Formation of mutagenic nitrodibenzopyranones and their occurrence in ambient air

Inflammatory responses to secondary organic aerosols (SOA) generated from biogenic and anthropogenic precursors

“…It is therefore possible that the aromatic functionality present in the majority of naphthalene SOA products results in the involvement of very different cellular pathways, leading to outlier inflammatory endpoint responses. Various products of naphthalene oxidation such as nitroaromatics and polyaromatics are known to have mutagenic properties and may induce the formation of DNA adducts (Baird et al, 2005;Helmig et al, 1992). As such, it is possible that these products may induce health effects via other pathways as well and naphthalene SOA exposure may have effects beyond redox imbalance and oxidative stress.…”

“…Several patterns were also noted for SOA systems whose products shared similar functionalities and chemical structures. For instance, photooxidation products from pentadecane and β-caryophyllene share similarities with long chain fatty acids and may participate in membrane insertions, whereas many known products of naphthalene photooxidation are mutagens capable of inducing cellular pathways beyond those that affect the cellular redox balance (Baird et al, 2005;Helmig et al, 1992). Given these observations, it may be possible to roughly predict responses based on known SOA products as SOA systems whose products share similar functionalities and carbon chain length are likely to induce similar cellular pathways and produce similar levels of various inflammatory endpoints.…”

Comparative mutagenicity assessment of aerosols in emissions from biofuel combustion

“…PAHs as well as numerous PAH derivatives, i.e., alkylated PAHs, nitro-PAHs, oxygenated PAHs, quinones, hydroxy and hydroxynitro compounds, are produced by the incomplete combustion of fuels such as coal, gasoline, diesel and biofuels (Beak et al, 1991;Matsumoto et al, 1998). The mutagenicity and carcinogenicity of PAHs associated with combustion and ambient aerosols have been conclusively demonstrated through bacterial assays, human cell mutagenicity assays, animal assays and epidemiological studies (Hannigan et al, 1998;Helmig et al, 1992;Kamens et al, 1984;Kleindienst et al, 1986;Mastrangelo et al, 1996;McCrillis et al, 1992;Moller and Alfheim, 1980). The Ames assay test, a plate incorporation test based on genetically engineered microorganisms offers a relatively quick method for mutagenicity assessment and has been widely used as a screening tool for determining health risks associated with emissions, effluents and specific chemicals (Madill et al, 1999;Maron and Ames, 1983).…”

“…While the PAHs are indirect-acting mutagens, requiring activation by the mammalian enzyme system before mutagenicity is expressed, some of the PAH derivatives, i.e., the nitrated PAHs are strong direct-acting mutagens (Helmig et al, 1992). The higher direct-acting mutagenicity in vehicular emissions than in the indoor environments, measured by Pierson et al (1983), was attributed to PAH derivatives formed during incomplete combustion.…”

Sorption and chemical transformation of PAHs on coal fly ash. Final technical report

“…Such processes can have important ramifications, especially when the products are more hazardous than the parent compounds (e.g., conversion of PAHs to strongly mutagenic nitro derivatives [14]). The chemical fate of PAHs in the --vapor phase has received extensive and careful study, especially by Atkinson and coworkers [7,15,16], and appears to be well understood. However, the nature of chemical transformation of PAHs in the particulate phase, and the manner in which such phenomena may be influenced by the chemical and physical properties of the particulate matter, is much less fully characterized and understood [5].…”