Silicon is a Frequent Component of Atmospheric Nanoparticles

Bzdek, Bryan R.; Horan, Andrew J.; Pennington, M. Ross; Janechek, Nathan J.; Baek, Jaemeen; Stanier, Charles O.; Johnston, Murray V.

doi:10.1021/es5026933

Cited by 59 publications

(59 citation statements)

References 64 publications

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“…Another interesting observation was that PM2.5 mass often increased when using/applying personal care products such as skin creams, hair remedies, and antiperspirants. This observation is consistent with the reports of Bzdek et al (2014) and Tang et al (2015) and who found siloxanes present in personal care products are very common components of urban particles. The exact origin of PM spikes observed during restroom visits is unknown; however, a variety of production mechanisms can be envisioned.…”

Section: Personal Monitoringsupporting

confidence: 93%

Portable, Ambient PM_2.5 Sensor for Human and/or Animal Exposure Studies

Cao

Thompson

2017

Analytical Letters

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A field portable device for logging PM2.5 mass concentration data has been developed. The device combines the Arduino microprocessor with an SD card, an Sharp DN7C3CA006 optical dust monitor, and 10 000 mAh battery. The PM2.5 dust sensor uses a virtual impactor to size select particles prior to illuminating them with an LED. The LED is triggered by a circuit controlled with the Arduino. Nephelometric detection at 120 referenced to incidence is employed. The voltage signal reported by the dust sensor is converted to PM2.5 mass thru calibration onboard the Arduino. Data points can be saved to the SD card as rapidly as 0.3 s, although averaging signals over 60 s produced more optimal detection limits. For a 60 s average, the PM2.5 mass limit of detection was 9 g/m 3 indicating the sensor will be useful for monitoring human exposure to fine particles. Portable exposure monitoring has been demonstrated with the Downloaded by [University of Lethbridge] at 15:20 25 June 20162 sensing platform as several individuals carried the device with them during daily activities in Lubbock, TX and Atlanta, GA. For this group of test subjects, values of PM2.5 exposure varied from 0 to 1000 g/m 3 during the sampling periods. It was observed that, by far, the highest levels of PM2.5 occur during periods of cooking, or being near cooking operations. Other periods of high PM2.5 occurred during ground transportation, use of personal care products, vacuuming, and visiting restrooms. When hourly personal exposure data was correlated with hourly average PM2.5 for outdoor air for the Atlanta dataset, a very weak correlation was found (R 2 = 0.026). For only two of eight sampling periods did the personal monitoring estimate of exposure agree with that predicted by outdoor monitoring to within 15%. Personal exposure was often affected by circumstantial, short-term, high exposure events that are difficult to model or predict effectively.The short-term exposure events generally cause true exposure to be higher than that predicted by using outdoor ambient PM2.5 to generate estimates. This finding complicates interpretation of epidemiological studies that find links between ambient outdoor PM2.5 levels and human health, while it buttresses the case for employing personal ambient monitors.

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Section: Personal Monitoringsupporting

confidence: 93%

Portable, Ambient PM_2.5 Sensor for Human and/or Animal Exposure Studies

Cao

Thompson

2017

Analytical Letters

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“…The EDS elemental analysis of particles collected during the three types of activities showed a chemical composition similar to that generated by other anthropogenic and natural sources [21,42]. …”

Section: Discussionmentioning

confidence: 99%

Ultrafine Particle Distribution and Chemical Composition Assessment during Military Operative Trainings

Campagna

Pilia

Marcias

et al. 2017

IJERPH

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(1) Background: The assessment of airborne particulate matter (PM) and ultrafine particles (UFPs) in battlefield scenarios is a topic of particular concern; (2) Methods: Size distribution, concentration, and chemical composition of UFPs during operative military training activities (target drone launches, ammunition blasting, and inert bomb impact) were investigated using an electric low-pressure impactor (ELPI+) and a scanning electron microscope (SEM), equipped with energy-dispersive spectroscopy (EDS); (3) Results: The median of UFPs, measured for all sampling periods and at variable distance from sources, was between 1.02 × 103 and 3.75 × 103 particles/cm3 for drone launches, between 3.32 × 103 and 15.4 × 103 particles/cm3 for the ammunition blasting and from 7.9 × 103 to 1.3 × 104 particles/cm3 for inert launches. Maximum peak concentrations, during emitting sources starting, were 75.5 × 106 and 17.9 × 106 particles/cm3, respectively. Particles from the drone launches were predominantly composed of silicon (Si), iron (Fe) and calcium (Ca), and those from the blasting campaigns by magnesium (Mg), sulphur (S), aluminum (Al), iron (Fe), barium (Ba) and silicon (Si); (4) Conclusions: The investigated sources produced UFPs with median values lower than other anthropogenic sources, and with a similar chemical composition.

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“…The probability that a newly formed nanoparticle will grow to a CCN-relevant size depends on its growth rate relative to the loss rate from, e.g., coagulation or scavenging by preexisting aerosols (Kuang et al, 2010). Uncertainties in predicting the conditions that favor CCN formation make it challenging to accurately predict future impacts of radiative forcing (Carslaw et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Nanoparticle growth by particle-phase chemistry

Apsokardu¹,

Johnston²

2018

Atmos. Chem. Phys.

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Abstract. The ability of particle-phase chemistry to alter the molecular composition and enhance the growth rate of nanoparticles in the 2-100 nm diameter range is investigated through the use of a kinetic growth model. The molecular components included are sulfuric acid, ammonia, water, a non-volatile organic compound, and a semi-volatile organic compound. Molecular composition and growth rate are compared for particles that grow by partitioning alone vs. those that grow by a combination of partitioning and an accretion reaction in the particle phase between two organic molecules. Particle-phase chemistry causes a change in molecular composition that is particle diameter dependent, and when the reaction involves semi-volatile molecules, the particles grow faster than by partitioning alone. These effects are most pronounced for particles larger than about 20 nm in diameter. The modeling results provide a fundamental basis for understanding recent experimental measurements of the molecular composition of secondary organic aerosol showing that accretion reaction product formation increases linearly with increasing aerosol volume-to-surface-area. They also allow initial estimates of the reaction rate constants for these systems. For secondary aerosol produced by either OH oxidation of the cyclic dimethylsiloxane (D 5 ) or ozonolysis of β-pinene, oligomerization rate constants on the order of 10 −3 to 10 −1 M −1 s −1 are needed to explain the experimental results. These values are consistent with previously measured rate constants for reactions of hydroperoxides and/or peroxyacids in the condensed phase.

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Silicon is a Frequent Component of Atmospheric Nanoparticles

Cited by 59 publications

References 64 publications

Portable, Ambient PM_2.5 Sensor for Human and/or Animal Exposure Studies

Portable, Ambient PM_2.5 Sensor for Human and/or Animal Exposure Studies

Ultrafine Particle Distribution and Chemical Composition Assessment during Military Operative Trainings

Nanoparticle growth by particle-phase chemistry

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Silicon is a Frequent Component of Atmospheric Nanoparticles

Cited by 59 publications

References 64 publications

Portable, Ambient PM2.5 Sensor for Human and/or Animal Exposure Studies

Portable, Ambient PM2.5 Sensor for Human and/or Animal Exposure Studies

Ultrafine Particle Distribution and Chemical Composition Assessment during Military Operative Trainings

Nanoparticle growth by particle-phase chemistry

Contact Info

Product

Resources

About

Portable, Ambient PM_2.5 Sensor for Human and/or Animal Exposure Studies

Portable, Ambient PM_2.5 Sensor for Human and/or Animal Exposure Studies