A5023983175- Air Quality and Health Impacts
- Air Quality Monitoring and Forecasting
- Energy and Environment Impacts
- Atmospheric chemistry and aerosols
- Climate Change and Health Impacts
- Noise Effects and Management
- Vehicle emissions and performance
- Energy, Environment, and Transportation Policies
- Atmospheric aerosols and clouds
- Inhalation and Respiratory Drug Delivery
- Indoor Air Quality and Microbial Exposure
- Oil Spill Detection and Mitigation
- Infection Control and Ventilation
- Hybrid Renewable Energy Systems
- Advanced Chemical Sensor Technologies
- Aeolian processes and effects
- Social Acceptance of Renewable Energy
- Atmospheric and Environmental Gas Dynamics
- Particle Dynamics in Fluid Flows
- SARS-CoV-2 and COVID-19 Research
- Toxic Organic Pollutants Impact
- COVID-19 impact on air quality
- Safety Warnings and Signage
- Visual Attention and Saliency Detection
- Traffic and Road Safety
Johns Hopkins University
2015-2024
Yale University
2020-2023
Environmental Health
2020
Colorado State University
2005-2017
University of Wisconsin–Madison
2017
Renmin University of China
2017
Bloomberg (United States)
2017
University of California, Santa Barbara
2011-2014
Kraftanlagen (Germany)
1993
HNO-Praxis
1974
A microfluidic paper-based analytical device (μPAD) fabricated by wax printing was designed to assess occupational exposure metal-containing aerosols. This method employs rapid digestion of particulate metals using microliters acid added directly a punch taken from an air sampling filter. Punches were then placed on μPAD, and digested transported detection reservoirs upon addition water. These contained reagents for colorimetric Fe, Cu, Ni. Dried buffer components used set the optimal pH in...
Due to the rapid development of low-cost air-quality sensors, a rigorous scientific evaluation has not been conducted for many available sensors. We evaluated three Plantower PMS A003 sensors when exposed eight particulate matter (PM) sources (i.e., incense, oleic acid, NaCl, talcum powder, cooking emissions, and monodispersed polystyrene latex spheres under controlled laboratory conditions also residential air ambient outdoor in Baltimore, MD). The PM2.5 exhibited high degree precision R2...
Low-cost sensors are effective for measuring the mass concentration of ambient aerosols and secondhand smoke in homes, but their use at concentrations relevant to occupational settings has not been demonstrated. We measured four (salt, Arizona road dust, welding fume, diesel exhaust) with three types low-cost (a DC1700 from Dylos two commodity Sharp), an aerosol photometer, reference instruments up 6500 μg/m3. Raw output was used assess sensor precision develop equations compute...
We compared the performance of a low-cost (∼$500), compact optical particle counter (OPC, OPC-N2, Alphasense) to another OPC (PAS-1.108, Grimm Technologies) and reference instruments. measured detection efficiency OPCs by size from 0.5 5 μm for monodispersed, polystyrene latex (PSL) spheres. then number mass concentrations with those instruments three aerosols: salt, welding fume Arizona road dust. The OPC-N2 monodispersed was similar PAS-1.108 particles larger than 0.8 (minimum 79% at 1...
Hygroscopicity and cloud condensation nucleus (CCN) activity were measured for three mineral dust samples: one from the Canary Islands, representing North African transported across Atlantic; outside Cairo, to eastern Mediterranean; Arizona Test Dust, in southwestern United States. To reaerosolize bulk samples, samples either suspended high purity water particles generated by atomization, or resuspended dry air using a fluidized bed. Only Island sample aqueous suspension showed appreciable...
Abstract. A method is described that uses particle hygroscopicity measurements, made with a humidified tandem differential mobility analyzer (HTDMA), to determine solution water activity as function of composition. The use derived data in computations determining the ability aerosols serve cloud condensation nuclei (CCN) explored. Results for sodium chloride and ammonium sulfate are shown Part I. methodology yields activities critical dry diameters good agreement previously published data....
Cloud condensation nuclei (CCN) activity and ice nucleation behavior (for temperatures ≤−40 °C) of soot aerosols relevant for atmospheric studies were investigated. Soots chosen to represent a range physico-chemical properties, from hydrophobic through hydrophilicity, hygroscopic. These characteristics achieved generation by three different combustion sources; soots natural gas pyrolysis (original: TS; graphitized: GTS; oxidized: TOS), diffusion flame in an oil lamp burning aviation kerosene...
Abstract Saliency models have been frequently used to predict eye movements made during image viewing without a specified task (free viewing). Use of single set systematically compare free other tasks has never performed. We investigated the effect differences on ability three saliency performance humans novel database 800 natural images. introduced where 100 observers explicit perceptual judgments about most salient region. Other groups performed task, search or cued object task. Behavior...
