Occurrence and Potential Sources of Quinones Associated with PM2.5 in Guadalajara, Mexico

Abstract

This study aims to establish the influence of primary emission sources and atmospheric transformation process contributing to the concentrations of quinones associated to particulate matter of less than 2.5 µm (PM 2.5 ) in three sites within the Metropolitan Area of Guadalajara (MAG), namely Centro (CEN), Tlaquepaque (TLA) and Las Águilas (AGU). Environmental levels of quinones extracted from PM 2.5 filters were analyzed using Gas Chromatography coupled to Mass Spectrometry (GC-MS). Overall, primary emissions in combination with photochemical and oxidation reactions contribute to the presence of quinones in the urban atmosphere of MAG. It was found that quinones in PM 2.5 result from the contributions from direct emission sources by incomplete combustion of fossil fuels such as diesel and gasoline that relate mainly to vehicular activity intensity in the three sampling sites selected. However, this also suggests that the occurrence of quinones in MAG can be related to photochemical transformation of the parent Polycyclic Aromatic Hydrocarbons (PAHs), to chemical reactions with oxygenated species, or a combination of both routes. The higher concentration of 1,4-Chrysenequinone during the rainy season compared to the warm-dry season indicates chemical oxidation of chrysene, since the humidity could favor singlet oxygen collision with parent PAH present in the particle phase. On the contrary, 9,10-Anthraquinone/Anthracene and 1,4-Naftoquinone/Naphthalene ratios were higher during the warm-dry season compared to the rainy season, which might indicate a prevalence of the photochemical formation during the warm-dry season favored by the large solar radiation typical of the season. In addition, the estimated percentage of photochemical formation of 9,10-Phenanthrenequinone showed that the occurrence of this compound in Tlaquepaque (TLA) and Las Águilas (AGU) sites is mainly propagated by conditions of high solar radiation such as in the warm-dry season and during long periods of advection of air masses from emission to the reception areas. This was shown by the direct association between the number hourly back trajectories arriving in the TLA and AGU from Centro and other areas in MAG and the highest photochemical formation percentage.

Polycyclic Aromatic Hydrocarbons (PAHs) Associated with PM2.5 in Guadalajara, Mexico: Environmental Levels, Health Risks and Possible Sources

“…Because HMW-PAHs have the lowest vapor pressure, that group of compounds tends to be more strongly associated with the particle phase than MMW-and LMW-PAH S [20]. Individual average environmental levels of PAHs in PM 2.5 determined in this study ranged from 0.03 ng·m −3 (Acn) to 1.45 ng·m −3 (BghiP), which are the same order of magnitude as those recently reported [17], who found environmental levels of PAHs in PM 2.5 ranging from 0.01 ng·m −3 (Flu) to 1.25 ng·m −3 (BghiP) at three urban sites located in Guadalajara, México in 2012. In comparison with Mexico City, the highest city in Mexico, the concentrations found here are of the same order of magnitude as those levels reported by [21] and [22] for five local urban sites, which were found to range from 0.02 ng·m −3 (Flu) to 1.45 ng·m −3 (BghiP) but were approximately one order of magnitude lower than those recently reported, from 0.81 ng·m −3 (Acn) to 2.14 ng·m −3 (BghiP), at an urban and a semi-urban site in Cuernavaca, Mexico [23].…”

“…Although there is an atmospheric monitoring network and studies on trace metals and inorganic ions in PM 2.5 [15,16], it is still necessary to undertake organic chemical characterization of breathable particulate matter to identify sources and to provide support to local government in the design of viable strategies with benefits to the population. A recent study found that naphthalene, phenanthrene, anthracene and chrysene likely undergo photochemical transformation to their quinones compounds, which were found in PM 2.5 at three urban locations within the Metropolitan Zone of Guadalajara during the dry and rainy season in 2012 [17]. However, there are no published data on PAHs associated with PM 2.5 before 2012.…”

Observed Daily Profiles of Polyaromatic Hydrocarbons and Quinones in the Gas and PM1 Phases: Sources and Secondary Production in a Metropolitan Area of Mexico

“…Prior to extraction, quartz filters and PXP were spiked with surrogates (SS) (Sigma-Aldrich) at 1600 ng [44,45]. This step was repeated twice, each one with a clean solvent (to improve the extraction efficiency),…”

“…Prior to extraction, quartz filters and PXP were spiked with surrogates (SS) (Sigma-Aldrich) at 1600 ng mL −1 (fluorene-d10, fluoranthene-d10, pyrene-d10, benzo[a]pyrene-d10, 1,4-naphthoquinone-d6, anthraquinone-d8) to quantify the effect of the sample processing methodology on the analytes of interest. The extraction of PAHs and quinones from the gas and PM 1 phases was performed using methylene chloride (25 mL for PM 1 and 40 mL for the gas phase) of HPLC grade (Honeywell Burdick & Jackson Company, Muskegon, MI, USA) in an ultrasonic bath (Branson model 5800, Emerson Electronic Co., Wallingford, CT, USA) at 45 • C for 30 min [44,45]. This step was repeated twice, each one with a clean solvent (to improve the extraction efficiency), recovering the extractant in a flask.…”

Air Pollution in an Urban Area of Mexico: Sources of Emission (Vehicular, Natural, Industrial, and Brick Production)

“…Barradas-Gimate et al [29] carried out a study in 2014 at the Centro and Tlaquepaque during the warm dry season and at Centro and Las Aguilas during the rainy season, with the objective of determining the atmospheric levels and sources of quinones in PM 2.5 . The highest concentration of Σ 16 PAHs occurred in Tlaquepaque (7.62 ± 2.03 ng m −3 ) in the warm dry season and the lowest was recorded in Las Aguilas (2.98 ± 0.55 ng m −3 ).…”