Themed collection Celebrating Environmental Science: Atmospheres’ First Year

Hydrogen may play a major role as an energy source to support net zero but combustion leads to emissions of NO_x, a key air pollutant. Delivering optimal air quality co-benefits may need more ambitious hydrogen-specific emission standards developing.

Iron in mineral dust can catalyze reactions with atmospheric organics that lead to the formation of brown carbon (BrC) that impact the climate in a number of ways.

DTRs from February to June during the COVID-19 pandemic are greater than 3 standard deviations above the climatological mean DTR.

To clarify the human health risk of inhalation of gaseous elemental mercury (GEM), we measured GEM concentrations in three artisanal small-scale gold mining (ASGM) areas of Palu (Central Sulawesi), Muara Aman (Benkulu in Sumatra), and Palangka Raya (Central Kalimantan).

Black carbon measurements at Maitri, Antarctica during XXXVIII Antarctica expedition and found 82 ng m⁻³ and Patagonia is a definitive BC origin in addition to the day-to-day station related activities.

Direct measurement with personal samplers captures the chemical complexity of PM_2.5 exposures better than fixed monitors. To investigate biological effects, lung cells were exposed to extracts of exposure PM_2.5 samples.

New emissions of methane and chloroform, with concurrent depositions of ozone and hydrogen were determined from the peat bogs of Ireland.

Size-resolved organic aerosol (OA) analysis elucidated largely different size distributions of primary and secondary OA, and oxidation states between urban and rural sites in different seasons.

Nitrous acid (HONO) is a key precursor to the principal atmospheric oxidant OH. HONO measurements during a solar eclipse show little variation, implying the main HONO sources are photolytic, approximately balancing removal through photolysis.

Secondary organic aerosols (SOA) constitute an important fraction of fine-mode atmospheric aerosol mass.

Our results indicate that lockdown measures induced a mild increase in secondary organic aerosol (SOA) concentrations in areas with substantial reductions in nitrogen dioxide (NO₂) concentrations, i.e. the “Greater Milan” area.

Impact of lockdown measures on the air pollutants and particle number size distribution.

The mechanism of aqueous-phase OH-oxidation of pinic acid was investigated for the first time, and norpinic acid and 3-methyl-1,2,3-butanetricarboxylic acid were identified as major products. The mechanism is pH-dependent, with enhanced yields under basic conditions.

Water-soluble BrC in freshly emitted boreal peat combustion particulate matter spans a wide range of molecular sizes, polarities, and light absorption properties; in addition, its largest fraction undergoes solvent-dependent aggregation/dissociation.

DFT calculations show that skatole oxidation products may likely initiate the formation of nucleation precursors in the atmosphere.

For better insight into passive air sampling, we monitored PAHs with PE sheets during 8 seasons at 3 locations. A numerical model was applied to fit the limiting air-side boundary layer, which was surprisingly stable around 1 mm in all locations.

Mineral dust is responsible for the ice-nucleating properties of aerosol samples collected over the British Isles below ∼−20 °C, while an additional source, potentially biogenic, must explain the ice-nucleating properties at higher temperatures.

Molecular-level analysis of High Arctic aerosols sampled on a cruise to the North Pole shows: (1) a wide range of semi-volatile organic compounds, (2) no clear relationship between DMS oxidation products in the gas- and particle-phase

Molecular composition, viscosity, and phase state were investigated for secondary organic aerosol derived from synthetic mixtures of volatile organic compounds representing emissions from healthy and aphid-stressed Scots pine trees.

Vehicles show higher emissions at cold temperature. Nevertheless, emissions during real world tests can be below Euro 6d-TEMP requirements. The relatively high PN emissions from gasoline and PHEV vehicles indicate there is still room for improvement.

Chamber experiments may over emphasize peroxy radical cross reactions due to lower concentrations of reactants that directly convert OH into HO₂.

This study examines the volatility distribution of organic emissions from solid fuel combustion sources from Delhi, India, and examines the chemical drivers of the OH reactivity and the secondary organic aerosol production potential.

Measurements of partitioning of nitric acid and sulfuric acid between aqueous and organic phases show organic-phase acid is significant, which has implications for aerosol chemistry factors. These acids can then participate in organic reactions.

Our previous work demonstrated formation of highly insoluble and strongly light-absorbing organic particles in reactions between catechol or guaiacol with Fe(III) under pH = 3 conditions characteristic of aerosol liquid water.

Condensed phase mass transport in single aerosol particles is investigated using a linear quadrupole electrodynamic balance (LQ-EDB) and the Maxwell–Stefan (MS) framework.

The photosensitized chemistry of three aromatic ketones (xanthone, flavone, and acetophenone) and also of secondary organic aerosols (SOAs) arising from the photo-oxidation of naphthalene was investigated by means of transient absorption spectroscopy.

Cloud cycling plays a key role in the evolution of atmospheric particles and gases, producing secondary aerosol mass and transforming the optical properties and impacts of aerosols globally.

This study calls attention to the primary emissions of semivolatile oxygenated organic compounds (SV-OVOCs) and demonstrates how mapping out the near-canopy concentration can effectively isolate atmospheric SV-OVOC production from direct emissions.