Abstract

This paper reviews the state of air quality in Ho Chi Minh City as conducted by several organisations in recent years. A comparison of the air quality in HCM City with some other cities in the region is also made. It is shown that the air quality of both indoor and outdoor (ambient) has been deteriorated in recent years. This is mainly due to the increase in the usage of vehicles and an increasing number of industries in and around the city.

Compared with other cities, such as Beijing, Tokyo, Bangkok and Manila, the level of SO2 pollution is below those of these cities while the levels of CO and NO2 are approaching the levels of these cities. In the case of particle pollution, the peak particle level at some heavy traffic sites in HCM City is very high and exceeds those of Bangkok and Manila. The lead pollution is less than that of Bangkok. However, the lead level will be rapidly increasing unless concrete action is implemented.

Experiences of other cities in the area of environment management can be applied to prevent serious degradation of air quality in the city. Suggestion for some measures that can be incorporated quickly into an integrated air quality and transport management plan is presented.

Introduction

Ho Chi Minh (HCM) City is a major city in Vietnam with a population of 4.7 millions (1994) with a natural growth rate of 1.49%, not counting migrants (mainly from the country areas) and temporary residents. It has an area of about 2,056 km and an average density of 2,282 inhabitants/ km . The tropical climate has a yearly average temperature of 27 C and relative humidity of 77.8% (1).

As in other bustling and growing cities in the region, the main contribution of air pollution is from motor vehicles. Besides motor vehicles, industrial sources in the city and surrounding areas of Dong Nai province are also contributing to the air pollution problem especially in the residential areas around these sources.

As projected, with an estimated annual population growth rate of 1.63 percent, the population of the city will easily exceed 5 millions in the year 2000. This means the city is in the category of supercities. Eventhough, it is still not in the league of megacities, such as those of Bangkok, Jakarta, Beijing or Manila, the high economic growth in recent years has accompanied a rapid degradation of environment quality. Frequent visitors to the city are usually struck by the rapid increasing of congestion and the amount of traffic in many streets, reminiscing of the situation in Bangkok in the 80s.

Due to an increase level of air pollution in the city, a number of organisations in the city have recently conducted some initial studies of air quality and the effects of air pollution on the population. Permanent monitoring stations are not yet established but data are collected occasionally, for a number of days, at a number of sites in the city. These sites are mainly near heavy traffic roads. The collected data are not yet comprehensive to give an overall picture but is indicative enough to give some information on the state of air quality in HCM City.

Air Pollution due to motor vehicles

Recent data measured from a number of monitoring stations operated by the Center for Environmental Technology and Management (CEFINEA) of Ho Chi Minh University of Technology has been available and published (1)(3)(5). These data show that many air pollutants such as CO, NO2, particles have concentrations exceeded the standard levels. The noise level is also persistent high.

During one particular day on the 25/04/1996, the data measured from the intersection of Dinh Tien Hoang and Dien Bien Phu streets shows that the maximum hourly concentration of particles is 3.6 mg/m3 , 12 times the current Vietnamese standard (3).

The concentration of CO measured on 25/04/1996 is 62.65mg/m3, 1.5 above the standard. Similarly, the NO2 concentration measured on 23/04/1996 exceeds the standard 1.5 times. The average noise level is between 76 to 86 dBA with a peak of 98dBA while the standard for residential area is 60dBA (3).

The air pollution in the city is overwhelmingly due to motor vehicles. In 1996, the city has more than 1.1 million, of which motor cycles are more than 1 million. In 1997, there are about 1.1 million motor cycles and 101,000 cars. In 1997 statistical collection, each month, there are more than 1,000 are added to the city traffic. The vehicles currently use mainly leaded petrol. The following table shows the breakdown of different types of vehicles registered in 1997.

Types	Number
Trucks	14,073
Company-operated buses	591
Vans and small trucks	1,082
Small buses	1,601
Cars	194,777
Standard car taxis	2,712
Three-wheeled taxis	1,935
Motorcycles	1,288,754

Table 1 – Vehicle statistics (1997)
Source: Institute of Tropical Technology and Environment, HCM City

At the end of 1999, the records at the Office of Land Traffic Police (Phong Canh Sat Giao Thong Duong Bo) in Ho Chi Minh City show that there was 1,681,760 registered motorcycles, and 3-wheeled motorcycles (32) which is about 9.3 times the number in 1975. While the numbers of non-motorised transport vehicles such as bicycles and 3-wheeled cycles (“xich lo”) were more than 2 millions and 60,000 respectively. The upgrade of roads and building of new ones does not keep pace with the growth of motorcycle density. The road availability decreases from 5m2 for each motorcycle in 1975 to about 1m2 in 2000.

Since 2000, with the introduction of low-cost affordable motorcycles imported from China to Vietnam, the number of new motorcycles increases dramatically. In the first 9 months of 2000, the number of imported motorcycles is 935,6000, 2/3 of which is from China. At the beginning of 2000, the Office of Land Traffic Police reported that there was about 8,000 new motorcycles registering each month (32). But, from May 2000, that number increases 3 times when the imported Chinese motorcycles began dominating the sale of new motorcycles. In September 2000, each day the number of new registered motorcycles is about 1,300 to 1,4000. This rapid rise has an adverse impact on the traffic situation in the City, with more severe congestion occurring throughout the main traffic nodes in the city. There are more than 60 such nodes in the city. At the end of 2000, it is estimated that there are more than 1.9 million motorcycles in the city.