Background: Although previous studies suggest that exposure to traffic-related pollution during childhood increases the risk of overweight or obesity (COWO), role early life fine particulate matter (aerodynamic diameter <2.5μm; PM2.5) and its joint effect with mother's prepregnancy body mass index (MPBMI) on COWO remain unclear. Objectives: The present study was conducted examine individual effects ambient PM2.5 exposures MPBMI COWO. Methods: We estimated in utero first 2 y (F2YL), using...
Ethylene oxide ("EtO") is an industrially made volatile organic compound and a known human carcinogen. There are few reliable reports of ambient EtO concentrations around production end-use facilities, however, despite major exposure concerns. We present
Abstract. A method has been developed for using particle hygroscopicity measurements made with a humidified tandem differential mobility analyzer (HTDMA) to determine water activity as function of solute weight percent. In Part I, the was tested particles composed sodium chloride and ammonium sulfate. Here, we report results several atmospherically-relevant organic species: glutaric acid, malonic oxalic acid levoglucosan. Predicted activities aqueous dicarboxylic solutions are quite similar...
The interaction of water with laboratory soots possessing a range properties relevant for atmospheric studies is examined by two complementary methods: gravimetrical measurement uptake coupled chemical composition and porosity analysis HTDMA (humidified tandem differential mobility analyzer) inference accompanied separate TEM (transmission electron microscopy) single particles. first method clarifies the mechanism bulk soot allows classification respect to its hygroscopicity. second...
Abstract. Dust particles represent a dominant source of particulate matter (by mass) to the atmosphere, and their emission from some regions has been shown be transported on regional hemispherical scales. particles' potential interact with water vapor in atmosphere can lead important radiative impacts climate system, both direct indirect. We have investigated this interaction for several types dust aerosol, collected Southwestern United States Saharan region. A continuous flow diffusion...
We examine the observed relationships between molar volume (the ratio of mass and density) cloud condensation nuclei (CCN) activity for sufficiently soluble organic compounds found in atmospheric particulate matter. Our data compilation includes new CCN certain carbohydrates oligoethylene glycols, as well published compounds. compare predictions using water activities based on Raoult's law Flory‐Huggins theory to observations. The expression, with an assumed surface tension pure water,...
Particulate matter (PM) air pollution has a significant impact on human morbidity and mortality; however, the mechanisms of PM-induced toxicity are poorly defined. A leading hypothesis states that airborne PM induces harm by generating reactive oxygen species in around tissues, to oxidative stress. We report here system employing microfluidic electrochemical sensor coupled directly particle-into-liquid sampler (PILS) measure aerosol activity an on-line format. The measurement is based...
Human exposure to particulate matter (PM) air pollution has been linked with respiratory, cardiovascular, and neurodegenerative diseases, in addition various cancers. Consistent among all of these associations is the hypothesis that PM induces inflammation oxidative stress affected tissue. Consequently, a variety assays have developed quantify activity as means characterize its ability induced stress. The vast majority rely on high-volume, fixed-location sampling methods due limitations...
Traffic-related air pollution is associated with increased mortality and morbidity, yet few studies have examined strategies to reduce individual exposure while commuting. The present study aimed quantify how choice of mode route type affects personal pollutants during We analyzed within-person difference in exposures multiple (black carbon (BC), monoxide (CO), ultrafine particle number concentration (PNC), fine particulate matter (PM2.5)) commutes between the home workplace for 45...
Growing evidence links household air pollution exposure from biomass cookstoves with elevated blood pressure. We assessed cross-sectional associations of 24-hour mean concentrations personal and kitchen fine particulate matter (PM2.5 ), black carbon (BC), stove type pressure, adjusting for confounders, among 147 women using traditional or cleaner-burning Justa stoves in Honduras. investigated effect modification by age body mass index. Traditional users had (standard deviation) PM2.5 126...
Development of an air quality monitoring network with high spatio-temporal resolution requires installation a large number pollutant monitors. However, state-of-the-art monitors are costly and may not be compatible wireless data logging systems. In this study, low-cost electro-chemical sensors manufactured by Alphasense Ltd. for detection CO oxidative gases (predominantly O3 NO2) were evaluated. The voltages from three gas recorded every 2.5 sec when exposed to controlled concentrations in...
This study investigated the role of microenvironment on personal exposures to black carbon (BC), fine particulate mass (PM2.5), monoxide (CO), and particle number concentration (PNC) among adult residents Fort Collins, Colorado, USA. Forty-four participants carried a backpack containing monitoring instruments for eight nonconsecutive 24-hour periods. Exposures were apportioned into five microenvironments: Home, Work, Transit, Eateries, Other. Personal exhibited wide heterogeneity that was...