港巴889線

 1. Introduction 

1.1What is odor problem: 

As the name suggests, odor problem is the negative impact cause by the air which surround to human. With the atmospheric environment contaminated by chemical or biological particle. Odor problem will affect different aspect of human and environment, like quality of environment, health of human etc. According to previous study   odor problem was definite as the contaminants directly or indirectly result from human activities, and that will cause different negative effect to human, animal and environment. For the aspect of human health, odor will generate the negative physical symptoms include sensory irritations, headaches, respiratory problems etc. Those negative physical symptoms are mainly cause from emotional stresses if prolong exposure under odor. On the other hand, odor can also impair the safety of one person. For the aspect of animal, odor problem can cause injury and put animal life a risk. For the aspect of environment, odor can impair the quality of natural environment. 

1.2 Odor problem in Hong Kong:

Odor problem in Hong Kong are mainly originated from anthropogenic sources, like gas exhaust from vehicles, domestic and industrial effluent, gas exhaust from domestics and commercial activities etc.. For the aspect of vehicle, it should be classify as roadside odor problem, the main source of roadside odor problem are diesel vehicle that emit large amount of particles and nitrogen oxides. Due to the high-rise building at two side of the road, roadside odor are always difficult to disperse, this become the major reason of high odor level at roadside. On the aspect of sewage, the source of sewage impact to marine water are very wide, cover to agricultural waste, organic compound, industrial waste, livestock waste etc. The main reason of those case are citizens want to escape from paying the sewage charge. They might discharge the sewage to the water bodies directly. Base on chemicals, livestock having a strong odor, when those discharge to the rivers or sea, its odor will contaminate the marine water, cause marine water odor problem. Looking back to the cause in Hong Kong, according to the article  ,  the concentration of various of POPs are rising, trust that the sources of odor are come from the POPs recorded at the coastal water like Organochlorine, Polybrominated diphenyl ethers, Polycyclic Aromatic Hydrocarbons. The generate of those POPs are relate to human activities for example using pesticides.  

For the impact of marine water odor problem, not only lead marine water to stink, but also cause increase in bacterial amount of marine water and pathogen spread. Moreover, the odor problem of marine water will also cause to cancer, those chemical compounds of POPs had already state as carcinogen, once the chemical compounds of POPs has absorb, it will accumulate inside human body and form liver cancer, stomach cancer, lung cancer etc. One of the example is the coastal near Tsuen Wan West Station, based on the wrong setting of water pipe and the sewage was flow into storm drainage system, caused sewage generated by human activities were all discharged to the sea, cause the odor problem of Rambler Channel near Tsuen Wan was perplex over 20 years.   

For the aspect of gas exhaust from high-rise building, generally, the odor from high-rise building are from the exhaust system because the exhaust system of high-rise building are connect to a large amount of facilities inside the building included range hood, air-conditioner ventilation system, exhaust fan etc. Those are related to the odor generate by the machine operation and human activities. Those activities will generating smell, after the mixing process of difference kinds of smell, at the same time, a varieties of chemical reaction compounds like Aldehydes, Ketones, Hydrocarbons, Fatty acids, Alcohols, Esters, Lactones, Heterocyclic compounds, Aromatic compounds will also processing a mixing process and then generate odor. When the odor smell exhaust to outdoor, cause odor problem. 

To talk about the health impact of gas exhaust from high-rise building to human, it can said that it’s similar to marine odor problem, it can cause carcinogen, especially lung cancer, the chemical compound generated like Aromatic compounds having strong toxicity. Not only personal, the odor problem will also generate group influence. In group influence, odor problem of gas exhaust from high-rise building will involve mental and psychology health. According to the article   state that the responses cause by odor stimulus are subjective, based on this response are depends on sensation caused by odor like pleasant and unpleasant. Annoyance will be the result when human was exposure to odor for either long-term or short-term period. After the annoyance are cased, stress-mediated responses will be trigger, finally, the psychology health of human are unhealthy, develop to a public health problem. One of the example of odor problem generate from high-rise building that are having upstairs temple at Hung Hom. The flats were exposed smoke and ashes, which came from a stove used to burning joss paper and paper sacrifices. When without install of any suitable air pollution control equipment, and the exhaust port of the stove was face to the lane behind the building, the odor of smoke emitted cause impact to the neighbors who living nearby. A spokesman to whom worked at EPA said that the stoves used in the ceremonial sites must be equipped with appropriate air pollution control equipment to deal with the smoke and ash generated by the burning of sorrows and paper sacrificial offerings. 