In one study (1), approximately 200,000 tons of petrol fuel and 190,000 tons of diesel fuel are consumed each year. The emission into the airshed is about 2,200 tons of SO2, and 25 tons of lead.

The economic growth in the past ten years reflects in the increasing large number of vehicles. During peak traffic period, on Cach Mang Thang Tam Street, the vehicle density count is 10,000 per hour compared to 5,800 per hour in 1990 and only 2,800 per hour in 1985 (1). The growth of traffic however is not matched by the upgrade and the construction of new roads. In 1994, the traffic density in some of the congested streets are presented in Table 2 (1)

Name of Street	Traffic Density (quantity/hour)
Ba Thang Hai	13,000
Tran Hung Dao	12,500
Hung Vuong	10,015
Ly Thuong Kiet	11,306

Table 2 – Traffic density at some streets

In 1980, the hourly average particle level from traffic streets is about 3 to 3.1 mg/m3 during wet rainy season and about 3.2 to 3.4 mg/m3 during dry season. However, in 1990, at the same locations, the hourly average level increases to 5 - 5.1 mg/m3 during wet season and 7.8 - 8 mg/m3 during dry season. The corresponding increase for SO2 is from 0.8 mg/m3 to 0.97 mg/m3 (3).

A recent study by CENIFEA (1), on the daily variation of some air pollutant concentration due to air traffic emission shows the following results:

(1) For CO, the daily average concentration at significant traffic crossings is between 2 to 10 mg/m3 with the maximum hourly value up to 23.3 mg/m3.

(2) The NO2 daily average concentration is between 0.05 to 0.25 mg/m3. The peak hourly value can reach 0.726 mg/m3 at Dinh Tien Hoang-Dien Bien Phu street and 0.6 mg/m3 at Hang Xanh roundabout.

(3) Dust particle concentration ranges from 0.8 to 15 mg/m3, at various times of the day, with the maximum concentration of 37 mg/m3 measured at the crossing of Dinh Tien Hoang and Dien Bien Phu streets on the 15 March 1995.

(4) Lead concentration at a number of sites varies between ~0 to 0.41 mg/m3 at various time of the day. The ratio of lead-contained samples and total analysed samples is low.

(5) The air pollutant concentration varies depending on the month due to seasonal effects. At the Minh Phung - Hau Giang crossing, the monthly average concentration for CO is 0.06 to 4 mg/m3, for NO2 0.05 to 0.3 mg/m3 and TSP 0.4 to 1 mg/m3. In the dry season, the average concentration is 2-3 times higher that that in the rainy season.

Recent annual trend result from roadsite monitoring at Hang Xanh, a major traffic node in the north east of the city (33) is shown below. Particles and lead annual average concentrations are many times above the WHO standard for all years from 1997 to 2000.

	Carbon Monoxide (CO) mg/m3	Total Suspended Particulate (TSP) mg/m3	Lead (Pb) microgram/m3	Nitrogen dioxides (NO2) mg/m3
1997	9.85	0.55	2.5	0.097
1998	6.88	0.73	2.5	0.119
1999	6.94	0.99	2.5	0.122
2000	7.99	0.96	2.4	0.139
WHO Standard (annual average)		0.06-0.09	0.5-1

Table 3 – Annual average concentration at Hang Xanh

In 2000, four new fixed continuous monitoring stations were set up at a number of urban non-roadside sites. The first monitoring data obtained is shown in Table 4 below

Monitoring stations	Air pollutant concentrations (mg/m3)
	TSP	SO2	NO2	CO	O3
HCMC DOSTE	0.08-1.1	0.01-0.10	0.02-0.13	0.0-20
Hong bang Secondary school, District 5	0.08-1.06	0.02-0.11	0.03-0.14	0.0-25
Thu Duc Urban Management Department	0.08-1.2	0.05-0.17	0.0-0.05
Tan Son Hoa Meteorological station	0.08-1.2		0.0-0.07	0.0-4.0	0.0-0.15
Vietnam ambient air standard (1 hour)	0.3	0.5	0.4	40	0.2

Table 4 - Air quality monitoring data from 5 to 11 May 2000 (34)

Air pollution due to industrial sources

Industries also contribute significantly to the pollution especially for areas near the sources. Many of these sources are small factories and the indoor pollutant levels inside these sources are very high. There are 700 large industrial sources and about 24,000 small-scale factories in and around the city. The large industrial sources are mainly concentrated in Nha Be and Thu Duc areas. The small factories, mainly family business, are scattered in all districts with the largest concentration is in the District 5, 6, 11 and Tan Binh (1).

Almost all of these sources are located in residential areas. Many of the types of equipment and technology are old and have been in operation for more than 10 years. Some of them are more than 25 years old and are not fitted with any pollution control devices (1). A survey conducted recently, shows many foreign joint-ventured factories operated with outdated imported equipment causing considerable environmental pollution (14).

