Low-cost particulate matter (PM) sensors are promising
tools for supplementing existing air quality monitoring networks. However,
the performance of the new generation of low-cost PM sensors under ...field
conditions is not well understood. In this study, we characterized the
performance capabilities of a new low-cost PM sensor model (Plantower model
PMS3003) for measuring PM2.5 at 1 min, 1 h, 6 h, 12 h, and 24 h
integration times. We tested the PMS3003 sensors in both low-concentration suburban
regions (Durham and Research Triangle Park (RTP), NC, US) with 1 h
PM2.5 (mean ± SD) of 9±9 and 10±3 µg m−3, respectively, and a high-concentration urban
location (Kanpur, India) with 1 h PM2.5 of 36±17 and 116±57 µg m−3 during monsoon and post-monsoon
seasons, respectively. In Durham and Kanpur, the sensors were compared to a
research-grade instrument (environmental β attenuation monitor, E-BAM) to determine how these sensors perform across
a range of PM2.5 concentrations and meteorological factors (e.g., temperature and relative
humidity, RH). In RTP, the sensors were compared to three Federal
Equivalent Methods (FEMs) including two Teledyne model T640s and a
Thermo Scientific model 5030 SHARP to demonstrate the importance of the type
of reference monitor selected for sensor calibration. The decrease in 1 h
mean errors of the calibrated sensors using univariate linear models from
Durham (201 %) to Kanpur monsoon (46 %) and post-monsoon (35 %)
seasons showed that PMS3003 performance generally improved as ambient
PM2.5 increased. The precision of reference instruments (T640:
±0.5 µg m−3 for 1 h; SHARP: ±2 µg m−3 for
24 h, better than the E-BAM) is critical in evaluating sensor performance,
and β-attenuation-based monitors may not be ideal for testing PM
sensors at low concentrations, as underscored by (1) the less dramatic error
reduction over averaging times in RTP against optically based T640 (from 27 % for 1 h to 9 % for 24 h) than in Durham (from 201 % to 15 %);
(2) the lower errors in RTP than the Kanpur post-monsoon season (from 35 % to
11 %); and (3) the higher T640–PMS3003 correlations (R2≥0.63) than SHARP–PMS3003 (R2≥0.25). A major RH influence was
found in RTP (1 h RH =64±22 %) due to the relatively high
precision of the T640 measurements that can explain up to ∼30 % of the variance in 1 min to 6 h PMS3003 PM2.5 measurements. When
proper RH corrections are made by empirical nonlinear equations after using
a more precise reference method to calibrate the sensors, our work suggests
that the PMS3003 sensors can measure PM2.5 concentrations within
∼10 % of ambient values. We observed that PMS3003 sensors
appeared to exhibit a nonlinear response when ambient PM2.5 exceeded
∼125 µg m−3 and found that the quadratic fit is
more appropriate than the univariate linear model to capture this
nonlinearity and can further reduce errors by up to 11 %. Our results
have substantial implications for how variability in ambient PM2.5 concentrations, reference monitor types, and meteorological factors can
affect PMS3003 performance characterization.
