A Decade of Aerosol and Gas Precursor Chemical Characterization at Mt. Lemmon, Arizona (1992 to 2002)

Matichuk, R. I.; Barbaris, Brian; Betterton, Eric A.; Hori, Masahiro; Murao, Naoto; Ohta, Sachio; Ward, D.

doi:10.2151/jmsj.84.653

Cited by 10 publications

(14 citation statements)

References 29 publications

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“…An analogous analysis for the major inorganic and carbonaceous components showed long-term reductions in sulfate, elemental carbon and organic carbon, attributable to the closure of regional copper smelters and other implemented source controls for pollutants such as SO 2 (Matichuk et al, 2006; Sorooshian et al, 2011). This study shows that Chiricahua and Tonto have experienced statistically significant reductions in As during all seasons since 1988 (seasonal range: 0.18 – 0.33 ng m −3 y −1 and 0.03 – 0.10 ng m −3 y −1 , respectively).…”

Section: Resultsmentioning

confidence: 99%

Spatiotemporal distribution of airborne particulate metals and metalloids in a populated arid region

Prabhakar

Sorooshian

Toffol

et al. 2014

Atmospheric Environment

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A statistical analysis of data from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network of aerosol samplers has been used to study the spatial and temporal concentration trends in airborne particulate metals and metalloids for southern Arizona. The study region is a rapidly growing area in southwestern North America characterized by high fine soil concentrations (among the highest in the United States), anthropogenic emissions from an area within the fastest growing region in the United States, and a high density of active and abandoned mining sites. Crustal tracers in the region are most abundant in the summer (April – June) followed by fall (October – November) as a result of dry meteorological conditions which favor dust emissions from natural and anthropogenic activity. A distinct day-of-week cycle is evident for crustal tracer mass concentrations, with the greatest amplitude evident in urban areas. There have been significant reductions since 1988 in the concentrations of toxic species that are typically associated with smelting and mining. Periods with high fine soil concentrations coincide with higher concentrations of metals and metalloids in the atmosphere, with the enhancement being higher at urban sites.

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Section: Resultsmentioning

confidence: 99%

Spatiotemporal distribution of airborne particulate metals and metalloids in a populated arid region

Prabhakar

Sorooshian

Toffol

et al. 2014

Atmospheric Environment

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“…Regions with lower rain pH values include the eastern United States, eastern Mediterranean, Canada, Turkey, Thailand, Singapore, and China (Granat et al, 1996; Al-Momani et al, 1997; Sirois et al, 2000; Balasubramanian et al, 2001; Qin and Huang, 2001; Basak and Alagha, 2004; Likens, 2007). It is cautioned that the temporal range of measurements is varied for these studies, which can affect pH comparisons; for example, reductions in sulfur dioxide (SO 2 ) emissions in the Southwest over the last several years have resulted in reduced particulate sulfate levels (Matichuk et al, 2006; Sorooshian et al, 2011), which influences precipitation pH.…”

Section: Resultsmentioning

confidence: 99%

Aerosol and precipitation chemistry in the southwestern United States: spatiotemporal trends and interrelationships

et al. 2013

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This study characterizes the spatial and temporal patterns of aerosol and precipitation composition at six sites across the United States Southwest between 1995 and 2010. Precipitation accumulation occurs mostly during the wintertime (December–February) and during the monsoon season (July–September). Rain and snow pH levels are usually between 5–6, with crustal-derived species playing a major role in acid neutralization. These species (Ca2+, Mg2+, K+, Na+) exhibit their highest concentrations between March and June in both PM2.5 and precipitation due mostly to dust. Crustal-derived species concentrations in precipitation exhibit positive relationships with SO42−, NO3−, and Cl–, suggesting that acidic gases likely react with and partition to either crustal particles or hydrometeors enriched with crustal constituents. Concentrations of particulate SO42− show a statistically significant correlation with rain SO42− unlike snow SO42−, which may be related to some combination of the vertical distribution of SO42− (and precursors) and the varying degree to which SO42−-enriched particles act as cloud condensation nuclei versus ice nuclei in the region. The coarse : fine aerosol mass ratio was correlated with crustal species concentrations in snow unlike rain, suggestive of a preferential role of coarse particles (mainly dust) as ice nuclei in the region. Precipitation NO3− : SO42− ratios exhibit the following features with potential explanations discussed: (i) they are higher in precipitation as compared to PM2.5; (ii) they exhibit the opposite annual cycle compared to particulate NO3− : SO42− ratios; and (iii) they are higher in snow relative to rain during the wintertime. Long-term trend analysis for the monsoon season shows that the NO3− : SO42− ratio in rain increased at the majority of sites due mostly to air pollution regulations of SO42− precursors.

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“…Wind gusts reaching 60 mph are not uncommon at Mt. Elden, particularly during the monsoon season; hence, windblown soils could have entered the clouds as particulate and served as cloud condensation nuclei (Matichuk et al 2006).…”

Section: Major Ions and Phmentioning

confidence: 99%

“…The previously cited studies are several years old, and over the last years, there has been a substantial decrease in sulfur emission, which might have changed the chemistry at these sampling sites. Decrease of SO 2 concentrations in Arizona have been documented by Matichuk (2006) at Mt. Lemmon between 1992 and 2002.…”

Section: Major Ions and Phmentioning

confidence: 99%

The Chemistry of Intercepted Clouds in Northern Arizona during the North American Monsoon Season

Hutchings

Robinson

McIlwraith

et al. 2008

Water Air Soil Pollut

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Cloudwater samples have been collected for the first time at a high-elevation site in the US interior Southwest. Cloud samples were collected at the summit of Mt. Elden near Flagstaff, Arizona. The samples were analyzed for pH, ionic composition, trace metals, organic carbon content, and volatile organic compounds. All of the samples showed high pH values (5.12-6.66), which appear to be the result of soil/crustal acid-neutralizing components. Ammonium and nitrate were the dominant ionic species. Organic carbon concentrations ranged from 3 to 18 mg/l. Volatile aromatic compounds (toluene, ethylbenzene, and xylenes) were detected, although they did not contribute significantly to the dissolved organic matter (<1% of dissolved organic carbon). Still, their aqueous-phase concentrations were substantially higher than equilibrium partitioning from the gas phase would suggest. Metal concentrations were high when compared to other cloud studies in remote areas. Overall, with the exception of pH, the cloud chemistry showed marked inter-event variability. The source of the variability was investigated using NOAA HYSPLIT dispersion calculations. Like the cloud composition, the air mass back trajectories differed widely from event to event, and consistently, air masses that passed over highly urbanized areas had higher trace metal, organic, and ion concentrations than more pristine air masses.

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A Decade of Aerosol and Gas Precursor Chemical Characterization at Mt. Lemmon, Arizona (1992 to 2002)

Cited by 10 publications

References 29 publications

Spatiotemporal distribution of airborne particulate metals and metalloids in a populated arid region

Spatiotemporal distribution of airborne particulate metals and metalloids in a populated arid region

Aerosol and precipitation chemistry in the southwestern United States: spatiotemporal trends and interrelationships

The Chemistry of Intercepted Clouds in Northern Arizona during the North American Monsoon Season

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