1.3 Odor detection method: 

There are a variety of methods to detect odor, apart from the field inspection, method which will use in this project, there are still having different method that are more scientific and more precision. According to the article “Comprehensive Feasibility Study for the Revised Scheme of South East Kowloon Department” odor can detect by using Hydrogen Sulphide Monitoring method. Hydrogen Sulphide Monitoring method is a method which utilize Jerome H2S Analyzers to record the concentration of H2S which will emit odor at low concentration by utilize a gold sensor to detect the hydrogen sulphide. Jerome H2S Analyzers is control by microprocessor can ensure that the analyses are accurate and rapidly. On the other head, Olfactometry Analysis is also a method of detecting odor. This method is fulfilled to Dutch National Standard Method (NVN2820). The common way to achieve the Olfactometry Analysis is to use 40L plastic bag to collect air sample. One thing that need to consider is weather condition including wind direction, wind speed and temperature should also be record. 

The advantages of using Jerome H2S Analyzers are this instrument do not respond to CO, CO2, SO2 and vapor and the potential inferences of this instrument are rare. Some of the chemical compound like Chlorine, NO2 and mercaptans will influent the analyze result. But the special design of filter install on analyzer can decrease the concentration of Chlorine and NO2 cause to decrease the level of interference by these two chemical compounds and provide a high accuracy result. For the advantages of using Olfactometry Analysis to detect odor are this method are deriving a value from the direct correlation between the odor and the sensitivity of the detector being used e.g. human nose. 6   

1.4 Odor treatment technology: 

Following the improvement of technology, odor treatment technology are more varieties than before. Odor treatment technology nowadays can act as monitoring, controlling use. According to the article , adsorption is one of the technology of odor treatment. Means that to utilize assignation materials like activated carbon, activated alumina, silica gels and zeolites to attach the odorous compounds, purpose is to control the odorous compounds flow, drift in the air to decrease the odor. Adsorption can divide into chemical adsorption and physical adsorption. For the aspect of physical adsorption, the material which had adsorbed will not change their nature at the process of physical adsorption, suction are easy to escape. For the aspect of chemical adsorption, it utilize the attraction of chemical bond to adsorb the odorous compounds. The nature of suction will change at the process of chemical changes. To compare the adsorption ability of chemical and physical adsorption, chemical adsorption are stronger than physical adsorption. 

On the other hand, the technology of fixed bed reactors and packed bed reactors are also a kind of odor treatment technology. For the fixed bed reactors, after the gas pass through the stationary bed, absorption and desorption are require when the fixed bed reactors are continuous operation. The purpose is to achieve the process of adsorb and re-diluting the desorb. The advantages of fixed bed reactors is that the flow of fluid within the bed is close to the flat flow, and a smaller amount of catalyst and a smaller reactor volume can be used to achieve greater throughput. Since the residence time can be strictly controlled, the temperature distribution can be appropriately adjusted, and thus it is particularly advantageous to achieve high selectivity and conversion. And it can be operated under high temperature and high pressure.

