Day-of-week trends in carbonaceous aerosol composition in the urban atmosphere

Lough, Glynis C.; Schauer, James J.; Lawson, Douglas R.

doi:10.1016/j.atmosenv.2006.03.009

Cited by 55 publications

(35 citation statements)

References 30 publications

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“…S1(b). BC concentrations reported here are similar to other locations in the USA (Jeong et al, 2004;Lough et al, 2006;Park et al, 2006) and Europe (Saha and Despiau, 2009) but lower than those observed at some Asian sites (Baxla et al, 2009;Salako et al, 2012;Swamy et al, 2012).…”

Section: Annual Trendssupporting

confidence: 69%

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Long Term Black Carbon Measurements at Two Urban Locations in New York

Rattigan

Civerolo

Doraiswamy

et al. 2013

Aerosol Air Qual. Res.

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Measurements of PM 2.5 black carbon (BC) over an 8-9 year period are used to characterize temporal patterns at sites in New York City (NYC) and Rochester, NY. Annual mean BC at the NYC location ranges from 1.4 to 2.0 μg/m 3 , whereas mean concentrations at Rochester are approximately a factor of 2-3 lower. BC amounts to 15-20% of PM 2.5 mass in NYC compared to 7-10% at Rochester. Seasonal patterns reveal the highest BC concentrations in NYC from November to February versus June to November at Rochester. At both locations, mean weekday (Monday-Friday) BC concentrations are statistically higher compared to weekends (Saturday and Sunday). Weekday BC diurnal profiles exhibit a morning peak between 6-10 AM EST followed by an afternoon minimum, with a secondary peak in the late evening. Sunday BC diurnal profiles show highest concentrations at night, from 8 PM to 2 AM. These patterns are consistent with vehicle counts on nearby roadways and boundary layer dynamics at both locations. Simultaneous measurements of BC at 370 and 880 nm show an enhancement in BC 370 relative to the BC 880 from October to March. This enhanced signal is most evident at Rochester during late evening and early morning hours (8 PM to 4 AM) on weekends, and is attributed to UV absorbing species (such as wood smoke markers) in the ambient particle mixture. At the NYC site, the levels of Nickel (Ni) and Cobalt (Co) in PM 10 are elevated during the heating season due to residual oil combustion. The long term datasets are used to explore the seasonal relationship between BC 880 and EC at both sites.

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Section: Annual Trendssupporting

confidence: 69%

“…Elevated BC was observed during weekdays at other urban sites (Baxla et al, 2009;Saha and Despiau, 2009;Cheng et al, 2012;Swamy et al, 2012). Lough et al, (2006) found elevated EC and motor vehicle molecular markers during weekdays at Los Angeles.…”

Section: Weekday/weekend Patternmentioning

confidence: 99%

Long Term Black Carbon Measurements at Two Urban Locations in New York

Rattigan

Civerolo

Doraiswamy

et al. 2013

Aerosol Air Qual. Res.

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“…However, rBC mass concentrations were systematically higher for weekdays than weekends for all hours of the day besides the early morning hours. This is likely due to higher diesel truck activity on weekdays versus weekends (Marr and Harley, 2002;Lough et al, 2006). The average diurnal cycle for weekdays in this study shows less variability than our recent study (Krasowsky et al, 2016) reporting measurements in Rubidoux during winter.…”

Section: Diurnal Cycles Of Rbc Mass Concentrations and Number Fractiocontrasting

confidence: 49%

Characterizing the evolution of physical properties and mixing state of black carbon particles: from near a major highway to the broader urban plume in Los Angeles

Krasowsky¹,

McMeeking²,

Sioutas³

et al. 2017

Preprint

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Abstract. Black carbon particles can have deleterious human health consequences and impact regional and global climate. 10Uncertainties remain in part due to incomplete knowledge on the evolution of physical properties and mixing state of black carbon from sources to the remote atmosphere. We aim to understand how road-to-ambient processing and longer timescale aging in an urban plume affect black carbon physical properties. Refractory black carbon (rBC) was measured during summer 2016 using a Single Particle Soot Photometer (SP2) in two distinct environments: near a major freeway and downwind of downtown Los Angeles. The near-road measurements were made at distances ranging from 30 to 114 m 15 downwind of Interstate 405 in Los Angeles. These results were compared with measurements performed 100 km east of Los Angeles in Redlands, California. Coatings on rBC particles were quantified using two methods. As distance from the highway increased at the near-road site, we observed decreases in rBC mass and number concentrations and increases in the number fraction of rBC particles with thick coatings (f). The latter likely occurred due to rapid processing of the highway plume and entrainment of urban background particles. Most rBC-containing particles measured near the highway were either 20 uncoated or thinly-coated. In Redlands, we found that rBC mass concentrations on weekdays were similar to those observed at the furthest measured distance from the highway (114 m). However, rBC number concentrations for the smallest measured sizes were an order of magnitude lower in Redlands than all measured distances from the highway. Observations of f indicate that values in Redlands during periods when estimated photochemical age was highest (6-8 hours) were similar to corresponding values at the furthest measured distance from the highway. This suggests that the residence time of air in the 25 Los Angeles basin under typical summertime conditions measured during this campaign may not be sufficient for rBC to acquire thick coatings. However, under certain meteorological conditions, f was observed to be ~0.20 in Redlands, with coating thickness histograms showing a larger contribution of rBC particles with coating thickness > 80 nm. This occurred during a weekend day when local emissions from diesel vehicles were lower (compared to weekdays) and winds brought air from the desert regions to the Northeast of Los Angeles, both of which would increase the relative contribution of remote 30 sources of rBC. Afternoon values of f (and O 3 ) were found to be systematically higher on weekends than weekdays, suggesting that the "weekend effect" can create more thickly-coated rBC particles presumably due to enhanced secondary organic aerosol and reduced available rBC as condensation sites.Atmos. Chem. Phys. Discuss., https://doi

