A Comparative Study of Air Pollution-Related Morbidity Among Exposed Population of Delhi
Author(s): A Sagar, M Bhattacharya, Vinod Joon
Vol. 32, No. 4 (2007-10 - 2007-12)
ISSN No. 0970-0218
A Sagar, M Bhattacharya1, Vinod Joon1
Abstract
Background: Vehicular pollution is increasing in Indian cities, which may lead to increased number of patients with
diseases related to air pollution. Present study was undertaken to assess the pattern of morbidity in two areas of
Delhi, one highly polluted area (HPA) and the other low polluted area (LPA). Materials and Methods: Subjects were
interviewed regarding socioeconomic status and exposure history. Symptoms during the last month were recorded
in a questionnaire and weight, height and peak expiratory flow rate (PEFR) were measured. Air pollution data were
obtained from the monitoring stations of Central Pollution Control Board (CPCB). Results: A total of 640 subjects
participated in the study. Majority of the patients in both the areas were educated till primary but 24% in HPA and
13% in LPA were graduates. Current levels of all pollutants (except SO2 and NOx) were above the safety levels
prescribed by CPCB in both the areas, but the values were much higher in HPA. The values of PEFR amongst study
population were more compromised in HPA. The difference in mean PEFR values among the populations in LPA and
HPA were found to be statistically significant (P < 0.05). The mean number of symptoms experienced by subjects of
HPA was more as compared to LPA (P < 0.05). Frequency of occurrence of symptoms varied with duration of stay
in the study area. Children were affected more than the adults. Conclusion: Air pollution has a deleterious effect
on various systems of the body.
Keywords: Air pollution, exposure, health effects, peak expiratory flow rate, vehicular emissions
Air quality is deteriorating especially in metropolitan
cities, mainly due to vehicular emissions. There is good
evidence that the health of 900 million urban people over
the world is deteriorating daily because of high levels of
ambient air pollutants.1 The toxicology of air pollution
is exceedingly complex as there are different types of
pollutants affecting individual differently.2
The pollutants in air namely SO2, NOx and suspended
particulate matter (SPM) damage the human respiratory
and cardio respiratory systems in various ways. The
elderly, children, smokers and those with chronic
respiratory diseases are most vulnerable.3 It has been
reported that high levels of pollution affect mental and
emotional health too. Amongst the symptoms, feeling of
fatigue, exhaustion, low mood, nervousness, irritation
of eyes and stomach aches have shown a significant
association with air quality. Inhalation of fumes is
associated with recurrent colds, chronic bronchitis and
hyperactive airways.4 Elevated lead levels in children
have been associated with impaired neurological
development as measured by lowered IQ, poor school
performance and behavioural difficulties.3
Environmentalists claim that living in an Indian metropolitan
city is like smoking 10-20 cigarettes every day. More than
40,000 people die pre-maturely every year because of
air pollution, says a World Bank report, of which Delhi’s
share is the highest (19%).5 The estimates of disease
burden due to urban air pollution are based on the impact
of air pollution on mortality. The impact of air pollution on
morbidity could not be included in the calculations due to
lack of reliable epidemiological data. Few studies have
been conducted on the health effects of air pollution in
the general population of Delhi. This study is an effort to
identify the adverse health impacts due to air pollution on
communities residing in areas of high and low ambient
pollution levels.
Materials and Methods
This descriptive study was carried out in Delhi, the
capital of India. The study areas were taken up randomly
from among the areas already identified by the central
pollution control board. Daryaganj was identified as highly
polluted area (HPA) and Gazipur as low polluted area
(LPA). The mean level of pollutants during the previous
1 year was recorded. Two population groups, one from
HPA and other from LPA were selected for this study.
A sample of 320 people each was taken up from both LPA
and HPA. The sample size was based on the prevalence
of symptoms and signs in the studies done earlier, which
had found the frequency of mucosal irritation as 39.7%
and eye symptoms as 26.9%6 with 10% error. Inclusion
criteria for the study was that the person should be
living and working in the selected areas for more than
6 months, be below 45 years (to rule out respiratory
symptoms associated with old age) and be a non-smoker.
The study population was disaggregated into four age
groups. The age groups were: 0-5 years, 6-13 years,
14-22 years and 23-45 years, with a sample size of
80 subjects in each age group. Males outnumbered
females in both the areas. In HPA, 78% and in LPA,
75% subjects were males.
A pre-coded structured interview schedule was prepared
to collect the data. Past history of relevant illness
was obtained from the medical records of individuals.
Medical examination and certain measurements like
weight, height, blood pressure and peak expiratory
flow rate (PEFR) were carried out on the spot for each
study subject. The levels of pollutants namely SPM
[respirable suspended particulate matter (RSPM) and
total suspended particulate matter (TSPM)], NO2, SO2
and lead as measured by CPCB were obtained by the
investigators. The adverse health effects of pollutants
were based on the list of symptoms prepared by the
Society for Environment and Health.7 The data were
analysed with SPSS and appropriate statistical tests like
chi-square test, odds ratio and standard error of mean
were used.