 2. Objective:

2.1 Conduct odor monitoring by using field inspection: 

For this project, there will be sessions of field inspection to monitor odor in outdoor environment. And the field inspection way which I have chosen to monitoring odor conducted will be BS EN 16841-1: 2016 Grid Method. Generally speaking, this method involves utilizing human nose to smell whether there are having odor or not at designated time and location, and the location to monitoring odor conducted are form as grid line when all of the location were connected. According to the article , BS EN 16841-1: 2016 Grid Method need to set the measurement points at the corners of assessment square form by streets. Utilize this method need to measure the odor generated repeatedly to let the data to be accurate. For the result, output, it can define the result into ‘odor hour’ and ‘non-odor hour’, ‘odor hour’ means that surveyor can smell the odor 6 times or above in an hour, if the surveyor smells the odor under 6 times in an hour, it defines as ‘non-odor hour’. At the end, all the data collected need to summing up to count the total times that can smell the odor to the total times of smelling the odor group by group, 4 measurement points as a group, finally, a percentage can be output. For the aspect of measurement, 10 timed intervals for smelling the odor will be conduct, each timed interval will be host for 1 minute and smell at each 10 seconds, each measurement point need to survey total 10 minutes and get 60 data. As the mention above, if odor reaches or exceeds a percentage odor time of 10% at one hour (6 times out of 60 times), this can classify as ‘odor hour’

2.2 Comment on the possible use of BS EN 16841-1: 2016 Grid Method in Hong Kong:

The purpose of utilize BS EN 16841-1:2016 Grid Method to monitoring odor is to observe which kinds of odor source will be appear and the appear frequency of different kinds of odor sources at different places. To look back to the environment in Hong Kong, especially urban area, the odor is come from variety source, like odor from building, odor from the gas made by moving machine or from nature etc. Beside the busy street in urban area, it’s possible to use BS EN 16841-1:2016 Grid Method to monitoring odor because the environment of urban area- high rise building build along the street, large number of vehicles appear are easily to cause “Street Canyon Effect”. Once “Street Canyon Effect” appear, the result of odor pollution will be clear, utilize BS EN 16841-1:2016 Grid Method will be easier to catch the result of odor pollution.

  Canyon Effect will affect the accuracy of Grid Method measurement on different factors. In terms of climate factor like wind direction, if the wind direction is parallel to the street, the channelization and Venturi effects will increase the dispersion of air pollution matter inside street canyon and increase the air quality inside street canyon at the same time, the odor occur at that time will be rare. But at the time that wind direction is perpendicular to the street, the vortex form inside the street canyon will restrict the air flow, decrease the dispersion of air pollution matter, the air pollution concentration will be increase, the odor will occur obvious due to air pollution concentration is high.  The measurement conduct at the time that wind direction is parallel to the street can’t show the accurate situation of odor pollution because the odor occur is rare while the odor occur at the time that wind direction is perpendicular to the street are much. The result measured are unsteady, it is hard to show the accurate situation of odor pollution due to affect by wind direction. For the aspect of human activities in different time in a day, human activities will occur odor, it is mentioned above that the odor pollution problem are mainly originated from anthropogenic source, the human activities inside canyon will affect the amount of odor occur directly. Generally, the odor occur in early morning is less base on the human activities in early morning are rare compare to morning, noon and afternoon. The air pollution matter will trap inside street canyon and accumulate when the human activities are prosperous, the odor pollution problem is serious at that time. The result measure in different time in a day will occur great contrast, this cause will affect the accuracy of Grid Method measurement. For the aspect of site topography , the transport, dispersion and fate in the environment of volatile odor form in industrial and urban area will control by few factors, site topography is one of the factor. 

I am applying random when formulating the sampling grid, those are the high opportunity rate to detect odor. 

To ensure the representativeness of the data, it should conduct the measurement at suitable, this means that it should measure in the time that have more human activities like noon and suitable place (the place that near the possible sources). The weather (wind direction) are also need to consider before measurement because wind will adsorb air pollutants that contain odor.

3. Methodologies

3.1. Sampling location (map, describe surrounding environment

The surveying location have been chosen at 4 places near Choi Hung Road and San Po Kong. The main reason of chose Choi Hung Road and San Po Kong to do surveying is to survey the odor after improvement project of Kai Tak Nullah and the gas emission from vehicles and high-rise buildings at San Po Kong. Those are the place that can easy to monitor the odor and produce odor artificial. Map of 4 places has shown in Appendix.