Investigation by the Center for Environmental Technology and Management (CENIFEA) (1) shows that the total dust concentration (Total Suspended Particulate, TSP) is very high in the indoor environment of almost all industry types especially in the construction material and metallurgy industries.

The total emission of pollutants to the airshed due to fuel consumption of all industries each year is 30,000 tons of SO2, 5,750 tons of NO2 and 1,650 tons of particulate. In addition, the metallurgy industry produces between 2,840 to 4,260 tons of particulate and between 994 to 1,420 tons of CO per year (1).

In 1995, of 43 company factories on the black list, 30 % of these are in Thu Duc, an industrial growth area in the north, near HCM City. Two major companies, Posvina and PS (toothpaste production), are emitting large quantity of acid gases each day to the surrounding residential areas (5). Residents complained about the pollution effect of these sources and was reflected in the media such as against the factory operated by the noodle company, Miliket. In HCM City suburb of Tan Binh, the steel work factory operated by Southern Steel Corporation ( Cong ty Thep mien Nam) is also a target of complain (4).

The ambient air pollutant concentrations of some pollutants around some industrial sources are shown in Table 5 (1). A number of them, such as the Tan Binh steel work and the Miliket noodle company, exceeds the ambient standards for dust, SO2 or NO2.

No	Industry and sampling site	Dust (TSP)	SO2	CO	NO2	Others
1	Chana textile - Outside factory, distance 25 m	0.18	0.142	0.08
2	Phuong Dong detergent- Outside factory, distance of 15m	0.4	0.42	0.3
3	Quan khu 7 Cement Outside factory, distance of 40m Outside factory, distance of 120m	0.8 0.4	0.26 0.22	0.055 0.022	1.78 0.66
4	Tan Binh metallurgy Outside, distance of 40m Administrative area	0.51 1.3	0.76 0.36	0.4 0.154
5	Nha Be metallurgy - Administration area	0.3		0.277
6	Miliket instant noodle -Outside	0.7	0.35	0.1	3	HC: 15
	Standard (daily average)	0.2	0.3	5	0.1

Table 5 - Air pollutant concentration outside some industries in HCM City (in mg/m3)

Each year, since 1996, more industrial parks are opened in the north, Thu Duc-Bien Hoa area, in the south, Nha Be (South Saigon) and recently in the north-east, Hoc Mon area. All types of industry are established at these areas. These industries are operated all-year round. From the meteorological viewpoint, the location of the industrial parks is not conducive for the air pollutants to be dispersed quickly from the urban area of HCM City.

As measured at Tan Son Nhat meteorological station from 1952 to 1981, on average during the dry season, the dominant wind direction is from the north, south and southeast with wind speed ranging from 2.2m/s to 3.3m/s. During the rainy period, however, the wind direction is coming mainly from the west and southwest, with wind speed in the range of 3.3m/s to 3.7m/s.

The air quality is much improved due to the effect of the rain (as shown by the measurement at a number of monitoring stations in the city). The location of the industrial areas in the north and south of the city will have an adverse effect on the air quality in HCM City. It is more appropriate to locate industrial zones in the under-developed west and north-west areas of the city, such as Hoc Mon or Cu Chi. Recently, a few industries have been established but there is no priority in infrastructure investment in those areas.

Health effects of air pollution

It is known that some primary pollutants, such as particles (PM10 and PM2.5), nitrogen oxides, sulphur dioxide, carbon monoxide and secondary pollutant, such as ozone cause adverse effects on people health. This ranges from respiratory symptoms to diseases such as sinusitis, bronchitis and asthma. Particles have also been shown to cause an increase in the mortality rate. People with asthma and respiratory diseases are highly susceptible to particles, nitrogen oxides, sulphur dioxide and ozone. In addition, lead particles had serious effects on children development. Children with high lead levels are deficient in weight, tend to have low count of red blood cells. Their IQs are also lower than those with lower lead levels.

There is an extensive literature on the studies of health effects of air pollutants. Most of the studies are conducted in the developed countries such as the US, Germany. Recently, the results of the studies have been used to set up revised guideline and standard for many criterion pollutants such as ozone, carbon monoxide, particles (PM10 and PM2.5). The economic impact of air pollution and benefit of setting a lower level standard for particles is substantial (6).

In Vietnam and other regional countries, the health aspect of air pollution is now acknowledged as an important public health issue. Studies have been conducted and published. The results show an adverse effect on quality of people life exposed to high level of pollutants.

The health effect of air pollution on the traffic police officers was recently conducted by the Labour Protection Unit of HCM City (Phan Vien Bao Ho Lao Dong Tp HCM) (5). Due to long exposure of high levels of air and noise pollution, traffic police personnel suffer a tuberculosis rate of 2.9 % while the average rate is 0.075 %. The rate (presumably using yearly data) of nose, throat and ear infection is 76% while 32% of them has reduced hearing abilities.

There is currently no known studies, conducted by the health authorities in HCM City, on the effects of air pollution due to gaseous pollutants or particles on the asthma or death rate. In addition, the level of lead in blood due to vehicle emission is not known.

