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Quinones are reactive organic compounds known to initiate reactions associated with a host of toxicological events. Their presence in different atmospheres has been demonstrated although their sources remain uncertain. As a result of their reactivity and instability during chemical analysis, only a limited number of studies have reported on atmospheric concentrations of quinones in ambient air. Furthermore, besides the limited information on quinones associated with particulate matter, no previous studies have quantified vapor-phase quinones. We report vapor- and particle-phase concentrations of 1,2- and 1,4-naphthoquinones (1,2-NQ, 1,4-NQ), 9,10-phenanthraquinone (9,10-PQ), and 9,10-anthraquinone (9,10-AQ), measured over a 5-year period in Southern California. The results showed that vapor-phase concentrations of the target quinones were in general higher than those in the particle-phase. Vapor-phase concentrations ranged from 80 pg/m3 for the AQ to 1747 pg/m3 for the 1,4-NQ, and the particle-phase concentrations between 13 pg/m3 for the 1,2-NQ and 250 pg/m3 for 9,10-AQ. The target quinones were found to be distributed between vapor- and particle-phase, with the exception of 9,10-PQ found only in the particle-phase. The differences observed in the concentrations among sites and seasons suggest different source contributions; source sites were dominated by primary sources, while downwind locations showed a high contribution from photochemical activity. [ABSTRACT FROM AUTHOR]

Ambient concentrations of 15 vapor-and particle-phase (PM2. 5) polycyclic aromatic hydrocarbons (PAHs), listed by the US EPA as priority pollutants, were measured between July 2002 and November 2003 in six Southern California communities participating in a multi-year chronic respiratory health study of schoolchildren. The communities were geographically distributed over two hundred kilometers, extending from Long Beach in coastal Los Angeles, to high mountain areas to the north and west of the Los Angeles basin, and south into Eastern San Diego County. Seasonal and spatial variation in the atmospheric concentrations of PAHs is of interest because this class of compounds includes potent mutagens, carcinogens, and species capable of generating reactive oxygen species (ROS) that may lead to oxidative stress. Naphthalene accounted for 95% of the total PAH mass; annual averages ranged from 89 to 142 ng m-3. Benzo[ghi]perylene (BGP) and the pro-carcinogen benzo[a]pyrene (BAP), present almost exclusively in the particle-phase, ranged respectively from 38 to 231 pg m-3 and 75 and 111 pg m-3, with the highest values observed in Long Beach, a community with a high volume of seaport-related activities, and Lancaster, a commuter dormitory community. A considerable increase in the particle-phase PAH concentration, relative to the vapor-phase, was observed as ambient temperature decreased. Cold/hot season ratios for PAHs in PM2. 5 averaged 5. 7, reaching 54 at Long Beach. The presented data underscore the importance of seasonal variations on atmospheric PAH concentrations. These observations are relevant to future interpretation and analysis of community-scale human health effects research. [ABSTRACT FROM AUTHOR]

Fifteen priority polycyclic aromatic hydrocarbons (PAHs) were measured in two rural communities (Atascadero and Lompoc) located several hundred km northwest of Los Angeles and in four urban communities 40-100 km downwind of Los Angeles (San Dimas, Upland, Mira Loma, and Riverside), during all seasons, from May 2001 to July 2002. PM 2.5 and vapor-phase PAHs were collected, on prebaked quartz fiber filters and PUF-XAD-4 resin, respectively, at 113 LPM, during 24 h periods, every eighth day, and quantified by HPLC-Fluorescence. At all sites vapor-phase PAHs contained >99.9% of the total PAH mass and were dominated by naphthalene (NAP), which varied from about 60 ng m -3 in Lompoc, a community with light traffic, to ∼580 ng m -3 in Riverside, a community traversed by ∼200,000 vehicles day -1 . During summer pollution episodes in urban sites, NAP concentrations reached 7-30 times annual averages. Except for summer episodes, concentrations of low MW PAHs showed small seasonal variations (∼2 times higher in winter). Similar concentrations of particle-phase PAHs were observed at all sites except for Lompoc. Benzo[ ghi ]perylene (BGP), a marker of gasoline exhaust emissions, showed the highest concentration among particle-phase PAHs, varying from 23.3 pg m -3 in Lompoc to 193 pg m -3 in Mira Loma. Benzo[ a ]pyrene and indeno[ 1,2,3-cd ]pyrene, found exclusively in the particle phase, were much higher in urban sites (∼40-100 pg m -3 ), than in Lompoc (∼12 pg m -3 ). Winter particle-phase PAHs were 2 to 14 times higher than summer levels. Particle-phase PAHs were negatively correlated with mean air temperature in urban sites (r = -0.50 to -0.75), probably resulting from surface inversions occurring during winter. The data suggest that in Southern California vehicular exhaust emissions are a major contributor to particle-phase PAHs. [ABSTRACT FROM AUTHOR]

Quinones are reactive organic compounds and are known to initiate reactions associated with many toxicological events. Their presence in air pollution has been demonstrated, but routine quantitative measurements are lacking. A quantitative method for the determination of four quinones was developed using diesel exhaust particles (DEP) and National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 1649a. The method was then used to analyze ambient air samples from different sites in Southern California. After extraction in dichloromethane, the target compounds were converted to their stable diacetyl derivatives and determined by electron impact GC-MS using selected ion monitoring. Calibration plots were obtained with deuterium-labeled internal standards. The four quinones, 1,2-naphthoquinone (1,2-NQ), 1,4-naphthoquinone (1,4-NQ), 9,10-phenanthraquinone (9,10-PQ), and 9,10-anthraquinone (9,10-AQ), were quantified in DEP, in SRM 1649a, and in ambient air samples of PM 2.5 collected in several rural and urban sampling locations upwind and downwind of major emission sources in Central Los Angeles. Mean concentration of individual target quinones ranged from 7.9-40.4 μg/g in the DEP, and from 5-730 pg/m 3 in the PM 2.5 samples. Precision (repeatability and reproducibility) varied from 2-22%. Further measurements of these species in future air samples should be considered in light of their potential health significance. [ABSTRACT FROM AUTHOR]