A gas chromatographic instrument for measurement of hydrogen cyanide in the lower atmosphere

Ambrose, J. L.; Zhou, Yong; Haase, K.; Mayne, Howard R.; Talbot, R. W.; Sive, B. C.

doi:10.5194/amt-5-1229-2012

Cited by 15 publications

(5 citation statements)

References 55 publications

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“…Excluding the BBP, the mean ambient HCN concentration of 35 ppt and maximum concentration of 132 ppt is comparable with other ground-based HCN measurements, both rural and urban (Ambrose et al, 2012;Knighton et al, 2009). The species with the highest correlations with HCN with the BBP removed are propanoic acid (R 2 = 0.79), HONO (R 2 = 0.76), MIC (R 2 = 0.75), formamide (R 2 = 0.71), and N-methylformamide (R 2 = 0.68).…”

Section: Identification and Behavior Of Key Speciessupporting

confidence: 79%

Observations of Isocyanate, Amide, Nitrate, and Nitro Compounds From an Anthropogenic Biomass Burning Event Using a ToF‐CIMS

et al. 2018

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Anthropogenic biomass burning is poorly represented in models due to a lack of observational data but represents a significant source of short‐lived toxic gases. Guy Fawkes Night (bonfire night) is a regular UK‐wide event where open fires are lit and fireworks are set off on 5 November. Previous gas phase studies of bonfire night focus on persistent organic pollutants primarily using off‐line techniques. Here the first simultaneous online gas phase measurements of several classes of compounds including isocyanates, amides, nitrates, and nitro‐organics are made during bonfire night (2014) in Manchester, UK, using a time‐of‐flight chemical ionization mass spectrometer (ToF‐CIMS) using iodide reagent ions. A shallow boundary layer and low wind speeds favor pollutant buildup with typical HCN, HNCO, and CH3NCO concentrations of tens of parts per thousand increasing by a factor of 13 to potentially harmful levels >1 ppb. Normalized excess mixing ratios relative to CO for a range of isocyanates and amides are reported for the first time. Using a HNCO:CO ratio of 0.1%, we distinguish emissions from flaming and smoldering combustion and report more accurate normalized excess mixing ratios for the distinct burning phases. While bonfire night is a highly polluting event, NO2 concentrations measured at this location are higher at other times, highlighting the importance of traffic as an NO2 emission source at this location. A risk communication methodology is used to equate enhancements in hourly averaged black carbon and NO2 concentrations caused by bonfire night as an equivalent of 26.1 passively smoked cigarettes.

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Section: Identification and Behavior Of Key Speciessupporting

confidence: 79%

Observations of Isocyanate, Amide, Nitrate, and Nitro Compounds From an Anthropogenic Biomass Burning Event Using a ToF‐CIMS

et al. 2018

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“…Consistent with our low HCN measurements, the authors found that HCN mixing ratios only spiked above the FTIR method detection limit of 3.2 ppbv on three occasions (isolated 1 min data points). Although prior measurements seem exceptionally high, our measurements are also on the low end of those reported for ground-level, ambient HCN in a rural region with little forest fire impact, which are on the order of a few hundred pptv (Ambrose et al, 2012). No significant long-term changes have been observed or expected for tropospheric HCN (Zhao et al, 2002) so it is unclear as to why the present measurements are so low.…”

Section: Overview Of Mobile Pollutant Measurementscontrasting

confidence: 56%

Elucidating real-world vehicle emission factors from mobile measurements over a large metropolitan region: a focus on isocyanic acid, hydrogen cyanide, and black carbon

