Modeling the Formation, Degradation, and Spatiotemporal Distribution of 2-Nitrofluoranthene and 2-Nitropyrene in the Global Atmosphere

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are common atmospheric pollutants and known to cause adverse health effects. Nitrated PAHs (NPAHs) are formed in combustion activities and by nitration of PAHs in the atmosphere and may be equally or more toxic, but their spatial and temporal distribution in the atmosphere is not well characterized. Using the global EMAC model with atmospheric chemistry and surface compartments coupled, we investigate the formation, abundance, and fate of two secondarily formed NPAHs, 2-nitrofluoranthene (2-NFLT) and 2-nitropyrene (2-NPYR). The default reactivity scenario, the model with the simplest interpretation of parameters from the literature, tends to overestimate both absolute concentrations and NPAH/PAH ratios at observational sites. Sensitivity scenarios indicate that NO2-dependent NPAH formation leads to better agreement between measured and predicted NPAH concentrations and that photodegradation is the most important loss process of 2-NFLT and 2-NPYR. The highest concentrations of 2-NFLT and 2-NPYR are found in regions with strong PAH emissions, but because of continued secondary formation from the PAH precursors, these two NPAHs are predicted to be spread across the globe.

Global Cancer Risk from Unregulated Polycyclic Aromatic Hydrocarbons

“…N-PAHs have been detected in a variety of environments, from urban (Albinet et al, 2007;Elzein et al, 2019) to remote (Drotikova et al, 2020;Lammel et al, 2017). The chemical formation of N-PAHs in the atmosphere has been simulated in regional-scale (Mulder et al, 2019) and global-scale (Wilson, 2020) atmospheric modeling studies; those studies, however, did not include a key particle-phase reaction with the nitrate radical (NO 3 ) that laboratory studies suggest could be an extremely efficient source of N-PAHs (Zelenov et al, 2018;P. Zhang et al, 2014).…”

Polycyclic aromatic hydrocarbons (PAHs) and their alkylated-, nitro- and oxy-derivatives in the atmosphere over the Mediterranean and Middle East seas

“…This, again, points to short atmospheric lifetimes of NPAHs. The OH reaction rate coefficients of PAHs and NPAHs are similar (Table S2, US EPA, 2019), but NPAHs are more prone to photolysis (Fan et al, 1996;Keyte et al, 2013;Wilson et al, 2020). This is furthermore supported by findings that the NPAH/PAH ratios in mid-latitudes are higher in winter than in summer, obviously since the photochemical sink of NPAHs in summer overcompensates the higher formation potential as a source of NPAHs (Nežiková et al, 2021).…”

Global Cancer Risk From Unregulated Polycyclic Aromatic Hydrocarbons

“…N-PAHs have been detected in a variety of environments, from urban (Albinet, Leoz-Garziandia, Budzinski, & ViIlenave, 2007;Elzein, Dunmore, Ward, Hamilton, & Lewis, 2019) to remote (Drotikova, Ali, Halse, Reinardy, & Kallenborn, 2020;Lammel et al, 2017). The chemical formation of N-PAHs in the atmosphere has been simulated in regional-scale (Mulder et al, 2019) and global-scale (Wilson, 2020) atmospheric modelling studies; those studies, however, did not include a key particle-phase reaction with the nitrate radical (NO3) that laboratory studies suggest could be an extremely efficient source of N-PAHs (Zelenov, Aparina, Kozlovskiy, Sulimenkov, & Nosyrev, 2018;P. Zhang et al, 2014).…”

“…N‐PAHs have been detected in a variety of environments, from urban (Albinet et al., 2007; Elzein et al., 2019) to remote (Drotikova et al., 2020; Lammel et al., 2017). The chemical formation of N‐PAHs in the atmosphere has been simulated in regional‐scale (Mulder et al., 2019) and global‐scale (Wilson, 2020) atmospheric modeling studies; those studies, however, did not include a key particle‐phase reaction with the nitrate radical (NO 3 ) that laboratory studies suggest could be an extremely efficient source of N‐PAHs (Zelenov et al., 2018; P. Zhang et al., 2014). Furthermore, as prior studies did not perform human health impact assessments, the importance of N‐PAHs in the context of human health, as well as in relation to other advancements in this field, are both unknown.…”