AIR QUALITY IN DELHI
Air is a precious resource that most of us take for
granted. Clean air is essential to maintaining
the delicate balance of life on this planet — not just for humans, but
wildlife, vegetation, water and soil. Air supplies us with oxygen, which
is essential for our bodies to live. Pure air is a mixture of several gases
that are invisible and odorless. It consists of about 78% nitrogen, 21% oxygen,
and less than 1% of argon, carbon dioxide, and other gases — as well as varying
amounts of water vapor.
WHAT
IS AIR QUALITY ????
The term “Air Quality” means the state of the air around us. Good air quality
refers to clean, clear, unpolluted air. Poor air quality is a result of a
number of factors, including emissions from various sources, both natural and
“man-made.” Poor air quality occurs when pollutants reach very high levels of
concentrations that endanger human health and the environment. Air
quality is degraded when unwanted chemicals or other materials are released
into the air in large amounts that are harmful for the health of people,
plants, animals, and our environment. The quality of the air depends on the
amount of pollutants, the rate at which they are released from various sources,
and how quickly the pollutants disperse in the surrounding area. Air pollution
can affect indoor air quality, as well. Indoor air pollutants include cigarette
smoke, mould, dust mites, pet dander, formaldehyde, volatile organic compounds
(VOCs) and radon gas.
AIR
QUALITY STATUS IN DELHI
According to a WHO survey of 1600 world cities, the air
quality of Delhi along with Gwalior in Madhya Pradesh and Raipur in
Chhattisgarh is the worst of any major city in the world. The world's average
PM10 levels, for the
period 2008 and 2013, based on data of 1600 cities in 91 countries, range from
26 to 208 micrograms per cubic meter of air (μg/m3), with the world
average being 71 μg/m3. 13
of the 25 cities worldwide with the highest levels of PM are in India. In 2010,
the year of the WHO survey, the average PM10 level in Delhi was 286. In 2013, the
PM2.5 level was 153.
These levels are considered very unhealthy. In Gwalior, the city with the worst
air quality in India, the PM10, and PM2.5 levels were 329 and 144 respectively.
The PM levels in Delhi have become worse since the WHO survey. In
December–January 2015, in Delhi, an average PM2.5 level of 226 was noted by US embassy
monitors in Delhi. Safe levels for PM according to the WHO's air quality
guidelines are 20 μg/m3 (annual mean) for PM10 and 10 μg/m3 (annual mean) for PM2.5.
METHODS FOR MEASURING AIR
QUALITY
A number of methods can be used to measure air quality, which
includes permanent monitoring stations in communities, mobile instrumentation,
and industrial stack monitoring. These monitoring stations measure the presence
of contaminants in the air, such as carbon
monoxide (CO),nitrogen dioxide (NO2), ozone (O3), particulate matter (PM2.5 and PM10), sulphur dioxide (SO2), and hydrogen sulphide (H2S). Contaminants
are measured in one of two ways: either
through continuous (real-time) monitoring where air is constantly measured and
the data is automatically transmitted to a central database and through non
continuous or discrete monitoring where contaminants collect on a filter or
canister over a specified period of time (such as one, three or six days). Then
a technician collects the filter or canister and sends it to a certified
laboratory for measurement and analysis. The Indian
Meteorological Department (IMD) has air quality
monitoring stations in Mathura
Road, IMD Delhi (Jor Bagh area), IGI Airport, IITM Delhi, Guru Teg Bahadur Hospital (Ghaziabad area), Dhirpur, Delhi
University, Pitampura, Aya Nagar (Gurgaon),
and Noida. The air pollution monitor of the U.S. Embassy in New
Delhi covers the area of Chanakyapuri.
PM 2.5 is a standard recognized by the U.S. Environmental Protection Agency and
allows us to compare against U.S. standard measures.
The Air Quality Index According to the U.S. Environmental
Protection Agency is given below
Air Quality Index (AQI)
|
PM2.5
Health Effects Statement
|
PM 2.5
Cautionary Statement
|
Good (0-50) |
PM2.5 air
pollution poses little or no risk.
|
None
|
Moderate (51-100) |
Unusually
sensitive individuals may experience respiratory symptoms.
|
Unusually
sensitive people should consider reducing prolonged or heavy exertion.
|
Unhealthy for Sensitive Groups (101-150) |
Increasing
likelihood of respiratory symptoms in sensitive individuals, aggravation of
heart or lung disease and premature mortality in persons with cardiopulmonary
disease and the elderly.
|
People with
heart or lung disease, older adults, and children should reduce prolonged or
heavy exertion.
|
Unhealthy
(151-200) |
Increased
aggravation of heart or lung disease and premature mortality in persons with
cardiopulmonary disease and the elderly; increased respiratory effects in
general population.
|
People with
heart or lung disease, older adults, and children should avoid prolonged or
heavy exertion; everyone else should reduce prolonged or heavy exertion.
|
Very Unhealthy
(201-300) |
Significant
aggravation of heart or lung disease and premature mortality in persons with cardiopulmonary
disease and the elderly; increase in respiratory effects in general
population.
|
People with
heart or lung disease, older adults, and children should avoid all physical
activity outdoors. Everyone else should avoid prolonged or heavy exertion.
|
Hazardous
(301-500) |
Serious
aggravation of heart or lung disease in persons with cardiopulmonary disease
and the elderly.
|
Everyone
should avoid all physical activity outdoors; people with heart or lung
disease, and children should remain indoors.
|
Air Pollution in India: Real time Air Quality
Index Visual Map- 17th February, 2016
Air Pollution in India: Real
Time Air Quality Index Visual Map for Delhi- 17th Feb, 2016
Source:
Source for Air Quality Map-