During May 2016 a very large boreal wildfire burned throughout the Athabasca Oil Sands Region (AOSR) in central Canada, and in close proximity to an extensive air quality monitoring network. This ...study examines speciated 24-h integrated polycyclic aromatic hydrocarbon (PAH) and volatile organic compound (VOC) measurements collected every sixth day at four and seven sites, respectively, from May to August 2016. The sum of PAHs (ΣPAH) was on average 17 times higher in fire-influenced samples (852 ng m−3, n = 8), relative to non-fire influenced samples (50 ng m−3, n = 64). Diagnostic PAH ratios in fire-influenced samples were indicative of a biomass burning source, whereas ratios in June to August samples showed additional influence from petrogenic and fossil fuel combustion. The average increase in the sum of VOCs (ΣVOC) was minor by comparison: 63 ppbv for fire-influenced samples (n = 16) versus 46 ppbv for non-fire samples (n = 90). The samples collected on August 16th and 22nd had large ΣVOC concentrations at all sites (average of 123 ppbv) that were unrelated to wildfire emissions, and composed primarily of acetaldehyde and methanol suggesting a photochemically aged air mass. Normalized excess enhancement ratios (ERs) were calculated for 20 VOCs and 23 PAHs for three fire influenced samples, and the former were generally consistent with previous observations. To our knowledge, this is the first study to report ER measurements for a number of VOCs and PAHs in fresh North American boreal wildfire plumes. During May the aged wildfire plume intercepted the cities of Edmonton (∼380 km south) or Lethbridge (∼790 km south) on four separate occasions. No enhancement in ground-level ozone (O3) was observed in these aged plumes despite an assumed increase in O3 precursors. In the AOSR, the only daily-averaged VOCs which approached or exceeded the hourly Alberta Ambient Air Quality Objectives (AAAQOs) were benzene (during the fire) and acetaldehyde (on August 16th and 22nd). Implications for local and regional air quality as well as suggestions for supplemental air monitoring during future boreal fires, are also discussed.
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•Atmospheric PAHs and VOCs were characterized during and after a boreal megafire•Daily averaged ΣPAHs increased from ∼50 ng m−3 up to 2900 ng m−3 during the fire.•ΣVOCs had minor-to-moderate enhancement from ∼46 ppbv up to 190 ppbv.•Normalized excess enhancement ratios were calculated for 20 VOCs and 23 PAHs•Daily benzene and acetaldehyde approached or exceeded hourly air quality objectives.
An ambient air particulate matter sampling study was conducted at the Wood Buffalo Environmental Association (WBEA) AMS-1 Fort McKay monitoring station in the Athabasca Oil Sand Region (AOSR) in ...Alberta, Canada from February 2010 to July 2011. Daily 24h integrated fine (PM2.5) and coarse (PM10–2.5) particulate matter was collected using a sequential dichotomous sampler. Over the duration of the study, 392 valid daily dichotomous PM2.5 and PM10–2.5 sample pairs were collected with concentrations of 6.8±12.9μgm−3 (mean±standard deviation) and 6.9±5.9μgm−3, respectively. A subset of 100 filter pairs was selected for element analysis by energy dispersive X-ray fluorescence and dynamic reaction cell inductively coupled plasma mass spectrometry. Application of the U.S. EPA positive matrix factorization (PMF) receptor model to the study data matrix resolved five PM2.5 sources explaining 96% of the mass including oil sands upgrading (32%), fugitive dust (26%), biomass combustion (25%), long-range Asian transport lead source (9%), and winter road salt (4%). An analysis of historical PM2.5 data at this site shows that the impact of smoke from wildland fires was particularly high during the summer of 2011. PMF resolved six PM10–2.5 sources explaining 99% of the mass including fugitive haul road dust (40%), fugitive oil sand (27%), a mixed source fugitive dust (16%), biomass combustion (12%), mobile source (3%), and a local copper factor (1%). Results support the conclusion of a previous epiphytic lichen biomonitor study that near-field atmospheric deposition in the AOSR is dominated by coarse fraction fugitive dust from bitumen mining and upgrading operations, and suggest that fugitive dust abatement strategies targeting the three major sources of PM10–2.5 (e.g., oil sand mining, haul roads, bulk material stockpiles) would significantly reduce near-field atmospheric deposition gradients in the AOSR and reduce ambient PM concentrations in the Fort McKay community.
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•Fine and coarse particulate matter was quantified in Fort McKay, Alberta.•Receptor modeling elucidated and quantified significant contributing sources.•58% of PM2.5 and 83% of PM10–2.5 was attributable to oil sands production operations.•25% of the observed PM2.5 was attributed to biomass combustion.