Kai Tak Nullah are surround by residential building and community facilities like school, market, shopping mall etc. are possible to cause odor by building gas exhaust. One place that are opportunity to cause odor problem by emit sewage are construction of Kai Tak Nullah treatment project. Mining work at river bottom to clean up the mud and improvement work are the odor source of Kai Tak Nullah. Odor problem was always appear before treatment project base on the historical factor ,Kai Tak Nullah is near to San Po Kong industrial area, the situation of illegal sewage emission was serious, furthermore, Kai Tak Nullah need to emit the sewage which is come from Tai Po and Sha Tin treatment works, so Kai Tak Nullah need to bear the odor which was came from long term water pollution by heavy metal and sediment, industrial building and sewage treatment work are also a possible sources of sewage odor of Kai Tak Nullah. But this factor were changed to minor factor by following the Kai Tak Nullah treatment project which started at 2000 century, government tried to improve the odor problem by the method of biological decontamination, improvement of drainage port, sewage interception etc. So, this project wants to survey the improvement of odor problem after treatment project of Kai Tak Nullah. 

For the aspect of San Po Kong, the survey point of this project are all located at inner street , high rise industrial building, commercial building are surrounding. Furthermore, heavy vehicles are always appear. Macroscopically, gas emission by human activities are common, obstruct to the distribution of building are all located along the road, the air pollution matter are difficult to dissipate, cause Street Canyon Effect, odor problem are always come from the air pollution matter. So, San Po Kong are also a good place to measure the odor. 

3.2. Sampling procedure: 

Before sampling, prepare and planning objectives are required. For the objective of planning, research about the black spot of odor problem is required. Aim to find the place that can record and reflect the odor problem evident, and to evaluate the environment factor like air circulation, placement of building etc. For the objective of preparing, log sheets for surveying the odor is required to record the result of survey. On the other head, a network and designated points are need to set before sampling, so that the sampling can process immediately. When the sampling is processing, its need to pay attention to appearance of odor and GPS location then record on the log sheet, whole process will using field inspection method (BS EN 16841-1: 2016 Grid Method). After sampling, utilize excel is require for input the data recorded into computer and process the latest work like auditing and mapping to present the data. 

3.2.1 Record GPS location: 

For each of the measurement point, it should be present as the GPS location (latitude and longitude). The reason will be GPS is an international universal positioning system, once to fill in the latitude and longitude on map, map will positioning the approximate location. So, this project will be utilize GPS to represent each of the measurement point. At the survey stage, one of the mission is to record GPS location to use the GPS data to show the measurement point. On the other head, record GPS location will be convenient to the latest work like making map to represent the survey result.

3.2.2 (Write steps – follow BS EN 16841-1:2016): 

As the mention above, the surveying method of this project will all following the procedure, steps of standard BS EN 16841-1-2016. The detail of surveying method BS EN 16841-1-2016 will mention at the following  . Area 250m x 250m grid which is recommended are need to draw across the assessment area, the measurement point are also necessary to define at the same time. When all the grid are finish to conduct, it may be necessary to process the condition work on the basis of local situation for example to rotate or shifting the measuring points. For the aspect of measurement point, its need to notices that it must close to places of assembly. Then, survey procedure start, each measurement point should measure 10 minutes conduct 10 intervals, each interval should measure for 1 minute, total 60 times for each measurement point. A review should be taken after 4 signal measurement per each measurement point. After survey, field inspection result which conduct at different times in a day and different measuring points should be gather.       

3.3 Log sheet design

About the design of log sheet, to consider the objective of the log sheet, include description of odor types, the length of time to measure at each measurement point, and the weather are the factors that need to consider. For the design of the part ‘Description of odor type’, the type of odor which are estimated and high chance to appear at the measuring time are input in this part when designing the log sheet. The purpose is to be the standard of measurement for reference. For the data record part, 10 data record boxes and each contain 6 grids has been drawn to record the data at each 10 seconds, so, total 60 data will be conduct after one-minute measurement.

