Publications by authors named "D R Worsnop"
Aircraft observations have revealed ubiquitous new particle formation in the tropical upper troposphere over the Amazon and the Atlantic and Pacific oceans. Although the vapours involved remain unknown, recent satellite observations have revealed surprisingly high night-time isoprene mixing ratios of up to 1 part per billion by volume (ppbv) in the tropical upper troposphere. Here, in experiments performed with the CERN CLOUD (Cosmics Leaving Outdoor Droplets) chamber, we report new particle formation initiated by the reaction of hydroxyl radicals with isoprene at upper-tropospheric temperatures of -30 °C and -50 °C.
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- Haze in Beijing is primarily due to harmful secondary organic aerosols formed from solid-fuel emissions and secondary processes involving aromatic compounds.
- In winter, pollution is mainly from solid-fuel combustion, with severe haze linked to aerosols transported from surrounding areas.
- In summer, aromatic emissions from nearby regions increase secondary organic aerosol levels, indicating that regional emission control strategies are essential for effective pollution management.
Dinitrogen pentoxide (NO) plays an essential role in tropospheric chemistry, serving as a nocturnal reservoir of reactive nitrogen and significantly promoting nitrate formations. However, identifying key environmental drivers of NO formation remains challenging using traditional statistical methods, impeding effective emission control measures to mitigate NO-induced air pollution. Here, we adopted machine learning assisted by steady-state analysis to elucidate the driving factors of NO before and during the 2022 Winter Olympics (WO) in Beijing.
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- * The study found that particle formation rates due to ion-induced processes are stable across temperature changes, while neutral particle formation rates increase significantly when temperatures drop from +10 °C to -10 °C.
- * Despite higher ionization rates, the formation of charged clusters is unlikely to be enhanced in upper tropospheric conditions; instead, neutral nucleation is expected to dominate, with humidity having little effect unless extremely low.
Article Synopsis
- The study introduces a fast polarity switching method in chemical ionization mass spectrometry, combining a multischeme chemical ionization inlet (MION) with an Orbitrap mass spectrometer to analyze trace species in complex samples effectively.* -
- By using reagent ions in both positive (diethylammonium) and negative (nitrate) polarities, the system enhances the detection of various compounds, like pesticides and reactive organic species, significantly compared to traditional methods.* -
- The MION-Orbitrap demonstrated high mass resolving power (280,000) and rapid polarity switching capability, allowing real-time monitoring and detection of a broader range of species, showing its potential as a versatile analytical tool.*