An unprecedented wildfire impacted the northern Alberta city of Fort McMurray in May 2016 causing a mandatory city wide evacuation and the loss of 2,400 homes and commercial structures. A two-hectare ...wildfire was discovered on May 1, grew to ~157,000ha by May 5, and continued to burn an estimated ~590,000ha by June 13. A comprehensive air monitoring network operated by the Wood Buffalo Environmental Association (WBEA) in and around Fort McMurray provided essential health-related real-time air quality data to firefighters during the emergency, and provided a rare opportunity to elucidate the impact of gaseous and particulate matter emissions on near-field communities and regional air pollution concentrations. The WBEA network recorded 188 fire-related exceedances of 1-hr and 24-hr Alberta Ambient Air Quality Objectives. Two air monitoring sites within Fort McMurray recorded mean/maximum 1-hr PM2.5 concentrations of 291/5229μgm−3 (AMS-6) and 293/3259μgm−3 (AMS-7) during fire impact periods. High correlations (r2=0.83–0.97) between biomass combustion related gases (carbon monoxide (CO), non-methane hydrocarbons (NMHC), total hydrocarbons (THC), total reduced sulfur (TRS), ammonia) and PM2.5 were observed at the sites. Filter-based 24-hr integrated PM2.5 samples collected every 6 days showed maximum concentrations of 267μgm−3 (AMS-6) and 394μgm−3 (AMS-7). Normalized excess emission ratios relative to CO were 149.87±3.37μgm−3ppm−1 (PM2.5), 0.274±0.002ppmppm−1 (THC), 0.169±0.001ppmppm−1 (NMHC), 0.104±0.001ppmppm−1 (CH4), 0.694±0.007ppbppm−1 (TRS), 0.519±0.040ppbppm−1 (SO2), 0.412±0.045ppbppm−1 (NO), 1.968±0.053ppbppm−1 (NO2), and 2.337±0.077ppbppm−1 (NOX). A subset of PM2.5 filter samples was analyzed for trace elements, major ions, organic carbon, elemental carbon, and carbohydrates. Sample mass reconstruction and fire specific emission profiles are presented and discussed. Potential fire-related photometric ozone instrument positive interferences were observed and were positively correlated with NO and NMHC.
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•Horse River Fire had a major air quality impact on the city of Fort McMurray.•PM2.5 enhancements at the community monitoring sites ranged from a factor of 19–54.•Significant enhancements of NMHC, NH3, BC, DC, TRS, NOx, and H2S were observed.•First observations of reduced sulfur compounds (TRS/H2S) emissions from a wildfire•Fire PM2.5 profiles were uniform across the network, can be used as a fingerprint.
The Canadian Federal Government promulgated new and lower NO
Ambient Air Quality Standards (CAAQS) that went into effect in 2020 with additional decreases scheduled for 2025. The new hourly and ...annual NO
CAAQS are 60 and 17 ppb, respectively, and the 2025 hourly and annual CAAQS are 42 and 12 ppb, respectively. The province of Alberta has also promulgated Ambient Air Quality Objectives (AAAQO) for NO
currently set to 159 and 24 ppb on an hourly and annual basis, respectively. The Wood Buffalo Environmental Association (WBEA) in northeastern Alberta, Canada monitors NO
at 21 community and industrial sites throughout the Athabasca Oil Sands Region (AOSR), for regulatory compliance using Thermo-Environmental (TEI) Model 42i Federal Reference Method (FRM) designated NO-NO
-NOx analyzers. The 42i measures NO directly via NO-O
chemiluminescence, and NOx following the reduction of oxidized nitrogen to NO by a heated internal molybdenum converter. The difference between the NOx and NO channels is reported as NO
. This study presents the results of a three-year (2018-2021) WBEA comparison of four continuous NO
analyzers: TEI 42i FRM; the API Model T500U cavity attenuated phase shift (CAPS) Federal Equivalent Method (FEM); a total reactive odd nitrogen analyzer (TEI Model 42i-Y); and a TEI 42i equipped with an external photolytic converter. The study showed that NO
data from all analyzers were highly correlated and in general agreement, with r
values (vs. the CAPS) ranging from 0.990-0.997 and slopes ranging from 0.933-0.992. Mean NO
concentrations over the study period ranged from 7.2-7.5 ppb. Differences between the TEI 42i, TEI 42i-Y, and PhoNO, relative to the CAPS were all positive and highly significant (
< 0.0001), based upon nonparametric tests. The potential impact from the selection of different FRM/FEM measurement methods on current and future Canadian 2025 regulatory compliance in the region is evaluated.
