Formation of indoor nitrous acid (HONO) by light-induced NO2 heterogeneous reactions with white wall paint.
Gaseous nitrogen dioxide (NO2) represents an oxidant that is present in relatively high concentrations in various indoor settings. Remarkably increased NO2 levels up to 1.5 ppm are associated with homes using gas stoves. The heterogeneous reactions of NO2 with adsorbed water on surfaces lead to the generation of nitrous acid (HONO). Here, we present a HONO source induced by heterogeneous reactions of NO2 with selected indoor paint surfaces in the presence of light (300 nm<λ<400 nm). We demonstrate that the formation of HONO is much more pronounced at elevated relative humidity. In the presence of light (5.5 W m(-2)), an increase of HONO production rate of up to 8.6·10(9) molecules cm(-2) s(-1) was observed at [NO2]=60 ppb and 50% relative humidity (RH). At higher light intensity of 10.6 (W m(-2)), the HONO production rate increased to 2.1·10(10) molecules cm(-2) s(-1). A high NO2 to HONO conversion yield of up to 84% was observed. This result strongly suggests that a light-driven process of indoor HONO production is operational. This work highlights the potential of paint surfaces to generate HONO within indoor environments by light-induced NO2 heterogeneous reactions.
Aix Marseille University, CNRS, FRE 3416, Case 29, 3 place Victor Hugo, 13331, Marseille Cedex 3, France.
Vincent
V
Bartolomei
Matthias
M
Sörgel
Sasho
S
Gligorovski
Elena Gómez
EG
Alvarez
Adrien
A
Gandolfo
Rafal
R
Strekowski
Etienne
E
Quivet
Andreas
A
Held
Cornelius
C
Zetzsch
Henri
H
Wortham
D016902:Air Pollution, Indoor / Q000032:analysis; D006798:Housing; D008027:Light; D009585:Nitrogen Dioxide / Q000737:chemistry*; D009608:Nitrous Acid / Q000737:chemistry*; D010150:Paint / Q000009:adverse effects / Q000032:analysis* / Q000528:radiation effects*; D014867:Water / Q000737:chemistry
D014867:Water; D009585:Nitrogen Dioxide; D009608:Nitrous Acid