Redox and electrophilic properties of vapor- and particle-phase components of ambient aerosols

Abstract

Particulate matter (PM) has been the primary focus of studies aiming to understand the relationship between the chemical properties of ambient aerosols and adverse health effects. Size and chemical composition of PM have been linked to their oxidative capacity which has been postulated to promote or exacerbate pulmonary and cardiovascular diseases. But in the last few years, new studies have suggested that volatile and semivolatile components may also contribute to many adverse health effects. The objectives of this study were: i) assess for the first time the redox and electrophilic potential of vapor-phase components of ambient aerosols, and ii) evaluate the relative contributions of particle- and vapor-fractions to the hazard of a given aerosol. To achieve these objectives vapor- and particle-phase samples collected in Riverside (CA) were subjected to three chemical assays to determine their redox and electrophilic capacities. The results indicate that redox active components are mainly associated with the particle-phase, while electrophilic compounds are found primarily in the vapor-phase. Vapor-phase organic extracts were also capable of inducing the stress responding protein, heme-oxygenase-1 (HO-1), in RAW264.7 murine macrophages. These results demonstrate the importance of volatile components in the overall oxidative and electrophilic capacity of aerosols, and point out the need for inclusion of vapors in future health and risk assessment studies.

Ambient ultrafine particles provide a strong adjuvant effect in the secondary immune response: implication for traffic-related asthma flares

“…In this regard, we have previously demonstrated that there is an excellent correlation between the PAH content of ambient UFP and their ability to act as an adjuvant in the primary immune response (36). Quinones, which can also be formed from the enzymatic conversion of PAH, are capable of generating ROS through redox cycling and electrophilic chemistry that may be relevant to the generation of oxidative stress deep in the lungs of the animals (15,37,57). The particle exposure site in this study is generally characterized by a higher content of redoxcycling organic chemicals as also evidenced by the high OC content (81.6%) of the particles that were collected near the 110 Los Angeles Freeway (Supplemental Fig.…”

Covalent binding of quinones activates the Ah receptor in Hepa1c1c7 cells

“…A variety of quinones, including 1,4-benzoquinone (1,4-BQ), 1,2-naphthoquinone (1,2-NQ), and 1,4-NQ are found in diesel engine exhaust, burning coal, cigarette smoke (Eiguren-Fernandez et al, 2010;Batterman et al, 2012;Wallace, 1989) and as metabolites during exposure of experimental animals and cultured cells (Wilson et al, 1996). Butylated hydroxyanisol (BHA) and tert-butyl-1, 4-hydroquinone (TBHQ), which are used as a food and cosmetic additive to preserve oils, are metabolized to tertbutyl-1,4-benzoquinone (TBQ) (Verhagen et al, 1989;Snyder and Hedli, 1996).…”

Numerical Simulation of Ultrafine Particle Dispersion in Urban Street Canyons with the Spalart-Allmaras Turbulence Model

“…Monitoring atmospheric aerosol is important for several reasons: the toxic nature of the particles due to the organic compounds on itself (Eiguren-Fernandez et al, 2010), the ability of UFPs to penetrate in the epithelial cells of the lower respiratory tract and accumulate in lymph nodes (Nel et al, 2006), the oxidative damage effects on DNA which may increase the risk of cancer (Møller et al, 2008), and the potential association with paediatric asthma (Andersen et al, 2008) are some of the harmful effects on human health caused by exposure to nanoparticles.…”