Investigation of Particulate Matter Size, Concentration and Mass Emissions from Small Handheld 2-Stroke Spark Ignition Engines

Quality of air, change in the climate and exposure of humans to pollutants have become major concerns globally over the past decade. Particulate matter has been linked to many adverse health effects. Internal combustion engines are major source of PM emissions. Knowing the adverse health effects of particulate matter, the regulatory agencies are in the process of introducing strict regulations to limit the quantity of PM emitted by off-road small handheld gasoline engines. Two-stroke small engines typically emit more smoke as they burn oil-gasoline mixture compared to four-stroke engines running on gasoline only. Current regulations in the United States for these engines regulate only HC+NOx and CO emissions. In spite of their contribution to atmospheric pollution and negative health effects, the PM emissions from handheld, two-stroke engines are yet to be regulated. This led to this study of particulate matter emissions from these engines.;The main objective of this study was to measure particulate matter size, concentration and mass distributions from 2-stroke handheld 25cc weed whacker engine and to evaluate the effect of heat treatment on these emissions in removal of volatile fractions. The exhaust sample was heat treated to different temperatures (200 °C, 150 °C, and 100 °C) before measuring the distributions to better understand what fraction of particulate matter is solid or volatile. Tests were performed in Center for Alternate Fuels, Engines and Emissions Laboratory (CAFEE) at West Virginia University. A Scanning Mobility Particle Sizer (SMPS) Model was used for measuring the particle size distribution and concentrations. The engine was operated at two steady-state modes (wide open throttle) WOT and Idle mode. The WOT mode resulted in a count median diameter (CMD) of 14.1nm when heat treated the sample to 200 ºC compared to 32.1nm for sample in CVS whereas the idle mode resulted in CMD of 5.94nm and 31.1nm respectively. This indicated the existence of volatile particles. These Nano-particles are proved to be harmful to health. Results obtained from the data for the sample in CVS and compared to the data for the heat treated samples, show that the influence of volatile fraction on PM size distribution is reduced with increase in sample conditioning temperatures. The density function used for mass distribution calculations by SMPS does not take diameter of the particle into consideration and so these calculations were compared with the mass distribution calculated by using IPSD method or effective particle density method since previous studies indicated that at ultra-low emission levels this method proved to give more precise results. This comparison resulted in a good correlation in the particle mass distribution given by SMPS

The Modern Grounds Maintenance Worker

More than 1 million workers are employed in Grounds Maintenance operations in the United States today. These workers perform varied but recurring tasks necessary to maintain the orderly and healthful function of parks, residential and commercial landscapes, and institutional grounds. Technological advancements in machinery have, over time, vastly increased the productive impact of each worker. While fewer workers are needed per acre, the same advances in production have amplified some types of health risk to this work population. This inquiry identified the primary chronic stressors inherent in modern grounds maintenance work, chiefly exposures to noise and respirable engine emissions. The results reveal a number of conditions of concern, and support a strong need for awareness training and control options for this population and its managers in order to reduce risk of chronic adverse health effects

Quantification Of Emissions From Lawn And Garden Equipment In Central Florida

The objective of this study was to evaluate the practical limits of EPA\u27s NONROAD 2005 to accurately simulate Central Florida conditions, especially with regard to lawn and garden equipment. In particular we investigated a NONROAD emission inventory using default inputs and then created a locally specific emission inventory. These emission inventories were prepared for Orange, Osceola, and Seminole county and focused only on the VOC and NOx emissions caused by lawn and garden equipment. The model was manipulated to assess its ability to represent this specific category of nonroad equipment for a given airshed first by running a base case scenario using default data and then by developing a locally-specific scenario through administration of a survey. The primary purpose of the survey was to evaluate local values for equipment population, equipment characteristics, activity estimates, and other relevant information. To develop these local input estimates, data were collected concerning population and usage statistics in the Central Florida area and were combined with emission factors, load factors, allocation factors, and other needed values that have been previously established by the U.S. EPA. The results of the NONROAD model were compared with the resulting emission estimates calculated from locally derived inputs, and as a result of the analysis an accurate emission estimate was calculated. In addition, several possible air quality action steps were further assessed according to feasibility, cost, and predicted emission benefit. These potential management projects were further investigated by assessing the success of other similar projects in other cities in an effort to establish specific costs and emission benefits as they relate to the tri-county area

