Mehdi Amouei Torkmahalleh

PM2.5 and ultrafine particles emitted during heating of commercial cooking oils.

UNLABELLED Seven commercial cooking oils were investigated to determine the PM(2.5) mass and ultrafine particle (UFP) emission rates and emission fluxes (rates per area). The results of this study showed that at 197°C soybean, safflower, canola, and peanut oils produced lower PM(2.5) emission fluxes (6.1 × 10(5), 3.0 × 10(5), 5.4 × 10(5), and 3.9 × 10(5) μg/min/m(2), respectively) than corn, coconut, and olive oils (2.7 × 10(6), 2.9 × 10(6), and 5.7 × 10(6) μg/min/m(2), respectively). Similarly, the total particle number flux at 197°C was lower for soybean, safflower, and canola oils (3.5 × 10(13), 8.6 × 10(13), and 1.0 × 10(14) #/min/m(2), respectively) than the corn, coconut, olive, and peanut oils (2.4 × 10(14), 1.4 × 10(14), 1.7 × 10(14), and 3.8 × 10(14) #/min/m(2), respectively). In general, oils with a higher smoke temperature resulted in lower particle concentrations over the measured temperature range (131-197°C). The percentage of UFP (particle diameter D(p) 10-100 nm) to total particles (D(p) 10-500 nm) ranged from 76 to 99% for this temperature range. Particles below 10 nm in diameter were not measured. The particle number size distribution showed a polydisperse behavior with major mode sizes ranging from 25 nm (for peanut oil) to 82 nm (for soybean oil) at an oil temperature of 197°C. PRACTICAL IMPLICATIONS The study presents particle number and mass concentrations, size distributions, emission rates, and emission fluxes from heating common cooking oils. The emission rates and emission fluxes can be used as inputs to models for indirect exposure analysis studies. The study may also be used to provide guidance on choosing oils that result in lower emission rates when heated.

The Impact of Deliquescence and pH on Cr Speciation in Ambient PM Samples

The 2 chromium oxidation states found in ambient atmospheric particulate matter (PM) are trivalent [Cr(III)] and hexavalent [Cr(VI)] chromium. Cr(III) is a trace element essential for the proper function of living organisms. However, Cr(VI) is toxic and exposure to Cr(VI) may lead to cancer, nasal damage, asthma, bronchitis, pneumonitis, inflammation, dermatitis, and skin allergies. Therefore, it is important to accurately discriminate between these 2 species in atmospheric PM samples. This work focuses on the effect of deliquescence and pH on chromium speciation in filter samples of airborne PM collected in the northeastern USA. The deliquescence relative humidity (DRH) and liquid water mass content determined for the ambient particle samples are in good agreement with previously reported values for ammonium sulfate and ammonium nitrate suggesting that these 2 salts control the hygroscopic properties of the ambient particles in the northeastern USA. The loss of Cr(VI) increases significantly up to 85% at acidic pH as Cr(III) becomes more stable. Under basic pH conditions, deliquescence increases the loss of Cr(VI) such that up to 33% reduction was observed at 96% relative humidity (RH). No statistically significant difference was observed for Cr(VI) and Cr(III) interconversion over a range of ambient PM mass. Because of the effect of deliquescence on chromium speciation at basic pH, a new design criterion for Cr(VI) samplers can be defined to preserve the collected Cr(VI). DRH of sodium bicarbonate, K2Cr2O7, and Cr(NO3)3 was found to be 91%, 94%, and 52%, respectively. Copyright 2012 American Association for Aerosol Research

Review of factors impacting emission/concentration of cooking generated particulate matter

Studies have shown that exposure to particulate matter (PM) emitted while cooking is related to adverse human health effects. The level of PM emissions during cooking varies with several factors. This study reviewed controlled studies available in the cooking PM emissions literature, and found that cooking method, type and quality of the energy (heating) source, burner size, cooking pan, cooking oil, food, additives, source surface area, cooking temperature, ventilation and position of the cooking pan on the stove are influential factors affecting cooking PM emission rates and resulting concentrations. Opportunities to reduce indoor PM concentrations during cooking are proposed. Minor changes in cooking habits and manner might result in a substantial reduction in the cooks exposure to the cooking PM. Finally, the need for additional studies is discussed.

