Introduction
Nepal is a small Himalayan kingdom representing a transitional mountain area between the fertile Gangetic plain of India (East Southwest) and the arid plateau of Tibet, China (North). It has its elongated rectangular shape roughly with northwest to southeast orientation. The country has 147,181 sq.km. in area, which accounts as 0.03 percent of land area of the earth and the population of 18.5 million in 1991. It lies to the sub-tropical to mountainous regions of the world at 260 22’ to 300 27’ N latitude and 800 4’ to 880 15’ E longitude. Administratively, Nepal is divided in 5 Development Regions, 14 zones, 75 districts, 3912 village Development committees and 58 municipality.
Nepal displays extreme variations in natural environment ranging from tropical plain to alpine heights, traditionally classified into three major geographical regions: the Terai plains, Hill and Mountain regions. The environmental aspects of terai (below 300m) include large-scale deposition forms and increasing deforestation for land colonization. It has extensive fertile land that supports the large population. The hill region (300-3000m), the traditional zone of Nepalese settlement also has a large population subsisting mainly on agriculture. Much of natural vegetation has been cleared for cultivation or grazing. Natural process of erosion are active both in the form of slow degradation and catastrophic landslides. The mountain region (above 3000m) is a marginal area for human occupancy, where glacial and pre-glacial processes of erosion predominate. The sparse population subsists on agriculture, pastoralism and trade (UEMP 1994).
Urban growth is terms of area, human population, industry transport etc. has been recognized as a worldwide phenomenon. The World health Organization estimates that almost one half of world population in now living in and around urban centers of the world. Such concentration of human activities is small areas is evitable exerts severe strain on the available natural resource of the region. Consequently, the release of pollution loads is to the environment is outstripping the carrying capacities of almost all major urban centers of the world leading to a series of environment related problem. In Nepal also the situation is not different but rather worse. The scale of activities here is comparatively much lower but the extent of negative impact is greater simply because of almost total lack planning, regulation and control.
Along with increasing industrial and commercial activities, pressures on the existing infrastructures roads, sewerage, drainage, solid waste management and existing transportation are grown with as increasing incidence of environmental deterioration (UEMP, 1994).
As pollution regulation and management is not stringent in Nepal. There is no reliable treatment of sewerage, no strict controls on vehicular exhaust levels or pollution - prone industries, no effective regulation of pesticide use, no systematic monitoring of water quality and very little laboratory facilities. Thus, the existing environmental issues in Nepal have become prominent topics of concern for the last few years.
The major environmental problems evident in the urban areas are physical congestion, water and air pollution, and lack of cleanliness, loss of open spaces and loss of cultural property. Whereas water pollution can be linked with domestic waste, solid waste and industrial waste and there their collection, treatment and discharge management and practices. Air pollution can be seen as a fall-out of industrial emissions, house energy usage pattern, vehicular emission and microclimate (UEMP, 1994).
The quality of ambient air is basically a localized problem (IUCN, 1991). Presently, the core areas of major urban centers such as Kathmandu Valley, Birgunj, and Biratnagar etc. have been facing the visible threat of air pollution due to increasing number of vehicles and pollution prone industries.
Kathmandu, the capital of Nepal is the focus of all major facets of a country, namely economic, tourism, culture, politics, administration and natural environment. The expanding city of Kathmandu has resulted in population growth through continuous migration. As the result of it, the city population is dramatically increased. The population census of 1991 showed that the urban population of Kathmandu is 6,61,836 with the growth rate of 5.99. (A Comp. on Env. Statistics of Nepal, 1998).
Air pollution has emerged as the most visible components of environmental degradation in Kathmandu valley for the last couple of years. The valley is especially vulnerable to air pollution due to its bowl- like topography, exploding population inflow, rapid urbanization, valley centric industrialization and significant increase of vehicular transport in narrow streets. The bowl like topography restricts wind movement and retains the pollutants in the atmosphere especially during period of thermal inversion over Kathmandu, where cold air flowing down from the mountains is trapped under a layer of warmer air, which acts like a lid over a bowl (A Comp. on Env. Stat. Of Nepal, 1998).