In Bangkok, Thailand, the traffic police reckon 40% of their number have chronic lung ailments. It is not unusual to see they have scarves or white clothes wrapped around their mouths and noses. A Public Health Ministry study (10) of 214 people who regularly use buses at a station found that 26% suffered ill effects from carbon monoxide (CO). These people were exposed to a CO level of 67 ppm (parts per million) against the standard of 10 ppm. This is not included the effects due to gaseous gases such as the highly toxic and mutagenic polycyclic aromatic hydrocarbons (PAH). A comprehensive study (10) of lead level in the blood of children has shown that, before the introduction of unleaded petrol in 1991, the average lead level was 17 micrograms/decilitre and reduced to 9.23 micrograms/decilitre in 1996. The acceptable level, as specified by the US Center of Disease Control, is 10 micrograms/decilitre.

A similar study, the Urban Air Project, conducted by the Philippines Department of Environment and Natural Resources (DENR) in 1994 showed that of a sample group of 170,000 people in the cities exposed to lead pollution and traffic: 762 (or 0.45 %) had varying degrees of coronary diseases and 91,207 (or more than 50%) suffered from hypertension. This study also showed that at least 39% of the lead pollution came from cars and 58% came from public utilities vehicles (17). In Jakarta, air pollution in industrial and heavy traffic areas has been identified as a significant contribution to the increased incidence of lung diseases (28).

A study, funded by the World Bank, on the effect of particulate pollution in Jakarta (30) has estimated that exposure of particulate concentration above the WHO standard caused an additional 1,200-2,300 deaths, 184,000-541,000 asthma attacks and 5.3-11.8 million lost work days in 1989.

In Kaohsiung (Taiwan), where the major source of air pollution is due to industries, a study (9) showed that people living within 3km of the industrial area have a 6-fold increase in the risk of lung cancer. It also showed an increase of 2-4 times the incidence in brain tumours for inhabitants close to a petrochemical plant and a higher rate of leukemia, and cancers of the lung, kidney, and urinary bladder. Other study (18) showed that school children in urban and industrial areas had significant more respiratory symptoms and diseases compared to those in the rural areas.

The higher level of sulphur dioxide in ambient air has been associated with higher mortality rate in Seoul, in which susceptible old people have higher risk of premature death (27). In Beijing, the high level of sulphur dioxide in winter was significantly associated with increased mortality. The risk of total mortality was estimated to increase by 11% with each doubling in sulphur dioxide concentration. The association with a doubling sulphur dioxide was significant for chronic obstructive disease (29%), pulmonary heart disease (19%) and cardiovascular disease (11%) (29).

Comparison with other regional cities

Comparing with other cities in the regions, which also experienced rapid economic growth in recent decades, the air pollution problem in HCM City is not as bad but rapidly becoming a serious problem unless some measures are taken.

As the population is rapidly increasing and the continuing growth of vehicle usage, the air pollution at some section of the city, especially near heavy traffic or highly congested road, will reach the level of those of high polluted cities in the region. In megacities, defined as cities having a population over 10 millions by the year 2000, such as Beijing, Bangkok, Jakarta and Manila, the present situation is already alarming.

In each country, the air quality standard is usually defined by the national environment organisation in that country. These standards are usually different from country to country. It is therefore more useful to compare the air quality based on the World Health Organisation (WHO) recommended goals. The different standards of some selected countries and the WHO goals are shown in Appendix 1.

It is difficult to compare the air quality of various cities using the average values measured at some specific locations as these locations may not be representative of the whole airshed region. The method of measurement can be very different in each country. Normally, a reference standard such as used by the US EPA is adopted but, more often than not, the instrumentation and quality assurance protocol is different. For example, during the author visit at one monitoring location in Ho Chi Minh City, the nitrogen oxide instrumentation were made in-house by CENIFEA (in 1998, CENIFEA was changed to Institute of Environment and Resources, IER). In addition, there were no calibration done on a daily basis. Furthermore, the population exposure to air pollutants are hard to measure. Nevertheless, it is informative to compare the air quality of some cities using values of the worst pollution events that happen at some locations in the concerned cities.

Particles

Total suspended particulate (TSP) pollution is reported (11) as serious in major cities in Asia, including Bangkok, Manila, Jakarta, Beijing, Seoul, Bombay and Calcutta.

The particulate level in Bangkok and Jakarta were so bad that the World Bank called for “immediate action” to tackle the problem (7)(16) in these two cities. One in six people in Bangkok now suffer from allergies because of the high level of particles in the air (7). The levels of particles at some traffic sites are very high. Measured hourly values have been reported as high as 2.18mg/m3 at one site (7). The annual average level, between 1980 to 1987, near the commercial centre of Jakarta is around 0.4-0.5mg/m3 (16) which is 8 times above the WHO annual goal.

In Manila, the daily average concentration of particles is 3 times the WHO and the Philippine standard level of 0.15 mg/m3 (15). The TSP level in Beijing is very high during winter season. This is due to the use of coal as the main source of heating and power generation. According to the National Environmental Protection Agency (NEPA) of China, the annual consumption of 33 million tons of coal in Beijing frequently reduces the visibility in the city to as little as a quarter mile (22). Ando et al (2) has reported that the 1991 monthly average value in Beijing is about 0.217 mg/m3 and the maximum hourly particle level around the residential area approaches a level of 0.8 mg/m3. Even during summer, as in 1985, the monthly particle level was approaching 0.2mg/m3. The statistics released recently by WHO a (22) show that in some of China’s larger cities, the annual average of suspended particulate is between 0.3 to 0.4 mg/m3.