Size segregated PM and its chemical composition emitted from heated corn oil

&NA; Characterization of the airborne particulate matter (PM) emitted from cooking components including cooking oil, and additives like salt has not been carefully investigated. This study provides new data on the concentration, composition, and emission rates/fluxes of PM (less than 3.3 &mgr;m) generated during heating corn oil and corn oil with added table salt. The concept of emission flux was employed to estimate the emission rates in this study. A statistically significant reduction of 47.6% (P<0.05) in the total PM emission rate and emission flux were observed when salt was added to the heated corn oil (5.15×101 mg min−1) compared to the pure oil (9.83×101 mg min−1). The OC emission rate decreased 61.3% (P<0.05) when salt was added to the corn oil (2.35×101 mg min−1) compared to the pure corn oil (5.83×101 mg min−1). With the salt, the total EC emission rate was 6.99×10−1 mg min−1, a 62.7% reduction in EC emission compared to pure corn oil (1.88 mg min−1). These results suggest that table salt can be added to the corn oil prior to frying to reduce exposure to cooking generated PM. HighlightsSize segregated PM, OC and EC mass emission rates and concentrations were measured.Fe, Ti and Sr were the three most abundant trace elements in the PM.Pb, Mn, and V concentrations were greater than the WHO exposure limit.Table salt reduced PM emission emitted from corn oil.Table salt reduced the supersaturation level of emitted vapor from corn oil.

Improved atmospheric sampling of hexavalent chromium

Hexavalent chromium (Cr(VI)) and trivalent chromium (Cr(III)) are the primary chromium oxidation states found in ambient atmospheric particulate matter. While Cr(III) is relatively nontoxic, Cr(VI) is toxic and exposure to Cr(VI) may lead to cancer, nasal damage, asthma, bronchitis, and pneumonitis. Accurate measurement of the ambient Cr(VI) concentrations is an environmental challenge since Cr(VI) can be reduced to Cr(III) and vice versa during sampling. In the present study, a new Cr(VI) sampler (Clarkson sampler) was designed, constructed, and field tested to improve the sampling of Cr(VI) in ambient air. The new Clarkson Cr(VI) sampler was based on the concept that deliquescence during sampling leads to aqueous phase reactions. Thus, the relative humidity of the sampled air was reduced below the deliquescence relative humidity (DRH) of the ambient particles. The new sampler was operated to collect total suspended particles (TSP), and compared side-by-side with the current National Air Toxics Trends Stations (NATTS) Cr(VI) sampler that is utilized in the U.S. Environmental Protection Agency (EPA) air toxics monitoring program. Side-by-side field testing of the samplers occurred in Elizabeth, NJ, during the winter and summer of 2012. The average recovery values of Cr(VI) spikes after 24-hr sampling intervals during summer and winter sampling were 57 and 72%, respectively, for the Clarkson sampler, while the corresponding average values for NATTS samplers were 46% for both summer and winter sampling, respectively. Preventing the ambient aerosol collected on the filters from deliquescing is a key to improving the sampling of Cr(VI). Implications: This study describes a sampler that provides cooling and drying of the particle collection filter by reducing the ambient air relative humidity to below deliquescence relative humidity of ambient particles. This Clarkson Cr(VI) sampler improved the measurement of ambient Cr(VI) concentration. It showed higher Cr(VI) recovery during field tests (71.8 ± 4.9% in winter and 57.1 ± 0.2 % in summer) compared to the current EPA Cr(VI) sampler (46.2 ± 10.8% in winter and 46.0 ± 1.6% in summer) that is employed in the National Air Toxics Trends Stations (NATTS) monitoring program. Supplemental Materials: Supplemental materials are available for this paper. Go to the publishers online edition of the Journal of the Air & Waste Management Association.

Investigating the impact of different sport trainings on particulate matter resuspension in a sport center using well-characterized reference instruments and a low-cost monitor

The present study investigated the exposure of teenagers, adults, and students to PM1, PM2.5, PM4, PM10, particle number concentration at two sport facilities of Nazarbayev University including Gymnastics Hall and Multi-purpose Hall. Measurements were conducted during variety of sport training sessions including soccer, basketball, volleyball, Mixed Martial Arts (MMA), boxing, table tennis, etc. A low-cost instrument, Dylos was employed to compare its performance against two TSI instruments. In overall, the Dylos showed acceptable peaks when the source of particle resuspension was present. However, no correlation was observed between Dylos data and Dusttrak fine and coarse particle data. The average PM2,5 and PM10 concentrations were found to be below the WHO limits. The number of participants during the training sessions and sports involving balls including basketball, soccer and volleyball were the two factors responsible for the observed increased particle resuspension.

Contributions of burner, pan, meat and salt to PM emission during grilling

&NA; Grilling ground beef meat was conducted in two locations at Nazarbayev University, Kazakhstan. The experiments were designed such that only particles from beef meat were isolated. A similar experimental protocol was applied at both locations. The average particle number and mass emission rates for grilling pure meat itself (excluding particles from pan and burner) were found to be 9.4 × 1012(SD = 7.2 × 1012 particle min−1 and 7.6 × 10 (SD = 6.3 × 10) mg.min−1, respectively. The PM emissions (number and mass) from the burner were found to be negligible compared to the pan and meat emissions. Ultrafine particle (UFP) concentrations from the heated pan itself were comparable to those of grilled meat. However, the particle mass concentrations from the pan itself were negligible. Approximately an hour of continuous heating resulted in zero emissions from the pan.