: The study objective was to compare/evaluate different regulatory NO
measurement techniques from a regional monitoring authority in a routine network operational context. Relatively small NO
differences resulted in significant differences with respect to regulatory compliance triggers, particularly hourly standards based on daily extreme value statistics (e.g., 99th percentiles). For example, mean hourly NO
△ differences ranged from 0.02-0.26 ppb over the study period but resulted in 2-3 ppb differences in the 3-year hourly CAAQS metrics. These differences could affect regulatory CAAQS and LARP compliance (management level) at monitoring sites observed during 2019 annual and 2020 hourly LARP trigger exceedances.
The Canadian Federal Government promulgated new and lower NO
2
Ambient Air Quality Standards (CAAQS) that went into effect in 2020 with additional decreases scheduled for 2025. The new hourly and ...annual NO
2
CAAQS are 60 and 17 ppb, respectively, and the 2025 hourly and annual CAAQS are 42 and 12 ppb, respectively. The province of Alberta has also promulgated Ambient Air Quality Objectives (AAAQO) for NO
2
currently set to 159 and 24 ppb on an hourly and annual basis, respectively. The Wood Buffalo Environmental Association (WBEA) in northeastern Alberta, Canada monitors NO
2
at 21 community and industrial sites throughout the Athabasca Oil Sands Region (AOSR), for regulatory compliance using Thermo-Environmental (TEI) Model 42i Federal Reference Method (FRM) designated NO-NO
2
-NOx analyzers. The 42i measures NO directly via NO-O
3
chemiluminescence, and NOx following the reduction of oxidized nitrogen to NO by a heated internal molybdenum converter. The difference between the NOx and NO channels is reported as NO
2
. This study presents the results of a three-year (2018-2021) WBEA comparison of four continuous NO
2
analyzers: TEI 42i FRM; the API Model T500U cavity attenuated phase shift (CAPS) Federal Equivalent Method (FEM); a total reactive odd nitrogen analyzer (TEI Model 42i-Y); and a TEI 42i equipped with an external photolytic converter. The study showed that NO
2
data from all analyzers were highly correlated and in general agreement, with r
2
values (vs. the CAPS) ranging from 0.990-0.997 and slopes ranging from 0.933-0.992. Mean NO
2
concentrations over the study period ranged from 7.2-7.5 ppb. Differences between the TEI 42i, TEI 42i-Y, and PhoNO, relative to the CAPS were all positive and highly significant (p < 0.0001), based upon nonparametric tests. The potential impact from the selection of different FRM/FEM measurement methods on current and future Canadian 2025 regulatory compliance in the region is evaluated.
Implications: The study objective was to compare/evaluate different regulatory NO
2
measurement techniques from a regional monitoring authority in a routine network operational context. Relatively small NO
2
differences resulted in significant differences with respect to regulatory compliance triggers, particularly hourly standards based on daily extreme value statistics (e.g., 99th percentiles). For example, mean hourly NO
2
△ differences ranged from 0.02-0.26 ppb over the study period but resulted in 2-3 ppb differences in the 3-year hourly CAAQS metrics. These differences could affect regulatory CAAQS and LARP compliance (management level) at monitoring sites observed during 2019 annual and 2020 hourly LARP trigger exceedances.
The increasing size and frequency of wildland fires are leading to greater potential for cardiopulmonary disease and cancer in exposed populations; however, little is known about how the types of ...fuel and combustion phases affect these adverse outcomes.
We evaluated the mutagenicity and lung toxicity of particulate matter (PM) from flaming vs. smoldering phases of five biomass fuels, and compared results by equal mass or emission factors (EFs) derived from amount of fuel consumed.
A quartz-tube furnace coupled to a multistage cryotrap was employed to collect smoke condensate from flaming and smoldering combustion of red oak, peat, pine needles, pine, and eucalyptus. Samples were analyzed chemically and assessed for acute lung toxicity in mice and mutagenicity in
.