There is little data on the measured particle levels in the residential areas of HCM City. At the four established continuous monitoring stations in 2000, the monitoring data for 5 to 11 May 2000 showed that the peak values at these stations exceeded the 1 hour national standard of 0.3mg/m3 by 4 times (34).

However, data from some heavy traffic sites showed that the average peak hourly value of TSP is of the order of 6mg/m3 (3). This is very high compared to the peak value of about 0.4mg/m3 measured at the main traffic roads in Tokyo (2). Away from street level, at one site measured from the top of an eight-storey building, the monthly average ranges from 75 to 150 mg/m3 for a period of 1993 to 1994 (19). Even at this site from the street, the annual average is already exceeding the annual WHO standard of 60-90 mg/m3.

The monthly average of TSP reaches 1mg/m3 during the dry season at one street crossing (1). From the monthly average value above, the daily average can be inferred to a value of the same order. This is about 6 times the WHO standard. The maximum hourly value of 15 mg/m3 was recorded at another street. This is much higher than the maximum level reported in Bangkok from traffic sites.

It is clear that particle air pollution due to vehicles is a serious problem in HCM City. It is significantly higher than the particle pollution due to traffic in some other cities such as Bangkok and Manila but is still less than those cities in China such as Beijing. Beside vehicle traffic, the recent construction boom at many sites in HCM City also contributes significantly to the level of particle pollution (24).

In contrast, for indoor environment in HCM City, the domestic fuel usage for cooking has been recently switched from oil and wood to cheaper natural gas. This contributes to a reduced particle and carbon monoxide exposure.

Fine particles (PM10 and PM2.5)

Fine particles are respirable components in the TSP. PM10 and PM2.5 are particulate matter with aerodynamic diameters less than 10mm and 2.5mm respectively. They are major sources of public health concerns. At the present, fine particles are not measured in many cities. We can infer some estimates of fine particle levels using data available in cities, which has similar emission characteristics.

As shown above, in Ho Chi Minh City, away from the street, at the site on the top of an eight-storey building, the TSP level is about 100 mg/m3 as measured by the Dalat Nuclear Research Institute (19). At this height, it can be assumed that most of TSP comes from PM10. If this site can be considered as a representative for the whole city, then the annual value for PM10 is of the order of 0.1 mg/m3. This is comparable to an annual average of 0.07mg/m3 measured in Taipei in 1994 (9).

In a recent preliminary study conducted jointly by the Korean Ministry of Environment and the US EPA (8), it has been reported that ultrafine particulate matter (PM2.5) daily average measured at two sites in Seoul were about 74 and 180 respectively. Roughly, 50% of PM-10 samples are made up of PM2.5. That means the level of TSP including fine particles PM10 and PM2.5 can reach up to 1mg/m3. The WHO standard for fine particles PM10 is 0.07mg/m3.

A detailed study of the fine particle level in Jakarta by the Indonesian Environment Impact Management Agency with Ausaid help (16), has shown that the monthly average level of PM10 in centre of Jakarta is between 0.04 mg/m3 in the wet season to 0.08 mg/m3 in the dry season. The maximum daily average measured can reach a value of 0.14 mg/m3. For fine particle PM2.5, the monthly average level is between 0.02mg/m3 (set season) to 0.04 mg/m3 (dry season).

If this data is extrapolated to other cities (such as Ho Chi Minh City which has a high proportion of motor cycles and 3-wheels vehicles like in Jakarta), it is clear that all major cities in the region including HCM City has fine particle levels exceeding many times the WHO goal for PM10. The latest statistics released by WHO in 1998 shows that the annual mean concentration of PM-10 in Southeast Asia range between 0.1 to 0.3 mg/m3 (22).

Lead

The daily measured lead concentration measured at various sites in HCM City has been reported to contain lead concentration from trace value ~0 up to 0.41mg/m3 (1). The daily average at some sites could therefore be very high. It is likely that the yearly averages for a number of sites could exceed the WHO annual goal. At the most heavily traffic site, Hang Xanh roundabout, the measured annual average concentrations (1997, 1998, 1999 and 2000) are more than 2 times above the annual WHO standard (33).

However, at one particular site, as measured by Dalat Nuclear Research Institute, for the period of 1993-1994, the monthly average lead concentration measured for the dry season is 0.199 mg/m3 and 0.159 mg/m3 in the rainy season (19). The annual average at this site is ~0.18 mg/m3 which is below the annual WHO goal.

This level is still high but , however, is not as bad as in Bangkok. In Yaowarat area, the annual lead level was recorded at 0.96 mg/m3 in 1996 (10) even long after the introduction of the unleaded petrol in 1991. Before 1991, the lead level was as high as 2.34mg/m3. Other cities also recorded high level of lead concentration, such as Manila where the annual lead level exceeds the WHO goal (15) and Lahore in Pakistan where the annual average lead concentration at traffic sites is 0.004mg/m3, 3 times the recommended WHO goal (12).

