Broom and dust

  • Dust control does not require a high level of technology; it can be achieved through a multi-pronged approach
- Naresh Koirala
The government attributes the dust to ongoing construction in the city, thereby implying construction without diffusion of dust particles is not possible. This is, of course, nonsense

May 22, 2017-Article 30 (1) of the constitution guarantees every Nepali the right to live in a clean and healthy environment. Article 30(2) confers a right of compensation to anyone whose health is affected by environmental pollution or degradation. Yet, in Kathmandu—the country’s Capital—such rights are brazenly breached, and no one in authority seems to care. 

In January 2017, the Ministry of Science, Technology and Environment reported that Kathmandu’s air contained 400 micrograms of particulate matter—over three and a half times greater than the National Ambient Air Quality Standard. Walking around Kathmandu feels like walking through a dust storm. Kathmandu’s hospitals have reported a significant increase in respiratory illnesses among city residents in the last couple of years. No one has yet assessed how dust has damaged properties.

Lack of will

The government attributes the dust to ongoing construction in the city, thereby implying construction without diffusion of dust particles is not possible. This is, of course, nonsense. The major construction activities in Kathmandu include installation of utility pipes—water and sewer—and the widening of the Ring Road. There is nothing exceptional about such work. They are so common that you could call them the staple of municipal/civil engineers around the world. 

In countries where I have worked, the construction-generated dust from such projects is supressed before they become airborne. The majority of the projects are completed on schedule with little disruption to business and public life. When the impact becomes unavoidable, for example if excavations restrict access to a business, the government financially compensates the business owners. 

In Nepal, we know the story. The dust is wilfully allowed to be airborne, seriously impacting public health. The impact on business is not even part of the conversation.

How is it that others manage to carry out construction work properly, yet we create a public health hazard doing exactly the same thing? Is it the technology or a basic lack of will to do it right?

Dust control does not require a high level of technology. It is achieved through a multi-pronged approach. This includes legislation, which sets air quality standards; contractual requirements, which force construction contractors to devise methods of construction and ensures compliance with the standards; and rigorous construction quality monitoring by the owner.

Let us compare the method of pipe laying in Vancouver, Canada (where I have been involved in installing over 50km of pipelines) and in Kathmandu. The 

methods are essentially the same.  A trench is excavated; the pipe is lowered in the trench; the trench is backfilled with specified material (mostly sand), and when the backfill reaches the road surface, the road is paved with asphalt. The difference is in the staging of the various elements of the construction process. 

Cleaning attitudes

In Vancouver, the contractor does not excavate a trench to lengths greater than what can be backfilled within the day’s work shift—about 35m per shift. The sand backfill is compacted as the trench is filled and when the backfill reaches the surface, a temporary asphalt seal is applied on the backfill before the next length of the trench is excavated. Traffic is not allowed over the backfill until it is sealed (a final layer of asphalt is laid after completing a hydraulic test on the pipe). The rate of production—meters of pipe installed in the ground in a work day—is better than what is achieved in Kathmandu. The carefully staged construction limits the area affected by the excavation, helps compliance with the air quality standards and minimises the construction impact on the public.

In Nepal, the length of trench excavated is longer than what can be backfilled in a day; mountains of dirt are piled on the roadside for days; the trenches are left open for a long time, creating a public hazard; the backfill seldom meets specifications (this seriously impacts the long-term integrity of the pipe and compromises the life of the asphalt pavement). The backfill and the dirt stockpile become a source of airborne particulate matter during dry days and turn into mud pit during and immediately after rainfall. 

I am aware Nepali authorities dismiss comparison of Nepal’s engineering with that of developed countries out of hand. I can almost hear the shrill of protest—‘How can we do what they do in Vancouver?’

Of course, we can. The fact is Nepali contractors use the same excavators and dump trucks as the Vancouver contractors. We also have air quality standards. So why can’t we do what they do? What is missing? 

What is missing is the will—the will to do it right. There is nothing to stop our engineers and oversight authorities from forcing the contractor to use dust suppression techniques, for example staged construction and temporary sealing.  

The lack of will to protect the public from dusty air is evident not only in pipe laying work but also in Kathmandu’s Ring Road expansion and the widening of the Mungling-Narayanghat road (large sections of the road are excavated and left open for a long time); in stockpiles of uncontrolled building construction debris sitting on the roadside for months; in Kathmandu’s back roads left unpaved for years after spreading some gravel and sand mix on the surface. 

The directive of the Parliament’s Development Committee in early February to the relevant authorities overseeing Kathmandu’s pipe laying to purchase and operate more hydraulic brooms to keep roads dust-free does not even scratch the surface of the dust problem. Hydraulic brooms do not clean attitudes. 

Kathmandu’s continuing dust hazard despite the water spraying and the brooms proves the ineffectiveness of the directive. What is required is commitment from the politicians not to compromise public interests for personal or partisan gains and to demand accountability from project personnel. Tall order?  Hardly, if there is the will.


- Koirala is a Canada-based geotechnical consultant

Published: 22-05-2017 07:40

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