« Previous AbstractGossypol-enhanced P450 gene pool contributes to cotton bollworm tolerance to a pyrethroid insecticide    Next AbstractDoes reproductive isolation reflect the segregation of color forms in Spiranthes sinensis (Pers.) Ames complex (Orchidaceae) in the Chinese Himalayas? »

Environ Sci Technol

Title:		Evidence for the Importance of Semivolatile Organic Ammonium Salts in Ambient Particulate Matter
Author(s):		Tao Y; Murphy JG;
Address:		"Department of Physical and Environmental Sciences , University of Toronto Scarborough , Toronto , Ontario M1C 1A4 , Canada. Department of Chemistry , University of Toronto , Toronto , Ontario M5S 3H6 , Canada"
Journal Title:		Environ Sci Technol
Year:		2019
Volume:		20181218
Issue:		1
Page Number:		108 - 116
DOI:		10.1021/acs.est.8b03800
ISSN/ISBN:		1520-5851 (Electronic) 0013-936X (Linking)
Abstract:		"The gas/particle phase partitioning behavior of NH(3)/NH(4)(+) and other semivolatile constituents was measured by a custom-designed Denuder-MOUDI-Denuder integrated sampling system in Toronto, Canada. In this setup, upstream denuders were used to capture alkaline and acidic gaseous components, and particle phase components were captured by the filters on MOUDI stages. Downstream denuders captured any alkaline and acidic gases that exited the MOUDI apparatus, likely representing semivolatile constituents. In the ambient gas phase HCOOH was the most abundant acidic gas, with an average mixing ratio approximately 2-3 times higher than that of SO(2) and HNO(3). It was found that the majority (49-96%) of filter-collected NH(4)(+) volatilized during collection. NO(3)(-) volatilization could only explain 0.9-15% of NH(4)(+) loss from the filters. Instead, a strong correlation and nearly 1:1 molar ratio between downstream HCOO(-) and NH(4)(+) indicated that most of the semivolatile NH(4)(+) was originally balanced by organic acids in the ambient particle phase. The thermodynamic properties of HCOOH/HCOO(-) suggest that it should not have been present at high levels in the ambient particle phase, and we interpret its detection in the downstream denuder as evidence for larger organic acids that reacted to generate HCOOH prior to our offline measurement"
Keywords:		*Air Pollutants *Ammonium Compounds Canada Environmental Monitoring Particulate Matter Salts;
Notes:		"MedlineTao, Ye Murphy, Jennifer G eng Research Support, Non-U.S. Gov't 2018/12/05 Environ Sci Technol. 2019 Jan 2; 53(1):108-116. doi: 10.1021/acs.est.8b03800. Epub 2018 Dec 18"