et al. 2018

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A mobile laboratory equipped with state-of-the-art gaseous and particulate instrumentation was deployed across the Greater Toronto Area (GTA) during two seasons. A high-resolution time-of-flight chemical ionization mass spectrometer (HR-TOF-CIMS) measured isocyanic acid (HNCO) and hydrogen cyanide (HCN), and a high-sensitivity laserinduced incandescence (HS-LII) instrument measured black carbon (BC). Results indicate that on-road vehicles are a clear source of HNCO and HCN and that their impact is more pronounced in the winter, when influences from biomass burning (BB) and secondary photochemistry are weakest. Plume-based and time-based algorithms were developed to calculate fleet-average vehicle emission factors (EFs); the algorithms were found to yield comparable results, depending on the pollutant identity. With respect to literature EFs for benzene, toluene, C2 benzene (sum of m-, p-, and o-xylenes and ethylbenzene), nitrogen oxides, particle number concentration (PN), and black carbon, the calculated EFs were characteristic of a relatively clean vehicle fleet dominated by light-duty vehicles (LDV). Our fleet-average EF for BC (median: 25 mg kg −1 fuel ; interquartile range, IQR: 10-76 mg kg −1 fuel ) suggests that overall vehicular emissions of BC have decreased over time. However, the distribution of EFs indicates that a small proportion of high-emitters continue to contribute disproportionately to total BC emissions. We report the first fleet-average EF for HNCO (median: 2.3 mg kg −1 fuel , IQR: 1.4-4.2 mg kg −1 fuel ) and HCN (median: 0.52 mg kg −1 fuel , IQR: 0.32-0.88 mg kg −1 fuel ). The distribution of the estimated EFs provides insight into the real-world variability of HNCO and HCN emissions and constrains the wide range of literature EFs obtained from prior dynamometer studies. The impact of vehicle emissions on urban HNCO levels can be expected to be further enhanced if secondary HNCO formation from vehicle exhaust is considered.Published by Copernicus Publications on behalf of the European Geosciences Union.

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“…Consistent with our low HCN measurements, the authors found that HCN mixing ratios only spiked above the FTIR method detection limit of 3.2 ppbv on three occasions (isolated 1 min data points). Although prior measurements (Moussa et al, 2016) seem exceptionally high, our measurements are also on the low end of those reported for ground-level, ambient HCN in a rural region with little forest fire impact, which are on the order of a few hundred pptv (Ambrose et al, 2012). No significant long-term changes have been observed or expected for tropospheric HCN (Zhao et al, 2002) so it is unclear as to why the present measurements are so low.…”

Section: Overview Of Mobile Pollutant Measurementscontrasting

confidence: 62%

Response to referee 1 and 2

Wren¹

2018

Preprint

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A mobile laboratory equipped with state-of-the-art gaseous and particulate instrumentation was deployed across the Greater Toronto Area (GTA) during two seasons. A high-resolution time-of-flight chemical ionization mass spectrometer (HR-TOF-CIMS) measured isocyanic acid (HNCO) and hydrogen cyanide (HCN), and a high-sensitivity laserinduced incandescence (HS-LII) instrument measured black carbon (BC). Results indicate that on-road vehicles are a clear source of HNCO and HCN and that their impact is more pronounced in the winter, when influences from biomass burning (BB) and secondary photochemistry are weakest. Plume-based and time-based algorithms were developed to calculate fleet-average vehicle emission factors (EFs); the algorithms were found to yield comparable results, depending on the pollutant identity. With respect to literature EFs for benzene, toluene, C2 benzene (sum of m-, p-, and o-xylenes and ethylbenzene), nitrogen oxides, particle number concentration (PN), and black carbon, the calculated EFs were characteristic of a relatively clean vehicle fleet dominated by light-duty vehicles (LDV). Our fleet-average EF for BC (median: 25 mg kg −1 fuel ; interquartile range, IQR: 10-76 mg kg −1 fuel) suggests that overall vehicular emissions of BC have decreased over time. However, the distribution of EFs indicates that a small proportion of high-emitters continue to contribute disproportionately to total BC emissions. We report the first fleet-average EF for HNCO (median: 2.3 mg kg −1 fuel , IQR: 1.4-4.2 mg kg −1 fuel) and HCN (median: 0.52 mg kg −1 fuel , IQR: 0.32-0.88 mg kg −1 fuel). The distribution of the estimated EFs provides insight into the real-world variability of HNCO and HCN emissions and constrains the wide range of literature EFs obtained from prior dynamometer studies. The impact of vehicle emissions on urban HNCO levels can be expected to be further enhanced if secondary HNCO formation from vehicle exhaust is considered.

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A gas chromatographic instrument for measurement of hydrogen cyanide in the lower atmosphere

Cited by 15 publications

References 55 publications

Observations of Isocyanate, Amide, Nitrate, and Nitro Compounds From an Anthropogenic Biomass Burning Event Using a ToF‐CIMS

Observations of Isocyanate, Amide, Nitrate, and Nitro Compounds From an Anthropogenic Biomass Burning Event Using a ToF‐CIMS

Elucidating real-world vehicle emission factors from mobile measurements over a large metropolitan region: a focus on isocyanic acid, hydrogen cyanide, and black carbon

Response to referee 1 and 2

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