Modifications to the Sunset Laboratory Carbon Aerosol Monitor for the Simultaneous Measurement of PM<sub>2.5</sub> Nonvolatile and Semi-Volatile Carbonaceous Material

Grover, Brett D.; Eatough, Norman L.; Woolwine, Woods R.; Eatough, Delbert J.; Cary, Robert A.

doi:10.3155/1047-3289.59.8.1007

Cited by 10 publications

(12 citation statements)

References 20 publications

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“…Uncertainty due to random measurement errors is estimated to be 28%. Systematic errors due to particle volatility are possible [ Grover et al , 2009]. Significant discrepancies were observed between the AMS OA (organic aerosol mass, i.e., OM) and Sunset Labs OC, with a study average OM/OC slope of 3.28 and r 2 = 0.76, where a slope closer to 2 is more realistic [ Turpin and Lim , 2001; Hayes et al, submitted manuscript, 2012].…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Significant discrepancies were observed between the AMS OA (organic aerosol mass, i.e., OM) and Sunset Labs OC, with a study average OM/OC slope of 3.28 and r 2 = 0.76, where a slope closer to 2 is more realistic [ Turpin and Lim , 2001; Hayes et al, submitted manuscript, 2012]. Possible causes include loss of semi‐volatile compounds from the collection filter media within the OC/EC analyzer, or due to the presence of the denuder [ Grover et al , 2009]. Other unidentified systematic errors associated with the measurements cannot be ruled out.…”

Section: Experimental Methodsmentioning

confidence: 99%

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On the gas‐particle partitioning of soluble organic aerosol in two urban atmospheres with contrasting emissions: 2. Gas and particle phase formic acid

et al. 2012

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[1] Gas and fine particle (PM 2.5 ) phase formic acid concentrations were measured with online instrumentation during separate one-month studies in the summer of 2010 in Los Angeles (LA), CA, and Atlanta, GA. In both urban environments, median gas phase concentrations were on the order of a few ppbv (LA 1.6 ppbv, Atlanta 2.3 ppbv) and median particle phase concentrations were approximately tens of ng/m 3 (LA 49 ng/m 3 , Atlanta 39 ng/m 3 ). LA formic acid gas and particle concentrations had consistent temporal patterns; both peaked in the early afternoon and generally followed the trends in photochemical secondary gases. Atlanta diurnal trends were more irregular, but the mean diurnal profile had similar afternoon peaks in both gas and particle concentrations, suggesting a photochemical source in both cities. LA formic acid particle/gas (p/g) ratios ranged between 0.01 and 12%, with a median of 1.3%. No clear evidence that LA formic acid preferentially partitioned to particle water was observed, except on three overcast periods of suppressed photochemical activity. Application of Henry's Law to predict partitioning during these periods greatly under-predicted particle phase formate concentrations based on bulk aerosol liquid water content (LWC) and pH estimated from thermodynamic models. In contrast to LA, formic acid partitioning in Atlanta appeared to be more consistently associated with elevated relative humidity (i.e., aerosol LWC), although p/g ratios were somewhat lower, ranging from 0.20 to 5.8%, with a median of 0.8%. Differences in formic acid gas absorbing phase preferences between these two cities are consistent with that of bulk water-soluble organic carbon reported in a companion paper.Citation: Liu, J., et al. (2012), On the gas-particle partitioning of soluble organic aerosol in two urban atmospheres with contrasting emissions: 2. Gas and particle phase formic acid,

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Section: Experimental Methodsmentioning

confidence: 99%

Section: Experimental Methodsmentioning

confidence: 99%

On the gas‐particle partitioning of soluble organic aerosol in two urban atmospheres with contrasting emissions: 2. Gas and particle phase formic acid

et al. 2012

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“…AMS OA mass (OM) and Sunset Labs OC were highly correlated (for complete study r 2 = 0.76), but OM/OC ratios were significantly higher than expected (regression slope of 3.3 compared to 1.4–2.3 expected for typical urban environments [ Turpin and Lim , 2001]) [ Hayes et al , 2012]. This difference was likely attributed to the loss of semi‐volatile compounds from the inline carbon denuder or the collection filter media within the OCEC analyzer [ Grover et al , 2009]. Recent measurements (unpublished) in Atlanta for two weeks in the fall of 2011 comparing an Aerosol Chemical Speciation Monitor (ACSM, Aerodyne Research Inc. [ Ng et al , 2011]) with the same Sunset Labs OCEC instrument, operated identically to the CalNex study, showed excellent agreement (OM/OC regression slope of 1.7, r 2 = 0.92) between the two instruments, which is consistent with substantially lower contributions of semi‐volatile SOA in Atlanta [ Peltier et al , 2007].…”

Section: Experimental Methodsmentioning

confidence: 99%

On the gas‐particle partitioning of soluble organic aerosol in two urban atmospheres with contrasting emissions: 1. Bulk water‐soluble organic carbon

