside an oven where it was heated to high temperatures.

Filter evaluation and selection for heating, ventilation, and air conditioning systems during and beyond the COVID-19 pandemic.

Particle size removal efficiencies for 0.1-1.0 μm ( ) and 0.

Viral load of SARS-CoV-2 in droplets and bioaerosols directly captured during breathing, speaking and coughing.

Determining the viral load and infectivity of SARS-CoV-2 in macroscopic respiratory droplets, bioaerosols, and other bodily fluids and secretions is important for identifying transmission modes, assessing risks and informing public health guidelines. Here we show that viral load of SARS-CoV-2 Ribonucleic Acid (RNA) in participants' naso-pharyngeal (NP) swabs positively correlated with RNA viral load they emitted in both droplets >10 [Formula: see text] and bioaerosols <10 [Formula: see text] directly captured during the combined expiratory activities of breathing, speaking and coughing using a standardized protocol, although the NP swabs had [Formula: see text] 10[Formula: see text] more RNA on average. By identifying highly-infectious individuals (maximum of 18,000 PFU/mL in NP), we retrieved higher numbers of SARS-CoV-2 RNA gene copies in bioaerosol samples (maximum of 4.

Comprehensive characterization of mainstream marijuana and tobacco smoke.

Recent increases in marijuana use and legalization without adequate knowledge of the risks necessitate the characterization of the billions of nanoparticles contained in each puff of smoke. Tobacco smoke offers a benchmark given that it has been extensively studied. Tobacco and marijuana smoke particles are quantitatively similar in volatility, shape, density and number concentration, albeit with differences in size, total mass and chemical composition.

Relationship between Coating-Induced Soot Aggregate Restructuring and Primary Particle Number.

The restructuring of monodisperse soot aggregates due to coatings of secondary organic aerosol (SOA) was investigated in a series of photo-oxidation chamber experiments. Soot aggregates were generated by one of three sources (an ethylene premixed burner, a methane inverted diffusion burner, or a diesel generator), treated by denuding, size-selected by a differential mobility analyzer, and injected into a smog chamber, where they were exposed to the photo-oxidation products of p-xylene, which partitioned to form SOA coatings. The evolution of aggregates from their initial to final morphologies was investigated in situ by mobility and mass measurements and ex situ by transmission electron microscopy.

Soot aggregate restructuring due to coatings of secondary organic aerosol derived from aromatic precursors.

Restructuring of monodisperse soot aggregates due to coatings of secondary organic aerosol (SOA) derived from hydroxyl radical-initiated oxidation of toluene, p-xylene, ethylbenzene, and benzene was investigated in a series of photo-oxidation (smog) chamber experiments. Soot aggregates were generated by combustion of ethylene using a McKenna burner, treated by denuding, size-selected by a differential mobility analyzer, and injected into a smog chamber, where they were exposed to low vapor pressure products of aromatic hydrocarbon oxidation, which formed SOA coatings. Aggregate restructuring began once a threshold coating mass was reached, and the degree of the subsequent restructuring increased with mass growth factor.

Performance of pressurized metered-dose inhalers at extreme temperature conditions.

The performance of pressurized metered-dose inhalers (pMDIs) under a variety of temperature conditions was investigated. The effects of both inhaler temperature and ambient temperature were considered. The inhaler temperature ranged from -13.

The effect of altitude on inhaler performance.

The purpose of the study is to understand the effect of altitude on the performance of selected pressurized metered dose inhalers (pMDIs) and dry powder inhalers (DPIs). A testing apparatus that created consistent breath profiles through the Alberta Idealized Throat was designed to test five pMDIs and two DPIs at altitudes of 670, 2450, 3260, and 4300 m. Both gravimetric and chemical assays were conducted to determine the in vitro lung dose.

Effect of electrostatic charge on deposition of uniformly charged monodisperse particles in the nasal extrathoracic airways of an infant.

Background: The fraction of inhaled particles depositing in the nasal extrathoracic airways determines the amount of particles delivered to the lungs of infants. Electrostatic charge on particles can affect this deposition, and for this reason, deposition of charged aerosol particles in the Alberta Idealized Infant nasal geometry is examined.

Methods: Charged aerosol particles were generated via Plateau-Rayleigh jet breakup atomization with induction charging.

Response to comment on "Radiative absorption enhancements due to the mixing state of atmospheric black carbon".

Jacobson argues that our statement that "many climate models may overestimate warming by BC" has not been demonstrated. Jacobson challenges our results on the basis that we have misinterpreted some model results, omitted optical focusing under high relative humidity conditions and by involatile components, and because our measurements consist of only two locations over short atmospheric time periods. We address each of these arguments, acknowledging important issues and clarifying some misconceptions, and stand by our observations.

Radiative absorption enhancements due to the mixing state of atmospheric black carbon.

Atmospheric black carbon (BC) warms Earth's climate, and its reduction has been targeted for near-term climate change mitigation. Models that include forcing by BC assume internal mixing with non-BC aerosol components that enhance BC absorption, often by a factor of ~2; such model estimates have yet to be clearly validated through atmospheric observations. Here, direct in situ measurements of BC absorption enhancements (E(abs)) and mixing state are reported for two California regions.