The degree of air pollution problem depended on the kinds of sources, number of sources and quantities of air pollutants level emitted from each source. Industries are the important sources of air pollutants. Prevention and mitigation of these air pollution problem are best done at the emission sources. For reducing the quantities of air pollutants level from the sources, we need the data of emission sources; number; type and location; and the data on air pollutants which emitted from the sources; kinds and quantities.

Those data which concerned emission sources should be collected in emission database inventory. This database can be used as a tool for planning on prevention and mitigation of air pollution problem. The study areas covered 10 provinces as follows : Chiang Mai, Chon Buri, Kanchanaburi, Khon Kaen, Lampang, Nakhon Ratchasima, Ratchaburi, Rayong, Saraburi, Songkhla and 3 pollution control zones : Phuket, Pattaya, and Had Yai.

Industrial source inventory includes industrial plants, incinerators, power plants, oil and gas refineries. The study areas are rural in nature, and the type of industry falls mainly into agro-industry (converting farm products into marketable products). Most of the industrial plants surveyed use very little amount of fuel, with the exception of the power plants and cement factories. Based on discussions with the provincial authority the air pollution problem is mainly from dust and odors, while traditional pollutants such as sulfur dioxide and oxides of nitrogen are of minor importance in their opinion. As there are no quantitative emission inventory possible for odors, this study attempts to identify the problem in qualitative manner, such as addressing the problem of specific types of industry which have certain problem.

The list of industrial plants in the 12 study areas was obtained from Ministry of Industry. The number for each area is in Table 1. The types of industry are all in Category 3 according to the Factory Act (1992) that are believed to cause air pollution are as follow (type of industry, type of air pollutants, and the general observation based on the surveys).

Table1 Number of Factories by Provinces, Year 1994

Rice Mills
Chiang Mai887649 1,536
Chonburi2731,192 1,456
Kanchanaburi2001,036 1,236
Khon Khaen1,395805 2,200
Lampang1,065656 1,721
Nakhon Ratchasima2,3032,0044,307
Phuket8289 297
Ratchaburi260938 1,198
Rayong228804 1,032
Saraburi222590 812
Songkhla514775 17,093
Study Area7,3559,738 1,289
BMR74839,014 32,294
Thailand44,56059,014 103,574

Grain processing/storage
Main Pollutants: dust and combustion pollutants
The plants in this category are mainly silos and rice mills. The main air pollution sources are from transport of grain, the use of rice husks and shell to produce energy which can cause black smoke.
Main Pollutants: dust and combustion pollutants
Incinerators are found in industrial estates but in the study area on Saraburi, Chon Buri and Rayong have industrial estates with incinerators. Most of them are 500 kg/hr capacity but each estate have several of them. All of them are multi chamber type, using diesel oil and have air pollution test records which were found to be very clean operation. The hospitals in each province have at least one incinerator but were found to be rarely used.
Canning Industry
Main Pollutants: combustion pollutants, odors
Canning industry is for local agricultural product and is seasonal in nature. The boiling of agricultural product was found to consume small amount of fuel, and the odor is mainly from wastewater.
 Edible oil extraction
Main Pollutants: combustion pollutants, odors
Air pollution associated with this industry is mainly odor from wastewater. Fuel oil is used to generate the steam. There are very few factories in the study areas.
Food additives/Bakeries
Main Pollutants: combustion pollutants, odors
Fishmeal and bonemeal
Main Pollutants: dust, odor, combustion pollutants
According to the survey and discussion with provincial official, this type of factories has not generated much complaints on odors because the provinces, such as Chonburi and Rayong, have been successful in relocation of these plants to appropriate areas. The quality of operation, such as using fresh fish, has been successful that the problem of odors has been subsiding.
Main Pollutants: combustion pollutants
Textile plants are usually very large consumers of fuel oil, but in the study area most of them are local, such as silk spinning and are small operation.
Pulp and paper
Main Pollutants: combustion pollutants, odors
Only few plants are in the study area. The problem is mainly characteristic odors.
Main Pollutants: dust, combustion pollutants, odors
Tapioca pelletization factories are most numerous of all sources. The common cause of air pollution is odors, as dust problem has subsided due to better control. The main problem is now tapioca flour industry with wastewater odors. The whiskey industry also has the problem of odor from its wastewater treatment plants. Tobacco curing industry has been found to decline drastically in the North, with the closure of more than 80% of the curing houses, which used to cause air pollution due to the use of lignite.
Plastics and Chemicals
Main Pollutants: combustion products, odors
This type of industry is found exclusively in Rayong. As the factories are in industrial estates, there are no complaints of air pollution.
Oil refineries
Main Pollutants: dust, combustion products, odors
The major emissions are mainly sulfur dioxide and oxides of nitrogen, as well as hydrocarbons.
Main Pollutants: dust, combustion products
Ceramic industry based on this survey uses mainly LPG as fuel. Some of them still use firewood for low quality ceramics.
Main Pollutants: dust, combustion products
Glass factories use fuel oil is the cause of emissions.
Main Pollutant dust
Rock crushing plants cause severe dust problem.
Main Pollutants: dust, smelting products, combustion pollutants
All of them have baghouses as pollution control.
Machinery production
Main Pollutants: odors, combustion pollutants
This includes car and bus manufactures. The problem is volatile material used in paints.
Power generation
Main Pollutants: combustion pollutants, dust
Gas Separation
Main Pollutants: odors, combustion pollutants
The industrial plants above must be of registered capital more than 10 million baht and have more than 100 horsepower. This is to screen the small sources out due to the importance of the emission sources as compared to the overall emissions. The questionnaire was sent to each factory listed. The reply was processed individually to check for quality and reliability of information.
Calculation and estimation of emission factors was based on US.EPA; Document AP-42, Compilations of Air Pollutants Emission Factors. The sulfur in fuel oil is set at 2.5% and diesel oil at 0.5%. Emission from large sources are from:

a. As reported by monitoring results of the sources.

b. As submitted in the EIA reports.

c. As calculated from the questionnaires return.