Zhang¹,

Liu²,

Parker³

et al. 2012

J. Geophys. Res.

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[1] The partitioning of semi-volatile compounds between the gas and particle phase influences the mass, size and chemical composition of the secondary organic aerosols (SOA) formed. Here we investigate the partitioning of water-soluble organic carbon (WSOC) and the formation of SOA in Los Angeles (LA), California and Atlanta, Georgia; urban regions where anthropogenic volatile organic compound (VOC) emissions are dominated by vehicles, but are contrasted by an additional large source of biogenic VOCs exclusive to Atlanta. In Atlanta, evidence for WSOC partitioning to aerosol water is observed throughout the day, but is most prevalent in the morning. During drier periods (RH < 70%), the WSOC partitioning coefficient (F p ) was in proportion to the organic mass, suggesting that both particle water and organic aerosol (OA) can serve as an absorbing phase. In contrast, despite the higher average RH, in LA the aerosol water was not an important absorbing phase, instead, F p was correlated with OA mass. Particle water concentrations from thermodynamic predictions based on measured inorganic aerosol components do not indicate significant differences in aerosol hygroscopicity. The observed different WSOC partitioning behaviors may be attributed to the contrasting VOC mixture between the two cities. In addition, different OA composition may also play a role, as Atlanta OA is expected to have a substantially more aged regional character. These results are consistent with our companion studies that find similar partitioning differences for formic acid and additional contrasts in SOA optical properties. The findings provide direct evidence for SOA formation through an equilibrium partitioning process.

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“…This protocol allows for tracking of long-term EC reductions in response to control measures (Chen et al, 2012;Murphy et al, 2011). A semicontinuous version of the thermal/optical analyzer is in use (Bauer et al, 2009;Grover et al, 2008Grover et al, , 2009Turpin et al, 1990), but it only uses transmittance for the charring correction, which differs from the reflectance correction.…”

Section: Particle Size and Mass Concentrationmentioning

confidence: 99%

Air quality measurements—From rubber bands to tapping the rainbow

Hidy¹,

Mueller²,

Altshuler

et al. 2017

Journal of the Air & Waste Management Association

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It is axiomatic that good measurements are integral to good public policy for environmental protection. The generalized term for "measurements" includes sampling and quantitation, data integrity, documentation, network design, sponsorship, operations, archiving, and accessing for applications. Each of these components has evolved and advanced over the last 200 years as knowledge of atmospheric chemistry and physics has matured. Air quality was first detected by what people could see and smell in contaminated air. Gaseous pollutants were found to react with certain materials or chemicals, changing the color of dissolved reagents such that their light absorption at selected wavelengths could be related to both the pollutant chemistry and its concentration. Airborne particles have challenged the development of a variety of sensory devices and laboratory assays for characterization of their enormous range of physical and chemical properties. Advanced electronics made possible the sampling, concentration, and detection of gases and particles, both in situ and in laboratory analysis of collected samples. Accurate and precise measurements by these methods have made possible advanced air quality management practices that led to decreasing concentrations over time. New technologies are leading to smaller and cheaper measurement systems that can further expand and enhance current air pollution monitoring networks. Implications: Ambient air quality measurement systems have a large influence on air quality management by determining compliance, tracking trends, elucidating pollutant transport and transformation, and relating concentrations to adverse effects. These systems consist of more than just instrumentation, and involve extensive support efforts for siting, maintenance, calibration, auditing, data validation, data management and access, and data interpretation. These requirements have largely been attained for criteria pollutants regulated by National Ambient Air Quality Standards, but they are rarely attained for nonroutine measurements and research studies.

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Modifications to the Sunset Laboratory Carbon Aerosol Monitor for the Simultaneous Measurement of PM_2.5 Nonvolatile and Semi-Volatile Carbonaceous Material

Cited by 10 publications

References 20 publications

On the gas‐particle partitioning of soluble organic aerosol in two urban atmospheres with contrasting emissions: 2. Gas and particle phase formic acid

On the gas‐particle partitioning of soluble organic aerosol in two urban atmospheres with contrasting emissions: 2. Gas and particle phase formic acid

On the gas‐particle partitioning of soluble organic aerosol in two urban atmospheres with contrasting emissions: 1. Bulk water‐soluble organic carbon

Air quality measurements—From rubber bands to tapping the rainbow

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Modifications to the Sunset Laboratory Carbon Aerosol Monitor for the Simultaneous Measurement of PM2.5 Nonvolatile and Semi-Volatile Carbonaceous Material

Cited by 10 publications

References 20 publications

On the gas‐particle partitioning of soluble organic aerosol in two urban atmospheres with contrasting emissions: 2. Gas and particle phase formic acid

On the gas‐particle partitioning of soluble organic aerosol in two urban atmospheres with contrasting emissions: 2. Gas and particle phase formic acid

On the gas‐particle partitioning of soluble organic aerosol in two urban atmospheres with contrasting emissions: 1. Bulk water‐soluble organic carbon

Air quality measurements—From rubber bands to tapping the rainbow

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Modifications to the Sunset Laboratory Carbon Aerosol Monitor for the Simultaneous Measurement of PM_2.5 Nonvolatile and Semi-Volatile Carbonaceous Material