Unexplored volatile organic compound emitted from petrochemical facilities: implications for ozone production and atmospheric chemistry

Abstract

Abstract. A compound was observed using airborne proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) measurements in the emission plumes from the Daesan petrochemical facility in South Korea. The compound was detected at m/z 43.018 on the PTR-TOF-MS and was tentatively identified as ketene, a rarely measured reactive volatile organic compound (VOC). Estimated ketene mixing ratios as high as ∼ 50 ppb (parts per billion) were observed in the emission plumes. Emission rates of ketene from the facility were estimated using a horizontal advective flux approach and ranged from 84–316 kg h−1. These emission rates were compared to the emission rates of major known VOCs such as benzene, toluene, and acetaldehyde. Significant correlations (r2 > 0.7) of ketene with methanol, acetaldehyde, benzene, and toluene were observed for the peak emissions, indicating commonality of emission sources. The calculated average ketene OH reactivity for the emission plumes over Daesan ranged from 3.33–7.75 s−1, indicating the importance of the quantification of ketene to address missing OH reactivity in the polluted environment. The calculated average O3 production potential for ketene ranged from 2.98–6.91 ppb h−1. Our study suggests that ketene, or any possible VOC species detected at m/z 43.018, has the potential to significantly influence local photochemistry, and therefore, further studies focusing on the photooxidation and atmospheric fate of ketene through chamber studies are required to improve our current understanding of VOC OH reactivity and, hence, tropospheric O3 production.

Conditions Leading to Ketene Formation in Vaping Devices and Implications for Public Health

“…While the EVALI epidemic was due to acute respiratory damage from ketene derived from VEA, the general principle of acetates, including acetic acid itself, serving as starting materials for ketene formation holds and has been extensively documented in the chemistry literature. 13,17,20 In the gas phase, the reaction of ketene with water to form acetic acid has been shown to be relatively slow due to a high activation energy barrier, which is consistent with its potential to inflict lung tissue damage if inhaled. 32 Computational and experimental studies of chemical reaction energies indicate that a wide range of other acetates can also form ketene.…”

“…While the EVALI epidemic was due to acute respiratory damage from ketene derived from VEA, the general principle of acetates, including acetic acid itself, serving as starting materials for ketene formation holds and has been extensively documented in the chemistry literature. ,, In the gas phase, the reaction of ketene with water to form acetic acid has been shown to be relatively slow due to a high activation energy barrier, which is consistent with its potential to inflict lung tissue damage if inhaled . Computational and experimental studies of chemical reaction energies indicate that a wide range of other acetates can also form ketene. ,,, Thermal degradation of various esters into acids, aldehydes, olefins, and ketene has been previously well documented. , Among them, the thermal decomposition of phenyl acetate brought much attention recently because it shares a similar aryl acetate group with VEA, a possible causative chemical compound that is responsible for the EVALI outbreak. The key products in phenyl acetate gas-phase thermal degradation included phenol and ketene .…”

“…32 Computational and experimental studies of chemical reaction energies indicate that a wide range of other acetates can also form ketene. 8,13,17,20 Thermal degradation of various esters into acids, aldehydes, olefins, and ketene has been previously well documented. 33,34 Among them, the thermal decomposition of phenyl acetate brought much attention recently because it shares a similar aryl acetate group with VEA, a possible causative chemical compound that is responsible for the EVALI outbreak.…”

“…Case studies have demonstrated the type and severity of effects that occur . More recently, high concentrations of atmospheric ketene could be detected in the emission plumes from a petrochemical facility in South Korea using airborne time-of-flight mass spectrometry . This previously undocumented source of ketene highlights the urgent need for research into the detection of unknown sources of this elusive toxicant.…”