Quantification of alkenes on indoor surfaces and implications for chemical sources and sinks. (18th March 2020)

• Record Type: Journal Article
• Authors: Deming, Benjamin L.; Ziemann, Paul J.
• Is Part Of: Indoor air. Volume 30:Number 5(2020)
• Page Start: 914
• Page End: 924
• Publication Date: 2020-03-18
• Subjects: cooking -- indoor surfaces -- ozone -- skin oil -- surface alkenes -- surface films; Indoor air pollution -- Periodicals; Sick building syndrome -- Periodicals; Ventilation -- Periodicals; 613.5
• DOI: 10.1111/ina.12662
• Languages: English
• ISSNs: 0905-6947

Abstract

Abstract: Indoor surfaces are known to support organic films, but their thickness, composition, and variability between environments remain poorly characterized. Alkenes are expected to be a significant component of these films, with the reaction with O3 being a major sink for O3 and source of airborne chemicals. Here, we present a sensitive, microscale, nanospectrophotometric method for quantifying the alkene (C=C bond) content of surface films and demonstrate its applicability in five studies relevant to indoor air chemistry. Collection efficiencies determined for a filter wipe method were ~64%, and the overall detection limit for monoalkenes was ~10 nmol m −2 . On average, painted walls and glass windows sampled across the University of Colorado Boulder campus were coated by ~4 nm thick films containing ~20% alkenes, and a simple calculation indicates that the lifetime for these alkenes due to reaction with O3 is ~1 hour, indicating that the films are highly dynamic. Measurements of alkenes in films of skin oil, pan‐fried cooking oils, a terpene‐containing cleaner, and on various surfaces in a closed classroom overnight (where carboxyl groups were also measured) provided insight into the effects of chemical and physical processes on film and air composition.