English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Recent developments in high-resolution time-of-flight chemical ionizationmass spectrometry (HR-ToF-CIMS) have made it possible to directly detectatmospheric organic compounds in real time with high sensitivity and withlittle or no fragmentation, including low-volatility, highly oxygenatedorganic vapors that are precursors to secondary organic aerosol formation.Here, using ions identified by high-resolution spectra from an HR-ToF-CIMSwith acetate reagent ion chemistry, we develop an algorithm to estimate thevapor pressures of measured organic acids. The algorithm uses identified ionformulas and calculated double bond equivalencies, information unavailable inquadrupole CIMS technology, as constraints for the number of possible oxygen-containing functional groups. The algorithm is tested with acetate chemical ionization massspectrometry (acetate-CIMS)spectra of O3 and OH oxidation products of α-pinene andnaphthalene formed in a flow reactor with integrated OH exposures rangedfrom 1.2 × 1011 to 9.7 × 1011 molec s cm−3,corresponding to approximately 1.0 to 7.5 days of equivalent atmosphericoxidation. Measured gas-phase organic acids are similar to those previouslyobserved in environmental chamber studies. For both precursors, we find thatacetate-CIMS spectra capture both functionalization (oxygen addition) andfragmentation (carbon loss) as a function of OH exposure. The level offragmentation is observed to increase with increased oxidation. The predictedcondensed-phase secondary organic aerosol (SOA) average acid yields and O/C and H/C ratiosagree within uncertainties with previous chamber and flow reactormeasurements and ambient CIMS results. While acetate reagent ion chemistry isused to selectively measure organic acids, in principle this method can beapplied to additional reagent ion chemistries depending on the application

atmospheric measurement techniques

Application of high-resolution time-of-flight chemical ionization mass spectrometry measurements to estimate volatility distributions of α-pinene and naphthalene oxidation products