3.4 Results visualization

After the process of gather the survey data and input into excel, the data should compare with all of the data which collected, to show the trend of the data changing. All the data should present by the form of table, bar chart to show the data collect in one day or individual measuring point. Line chart to show all the data collected as the aim of show the trend of data change. Map are also one of the results visualization form, the form are mainly utilize in showing the data collected in different places in one day, to compare the high and low of the data in different places by utilize different chart which are common to use like pie chart, bar chart etc. on the map. The advantages of utilizing map is it can clearly to show, compare the data collected in different places, at the same time, the actual location of surveying can also show clearly. For this project, the form of results visualization will choose line chart, bar chart, and map will use in latest presentation part. 

4. Result

4.1. Odor results in table

4.2. Odor results in map

 

Figure 1.1& 1.2: Summary of result in October

 

Figure 1.3&1.4: Summary of result in November

 

Figure 1.5&1.6: Summary of result in December

 

Figure 1.7& 1.8: Summary of result in January

4.3. Description

The survey has been conducted on October, 2018 to. Tables shows on part 4.1 has present the variety of odor source in different months and at different locations. 

According to the table “Summary of the result measure in October,2018”, and map “Summary of result in October”, it shows that point 2 is the most smelly point among 4 measuring points because point 2 had the highest frequency (41out of 60) and percentage (68.33%), it’s higher than other points with 43%-53%. For the aspect of odor source, apart from source no.0 (no smell),source no.2(odor from building exhaust) is the most frequency odor source appear at the whole measurement, with frequency 44 times among 4 points, higher than other sources with over 30 times. This shows that odor would be more appear near point 2 and odor from building exhaust was the main source of odor. 

 

According to the table “Summary of the result measure in November,2018” and map “Summary of result in November”. it shows that point 2 is the most smelly point among 4 measuring points because point 2 had the highest frequency (17,25 and 28 out of 60 respectively, total 70 times out of 180) among 3 days (1/11, 10/11 and 20/11) and percentage 28.33%, 41.67% and 46.67%, it’s higher than other points with. For the aspect of odor source, apart from source no.0 (no smell), source no.5 (others) is the most frequency odor source appear at the whole measurement with frequency 65 times among 12 points, and the seldom odor source is source no.3 with frequency 4 times, the frequency of source no.5 is 16 times more than source no.3. At the perspective of odor present result view by days, there had a upward trend from the beginning of November to the middle of November and slightly downward trend from the middle of November to the end of November. The frequency of odor was raise to 73/240 on 10/11 from 36/240 on 1/11, the increase rate reached 102.8% and dropped to 64/240 on 20/11 with decrease rate 12.3%. Overall, the frequency of odor was not so much, the frequency of odor detected just occupied 24.03% to the total times of measuring.

According to the table “Summary of the result measure in December 2018’’ and map “Summary of result in December”, it shows that point 3 is the most smelly point among 4 measuring points because point 3 had measured the most frequency( total 45 times out of 120 times) and percentage 37.5% among two days (4/12 and 25/12), it’s higher than other measuring points with. For the aspect of odor sources, apart from source no.0 (no smell), source no.5 (others) is the most frequency odor source appear at the whole measurement with frequency 45 times among 8 points, and the most seldom odor source is source no.3 with frequency 5 times, lower than source no.5 with 9 times. At the perspective of odor present result view by whole month, there had a downward trend from the beginning of December to the end of December. The frequency of odor was dropped to 63/240 from 72/240, the decrease rate was 14.28%. Overall, the frequency of odor was not so much, the frequency of odor detected just occupied 28.13% to the total times of measuring.

According to the table “Summary of the result measure in January 2019’’ and map “Summary of result in January’’, it shows that point 4 is the most smelly point among 4 measuring points because point 4 had measured the most frequency ( total 79 times out of 180 times) and percentage 43.9% among 3 days, it’s higher than other measuring points. For the aspect of odor sources, apart from source 0 (no smell),source 5 is the most frequency odor source appear at the whole measurement with frequency 125 times, and the most seldom odor source is source 3 with frequency 7 times, lower than source 5 with nearly 18 times. At the perspective of odor present result view by whole month , there had a upward trend from the beginning of January to the middle of January and had a downward trend from the middle of January to the end of January. The frequency of odor was raise to 82/240 on 22/1 from 69/240 on 11/1, the increase rate reached 18% and dropped to 75/240 on 29/1 with decrease rate 8.5 %. Overall, the frequency of odor was not so much, the frequency of odor detected occupied 31.39% to the total times of measuring.

