scholarly journals Long-path measurements of pollutants and micrometeorology over Highway 401 in Toronto

2017 ◽  
Author(s):  
Yuan You ◽  
Ralf M. Staebler ◽  
Samar G. Moussa ◽  
Yushan Su ◽  
Tony Munoz ◽  
...  
Keyword(s):  
Dispersion Model ◽  
Urban Air Pollution ◽  
Forecast Model ◽  
Emission Factors ◽  
Ammonia Nitrogen ◽  
Traffic Emissions ◽  
Mixing Ratios ◽  
Air Quality Forecast ◽  
Traffic Volumes

Abstract. Traffic emissions contribute significantly to urban air pollution. Measurements were conducted over Highway 401 in Toronto, Canada, with a long-path Fourier Transform Infra-Red Spectrometer (FTIR) combined with a suite of micrometeorological instruments, to identify and quantify a range of air pollutants. Results were compared with simultaneous in-situ observations at a roadside monitoring station, and with output from a special version of the operational Canadian air quality forecast model (GEM-MACH). Elevated mixing ratios of ammonia (0–23 ppb) were observed, of which 76 % were associated with traffic emissions. Hydrogen cyanide was identified at mixing ratios between 0 and 4 ppb. Using a simple dispersion model, an integrated emission factor of on average 2.6 g km−1 carbon monoxide was calculated for this defined section of Highway 401, which agreed well with estimates based on vehicular emission factors and observed traffic volumes. Based on the same dispersion calculations, vehicular average emission factors of 0.04, 0.36 and 0.15 g km−1 were calculated for ammonia, nitrogen oxide, and methanol respectively.

scholarly journals Long-path measurements of pollutants and micrometeorology over Highway 401 in Toronto

2017 ◽  
Vol 17 (22) ◽  
pp. 14119-14143 ◽  
Author(s):  
Yuan You ◽  
Ralf M. Staebler ◽  
Samar G. Moussa ◽  
Yushan Su ◽  
Tony Munoz ◽  
...  
Keyword(s):  
Dispersion Model ◽  
Urban Air Pollution ◽  
Forecast Model ◽  
Emission Factors ◽  
Ammonia Nitrogen ◽  
Traffic Emissions ◽  
Mixing Ratios ◽  
Air Quality Forecast ◽  
Traffic Volumes

Abstract. Traffic emissions contribute significantly to urban air pollution. Measurements were conducted over Highway 401 in Toronto, Canada, with a long-path Fourier transform infrared (FTIR) spectrometer combined with a suite of micrometeorological instruments to identify and quantify a range of air pollutants. Results were compared with simultaneous in situ observations at a roadside monitoring station, and with output from a special version of the operational Canadian air quality forecast model (GEM-MACH). Elevated mixing ratios of ammonia (0–23 ppb) were observed, of which 76 % were associated with traffic emissions. Hydrogen cyanide was identified at mixing ratios between 0 and 4 ppb. Using a simple dispersion model, an integrated emission factor of on average 2.6 g km−1 carbon monoxide was calculated for this defined section of Highway 401, which agreed well with estimates based on vehicular emission factors and observed traffic volumes. Based on the same dispersion calculations, vehicular average emission factors of 0.04, 0.36, and 0.15 g km−1 were calculated for ammonia, nitrogen oxide, and methanol, respectively.

scholarly journals In-situ observation of Asian pollution transported into the Arctic lowermost stratosphere

2011 ◽  
Vol 11 (21) ◽  
pp. 10975-10994 ◽  
Author(s):  
A. Roiger ◽  
H. Schlager ◽  
A. Schäfler ◽  
H. Huntrieser ◽  
M. Scheibe ◽  
...  
Keyword(s):  
Dispersion Model ◽  
Anthropogenic Pollution ◽  
Conveyor Belt ◽  
Particle Dispersion ◽  
The Arctic ◽  
In Situ Observation ◽  
Air Mass ◽  
Mixing Ratios ◽  
The North

Abstract. On a research flight on 10 July 2008, the German research aircraft Falcon sampled an air mass with unusually high carbon monoxide (CO), peroxyacetyl nitrate (PAN) and water vapour (H2O) mixing ratios in the Arctic lowermost stratosphere. The air mass was encountered twice at an altitude of 11.3 km, ~800 m above the dynamical tropopause. In-situ measurements of ozone, NO, and NOy indicate that this layer was a mixed air mass containing both air from the troposphere and stratosphere. Backward trajectory and Lagrangian particle dispersion model analysis suggest that the Falcon sampled the top of a polluted air mass originating from the coastal regions of East Asia. The anthropogenic pollution plume experienced strong up-lift in a warm conveyor belt (WCB) located over the Russian east-coast. Subsequently the Asian air mass was transported across the North Pole into the sampling area, elevating the local tropopause by up to ~3 km. Mixing with surrounding Arctic stratospheric air most likely took place during the horizontal transport when the tropospheric streamer was stretched into long and narrow filaments. The mechanism illustrated in this study possibly presents an important pathway to transport pollution into the polar tropopause region.

