Estimation of Emissions Due to Two-Stroke Engines in Khartoum

Abstract:This study intended measuring the emissions of carbon monoxide and particulate matter from two-stroke engines in Khartoum. Field data were collected through interviews, questionnaire, measurements and laboratory tests. Federal Test Procedure, United Nations Economic Commission and Japanese procedures have been applied to simulate the emissions form two-stroke engines on road. The measurements were carried out by using electronic portable equipment to measure the concentrations of pollutants in an ambient air. National Ambient Air Quality Standards and Air Quality Index were applied on measured emissions to determine and compare the risk rating of two-stroke engines emissions. We found that, different sites suffered from high concentration of carbon monoxide, particulate matter of 10 and 2.5 microns in diameter due to emissions from two-stroke engines. At the peak period from 12:00 pm to 7:00 pm, the average concentration of carbon monoxide, particulate matter of 10 and 2.5 microns in diameter exceeds the maximum permissible exposure limit by 568%, 265% and 579%, respectively. It was concluded to, the using of two-stroke engines contribute to one of the environmental problems in Sudan. Therefore, it was recommended to produce bio-lubricant oils for two-stroke engines instead of petroleum-based oils. In addition, standards and regulations must be more binding and restrictive to control the emissions, misuse of lubricants and raise awareness among users of two-stroke engines in Khartoum.


2.3
Laboratory instruments I.
Two-stroke engines The auto rickshaw is 3-wheeler vehicle with a 2-sttroke engine. It is considered a common form of urban transport as a vehicle for hire and for private use in many countries around the world, especially developing countries. Bajaj Auto is the world's largest auto rickshaw manufacturer. In Sudan, it is called "Raksha" and it is the most common mean of transportation.

II.
Sensitive gas analyzer; Aeroqual series 500 The series 500 air quality sensor enables accurate real-time surveying of common outdoor air pollutants, all in an ultraportable handheld monitor (Figure 2-1). Air quality professional typically use the series 500 for short-term air quality studies and carrying out checks on pollution "hot spots". The series 500 can also be deployed for short-term fixed monitoring by adding an optional outdoor enclosure [10]. Here it was used to measure the amount of CO concentration surrounding twostroke engines.

III.
Particles analyzer; Aerocet 831 The Aerocet 831 is a small, lightweight, battery operated, handheld mass profiler. This instrument simultaneously monitors PM1, PM2.5, PM4, PM10 and TSP levels. The multifunction rotary dial provides simple and efficient operation. The internal battery pack provides 8 hours of continuous operation. The Aerocet 831 stores up to 2,500 sample events, which can be viewed on the display or exported to a computer via the USB port ( Figure 2-2). The lightweight instrument is only 28 ounces that it is perfect survey tool for a wide range of applications [11].

Analysis and discussion of questionnaire
In spite of, 77% of two-stroke engines users are either young graduates or still studying, their information is very poor in lubricants. Not only that, but they have a misconception about the amount of oil used to blend with the fuel, which is "the greater the amount of oil mixed, the performance of two-stroke engines work optimized". In addition to that, poor quality oils are used as lubricant for two-stroke engines such as; four-stroke motor oils, which are not prepared for blending with fuel or combustion ( Figure 3-1, Figure 3-2).  66.7% of users of two-stroke engines have awareness about the effect of contaminated drinking water and food on their lives. Moreover, most of them complained of contaminated drinking water but the authorities did not care. 50% of the sample was aware of the impact of contaminated surface water on their health but believe that:" surface water treats itself from any pollution so, there is no negative impact on water quality or ecological life". Only people with respiratory or heart diseases who are concerned with air pollution and greenhouse effects (Figure 3-3

On Road
According to the sampling design, it was observed that, the concentration levels of measured pollutants in the sampled population were differed from period to period according to people activities during the day. The highest concentration levels of CO were found in the mid-day for all sampled populations, while at early morning, the concentration level of it was recorded the lowest values compared with the others in the target population. Even that they were still extremely exceeded the maximum permissible exposure limits (PEL) at different periods during the day (    It was found that, during the day except in the early morning, the target population is suffered from high contamination of CO. This degree of CO concentration causes serious aggravation of cardiovascular symptoms such as chest pain, in people with cardiovascular disease and impairment of strenuous activities in general population. Although, the concentration of CO in the early morning was lower than the rest of the day, the ambient air was found to be very unhealthy for people had been suffering from respiratory or heart diseases, the elderly and children. Therefore, people with cardiovascular disease such as angina should avoid exertion and everyone else should limit heavy exertion.   In the mid-day and early evening of the day, the samples that were absorbed through the filter showed a high concentration of PM10. That hazardous level is very dangerous for the symptoms of respiratory system and worsening the lung diseases. Therefore, everyone in the target population should any outdoor exertion and people with respiratory diseases should remain indoor.
The effect of PM10 contamination on ambient air in the early morning and mid-night was similar to PM 2.5 in the middle of night and in the early evening. It was unhealthy for people with respiratory or heart disease, the elderly and children because it increases the likelihood of respiratory symptoms, aggravation of the lung disease and premature mortality in persons with cardiopulmonary disease.
In the mid-day, the concentration of PM 2.5 in the air was found to be unhealthy, leading to the aggravation of heart or lung disease and premature mortality in people with cardiopulmonary disease and the elderly. In addition, the respiratory effects of the target population may be eroded, so everyone should reduce the prolonged effort.
The lowest level of PM2.5 contamination in the target population was measured in the early morning, which is considered relatively safe for people, but they have to be careful to maintain their health. In Figure 3-10; it was observed that the amount of CO concentration start at the highest level and decreased over a time when the speed of engine was decreased until the engine eventually was turned off. The measurements at a distance of 2 meters was done after the measurement at a distance of zero meter had been taken, so it was noted that the area was saturated with concentration of CO more over NAAQS for carbon monoxide concentration level in an ambient air, which it is very dangerous, and harmfully to human health and environment.
2. European procedure European driving cycle is simple and consisting of stable speeds. Although this procedure is considered the ideal position in the simulation of emissions, the concentration of CO level from two-stroke engines as result of using the commercial lubricant oils was very harmful and serious effects (Table 3-2). Table 3-2: CO emissions based on European procedure from two-stroke engines because of using the commercial lubricant oil

Reading
Emissions of CO using a commercial lubricant oil (ppm) CO Emissions at 0m (ppm) 73.74 CO Emissions at 2m (ppm) 50.52 3. Japanese procedure In this procedure, it was observed that the amount of CO emissions was very high at the start of the experiment (Table 3-3); this was due to the nature of this procedure cycles that are allowed the engines to warm up at a high speed.   For the different applicable procedures, the concentration of PM10 in ambient air was found to be hazardous and was consistent with the results obtained from road measurements ( Table 3-1). In addition, the concentration of PM2.5 in ambient air through the application of US and Japanese procedures was consistent with results obtained from road measurements, while the results obtained from the European procedure, were contrary to reality because they assume the ideal movement in emulating emissions. Table 3-4: AQI for the emissions of particulate matter from two-stroke engines through the application of international procedures Health Organization (WHO). Therefore, lubricant oils that were being used for two-stroke engines in Sudan it was inappropriate for the environment and human health and should be replaced by eco-friendly lubricants.

ACKNOWLEDGEMENT
We would like to acknowledge grant-funding support by Dr. Elfadil Elmelik in memory of the late son Eng. Elfatih. We are indebted to semi-final chemical engineering students who helped us in laboratory tests.