The average combustion efficiency was 73 and 98% for the smoldering and flaming phases, respectively. On an equal mass basis, PM from eucalyptus and peat burned under flaming conditions induced significant lung toxicity potencies (neutrophil/mass of PM) compared to smoldering PM, whereas high levels of mutagenicity potencies were observed for flaming pine and peat PM compared to smoldering PM. When effects were adjusted for EF, the smoldering eucalyptus PM had the highest lung toxicity EF (neutrophil/mass of fuel burned), whereas smoldering pine and pine needles had the highest mutagenicity EF. These latter values were approximately 5, 10, and 30 times greater than those reported for open burning of agricultural plastic, woodburning cookstoves, and some municipal waste combustors, respectively.
PM from different fuels and combustion phases have appreciable differences in lung toxic and mutagenic potency, and on a mass basis, flaming samples are more active, whereas smoldering samples have greater effect when EFs are taken into account. Knowledge of the differential toxicity of biomass emissions will contribute to more accurate hazard assessment of biomass smoke exposures. https://doi.org/10.1289/EHP2200.
Ambient air particulate matter (PM) was collected at the Wood Buffalo Environmental Association Bertha Ganter Fort McKay monitoring station in the Athabasca Oil Sand Region (AOSR) in Alberta, Canada ...from February 2010 to July 2011 as part of an air quality source assessment study. Daily 24-hour duration fine (PM2.5) and coarse (PM10–2.5) PM was collected using a sequential dichotomous sampler. 100 pairs of PM2.5 and PM10–2.5 were selected for lead (Pb) concentration and isotope analysis. Pb isotope and concentration results from 250 epiphytic lichen samples collected as far as 160 km from surface mining operations in 2008, 2011, and 2014 were analyzed to examine longer term spatial variations in Pb source contributions. A key finding was recognition of thorogenic 208Pb from eastern Asia in the springtime in the PM2.5 in 2010 and 2011. 206Pb/207Pb and 208Pb/207Pb isotope ratios were used in a three-component mixing model to quantify local, regional, and global Pb sources in the PM and lichen data sets. 47 ± 3% of the Pb in the PM2.5 at AMS-1 was attributed to sources from eastern Asia. Combined results from PM10–2.5 and PM2.5 indicate PM2.5 Pb contributions from eastern Asia (34%) exceed local AOSR sources of PM2.5 Pb (20%), western Canada sources of PM2.5 Pb (19%), and PM10–2.5 Pb from fugitive dust including oil sands (14%), tailings (10%), and haul roads (3%). The lichen analysis indicates regional sources contribute 46% of the Pb, local sources 32%, and global sources 22% over the 2008–2014 timeframe. Local sources dominate atmospheric Pb deposition to lichens at near field sites (0–30 km from mining operations) whereas regional Pb sources are prevalent at distal sites (30–160 km). The Pb isotope methodology successfully quantified trans-Pacific transport of Pb to the AOSR superimposed over the aerosol footprint of the world's largest concentration of bitumen mining and upgrading facilities.
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•Pb isotopes measured in PM2.5 and PM10–2.5 from Fort McKay, Alberta in 2010–2011•Eastern Asia sources contributed 47% of the Pb in the PM2.5 in 2010–2011.•Pb isotopes measured in lichens around mining operations in 2008, 2011, and 2014•46% of the lichen Pb from regional, 32% from local, and 22% from global sources
Wildland fire activity and associated emission of particulate matter air pollution is increasing in the United States over the last two decades due primarily to a combination of increased ...temperature, drought, and historically high forest fuel loading. The regulatory monitoring networks in the Unites States are mostly concentrated in larger population centers where anthropogenic air pollution sources are concentrated. Smaller population centers in areas more likely to be impacted by wildland fire smoke in many instances lack adequate observational air quality data. Several commercially available small form factor filter-based PM2.5 samplers (SFFFS) were evaluated under typical ambient and simulated near-to mid-field wildland fire smoke conditions to evaluate their accuracy for use in temporary deployments during prescribed and wildfire events. The performance of all the SFFFS tested versus the designated federal reference methods (FRM) was acceptable in determining PM2.5 concentration in both ambient (2.7–14.0 μg m−3) and chamber smoke environments (24.6–3044.6 μg m−3) with accuracies ranging from ∼92 to 98%. However, only the ARA Instruments model N-FRM Sampler was found to provide PM2.5 mass measurement accuracies that meet FRM guideline performance specifications under both typical ambient (97.3 ± 1.9%) and simulated wildland fire conditions (98.2 ± 1.4%).
