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surface ozone etc.) depending upon the available national capaci-

ties. Some other science and technology institutes and universities

are involved in the episodic measurement of ambient air quality in

the region for meeting their research requirements. Air pollution,

as a local issue, has also been partially addressed by legislation in

most of the countries of South Asia. However, a holistic action to

deal with this issue in the region is still lacking because the scien-

tific understanding about the linkage of observed pollution levels

with human health effects is still in its preliminary stages.

Therefore, there is a need to undertake appropriate research activ-

ities in the region, to get an in-depth understanding of these

linkages.

In this direction, a research project, the Assessment of the Effects

of High Particulate Pollutants on Pulmonary Health Status in

Selected Megacities of South Asia has been undertaken since late

2005, supported by the Asia Pacific Network for Global Change

Research (APN) to develop scientific capacity in the region. This

project aims to investigate the impacts of high particulate matter

concentrations on human respiratory health in selected megacities

of South Asia, where the particulate matter loading in ambient air

is, in general, very high due to various anthropogenic activities.

Through this project, multi-disciplinary country teams consisting

of health and aerosol experts are carrying out a study in target areas

in selected megacities: Colombo, Delhi, Dhaka, Kathmandu,

Kolkata and Lahore.

For this project, common protocols for health studies and air

pollution monitoring have been developed and are being followed

by all the country teams. In the first year, a sample survey of health

status of target population was carried out using common protocols

for both acute and chronic symptoms. The ambient air quality in

the target locations has also been monitored. The lung function

tests of the identified subjects in the target locations are also being

carried out using peak flow meters and/or Spirometers.

This project is expected to generate useful scientific

insights about the linkages between the air pollution

and health status in South Asia.

Ocular diseases

The human body is exposed to sunlight that contains

radiations ranging between UVB (wavelength ranging

from 280–315nm), UVA (wavelength ranging from

315–400nm), visible (wavelength ranging from

400–800nm) and infrared (IR; wavelength ranging from

800nm to 1mm). UVB wavelengths <295nm and UVC

(100–280nm) radiations are totally filtered by the

stratospheric ozone layer. However, UVA is not

absorbed by the stratospheric ozone and reaches the

Earth’s surface virtually unattenuated through clear

atmosphere. UVB radiation, being more energetic, is

more damaging to the eye and is absorbed by the cornea

and lens. UVA radiation has lower energy, but pene-

trates much deeper into the eye and may cause injury

to the retina. Epidemiological investigations have

reported a higher prevalence of cataracts in regions with

high levels of UV exposure. Various ocular disorders

induced and exacerbated by UV radiation (UVR)

include cataract, dry eye, pterygium, allergic diseases,

photokeratitis, ocular surface squamous neoplasia,

corneal degenerative changes and age-related macular

degeneration. Globally, excessive solar UVR exposure

is estimated to have caused a loss of about 1.5 million

disability-adjusted life years (DALYS), and 60,000

premature deaths in the year 2000.

The South Asian region predominantly lies in the

low stratospheric ozone belt because of its geographi-

cal location near the equator. Hence this region, in

general, receives higher dosages of UVR. The UV levels

have been found to be over 1,000 times higher at the

equator compared to the poles and levels increase

further with altitude. So, the high altitude and equa-

torial regions are the real hotspots for UV exposure.

However, no concerted scientific efforts have so far

been mounted in the South Asian region to assess the

impacts of higher UV radiations on human health. In

India, however, efforts have been mounted to generate

UVR maps

which revealed higher UVB dosages over

the Indian subcontinent.

The path ahead

In view of the limited resources and national capaci-

ties available in South Asia, major thrust is needed to

strengthen the observational networks for generating

data that is quality controlled and quality assured. The

development of user-friendly data products and their

timely distribution for use by health and other sector

experts is also a major challenge in the region. The

institutional and individual capacities are still inade-

quate in the South Asia region, and need to be further

strengthened to enable the generation of observational

data and their effective use for the proper assessment

of health impacts.

Lung function tests are carried out using peak flow meters and spirometers.

Here, one of the subjects in Sri Lanka takes a peak flow test

Photo: Dr. J. Ratnasiri, APN South Asian Health Project Team Coordinator for Sri Lanka

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