On an average a human body requires 30lb of air everyday to sustain its requirement of oxygen (Env. Pollution & Protection, 1995). This fact suggests that air pollution is indeed of great immediate concern than any other aspect of pollution. What makes air quality particularly vulnerable is that air unlike water or other waste cannot be reprocessed practically at some central locations and subsequently distributed for use. Air may get rejuvenated through photosynthetic process and cleared through precipitation, but these natural processes are limited in their effectiveness in urban areas. It is therefore seems evident that the protection of air quality is a vital consideration.
At present, not only natural factors, but also anthropogenic activities have also added large amount of macro and micro pollutants to the atmosphere, triggering the environmental problem. Though long-term data on pollution are lacking, available information reveals that the nature and extent of air pollution has a serious dimension in major urban areas and in some industrial sites in Nepal. Various studies done so far also indicate (1) Industrial hot spot area (2) types of major pollutants and (3) extent of concentration. But most of the study has been concentrated in the valley (A Comp. on Env. Stat. of Nepal, 1998).
The Himal Cement plant at Chobhar in Kathmandu has attracted considerable public attention for its dust emission, which can be seen from any point of the valley. Dust was emitted from the limestone crusher, saw mill, raw materials storage yard and limestone excavation processes (IUCN, 1991) ENPHO reported maximum PM10 and TSP concentration in the nearby areas showed of 206 m g/m3 and 402 m g/m3 respectively. But the gaseous pollutants such as SO2 and NO2 were within the WHO guidelines. It is estimated to discharge 6000 MT of dust particulate per year.
Brick manufacturing by Bull’s trench kilns owing to their process of material handling, firing technology, energy efficiency and also by virtue of consumption of substantial amount of dirty fuels, are potentially significant sources of atmospheric emissions. As the industries are located in a valley at the outskirts of the urban centers, impact of air pollutants released from these industries is visibly felt. The exact quantification of air pollutant is, however difficult without stack monitoring. Secondary information estimates that tons of dust particles, SO2, NO2, hydrocarbon, carbon monoxide and fluoride are emitted in the atmosphere. Out of a total of 179 operational commercial brick kilns in Kathmandu valley in 1994, 172 industries were the Bull’s trench kiln type (NESS, 1995) Among the remaining, six were semi-mechanized Hoffmann’s kiln and one vertical shaft kiln.
The rural areas are engulfed by heavy indoor air pollution. According to the survey the main source energy consumed by households in Nepal consists of traditional source: firewood, animal dung and litters (CBS, 1996). Use of traditional source of energy for cooking and heating purpose in poorly ventilated dwelling has been aggravating indoor air pollution.
Vehicular emission, is another principle contributor to air pollution. This is further magnified by leaded, substandard and adulterated fuel; narrow streets and poor traffic management, practice of importing old vehicles and poor vehicle maintenance (Joshi, 1993). Since 1999, unleaded petrol has been introduced in Kathmandu Valley. In the recent past vehicular population in large towns like Kathmandu, Patan, Birjunj, Biratnagar has been increasing very rapidly. The registered Vehicle of 1997/98 shows, out of 211,097 numbers of vehicles in whole Nepal, the registered vehicles in Bagmati zone itself is 140,000 which means another 27% increase over the last two years (CBS, 1998). In proportionate to the vehicle fleet increase, the consumption of petrol and diesel in the country have also risen considerably about 51% for petrol and 54% for diesel during the last four years (NOC). According to the recent data (1997/98) petrol and diesel consumption were 46939 kl and 302063 respectively. Out of those national consumption figures, the estimated consumption figures for the valley were 80% petrol and 27% diesel. The total road length in the valley in which the vehicles ply is estimated to be around 995 km (Nepal district profile, 1997) out of which 401 km is lack-topped 246 km gravel and 348 km earthen. Shrestha and Malla (1993) have done emission inventory load by adopting the energy consumption technique. The finding study showed total annual emission load from transportation sector is 12,422 tons. Likewise other study done by URBAIR showed total annual emission of TSP from vehicle exhaust is 570 tons.