5. Discussion

5.1. Odor type

According to the result, the odor type of this study can be divide into 5 types (odor from nullah, odor from building exhaust, green and astringency, odor from moving machine and others). The odor which appear most frequently among all the result will be the main odor that impact to the study area. 

The result recorded has showed that source no.2 (odor from building exhaust) and no.5 (others) is the most frequently appeared among all the sources. It is because the measuring point which in-front of building are near the central air-conditioning system air vent, separation air conditioner and smoke outlet. It’s possible that smell were occurred by those kinds of building exhaust. There are some reasons that will case air-conditioning system occur odor, like mold presence in HVAC system,  another reason can be come from dirty air filter, the main reason will be the air filter of AC system will adsorb the odor-causing contaminants when the AC system is circulates, so, the odor will exhaust if the air filters are not change frequently.  

For this case, the main source of causing odor from air-conditioning system from building exhaust will be 1. Dirty evaporator coil; 2. Clogged condensate drain line; 3. Leaky ductwork. For the aspect of dirty evaporator coil, it is possible that the mold will breed inside the dirty evaporator coil, it’s mentioned above that the breeding of mold will cause musty smell. The breed of mold is influent by environment, like the worst air quality surround the evaporator coil, no sunlight to (UV ray to kill the mold) and the moisture condense at the cold evaporator coils. For the aspect of clogged condensate drain line, if the moisture condense clog the condensate drainage line, when condensation forms on your evaporator coil, it drops into a drain pan, the water in drain pan can encourage the breed of mold. For the aspect of leaky ductwork, the air moves through duct system will lose due to leaky ductwork, so, mold can easy to enter the ductwork. 

The odor exhaust by air-conditioning system from building is just one of the source of odor exhaust, there are also having another odor source will are puzzle to Hong Kong now. Like odor from landfill sites. Odor from landfill sites are attract to sensitive reservoir nearby because of the land restriction of Hong Kong generally, cause not enough buffer zone between sensitive reservoir and landfill site. According to a survey, odor concentration at the nearest sensitive receivers of the landfill site is always below 5 ou/m3 with a chance of 99.99% based on the yearly, monthly and daily average weather data. The main odor sources are municipal waste include waste sludge from conventional biological treatment processes, municipal refuse from residential areas and construction wastes, but a different pattern to some chemical wastes including the sludge from a chemically enhanced precipitation process, and some industrial wastes.     

  

5.2. Odor time

According to the standard of BS EN 16841-1:2016 Grid Method, if odor reaches or exceeds a percentage odor time of 10% at one hour (6 times out of 60 times), this can classify as ‘odor hour’. For the result, the odor measuring time were centered on afternoon, and all of the measuring hours were reached the standard that exceeded a percentage odor time of 10% at one hour, this means that all of the measuring points are puzzle by odor pollution problem to a certain extent.

Odor time are impact by the changes of air quality, and the air quality will impact by the human activities at different period in one day and wind direction in different period , in this section, it will concentrate on wind direction to the impact of odor. For the example of the location of this survey, Kai Tak Nullah is locate at the west and north of measuring point 1 and 4. According to the log sheets, in 3 months of 2018 and 1 month in 2019, the wind force was usually slight and sometimes were no wind. According to the web page “The weather of October 2018’’, the prevailing wind direction of measuring day (26/10) was trend to south, 3 measuring day in November (1/11, 10/11 and 20/11) were trend to south and southwest respectively, 2 measuring day in December ( 4/12 and 25/12) were South-southwest and southwest and 3 measuring day in January (11/1,22/1 and 29/1) were southwest, south and South-southwest respectively. The reason of case odor detected because wind was coming from south and southwest direction, in point 1 and 4, the south of point 1 and 4 was face to nullah and road, the flowing air was attached the odor from main road and nullah adsorbed, case odor detected when the wind direction was south an. For the aspect of wind direction to the effect of Street Canyon Effect, because the majority of time the wind direction were trend to south and southwest, this wind direction was vertical to street in point 2 and 3, The eddy current will restrict the air flow, reduce the dispersion of air pollutants, increase the air pollution concentration, and the air will obviously produce odor due to air. In addition, the prosperous human activities in the afternoon produced air pollutants, it is nothing wrong to have a higher rate to detected odor in the afternoon. 

