Joint measurements of PM&amp;lt;sub&amp;gt;2. 5&amp;lt;/sub&amp;gt; and light-absorptive PM in woodsmoke-dominated ambient and plume environments

Zhang, K. Max; Allen, George; Yang, Bo; Chen, Geng; Gu, Jiajun; Schwab, James J.; Felton, Dirk; Rattigan, Oliver V.

doi:10.5194/acp-17-11441-2017

Cited by 24 publications

(23 citation statements)

References 25 publications

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“…The comparison with respect to previous years reveals that the SSA during lockdown daytime is higher by ~9% than the mean due to reasons discussed above (Figures 5c and 7h), but it exhibits a similar wavelength dependence, indicating negligible changes in aerosol-type composition. The SSAAE values during night-time are slightly lower due to the higher presence of BrC, while the enhanced RWB during the lockdown nights (mean BB% = 36%) could explain the lower SSAAE of 0.205 [118][119][120] since light-absorbing BrC displays lower decreasing rates of SSA at longer wavelengths compared to BC [73,121,122]. In supporting this statement, Katsanos et al SSA is an important climatic factor, and its spectral dependence has also been widely used as an indicator of aerosol types [94,[113][114][115].…”

Section: Modifications In Spectral Aerosol Scattering and Absorptionmentioning

confidence: 95%

Assessment of the COVID-19 Lockdown Effects on Spectral Aerosol Scattering and Absorption Properties in Athens, Greece

et al. 2021

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COVID-19 is evolving into one of the worst pandemics in recent history, claiming a death toll of over 1.5 million as of December 2020. In an attempt to limit the expansion of the pandemic in its initial phase, nearly all countries imposed restriction measures, which resulted in an unprecedented reduction of air pollution. This study aims to assess the impact of the lockdown effects due to COVID-19 on in situ measured aerosol properties, namely spectral-scattering (bsca) and absorption (babs) coefficients, black carbon (BC) concentrations, single-scattering albedo (SSA), scattering and absorption Ångström exponents (SAE, AAE) in Athens, Greece. Moreover, a comparison is performed with the regional background site of Finokalia, Crete, for a better assessment of the urban impact on observed differences. The study examines pre-lockdown (1–22 March 2020), lockdown (23 March–3 May 2020) and post-lockdown (4–31 May 2020) periods, while the aerosol properties are also compared with a 3–4 year preceding period (2016/2017–2019). Comparison of meteorological parameters in Athens, between the lockdown period and respective days in previous years, showed only marginal variation, which is not deemed sufficient in order to justify the notable changes in aerosol concentrations and optical properties. The largest reduction during the lockdown period was observed for babs compared to the pre-lockdown (−39%) and to the same period in previous years (−36%). This was intensified during the morning traffic hours (−60%), reflecting the large decrease in vehicular emissions. Furthermore, AAE increased during the lockdown period due to reduced emissions from fossil-fuel combustion, while a smaller (−21%) decrease was observed for bsca along with slight increases (6%) in SAE and SSA values, indicating that scattering aerosol properties were less affected by the decrease in vehicular emissions, as they are more dependent on regional sources and atmospheric processing. Nighttime BC emissions related to residential wood-burning were slightly increased during the lockdown period, with respect to previous-year means. On the contrary, aerosol and pollution changes during the lockdown period at Finokalia were low and highly sensitive to natural sources and processes.

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Section: Modifications In Spectral Aerosol Scattering and Absorptionmentioning

confidence: 95%

Assessment of the COVID-19 Lockdown Effects on Spectral Aerosol Scattering and Absorption Properties in Athens, Greece

et al. 2021

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“…7), indicating the significant contributions of BrC possibly from wood/biomass burning and agricultural waste. The organic species that are released from biofuel combustion are more sensitive to short wavelengths compared to particulates that are emitted during fossil fuel burning (Zhang et al, 2017;Li et al, 2018). This is because AAE measured at short wavelengths is much more sensitive to BrC aerosols and internally mixed aerosols (Dumka et al, 2018;Liakakou et al, 2019).…”

Section: The Wavelength Dependence Of the Light-absorption Coefficientmentioning

confidence: 99%

Characterizing Light-absorbing Aerosols in a Low-income Settlement in South Africa

Xulu

Piketh

Feig

et al. 2020

Aerosol Air Qual. Res.