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“…A "weekend effect" in concentrations of traffic-derived PM has been noted in previous studies (e.g., Grivas et al, 2012;Bae et al, 2004;Moteballi et al, 2003;Lim and Turpin, 2002;Jeong et al, 2004;Lough et al, 2006). To investigate whether a weekend effect could be discerned in the Riyadh dataset, two-sample t tests assuming unequal variances were performed for hourly EC and OC samples, grouped according to whether they were obtained on weekdays (Saturday to Wednesday) or on weekends (Thursday and Friday).…”

Section: Weekend Effect In Oc and Ec Concentrationsmentioning

confidence: 99%

Sources of PM<sub>2.5</sub> carbonaceous aerosol in Riyadh, Saudi Arabia

et al. 2018

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Abstract. Knowledge of the sources of carbonaceous aerosol affecting air quality in Riyadh, Saudi Arabia, is limited but needed for the development of pollution control strategies. We conducted sampling of PM 2.5 from April to September 2012 at various sites in the city and used a thermo-optical semi-continuous method to quantify the organic carbon (OC) and elemental carbon (EC) concentrations. The average OC and EC concentrations were 4.7 ± 4.4 and 2.1 ± 2.5 µg m −3 , respectively, during this period. Both OC and EC concentrations had strong diurnal variations, with peaks at 06:00-08:00 LT and 20:00-22:00 LT, attributed to the combined effect of increased vehicle emissions during rush hour and the shallow boundary layer in the early morning and at night. This finding suggested a significant influence of local vehicular emissions on OC and EC. The OC / EC ratio in primary emissions was estimated to be 1.01, close to documented values for diesel emissions. Estimated primary organic carbon (POC) and secondary organic carbon (SOC) concentrations were comparable, with average concentrations of 2.0 ± 2.4 and 2.8 ± 3.4 µg m −3 , respectively.We also collected 24 h samples of PM 10 onto quartz microfiber filters and analyzed these for an array of metals by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Total OC was correlated with Ca (R 2 of 0.63), suggesting that OC precursors and Ca may have similar sources, and the possibility that they underwent similar atmospheric processing. In addition to a ubiquitous dust source, Ca is emitted during desalting processes in the numerous refineries in the region and from cement kilns, suggesting these sources may also contribute to observed OC concentrations in Riyadh. Concentration weighted trajectory (CWT) analysis showed that high OC and EC concentrations were associated with air masses arriving from the Persian Gulf and the region around Baghdad, locations with high densities of oil fields and refineries as well as a large Saudi Arabian cement plant. We further applied positive matrix factorization to the aligned dataset of EC, OC, and metal concentrations (Al, Ca, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and V). Three factors were derived and were proposed to be associated with oil combustion, industrial emissions (Pb based), and a combined source from oil fields, cement production, and local vehicular emissions. The dominant OC and EC source was the combined source, contributing 3.9 µg m −3 (80 %) to observed OC and 1.9 µg m −3 (92 %) to observed EC.

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Day-of-week trends in carbonaceous aerosol composition in the urban atmosphere

Cited by 55 publications

References 30 publications

Long Term Black Carbon Measurements at Two Urban Locations in New York

Long Term Black Carbon Measurements at Two Urban Locations in New York

Characterizing the evolution of physical properties and mixing state of black carbon particles: from near a major highway to the broader urban plume in Los Angeles

Sources of PM<sub>2.5</sub> carbonaceous aerosol in Riyadh, Saudi Arabia

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Day-of-week trends in carbonaceous aerosol composition in the urban atmosphere

Cited by 55 publications

References 30 publications

Long Term Black Carbon Measurements at Two Urban Locations in New York

Long Term Black Carbon Measurements at Two Urban Locations in New York

Characterizing the evolution of physical properties and mixing state of black carbon particles: from near a major highway to the broader urban plume in Los Angeles

Sources of PM&lt;sub&gt;2.5&lt;/sub&gt; carbonaceous aerosol in Riyadh, Saudi Arabia

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Sources of PM<sub>2.5</sub> carbonaceous aerosol in Riyadh, Saudi Arabia