It is expected that the lead pollution in HCM City is getting worse unless the government authority introduce the use of unleaded petrol.

Sulphur dioxides

Currently, as reported by WHO, Beijing and Seoul has serious SO2 pollution. The WHO guidelines are often exceeded by more than a factor of two (11). In Beijing, coal-fired power stations and the use of coal for domestic heating contribute significantly to SO2 pollution in winter. In one study (2) conducted in Dec. 1991, the measured monthly average ambient SO2 concentration in residential area was 0.233 mg/m3 which was about 5 times of that measured around main roads in Tokyo. The extensive use of coal for energy in China has produce serious sulphur dioxide and carbon dioxide pollution in many major cities of China. It also causes acid rain problem even in neighbouring countries of Korea, Japan, Taiwan and Philippine (13).

Ho Chi Minh City does not have SO2 problem as the main SO2 sources are only some large factories located in the Thu Duc area. The main power source is from hydroelectricity and most domestic usage is from natural gas or electricity. However, the concentration level near some traffic sites and industries are very high. For example, outside Tan Binh factory, the measured maximum hourly concentration is 0.76mg/m3 at 40m (1), two times higher than the WHO guideline standard.

Nitrogen oxides

From the data measured by CENIFEA (1), the level of nitrogen oxides at some traffic sites in HCM City is very high.

The monthly average, for December 1991, of NO2 measured at various main roads in Tokyo is ~0.111 mg/m3. In Beijing, for the same period, the ambient monthly average concentration recorded in the residential area is about 0.07mg/m3 (2).

From the range of daily averages measured at a number of sites in HCM City, a monthly average of about 0.15 mg/m3 can be inferred. This value is about the same order as that measured in Tokyo. This suggested that the main causes of this high level be due to some highly congested roads and the poor emission control of the vehicle exhaust system. At urban sites, far from roadside traffic, the measured hourly data from the new fixed continuous monitoring stations however is less than the national standard (34).

Carbon monoxide

The main source of CO pollution is from motor vehicles, especially older vehicles without catalytic converter. The more the number of motor vehicles, the more the CO pollution is. In Bangkok, the daily average measured concentration of ambient CO at a number of roadside stations is between 8.9 to 20.35 mg/m3. In one public health study (10) conducted recently at a bus station, people were shown to be exposed to the hourly average concentration of 80mg/m3 of CO.

In HCM City, the hourly value, recorded at a number of traffic sites by CENIFEA (1), ranges from 0 to 23.3 mg/m3. However, on 25/4/1996, the maximum hourly value of CO was measured at 62.65 mg/m3, which is 1.5 times above the standard. Data from the new fixed continuous monitoring stations showed that the hourly value ranges from 0 to 25mg/m3 (34). It can be said the CO pollution in HCM is now approaching the level of Bangkok.

Ozone

Ozone is a secondary pollutant formed, in the presence of strong sunlight, from the reaction of oxygen with nitrogen oxides and hydrocarbon emitted mainly from motor vehicles. Smog, the combination of ozone and nitrogen oxides, is the most frequent gaseous type of air pollution in summer. In many cities in Asia, it is usual to have both particle pollution and smog happen at the same time.

Ozone pollution is frequently recorded as very high in Hong Kong and Taipei. Although ozone is not usually measured in Manila, Bangkok or Jakarta, ozone pollution is expected to be very high in these cities. The emission of motor vehicles without catalytic converters and the presence of strong sunlight for most hours of the day make the smog formation and the ozone concentration very likely to exceed the WHO standard. It is expected therefore that the smog level in HCM City be of the same level as that of other cities as the meteorological conditions and the emission characteristics are of similar nature.

Current measures and responses

The government has recognised the pollution problems causing rapid deterioration of the environment in recent years. After the Environment Law was adopted in 1994, on 26-04-1995, the Government issued a procedure to prosecute all cases of environment violation. In July 1995, the People Committee of HCM City has ordered the Department of Science, Technology and Environment (DOSTE, So Cong nghe va Moi truong) to conduct an inventory and inspection of all industrial air pollution sources in the city. Sources which has serious environment effects in relation to air, water and noise to the surrounding residents were asked to improve or risked of having the sites closed. There were 93 worst polluters listed in a black list publication. Some companies were forced to shut down temporarily, including MSG producer Vedan and processed meat manufacture Vissan (20).

The authority also started to move factories, especially those in the rubber, plastic, paper and detergent industries, to the industrial zones outside the city, mostly in Dong Nai province. This policy is in line with government regulations on industrial, export processing and high-tech zones. Currently there are 10 industrial parks in Dong Nai province.

In the area of environment management, recently the UN Development Program (UNDP) also provides a 1.12 million US dollars in a project called Capacity 21 Trust Fund to help the government to introduce environment issues in the development policies. This follows similar programs conducted before in China and India. To address the growing problem in Bien Hoa industrial area of the nearby province of Dong Nai, with roughly half of the factories having outdated emission control, the UNDP also has estimated that almost $1 billion US for clean up and waste reduction is required. Another related UNDP project is to convert some industrial processes (especially in cosmetics) to new processes for the protection of the ozone layer.