5.3. Odor location

The location which impact by odor seriously are looking for the frequency of odor appear and number of types of odor appear. At this study, there are 4 measuring point, the detail of 4 measuring point had shown in part 4.2 and 6.2. Among 4 measuring points, 3 measuring points are located at the roadside, 2 measuring points are located near the Kai Tak Nullah. It is possible that human activities will directly affect the frequency of odor exceed at a place. For this measurement, point 1 which is locate at the back of Kai Tak Nullah, the improvement work of Kai Tak Nullah were still processing, the improvement work include drilling and excavating the river bed, the odor exceed from sludge can be detected when measurement was conducting. At the point that located at roadside, two points (2 and 3) were face to the air-conditioners and the central air-conditioning system air vent were at the back, while the measurement was conduct, no matter air-conditioners and the central air-conditioning system air vent were operating. Air exhaust from air-conditioners and central air-conditioning system will adsorb the odor process from human activities inside the building to duct, odor will emit to street directly if the air-conditioning system are without install filter od duct cleaning. It seems like the result measured, base on the result in point 2 and 3, the frequency that can detected the odor from building exhaust were around 2-10 times at each measuring day and one measuring day was over 30 times among all of the measuring day. This reflect that point 2 and 3 are the place that effect by odor from air-conditioner.  

On the other hand, distribution of buildings and road are also one of the main factor that will affect the occur frequency of odor, this factor will result “Street Canyon Effect” which had mention in part 2.2. It is suitable to describe the situation at point 3. Point 3 located at the roadside that surround by industrial building. On the road, LPG public light bus, diesel double-decker bus, trucks were stay in-front of the measuring point. On the other hand, flow odor source were observed---burning of cigarette from smokers is one of the main source produce odor at point 2 and 3, lead smoke smell brimmed over point 2 and 3, point 2 and 3 are impact by smoke produce from cigarette and vehicle emission.

For the aspect of point 4, point 4 is one of the point that have the minor level of impact by odor. The main type of odor sources of point 4 were odor from nullah, odor from moving machine (vehicles emission) and others ( odor from cigarette burning usually). Point 4 was located on the midstream of Kai Tak Nullah, this section has already finished improvement, but there has still emitted smell from nullah intermittent.  

5.4. Impact of Odor to the environment

Once odor is exceed into surround environment, it is possible that the environment quality of surrounding district will be decrease, the main environment quality will be decrease is air quality. It is possible that air pollutant Sulphur dioxide, Nitrogen dioxide, Ozone, Carbon monoxide and Lead are the culprit of poor air quality and odor. 

Apart from the pollutants mention above, a possible odor source is fugitive dust, respirable suspended particulates emit from construction, it is a possible odor source of point 1 of this project measurement because the Kai Tak Nullah improvement project include drilling and excavating are still processing when I conducted measurement at point 1. The drilling and excavating process are excavate the soil at river bed, particle emit when the drilling and excavating process are conduct, the soil was river bed sludge, sludge will emit odor, on the other hand, particle suspended will adsorb the odor emit from sludge and spread through air flow, expand the odor pollution scope and the air will become turbid. 

For the aspect of Sulphur Dioxide, it will involve excitability smell when the concentration of Sulphur Dioxide is high. Sulphur Dioxide will case acid rain, destroy crops and tree, damage forest habitat directly, some of the species will extinct when the original habitat was destroyed. 