scholarly journals Temporal changes in the emissions of CH<sub>4</sub> and CO from China estimated from CH<sub>4</sub> / CO<sub>2</sub> and CO / CO<sub>2</sub> correlations observed at Hateruma Island

2013 ◽  
Vol 13 (8) ◽  
pp. 22893-22930 ◽  
Author(s):  
Y. Tohjima ◽  
M. Kubo ◽  
C. Minejima ◽  
H. Mukai ◽  
H. Tanimoto ◽  
...  
Keyword(s):  
Fossil Fuel ◽  
Dispersion Model ◽  
Temporal Changes ◽  
Particle Dispersion ◽  
Anthropogenic Sources ◽  
In Situ Observation ◽  
Mixing Ratios ◽  
Increasing Trend ◽  
Concentration Footprint

Abstract. In-situ observation of the atmospheric CO2, CH4, and CO mixing ratios at Hateruma Island (HAT, 24.05° N, 123.80° E) often show synoptic-scale variations with correlative elevations during winter, associated with air transport from the East Asian countries. We examine winter (November–March) trends in ΔCH4 / ΔCO2, ΔCO / ΔCO2, and ΔCO / ΔCH4 observed at Hateruma over the period 1999 to 2010. Although the ratios ΔCH4 / ΔCO2 and ΔCO / ΔCO2 both show an overall gradual decrease over the study period due to a recent rapid increase in fossil fuel consumption in China, we note that ΔCH4 / ΔCO2 and ΔCO / ΔCO2 remains relatively flat (no trend) during 2005–2010 and 1999–2004, respectively. The CO/CH4 slope on the other hand shows an increasing trend during 1999–2004 but a decrease during 2005–2010. Calculation of the concentration footprint for the atmospheric observation at HAT by using the FLEXPART Lagrangian particle dispersion model indicates that most of the short-term variations are caused by emission variations from North and East China. Combined with a set of reported emission maps, we have estimated the temporal changes in the annual CH4 and CO emissions from China under the assumption that the estimate of the fossil fuel-derived CO2 emissions based on the energy statistics is accurate. The estimated annual CH4 emissions, corresponding to non-seasonal sources or anthropogenic sources without rice fields, show a nearly constant value of 39 ± 6 TgCH4 yr−1 during 1998–2002, and then gradually increases to 46 ± 7 TgCH4 yr−1 in 2009/2010. The estimated annual CO emissions increase from 134 ± 26 TgCO yr−1 in 1998/1999 to 182 ± 33 TgCO yr−1 in 2004/2005, level off after 2005, and then slightly decrease to less than 160 TgCO yr−1 in 2008–2010.

scholarly journals In-situ observation of Asian pollution transported into the Arctic lowermost stratosphere

2011 ◽  
Vol 11 (5) ◽  
pp. 16265-16310 ◽  
Author(s):  
A. Roiger ◽  
H. Schlager ◽  
A. Schäfler ◽  
H. Huntrieser ◽  
M. Scheibe ◽  
...  
Keyword(s):  
Dispersion Model ◽  
Anthropogenic Pollution ◽  
Conveyor Belt ◽  
Particle Dispersion ◽  
The Arctic ◽  
In Situ Observation ◽  
Air Mass ◽  
Mixing Ratios ◽  
The North

Abstract. On a research flight on 10 July 2008, the German research aircraft Falcon sampled an air mass with unusually high carbon monoxide (CO), peroxyacetyl nitrate (PAN) and water vapour (H2O) mixing ratios in the Arctic lowermost stratosphere. The air mass was encountered twice at an altitude of 11.3 km, ~800 m above the dynamical tropopause. In-situ measurements of ozone, NO, and NOy indicate that this layer was a mixed air mass containing both air from the troposphere and stratosphere. Backward trajectory and Lagrangian particle dispersion model analysis suggest that the Falcon sampled the top of a polluted air mass originating from the coastal regions of East Asia. The anthropogenic pollution plume experienced strong up-lift in a warm conveyor belt (WCB) located over the Russian east-coast. Subsequently the Asian air mass was transported across the North Pole into the sampling area, elevating the local tropopause by up to ~3 km. Mixing with surrounding Arctic stratospheric air most likely took place during the horizontal transport when the tropospheric streamer was stretched into long and narrow filaments. The mechanism illustrated in this study possibly presents an important pathway to transport pollution into the polar tropopause region.

scholarly journals Quantification of Non-Exhaust Particulate Matter Traffic Emissions and the Impact of COVID-19 Lockdown at London Marylebone Road

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 190
Author(s):  
William Hicks ◽  
Sean Beevers ◽  
Anja H. Tremper ◽  
Gregor Stewart ◽  
Max Priestman ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Measurement Data ◽  
Emission Factors ◽  
Meteorological Conditions ◽  
Traffic Emissions ◽  
Atmospheric Particulate Matter ◽  
Exhaust Emission ◽  
Brake Wear ◽  
The Impact ◽  
Exhaust Particulate