In 1995, the Chamber of Commerce and Industries of Vietnam, with sponsors from World Wildlife Fund (WWF) and UN Development Program (UNDP), has organised a conference “Commercial development and Environment”. Many environment specialists have reported an alarming situation of environment pollution in many cities of Vietnam especially in HCM City. Besides air pollution, water and ground water pollution as well as waste pollution is now a serious problem that has to be tackled.

In Ho Chi Minh City, the government also actively implements the policy of moving houses near the creeks and canals. The policy encourages people to move to new places to protect the water and air quality as well as the hygiene of city living. Between 30 and 50 % of these areas are converted to park land with more tree coverage to provide fresh and clean environment to the city residents to escape the sultry weather and bad air quality. A number of ‘Green day’ and ‘Green week’ has been initiated with the participation of youth organisations to raise the awareness of environment in the population (5). In 1994, the government prohibited the production and the use of firecracker during New Year festivities. This leads to less level of lead and sulfur dioxides in ambient air during the festival months (usually January or February) (19).

On the issue of air pollution, a plan to set up a number of permanent air quality monitoring stations in HCM City and others in the Southern provinces has been actively pursued. More importantly, the HCM People Committee, in March 1996, announced the order to enforce the emission compliance of on-road vehicles (3). Since then, the traffic police department has conducted regular enforcement throughout the city. In the “Clean and Green” week, 12-19/5/96, 410 vehicles were booked for emission offence. In 2000, the city authority initiated a program to replace the old three-wheeled smoky “lambretta” with newer minibus by helping the owners and members of the lambretta cooperative in a deferred payment scheme. The lambretta are notorious as sources of highly polluting emission in the city.

The Ministry of Science Technology and Environment (MOSTE) currently has a plan to set up some permanent environment monitoring stations (EMS) in many cities, especially in Hanoi, HaiPhong and Da Nang, with help from other countries such as Canada. In HCM City, the HCM University of Technology has assisted in this effort by providing some technical help and evaluation. In 2000, the Department of Science, Technology and Environment (DOSTE) of HCM City has set up, for the first time, four fixed continuous monitoring stations as part of an UNDP Project (VIE/96/023) funded by the Danish Government (34). Additional five more fixed continuous monitoring stations will be established via another project funded by the Norwegian Government.

For air pollution, traffic flow and transport management is mostly important in containing the problem. The Department of Transport in HCM city had put a proposal to the People’s Committee to increase traffic flow at cross-road of 12-16m width by building tunnel at 4.5-5m depth and 8—8.5m wide. It is proposed that the first tunnel is to be built at the intersection of Nam Ky Khoi Nghia and Tran Huy Lieu streets. Traffic flow should be much improved if they are implemented. A feasibility study to build a traffic light centre has been completed in 1998. This centre will be able to control 48 routes and cross roads. A camera system at 4 crossroads and 48 traffic light columns in several city districts is also to be implemented. The complete system is being built with some financial aid from the French Government and is expected to be operated in April 2001.

At a recent seminar (1998) organised by the People’s Committee with the participation of the many city organisations and the Overseas Economic Cooperation Fund (OECF) of Japan, the finance for the development and the planning of urban traffic systems was discussed and proposed. A master plan of transport and communication prepared by the Municipal Department of Communication and Public Works was presented. In this plan, new main roads linking new urban centres to be developed toward the East and South of the city and a belt road around the city are to be built.

Three inner city railroad metro lines are also proposed: from Bien Hoa to Hoa Hung and Phu Lam; from Tan Son Nhat Airport to Ben Thanh Market (and then possibly crossing the Saigon River toward Thu Thiem and the new international airport to be built at Long Thanh, Dong Nai Province); from Cho Lon to the city centre and Binh Thanh district and then toward the East. For outer suburbs, there will be a northern sector linking Long Binh and Hoc Mon, a western sector linking Hoc Mon-Binh Chanh-Can Gio, a southern sector linking Hoc Mon-Binh Chanh-Tien Giang and an eastern sector linking Thu Duc-Long Binh-Long Thanh-Vung Tau (35). This is quite ambitious, however, it is not clear how the city, even with the help of overseas aid, can finance this project unless it can be funded by external body such as the World Bank. The metro project is planned for the period from 2001 to 2020.

The first stage of the project is to build the 3 inner city metro lines. The 7km Tan Son Nhat-Hoa Hung-Ben Thanh line will cost approximately 316 million USD. The 3.6 km long between Hoa Hung (Saigon station) and Ben Thanh will be underground. The 6km underground Ben Thanh-Binh Tay market line linking district 1, 5 and 6 will cost approxiamtely 395 million USD. The 8.5 km Binh Trieu-Saigon station line will be constructed above ground parallel to the old rail line will cost about 220 million USD. It is expected the construction will begin before 2005 (35).

Some suggestion for Air Quality management plan in HCM City

The experiences in dealing with the environment problems, in Asian and other world cities, that have happened in recent years can benefit the plan to manage the air quality in HCM City. Many of these cities have similar development pattern in line with the strong economic growth. In view of the growing problem in HCM City, the following practical measures could be considered and incorporated in the management plan.