•ProblemoThere is a need for rugged, lightweight, battery powered, PM2.5 filter-based samplers in small and low-cost form factors that can be deployed during wildland fire events to improve spatial resolution and accuracy of PM2.5 mass measurements.oEPA partnered with the United States Forest Service (USFS) in this research effort to improve confidence in small form factor filter-based PM2.5 monitoring devices in smoke.•ApproachoThe research was performed in an ambient environment at EPA's Ambient Air Innovative Research Site (AIRS, Research Triangle Parc, NC) in 2018.oIn addition, evaluations were performed during controlled burn chamber experiments at the U.S. Forest Service Rocky Mountain Fire Sciences Laboratory in Missoula, MT in 2019.oPM2.5 FRM methods were employed as reference to assess capabilities for accurate, interference-free determination of PM2.5 in biomass smoke.•ResultsoAll samplers in the study performed respectably in determining total PM2.5 concentrations with accuracies ranging from 93.1 to 98.2%.oThe ARA N-FRM was the only small form factor filter-based sampler to achieve EPA PM2.5 FRM mass measurement accuracy performance targets along with study-best accuracies in both ambient and chamber-based smoke testing.
The sources and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) atmospheric deposition in the boreal forests surrounding bitumen production operations in the Athabasca Oil Sands ...Region (AOSR), Alberta, Canada were investigated as part of a 2014 passive in-situ bioindicator source apportionment study. Epiphytic lichen species Hypogymnia physodes samples (n = 127) were collected within a 150 km radius of the main surface oil sand production operations and analyzed for total sulfur, total nitrogen, forty-three elements, twenty-two PAHs, ten groups of C1-C2-alkyl PAHs and dibenzothiophenes (polycyclic aromatic compounds; PACs), five C1- and C2-alkyldibenzothiophenes, and retene. The ΣPAH + PAC in H. physodes ranged from 54 to 2778 ng g−1 with a median concentration of 317 ng g−1. Source apportionment modeling found an eight-factor solution that explained 99% of the measured ΣPAH + PAC lichen concentrations from four anthropogenic oil sands production sources (Petroleum Coke, Haul Road Dust, Stack Emissions, Raw Oil Sand), two local/regional sources (Biomass Combustion, Mobile Source), and two lichen biogeochemical factors. Petroleum Coke and Raw Oil Sand dust were identified as the major contributing sources of ΣPAH + PAC in the AOSR. These two sources accounted for 63% (43.2 μg g−1) of ΣPAH + PAC deposition to the entire study domain. Of this overall 43.2 μg g−1 contribution, approximately 90% (39.9 μg g−1) ΣPAH + PAC was deposited within 25 km of the closest oil sand production facility. Regional sources (Biomass Combustion and Mobile Sources) accounted for 19% of ΣPAH + PAC deposition to the entire study domain, of which 46% was deposited near-field to oil sand production operations. Source identification was improved over a prior lichen-based study in the AOSR through incorporation of PAH and PAC analytes in addition to inorganic analytes.
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•Epiphytic lichen PAH bioindicator study conducted in Athabasca Oil Sands Region•Receptor modeling elucidated and quantified significant contributing sources.•C1-C2-alkyl PAHs and dibenzothiophenes utilized as tracer species•Petroleum coke and raw oil sand dust accounted for 67% of near field SPAH deposition.•Petroleum coke source required the use of C1-C2-alkyl PAH tracer species to resolve.
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