This research quantifies current sources of non-exhaust particulate matter traffic emissions in London using simultaneous, highly time-resolved, atmospheric particulate matter mass and chemical composition measurements. The measurement campaign ran at Marylebone Road (roadside) and Honor Oak Park (background) urban monitoring sites over a 12-month period between 1 September 2019 and 31 August 2020. The measurement data were used to determine the traffic increment (roadside–background) and covered a range of meteorological conditions, seasons, and driving styles, as well as the influence of the COVID-19 “lockdown” on non-exhaust concentrations. Non-exhaust particulate matter (PM)10 concentrations were calculated using chemical tracer scaling factors for brake wear (barium), tyre wear (zinc), and resuspension (silicon) and as average vehicle fleet non-exhaust emission factors, using a CO2 “dilution approach”. The effect of lockdown, which saw a 32% reduction in traffic volume and a 15% increase in average speed on Marylebone Road, resulted in lower PM10 and PM2.5 traffic increments and brake wear concentrations but similar tyre and resuspension concentrations, confirming that factors that determine non-exhaust emissions are complex. Brake wear was found to be the highest average non-exhaust emission source. In addition, results indicate that non-exhaust emission factors were dependent upon speed and road surface wetness conditions. Further statistical analysis incorporating a wider variability in vehicle mix, speeds, and meteorological conditions, as well as advanced source apportionment of the PM measurement data, were undertaken to enhance our understanding of these important vehicle sources.

scholarly journals Airborne determination of the temporo-spatial distribution of benzene, toluene, nitrogen oxides and ozone in the boundary layer across Greater London, UK

2015 ◽  
Vol 15 (9) ◽  
pp. 5083-5097 ◽  
Author(s):  
M. D. Shaw ◽  
J. D. Lee ◽  
B. Davison ◽  
A. Vaughan ◽  
R. M. Purvis ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Nitrogen Oxides ◽  
Linear Regression Analysis ◽  
Proton Transfer Reaction ◽  
Mixing Ratios ◽  
Spatially Resolved ◽  
Dual Channel ◽  
Benzene Toluene

Abstract. Highly spatially resolved mixing ratios of benzene and toluene, nitrogen oxides (NOx) and ozone (O3) were measured in the atmospheric boundary layer above Greater London during the period 24 June to 9 July 2013 using a Dornier 228 aircraft. Toluene and benzene were determined in situ using a proton transfer reaction mass spectrometer (PTR-MS), NOx by dual-channel NOx chemiluminescence and O3 mixing ratios by UV absorption. Average mixing ratios observed over inner London at 360 ± 10 m a.g.l. were 0.20 ± 0.05, 0.28 ± 0.07, 13.2 ± 8.6, 21.0 ± 7.3 and 34.3 ± 15.2 ppbv for benzene, toluene, NO, NO2 and NOx respectively. Linear regression analysis between NO2, benzene and toluene mixing ratios yields a strong covariance, indicating that these compounds predominantly share the same or co-located sources within the city. Average mixing ratios measured at 360 ± 10 m a.g.l. over outer London were always lower than over inner London. Where traffic densities were highest, the toluene / benzene (T / B) concentration ratios were highest (average of 1.8 ± 0.5 ppbv ppbv-1), indicative of strong local sources. Daytime maxima in NOx, benzene and toluene mixing ratios were observed in the morning (~ 40 ppbv NOx, ~ 350 pptv toluene and ~ 200 pptv benzene) and in the mid-afternoon for ozone (~ 40 ppbv O3), all at 360 ± 10 m a.g.l.

scholarly journals Exploring the atmospheric chemistry of nitrous acid (HONO) at a rural site in Southern China

2012 ◽  
Vol 12 (3) ◽  
pp. 1497-1513 ◽  
Author(s):  
X. Li ◽  
T. Brauers ◽  
R. Häseler ◽  
B. Bohn ◽  
H. Fuchs ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Nitrous Acid ◽  
Southern China ◽  
Rural Site ◽  
Pearl River Delta Region ◽  
Additional Source ◽  
Mixing Ratios ◽  
Photolysis Frequency ◽  
The Pearl River

Abstract. We performed measurements of nitrous acid (HONO) during the PRIDE-PRD2006 campaign in the Pearl River Delta region 60 km north of Guangzhou, China, for 4 weeks in June 2006. HONO was measured by a LOPAP in-situ instrument which was setup in one of the campaign supersites along with a variety of instruments measuring hydroxyl radicals, trace gases, aerosols, and meteorological parameters. Maximum diurnal HONO mixing ratios of 1–5 ppb were observed during the nights. We found that the nighttime build-up of HONO can be attributed to the heterogeneous NO2 to HONO conversion on ground surfaces and the OH + NO reaction. In addition to elevated nighttime mixing ratios, measured noontime values of ≈200 ppt indicate the existence of a daytime source higher than the OH + NO→HONO reaction. Using the simultaneously recorded OH, NO, and HONO photolysis frequency, a daytime additional source strength of HONO (PM) was calculated to be 0.77 ppb h−1 on average. This value compares well to previous measurements in other environments. Our analysis of PM provides evidence that the photolysis of HNO3 adsorbed on ground surfaces contributes to the HONO formation.

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