(1) Introduction of unleaded petrol and cleaner fuel

Spectacular gain in the reduction of lead levels has been achieved in many cities, which adopted a gradual phase-out of leaded vehicles. In Bangkok, Thailand, after unleaded petrol was introduced in July 1991, the 1996 study of newborn babies showed that the lead level in the blood is one third of that before the introduction of unleaded petrol (10). Even in adult, the lead level in blood has been shown lower than in neighbouring cities such as Manila, Kuala Lumpur. This can be attributable to lower lead levels in the atmosphere (25). Singapore has stopped the distribution and sale of leaded petrol since July 1998.

Of all pollution control measures, the abatement of lead is probably the most important gain in terms of the benefits for the health of people living in the cities, especially for children. However, the use of unleaded gasoline increases the level of volatile organic compounds such as benzene and toluene in the air. The newer car models can reduce the emission of these pollutants compared to the earlier models first introduced to use the unleaded petrol. In-used motor vehicle testing of exhaust emission in Bangkok has shown that the newer models significantly reduce the emission level of these pollutants (26).

Consideration should also be given to reformulated gasoline. Reformulated gasoline, or gasoline blended with ethanol or methanol, reduces significantly volatile organic compound emissions from cars. Volatile organic compounds contains many carcinogenic chemicals such as benzene, toluene.. Reformulated gasoline had been introduced and used in many cities in the US with significant gains such as the reduction of ozone formation. In 1998, the Central Pollution Control Board (CPCB) has proposed the introduction of reformulated gasoline (with 3 to 5% ethanol or methanol) on an experimental basis in New Delhi.

As SO2 is not a great concern in HCM City but consideration should be given for the encouragement of the use and the gradual introduction of low sulfur diesel fuel. Newly acquired commercial trucks, buses should have engines that are able to use low sulfur content fuel. This will reduce the SO2 emission from buses and utility vehicles, which are the main sources of high SO2 level near traffic sites. The introduction of low sulfur diesel fuel has been acted upon in Thailand in 1991. As Bangkok is relying on large power plants for electricity, power-generating plant also began to use clean coal technology in 1992.

(2) Set up standard for emission control of vehicles for registration and enforce the emission compliance of on-road vehicles. All new vehicles (including motorcycles) whether assembled, manufactured locally or imported are required to conform to the emission control regulation. The introduction of catalytic converter for motor vehicle should also be considered.

One example of this measure is that of the Thai MOSTE and the Pollution Control Department (PCD) who together set up emission standards for cars in 1992 and for motorcycles in 1993. In 1995, all buses, 3-wheeled cars (tuk-tuk) and boats were tested for emission compliance before registration.

In India, in an effort to clean up New Delhi polluted air, the Supreme Court ruled in 1999 that new cars sold in and around the capital must conform to Euro II emission standards in April 2000. Indian car manufacturer such as Maruti has announced that it will produce cars that meet the standard.

According to the Environment Committee of Ho Chi Minh City, up to 85% of on-road vehicles is not complied with the emission regulation. Since the beginning of 1996, enforcement of emission compliance of on-road vehicles has been applied by the traffic police. Some of the difficulties in the enforcement are the lack of emission standard and the fine for motorcycles is too low (3). In one of the reported check of 2,000 vehicles, 82% of these are not complied with emission and noise standards (32). A more effective measure is the check for emission compliance of vehicles to be eligible for registration. The check for emission should be done before any vehicle can be registered.

As nitrogen oxides and carbon monoxide pollution is very high in HCM City, the introduction of catalytic converters in the exhaust system of vehicles will improve the situation. These converters reduce the amount of nitrogen oxides, carbon monoxide and unburnt petrol escaping into the air. In New Delhi, the authority is now considering that all engines will need to be fitted with catalytic converters to reduce unburnt fuel.

Although measure, such as recently announced by the New Delhi authority to ban all taxis, buses and rickshaws that were more than 15 years old to combat the daily pollution blanket over the city, is too drastic for the situation in Ho Chi Minh City. However, regulation should be introduced to discourage the use of older fleets of cars, motor cycles.

(3) Establish some permanent on-line air quality monitoring stations

Monitoring of air quality is the main means to access the effectiveness of any air quality management plan as well as to provide the state of the air quality in the city. The design of the network and the type of pollutants to be measured is considered an important factor in accessing the state of the air quality for a particular city. Permanent continuous monitoring stations also provide data for finding the long-term trend of air pollutant level.

Following some lead in considering the importance of air quality monitoring as part of the environment management, a number of countries in the region has recently started establishing a network of air quality stations. The largest air quality monitoring network in Asia is in Taiwan with 66 monitoring stations throughout the large cities of the island with the majority in Taipei. In Bangkok, the Pollution Control Department has started to implement a phase I of establishing 8 permanent monitoring stations in 1993. This will be expanded to have 20 more stations in phase II in the next few years.

In Kuala Lumpur, the air monitoring was previously outsourced to private companies but recently the government has funded the University of Malaya to set up a few mobile stations to acquire data. This change was due to the arising legal problems in which the responsibility of data quality assurance was not clarified. As air quality data is essential in gauging the effect from the implementation of control strategy of air pollution, the government or city authority should always be the one i