Non-combustion pollutants such as volatile materials are filed separately and the information is mainly from the sources. The emissions factors in AP-42 also were used to compile the results and compared with the information from the sources, such as the steel and cement industry.

The emission database from stationery sources aims for majority of the air pollutants generated in the study area. This is usually performed, in the case of industrial fuels, to account for at least 80% of the fuel sales. In this study it was found that the amount of fuel sales are very small and the users are many small users, as well as the fact that fuels sold in one province can be used in other nearby provinces, as in the case of Chon Buri, that there is no likely chance to obtain the real fuel use figures for the study area.

Discussion by Locations

Pattaya has no large point source on the list. Confirmation with the officials of Pattya City confirmed that there is no industrial factory in the city which causes air pollution and nuisances to the people.
The major air pollution sources according to the industrial office is dust from rock crushing plants. According to the officers, the plants were ordered to spray the crushing mills with water, which is effective, but the majority of dust observed to be from road surface. There are no complaints at the province's largest industrial community.
The concern of provincial official is on tapioca flour plants which is caused by odors from wastewater treatment plants. The para rubber wood factories also create local problem with the odors from curing solution.
The air pollution problem is mainly odors form tapioca flour production, mainly from wastewater treatment.
Air pollution of the province, as concerned by the provincial authority is caused by odors from pulp and paper mill. Sugar mills operate 6 months per year and are located in rural area.
The major air pollution problems in the province are dust from cement plants and from rock crushing plants.
The major air pollution from industry is odors from feedmills and dust from rock crushing plants.
The major air pollution is dust from rock crushing plants and odors from tapioca flour plants. Sugar plants are usually equipped with cyclones and operated for about 6 month/year. They are located far away from the large communities.
Chiang Mai has the largest number of tobacco curing plants, but most of them were out of business during the past few years. The remaining industry is mixed, ranging from agro-industry to ceramics.
Lampang has the largest emission sources. The plants use lignite and the problem with sulfur dioxide has been evidenced in some winters.
The only large industrial plant is the tin smelting plant which has very good air pollution control.
A number of fish meal, rubber, and seafood processing plants are in the coastal region of the province. Air Pollution problem is mainly from odors.

Emission from Industrial Sources
Emission from industrial sources can be calculated from either top-down approach or bottom-up approach used the provincial fuel consumption data (Table 2). The bottom-up approach used each factory fuel consumption data obtained from the survey. The calculated emissions were shown in Table 3 and 4, respectively.

Table 2 Petroleum Consumption by Manufacturing Sector by Location (1994)

Fuel Consumption (1,000 liters)
Chiang Mai20,1071,534,074 7611,610 5071,485 7,80613,621
Chonburi4,363948,165 21714,781 2,2962,00419,713 1,937,861
Kanchanaburi 19,483724,18337 2,739486524 6,16410,740
Khon Khaen10,8861,336,519 1235,139 162784 17,77723,952
Lampang12,534797,846 646,760 264734 6,0361,721
Nakhon Ratchasima 20,4942,431,500119 7,8092,5161,119 15,5349,448
Phuket543194,178 3582,306 164534 4,5556,074
Ratchaburi5,196783,286 1515,496 394494 4,26128,460
Rayong3,552463,738 1314,147 4,2596439,210 26,011
Saraburi3,576558,073 1565,599 146396 8,730310,427
Songkhla7,3491,125,905 15210,628 2,2611,13010,076 18,012
Study Area108,12910,897,467 10177,013 13,4549,846109,863 2,386,328
BMR7,778 8,780,8551,129220,540 35,70326,760162,746 4,244,071
Thailand513,11559,095,319 115407,658 61,67552482470,096 6,992,001
Population density in persons/km2.   Area in km2

Table 3 Emission from Manufacturing Sector by Location (1994)

Total Emission
Chiang Mai74 915562 60810
Chonburi5,934 110,80613,946 2752,357
Kanchanaburi58 718428 37334
Khon Khaen144 1,6701,174 94604
Lampang30 204369 39424
Nakhon Ratchasima92 813965 90728
Phuket37 423306 30316
Ratchaburi104 1,697435 30308
Rayong117 1,6545,371 55436
Saraburi973 17,8412,552 71482
Songkhla96 1,208717 66673
Study Area7,659 137,94926,824 8477,470
BMR13,500 244,13837,829 1,51017,049
Thailand23,062 406,91873,864 3,54434,914
Units in Tons.

Table 4 Emission from Industrial Sources, 1994

Chiang Mai28 534717 17692 771
Chonburi35 21,4772,914 4,547157 1,715
Kanchanaburi43 19,67914,555 3,6562,239 6,699
Khon Khaen15 9826 6331 469
Lampang7 101,095 11959 371
Nakhon Ratchasima15 10688 245 32
Phuket3 14<1 2<1 <1
Ratchaburi60 20,43112,414 3,4771,538 7,210
Rayong126 44,8804,685 26,560856 4,609
Saraburi109 37,36060 2,85015 11,035
Songkhla15 1,5773 370<1 318

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