Various analyses have demonstrated that major cities of Nepal as well as Kathmandu’s air, especially is the vicinity of the main thorough fares, exhibits unacceptable levels of suspended particulate, lead and other pollutants that pose significant risk to human heath. The number of clear days per year in Kathmandu has been consistently decreasing in the past two decades. According to the study (Shrestha, 1994) the number of foggy days in Kathmandu has increased from about 38/year in 1970 to more than 60/year in 1994.
Deterioration of public health, especially due to increase in the respiratory and skin diseases has become a serious concern in the Kathmandu valley. The prevalence of chronic bronchitis was reported to be the highest in Jumla 24 percent. Whereas in mid-hills region of urban Kathmandu it was 8.8 percent (Pandey & Basnet, 1988). Overall impact of population is higher in women than in man, as women spend about 20 percent of their time in cooking related activities.
Indoor pollution of industries also poses a considerable threat to the health workers in some industries. Most common diseases prevalent were headache, respiratory problem and abdominal disorders.
Impact of Himal Cement on soil, water, vegetation and health was studied by ENPHO (1999). The soil of this region has become hard due to calcium deposition and this affects germination of seeds. The leafy vegetables like mustard, cabbage etc. were found injured due to dust deposition on the leaf surface. After 2-3 days of dust deposition holes appear on the leaf surface. The vegetable is not palatable around this area due to dust. Closing of stomatal pores due to the deposition of dust brings wilting and drooping of vegetable leaves. This has been observed in most dust prevalent area. The straw of rice, wheat and barley is not palatable for livestock. Cows and buffaloes suffer from diseases if they are fed on straws for a long time. Poor visibility and poor sunlight in winter also attributes to thick smoke and dust from the factory.
Health impact from Himal Cement was studied in the nearby villages. Out of 683, the total population, 0.87% was suffering from pneumonia, 8.19% person from bronchitis and 5.27% from asthma. In the survey, 0.14% is suffering from cataract, 7.75% from vision problems, 5.85% from conjunctivitis and 0.14% from night blindness. Similarly, skin problems like scabies, ringworm and wounds were 0.58%, 0.87% and 1.61% respectively. Other type of skin problem was 4.87%.
Exposure to vehicular exhaust leads to increase prevalence of various diseases viz. irritation, respiratory tract infection, bronchitis and asthma. Leaded gasoline, which is often adulterated, is available in Kathmandu and the large percentage of heavy vehicles runs on diesel. This can cause substantial damage to health and welfare of the people who are exposed to the resulting emission. Furthermore, leaded gasoline emits lead to the air resulting in a significant cause of decreased IQ among children, increased incidence of high blood pressure among adults and can be highly detrimental to unborn children.
Air pollution in Kathmandu is also causing damage to many historical buildings that represents the cultural heritage of the valley. Acid formed as a result of various sulphurous and nitrous oxides reacting with water can damage fine wood carving, marble and metallic exteriors common to many historical buildings of Nepal. The damage to cultural heritage not only deprives the residents of proud past, it also can negatively impact on tourist trade, an important contributor to the valley’s economy (Adhikari, 1998).
An October 1993 article in Newsweek painted a pessimistic, but accurate image of the air pollution situation in Kathmandu valley. Such negative publicity could have an adverse impact on tourism. In the early 1990’s, foreign currency revenues amounted to approximately US$60 million a year. Although no ‘dose-effect’ relationship of air pollution and tourism are available, it can be assumed that an approximately 10 percent decrease in tourism could lead to a loss of to US$6 million for Nepal. This is a very significant amount of foreign exchange for a country that has a negative balance of trade (URBAIR, 1996).
To sum it up existing environmental issues in the country have become prominent topics of concern for the last few years. Amid aggravating environmental conditions, notably soil erosion, deforestation and water as well as air pollution and their severe impacts on ecological balance, economic growth and human health certainly is of growing concern. Environmental problems are stemming primarily from ecological incompatible human activities pursued in the endeavor of fulfilling material needs (CEDA, 1993). So is in the case of air pollution. The economic cost of air pollution due to loss in human health potential, loss in tourism and damage to cultural heritage is significant, running into millions of dollars annually (Adhikari, 1998). Thus, Nepal urgently needs to prepare a comprehensive framework for policies to address the problems of pollution.