[Beauchamp2005] "Ozone induced emissions of biogenic VOC from tobacco: relationships between ozone uptake and emission of LOX products",
Plant, Cell & Environment
, vol. 28, no. 10: Wiley Online Library, pp. 1334–1343, 2005.
Volatile organic compound (VOC) emissions from tobacco (Nicotiana tabacum L. var. Bel W3) plants exposed to ozone (O3) were investigated using proton-transfer-reaction mass-spectrometry (PTR-MS) and gas chromatography mass-spectrometry (GC-MS) to find a quantitative reference for plants’ responses to O3 stress. O3 exposures to illuminated plants induced post-exposure VOC emission bursts. The lag time for the onset of volatile C6 emissions produced within the octadecanoid pathway was found to be inversely proportional to O3 uptake, or more precisely, to the O3 flux density into the plants. In cases of short O3 pulses of identical duration the total amount of these emitted C6 VOC was related to the O3 flux density into the plants, and not to ozone concentrations or dose–response relationships such as AOT 40 values. Approximately one C6 product was emitted per five O3 molecules taken up by the plant. A threshold flux density of O3 inducing emissions of C6 products was found to be (1.6 ± 0.7) × 10−8 mol m−2 s−1.
[Wisthaler2005] "Products of ozone-initiated chemistry in a simulated aircraft environment.",
Environ Sci Technol
, vol. 39, no. 13: International Centre for Indoor Environment and Energy, Technical University of Denmark (DTU), DK-2800 Kgs. Lyngby, Denmark., pp. 4823–4832, Jul, 2005.
We used proton-transfer-reaction mass spectrometry (PTR-MS) to examine the products formed when ozone reacted with the materials in a simulated aircraft cabin, including a loaded high-efficiency particulate air (HEPA) filter in the return air system. Four conditions were examined: cabin (baseline), cabin plus ozone, cabin plus soiled T-shirts (surrogates for human occupants), and cabin plus soiled T-shirts plus ozone. The addition of ozone to the cabin without T-shirts, at concentrations typically encountered during commercial air travel, increased the mixing ratio (v:v concentration) of detected pollutants from 35 ppb to 80 ppb. Most of this increase was due to the production of saturated and unsaturated aldehydes and tentatively identified low-molecular-weight carboxylic acids. The addition of soiled T-shirts, with no ozone present, increased the mixing ratio of pollutants in the cabin air only slightly, whereas the combination of soiled T-shirts and ozone increased the mixing ratio of detected pollutants to 110 ppb, with more than 20 ppb originating from squalene oxidation products (acetone, 4-oxopentanal, and 6-methyl-5-hepten-2-one). For the two conditions with ozone present, the more-abundant oxidation products included acetone/propanal (8-20 ppb), formaldehyde (8-10 ppb), nonanal (approximately 6 ppb), 4-oxopentanal (3-7 ppb), acetic acid (approximately 7 ppb), formic acid (approximately 3 ppb), and 6-methyl-5-hepten-2-one (0.5-2.5 ppb), as well as compounds tentatively identified as acrolein (0.6-1 ppb) and crotonaldehyde (0.6-0.8 ppb). The odor thresholds of certain products were exceeded. With an outdoor air exchange of 3 h(-1) and a recirculation rate of 20 h(-1), the measured ozone surface removal rate constant was 6.3 h(-1) when T-shirts were not present, compared to 11.4 h(-1) when T-shirts were present.