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Light-absorbing aerosols, particularly black carbon (BC), have significant impacts on human health and the climate. They are also the least-studied fraction of atmospheric particles, particularly in residential areas of southern Africa. The optical characteristics of ground-based light-absorbing aerosols from Kwadela Township in South Africa are investigated in this study. Daily averaged ambient PM 2.5 highest levels were 51.39 µg m-3 and 32.18 µg m-3 , whereas hourly averages peaked at 61.31 µg m-3 and 34.69 µg m-3 during winter and summer, respectively. Levels of daily averaged light-absorbing aerosols were 2.9 times higher (1.89 ± 0.5 µg m-3) in winter 2014 than in summer 2015 (0.66 ± 0.2 µg m-3). In both seasons, hourly averaged levels showed bimodal diurnal cycles, which correlated with the PM 2.5 diurnal patterns that indicated distinct peaks in the morning and evening. These diurnal cycle peak periods corresponded with the times of increased solid domestic fuel usage, road traffic, and also shallower boundary layer. On average, light-absorbing aerosols contributed a larger proportion of total ambient PM 2.5 levels in winter (6.5 ± 1.0%) than in summer (3.4 ± 1.0%). The winter average Absorption Ångstrӧm exponent AAE (370/880 nm) (1.7± 0.5), indicated the dominance of brown carbon (BrC) from biofuel/biomass burning and/or low-quality coal combustion emissions. In summer, the average AAE (370/950 nm) (1.3 ± 0.7), suggested the presence of BC and BrC in the mornings and evenings possibly from fossil fuel combustion sources. At midday and at night in summer, the AAE was close to 1, suggesting more BC contributions from sources such as diesel emissions during this time. A combination of BC and BrC particulates dominated on 50% and 5% of the summer days, respectively, whereas fresh BC were only measured in summer days (23%). Residential solid-fuel and/biomass combustion are important sources of light-absorbing aerosols in this study region, with concomitant human health and environmental impacts.

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“…Elevated levels of PM 2.5 at this site during the winter are primarily from residential wood heating appliances (Allen et al, 2004). Agreement was very good over a wide range of PM 2.5 concentrations (Zhang et al, 2017), with a slope of 1.08 and R 2 of 0.90 for 24-hour average values.…”

Section: Methodsmentioning

confidence: 79%

“…In rural areas, PM emissions from residential wood heating often dominate emissions from all other source sectors combined (EPA, 2018a), can account for 50% of total area source air toxics cancer risk (EPA, 2018b), and may be trending upwards in rural New York (Masiol et al, 2018;Blanchard et al, 2019). Woodsmoke PM tends to be higher when temperatures are colder as indicated by heating degree days (Zhang et al, 2017) due to the increased use of residential wood heating appliances.…”

Section: Introductionmentioning

confidence: 99%

“…Some of these studies used integrated filter PM sampling, and some had hourly or shorter average PM measurements. Timeresolved (on-line or continuous) measurements are useful in identification of specific sources; Snyder (2012) and Zhang (2017) measured PM in individual plumes using forward light scattering methods on mobile monitoring platforms.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Residential Woodsmoke PM2.5 in the Adirondacks of New York

Allen¹,

Rector²

2020

Aerosol Air Qual. Res.

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Although woodsmoke from residential wood heating can be the dominant source of winter PM 2.5 in rural areas, routine monitoring is done primarily in urban or suburban areas. To obtain data on elevated woodsmoke concentrations from nearby sources, the PM 2.5 , black carbon at 880 and 370 nm, particle-bound polycyclic aromatic hydrocarbons (PAHs), and wind speed and direction were measured during winter at three residential locations in Saranac Lake, New York. A paired-site design enabled the identification of local sources relative to larger spatial scales. With the exception of occasional regional PM events, the hourly measurements of this pollutant between the paired sites exhibited poor correlations, suggesting that local woodsmoke was responsible for the observed increases in PM values. One location that was adjacent to a residence with a wood stove, which was 40 meters from the monitoring site, experienced repeated episodes of elevated PM 2.5 concentrations, with a maximum 3-hour average of 150 µg m -3 , a maximum 24-hour rolling average of 64 µg m -3 , and a maximum midnight-to-midnight average of 46 µg m -3 . Despite these PM events, the data indicated that this location was likely in compliance with the current U.S. EPA National Ambient Air Quality Standards (NAAQS) for PM 2.5 . The daily PM 2.5 concentration peaked and troughed during the nighttime and the daytime, respectively, at all of the sites, which is consistent with local ground-level pollution sources, such as woodsmoke; this diel pattern was also confirmed by Aaethalometer Delta-C (DC) data, a woodsmoke PM indicator. The particle-bound PAH data was less specific than the DC data to the PM in the woodsmoke, partly because the instrument for the former also responds to traffic pollution. One site repeatedly displayed the influence of 2-cycle engine snowmobile exhaust during the early evening hours, with very high PAH concentrations but only modestly elevated DC concentrations. Subsequent tests showed that fresh 2-cycle small engine exhaust produces a somewhat weaker response than woodsmoke in the DC in terms of the concentration per unit of PM.

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Joint measurements of PM<sub>2. 5</sub> and light-absorptive PM in woodsmoke-dominated ambient and plume environments

Cited by 24 publications

References 25 publications

Assessment of the COVID-19 Lockdown Effects on Spectral Aerosol Scattering and Absorption Properties in Athens, Greece

Assessment of the COVID-19 Lockdown Effects on Spectral Aerosol Scattering and Absorption Properties in Athens, Greece

Characterizing Light-absorbing Aerosols in a Low-income Settlement in South Africa

Characterization of Residential Woodsmoke PM2.5 in the Adirondacks of New York

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