For the aspect of Nitrogen Oxides, the main sources of Nitrogen Oxides will be power plant and vehicle emission. As same as Sulphur Dioxide, Nitrogen Oxides will also case acid rain. Nitrogen Oxides is the main ingredient of Photochemical smog, it will react will organic compound under sunshine, construct ozone, which will decrease photosynthesis, impact to the normal growth of plants.

5.5. Possible use of BS EN 16841-1:2016 Grid Method in Hong Kong

In Hong Kong, there are a numerous kinds of facilities will exhaust odor, include: amenities like markets, public toilet, refuse collection point, petrol etc. It is effective to utilize Grid Method to measurement odor if the facilities mention above are locate in or near the measuring grid. So, Grid Method in Hong Kong can use to monitoring the odor pollution situation of the district which near the pollution sources like the facilities mention above. Usually, the monitoring content will be include the change of odor pollution situation through different months, seasons of relate district, to estimate the odor pollution problem of relate district in the future. 

There are some aims to conduct Grid Method and get the data of odor pollution situation, like to set the law to enforce the facilities which exhaust odor to reduce the odor emission and town planning for better environment. For the aspect of law enforcement, utilize Grid Method can discover the possible odor sources and the frequency of odor exhaust of relate odor sources, it is helpful to government to set up policies or law to restrict the activities that will occur odor pollution. For example of the district of this project measure, there are having facilities which will occur odor like public toilet, refuse collection point and petrol filling station belongs to the category of amenities near or inside the scope of measuring grid (Figure 2.1-2.3). Pollution problem not only influent to the scope of measuring grid, but also the adjacent community. Once the result measure by Grid Method are get by government, government can recognize the possible odor sources and estimate the relate activities that will occur odor, government can establish law or policies to restrict, enforce the organization which manage the facilities which occur odor to reduce emit odor.

There are the example of the department of Hong Kong government to implement policies to control the influent of odor to residents. The Environment Protection Department had implemented an policy named “Waste Diversion Plan”, due to  implement this policy , Environment Protection Department had minimized the impact to the residents near the refuse transfer station under waste diversion plan, the main  measures of “Waste Diversion Plan” were allocate the amount of waste received from each waste transfer station and landfill to make good use of waste treatment facilities with remaining disposal capacity and reduce the impact of waste diversion on the community environment .On the other hand, “Waste Diversion Plan” had also improve the waste treatment facilities inside the refuse transfer station to upgrade the operation effectiveness include to reduce the time of dumping waste of garbage trucks to reduce the odor exceed , in general , the process of dumping waste by garbage truck can finish in 30 minutes. The odor control facilities inside refuse transfer station were also upgrade under “Waste Diversion Plan” ,improve air purification equipment and install air curtain doors to further reduce odor emissions , the staff of the station will conduct three odor inspections every day, and there will be three independent inspections by independent consultants every week, so the odor manage performance can fulfil the requirement of contract. 

On the other hand, the aim of use Grid Method in Hong Kong will be implement town planning for better environment to think for the health of residents. It is mention above that Grid Method can utilize to detect the odor source, Grid Method can also use to determine which facilities are usually emit odor to surround community and have a high risk to hazard to the health of residents nearby, so in town planning, determine the  location of odor facilities can avoid the main community facilities like residential, schools, community centre etc. to build near odor facilities, impact the health and quality of life of residents . It’s not a very good town planning in the view of distribution of odor facilities with the main community facilities near the district of measuring grid (Figure 2.1-2.3) because there are still numerous of odor facilities (public toilet, refuse collection point and petrol filling station) located next to the main housing complex like Tung Tau Estate, Kai Tak Garden, Lower Wong Tai Sin Estate etc. ,but there are still serval parkway located between odor facilities and main housing complexs. Odor exceed from odor facilities will impact to the quality of life and health of residents to a certain extent like respiratory system, digestive system , mental health.

It is suggested that the buffer zone or parkway should locate between odor facilities and community facilities in the aspect of town planning to decrease the impact to residents. 

 

Figure 2.1: Distribution of public toilet 

 

Figure 2.2: Distribution of refuse collection point

 

Figure 2.3: Distribution of petrol filling station 

6. Appendix

6.1. Log sheet