Friday, October 13, 2006

Ultra violet radiation: Hyderabad fast turning into a radiation city

Syed Akbar
Hyderabad, Oct 13: Hyderabad is fast turning into a "radiation city" 
with harmful ultraviolet (UV) rays hitting the city at "extreme" levels.
UV forecasts for Hyderabad show that the radiation falling down on the 
city from the sun for most part of the year is on the higher side, which 
is an indication that all is not well with the ozone layer above and the 
city's atmosphere.
Hyderabad is bracketed with concrete jungles like Mumbai, Kolkata, 
Bangalore and Chennai as these cities record "extreme" UV radiation 
for more than three days a week. However, Delhi appears to be slightly 
better as the UV radiation levels there are generally "high" to "very 
high" but rarely "extreme".
Ultraviolet rays falling on the earth are classified into various 
categories based on the intensity of the radiation and the harm they 
cause to human beings and animals. The World Meteorological 
Organisation, a WHO body, has standardised the UV radiation levels 
with its "UV Index" which is a simple measure of the UV radiation 
level at the earth's surface. Hyderabad's UV Index shows a measure of 
11, the highest point in the UV scale.
No wonder then that there has been a spurt in skin diseases in 
Hyderabad may be because of extreme levels of UV radiation. "Most of 
the cases relate to photo-ageing and skin cancer due to penetration of 
the rays into the skin. Even if one is in a car the rays can penetrate the 
glass and impact the skin. The most common skin allergy cases that 
come to us are related to  UV radiation called polymorphic light 
eruption," senior dermatologist Dr Anup Lahari pointed out.
The values of the UV Index range from zero to 11 and the higher the 
Index value, the greater the potential for damage to the human body 
and the less time it takes for harm to occur. On the higher side is the 
"extreme" and on the lower side is the "very low". In between UV 
Index is categorised as "low", "medium", "high" and "very high".
The WMO and the World Climate Research Programme as also the 
India Meteorological Department regularly issue UV forecasts for 
different cities around the world and in India respectively. The IMD 
monitors UV levels at its 45 radiation observatories spread across the 
country.
The UV Index up to October 18 is 11 i.e. "extreme" for Hyderabad, 
Chennai and Mumbai, while it is 8 (very high) for Delhi, 7 (high) for 
Chandigarh and 10 (very high) for Kolkata. The Index last week was 
also "extreme" for most part of the week for Hyderabad and other cities 
except Delhi.
The main reason given for the high intensity of UV radiation in 
Hyderabad is rapid urbanisation and high levels of pollution.
"As UV radiation can neither be seen nor felt, the UV Index is an 
important tool to raise awareness of the problem and alert people on a 
daily basis to take prompt, appropriate and protective action. That 
Hyderabad has high UV Index is an indication that the ozone layer is 
not properly filtering the sunlight. If the ozone does its job properly, 
the harmful radiation are filtered out. The high UV Index shows that 
the ozone layer has become thin," says Prof OSRU Bhanu Kumar, head 
of the department of environmental sciences, Andhra University.
Health experts and environmentalists warn that damage from the 
exposure to the UV rays is cumulative and over a period of time it will 
lead to serious diseases of the eye, including cataract and macular 
degeneration.
Consultant radiologist of Care Hospital Dr B Murali suggested that one 
should go in for massive tree plantation and keep off the sun to the 
extent possible to avoid UV radiation. "UV radiation exposures are 
largely preventable. The best protection is achieved by practising a 
combination of recommended safe behaviours. Limit exposures to sun 
rays when they are the strongest i.e. between 10 am and 4 pm. Seek 
shades such as trees or umbrella whenever possible. Use a broad-
spectrum sunscreen with sun protection factor of at least 15. Sunglasses 
can provide 100 per cent protection," he said.
Children are at high risk as on an average they get three times more sun 
exposure and thus are subject to damaging cumulative effects of UV. It 
is estimated that 80 per cent of lifetime sun exposure occurs before 18 
years of age.
"With the UV rays being equally extreme even in a "garden city" like 
Bangalore, there has been an increase in eye related problems there. Dr 
NM Sudha, senior ophthalmologist from Bangalore, pointed out that 
ultra violet light is as a causative factor in several eye problems such as 
cataract, retinal degeneration and surface problems such as pterigyum. 

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