Experimental Study on Electrical Power Generation from 1 kW Engine Using Simulated Biogas Fuel

This research paper presented a biogas as a fuel for small 1 kW power engine. The simulated biogas fuel was tested on type of spark ignition engine of generator and it examined the engine performance at the constant engine speed under load transients. The generator was connected to load bank and it was functioned to generate a comparable result from the laboratory experiments by using gasoline, liquefied petroleum gas (LPG) and natural gas as fuel in the engine to be evaluated with simulated biogas. Based on study conducted, on more general proportion, 60% of methane (CH4) and 40% of carbon dioxide (CO2) in the simulated biogas was used. The results obtained from testing the engine have been found to be satisfactory. As the calculations on electric power generation, fuel flow rate, specific fuel consumption, (sfc) and engine efficiency have been made, the results showed that the performance of engine and exhaust emissions fuelled with gasoline would be a baseline for this project. It also showed that maximum specific fuel consumption for LPG and natural gas was decreased by 10% and 23.4% respectively when compared to gasoline and it is proven that the simulated biogas has consumed more fuel (1254.83 kg/kWh) with only reach up to 780 W. The power reduction of engine using simulated biogas was about 22% as compared to gasoline. In term of engine efficiency, gasoline, LPG, natural gas have generated 21%, 20.7%, 20.4% respectively while simulated biogas generated only 0.16% of engine efficiency

Temporal Variations in Methane Emissions from an Unconventional Well Site

Studies have aimed to quantify methane emissions associated with the growing natural gas infrastructure. Quantification is completed using direct or indirect methods—both of which typically represent only a snapshot in time. Most studies focused on collecting emissions data from multiple sites to increase sample size, thus combining the effects of geospatial and temporal variability (spatio-temporal variability). However, we examined the temporal variability in methane emissions from a single unconventional well site over the course of nearly 2 years (21 months) by conducting six direct quantification audits. We used a full flow sampling system that quantified methane mass emissions with an uncertainty of ±10%. Results showed significant temporal variation in methane mass emissions ranging from 86.2 to 4102 g/h with a mean of 1371 g/h. Our average emissions rate from this unconventional well pad tended to align with those presented in the literature. The largest contributor to variability in site emissions was the produced water tank which had emissions rates ranging from 17.3 to 3731 g/h. We compared our methane mass emissions with the total production for each audit and showed that relative methane loss rates ranged from 0.002 to 0.088% with a mean of 0.030%, typically lower than reported by the literature, noting that our data excluded well unloadings. We examined natural gas production, water production, and weather conditions for trends. The strongest correlation was between methane emissions and historical water production. Our data shows that even for a single site, a snapshot in time could significantly over-predict (3×) or under-predict (16×) methane emissions as compared to a long-term temporal average

Evaluation of exhaust flowrate measurement techniques for a mobile emissions monitoring system

West Virginia University designed and developed Mobile Emissions Monitoring System (MEMS) for the six settling Heavy-Duty Diesel Engine (S-HDDE) manufacturers. The MEMS measures emissions concentrations while operating in a real world environment. The best method for measuring the emissions concentrations was found to be through raw exhaust sampling. In order to properly calculate the emissions concentrations the total exhaust flowrate through the engine must be determined. The devices evaluated were an Annubar, an Accutube, a hot film anemometer, a Pitot static tube, a venturi, and a vortex shedder.;The evaluation of the devices was broken down into two parts, the first part included cold bench testing and the second engine testing. The venturi was found to be the best flow device for a MEMS because of the increased flow range over the vortex shedder and was well suited for the environment of compression ignition exhaust streams