Ozonolysis of monoterpenes in mechanical ventilation systems

Fick, Jerker; Pommer, Linda; Åstrand, Anders P.; Östin, Ronny; Nilsson, Carl-Axel; Andersson, Barbro

doi:10.1016/j.atmosenv.2005.07.013

Cited by 20 publications

(14 citation statements)

References 40 publications

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“…More importantly, the electrophilic nature of ozone also makes it reactive with unsaturated carbon-carbon bonds that are present in a wide range of molecules that partition to surface reservoirs, such as the components of skin oil and cooking oils (squalene, unsaturated triglycerides, cholesterol), 175,176,[186][187][188][189][190] and terpenoid compounds, especially polar compounds such as terpineol. [191][192][193][194][195] Olenic ozonolysis proceeds via formation of a primary ozonide (see Fig. 8), formed by the p-electrons in a carboncarbon double bond covalently bonding with unpaired electron density at the terminal oxygen atoms of an ozone molecule.…”

Section: (C) Multiphase Reactionsmentioning

confidence: 99%

The atmospheric chemistry of indoor environments

Abbatt

Wang

2020

Environ. Sci.: Processes Impacts

135

161

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Section: (C) Multiphase Reactionsmentioning

confidence: 99%

The atmospheric chemistry of indoor environments

Abbatt

Wang

2020

Environ. Sci.: Processes Impacts

135

161

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“…Ozone is known to initiate indoor chemistry. It has been observed that heterogeneous chemistry plays a significant part in oxidation (Fick et al., 2005; Wisthaler et al., 2005) and in some cases, the latter has faster reaction rates and higher product yields (Moise and Rudich, 2002). Although, many researchers have studied indoor surface reactions, only a few gaseous and surface products have been identified, and the effect of environmental conditions on this chemistry remains not fully understood (Morrison, 2008).…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous oxidation of squalene film by ozone under various indoor conditions

2009

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The effects of indoor conditions (ozone concentration, temperature, relative humidity (RH), and the presence of NO(x)) on heterogeneous squalene oxidation were studied with Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy. The heterogeneous kinetics of squalene-ozone reaction revealed a pseudo-first-order reaction rate constant of 1.22 x 10(-5)/s at [O(3)] = 40 ppb. Oxidation kinetics were insensitive to temperature over the range of 24-58 +/- 2 degrees C as well as to RH and presence of NO(x). Products, however, were affected by the environmental parameters. As temperature was increased, fewer surface products and more low molecular weight gaseous products were observed. Lower air exchange rates also enhanced gas phase reactions, allowing for formation of secondary gas phase products. As RH increased, there was a shift in product distribution from ketones to aldehydes, and the presence of NO(x) during squalene ozonolysis resulted in the formation of nitrated oxidation products. Identified surface products included 6-methyl-5-hepten-2-one, geranyl acetone, and long chain ketones and aldehydes, while gas phase products included formaldehyde, acetone, 4-oxopentanal (4-OPA), glyoxal, and pyruvic acid. Practical Implications Heterogeneous oxidation of squalene resulted in surface products including long chain aldehydes and ketones, and gas phase products including formaldehyde, a known human carcinogen (IARC 2006), and bicarbonyl compounds like: 4-oxopentanal (4-OPA), glyoxal, and pyruvic acid that are characterized as asthma triggers and sensitizers (Anderson et al., 2007; Jarvis et al., 2005). In addition, ozonolysis experiments in the presence of NO(x) showed the formation of nitrated surface oxidation products. Such nitrated products may have higher mutagenicity, carcinogenicity, or allergenic potential than their nitrate free counterparts (Franze et al., 2005; Pitts, 1983). Kinetic studies determined that at moderate ozone levels of 40 ppb (Uhde and Salthammer, 2007), and an estimated skin surface density of 4 x 10(15) molecules/cm(2), surface reaction would lead to a minimum product formation flux of 4 x 10(10) molecules cm(2)/s. As squalene is naturally occurring and continually produced by the human body, its concentration in the indoor environment cannot be controlled. However, this study highlights the importance of regulating air exchange rate, temperature, and ozone level in the indoor environment on the formation of potentially harmful or irritating squalene oxidation products.

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“…This suggested terpenes remained on the surface, enhancing ozone reactivity with that surface. Similarly, Fick et al. (2005) concluded that the inner surfaces of a heat exchanger were responsible for increased terpene conversion rates.…”

Section: Introductionmentioning

confidence: 99%

Reaction rates of ozone and terpenes adsorbed to model indoor surfaces

2011

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At present, it is unclear how important heterogeneous reactions will be in influencing indoor concentrations of terpenes, ozone and their reaction products. We observe that surface reaction probabilities were 10 to 100 times greater than their corresponding gas-phase values. Thus indoor surfaces do enhance effective reaction rates and adsorption of terpenes will increase ozone flux to otherwise low-reactivity surfaces. Extrapolation of these results to typical indoor conditions suggests that surface conversion rates may be substantial relative to gas-phase rates, especially for lower volatility terpenoids.

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Ozonolysis of monoterpenes in mechanical ventilation systems

Cited by 20 publications

References 40 publications

The atmospheric chemistry of indoor environments

The atmospheric chemistry of indoor environments

Heterogeneous oxidation of squalene film by ozone under various indoor conditions

Reaction rates of ozone and terpenes adsorbed to model indoor surfaces

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