Results
The mean values of all pollutants (except SO2 and
NO2) exceeded the recommended National Ambient Air
Quality Standards (NAAQS) prescribed for residential
areas in both Daryaganj and Gazipur, but the values
were much lower in Gazipur (LPA).8 The levels of TSPM,
RSPM and lead were much above the safety limits
prescribed for residential areas by the Central Pollution
Control Board for both the study areas.9 The TSPM levels
were 683 and 235 μg/m3 for HPA and LPA, respectively.
Fifty-two percent of people in HPA and 47.2% of people
in LPA had 3-5 years of stay in their respective areas,
and 32.2% of subjects of HPA and 44% of subjects of
LPA have been living in that area for nearly 2 years.
As shown in Table 1, majority of subjects in both HPA
and LPA were educated till primary. The percentage of
graduates was more in HPA than in LPA. In HPA, 84.4%
and in LPA, 79.4% of the subjects had knowledge about
air pollution as a hazard to health.
Table 2 shows that the values of PEFR were less in HPA
as compared to LPA. The PEFR is the indicator of lung
function, which is affected as a result of exposure to air
pollution.
When the differences in mean number of symptoms
experienced by the individuals of HPA and LPA were
compared, it was found that the symptoms were more
likely to occur in HPA population than in the subjects
residing in the LPA. Table 3 shows that higher percentage
of subjects of HPA suffered from different symptoms
like irritation of nose and eyes, watering of eyes and
nose, respiratory infections, breathlessness, ringing in
ears and headaches. When the differences between
various symptoms experienced by the subjects from HPA
and LPA areas were compared, it was found that the
symptoms were statistically significant except for a few
symptoms like febrile conditions and common cold.
The individual symptoms were analyzed for different age
groups and it was observed that the subjects residing
in HPA, irrespective of age were likely to have 1.7 to
3.37 times more chances of suffering with the symptoms
related to pollution, compared to the subjects residing in
LPA. Further, when we compared the symptoms among
different age groups, it was found that the age group
14-22 years had the lowest probability of occurrence
of various symptoms amongst all the age groups, while
the age group 6-13 years had the highest chance of
developing various symptoms.
Table 1: Educational status of the study subjects
Educational
status
High pollution
area, No. (%)
Low pollution
area, No. (%)
Total,
No. (%)
Illiterate
24 (7.5)
35 (10.9)
59 (9.2)
Primary
110 (34.3)
108 (33.7)
218 (34.0)
Middle
47 (14.6)
49 (15.3)
96 (15)
Matric
22 (6.8)
35 (10.9)
57 (8.9)
Senior
Secondary
44 (3.7)
52 (16.2)
96 (15)
Graduate
73 (23.1)
41 (13.0)
114 (17.9)
Total
320
320
640
P = 0.01
Table 2: Mean peak expiratory flow rates by duration of exposure
Duration of stay
High pollution area
Low pollution area
Mean
S.D.
Total
Mean
S.D.
Total
Up to 2 years
231.9
150.8
103
281.7
157.4
141
3-5 years
414.4
147.3
165
507.6
138.7
151
More than 5 years
527.3
57.2
52
590.4
51.4
28
P < 0.05
Table 3: Symptoms during previous 1 year
Symptoms
High pollution area, No. (%)
Low pollution area, No. (%)
P-value
Burning eyes
124 (38.8)
57 (17.8)
<0.001
Irritation of eyes
111 (34.7)
53 (16.6)
<0.001
Irritation of Nose
134 (41.9)
54 (16.9)
<0.001
Irritation of throat
136 (42.5)
50 (15.6)
<0.001
Watering of eyes
125 (39.1)
66 (20.6)
<0.001
Watering of nose
170 (53.1)
130 (40.6)
<0.001
Respiratory infection
86 (26.9)
36 (11.3)
<0.001
Black sputum
45 (14.1)
31 (9.7)
0.08
Cough
220 (68.8)
212 (66.3)
0.4
Breathlessness
112 (35)
48 (15)
<0.001
Chest pain
40 (12.5)
23 (7.2)
<0.02
Sneezing
168 (52.5)
135 (42.2)
0.008
Common cold
158 (49.4)
113 (35.3)
0.0003
Febrile condition
11 (3.4)
14 (4.4)
0.5
Suffocation
17 (5.3)
9 (2.8)
0.1
Ringing in ears
80 (25)
38 (11.9)
0.00001
Nausea
11 (3.4)
14 (4.4)
0.5
Headache
142 (44.4)
98 (30.6)
0.0003
Vomiting
45 (14.1)
98 (30.6)
<0.001
Total
320
320
Discussion
According to the World Health Report 2002, analyses
based on particulate matter estimates report that ambient
air pollution causes about 5% of trachea, bronchus
and lung cancer, 2% of cardio-respiratory mortality and
about 1% of respiratory infections mortality globally. This
amounts to about 1.4% (0.8 million) deaths and 0.8%
(7.9 million) of disability-adjusted life years. The adverse
effects of air pollution are more pronounced in developing
countries.10 The problem of air pollution is increasing
at an alarming rate in Delhi. It is India’s most polluted
metropolitan city with 70% air pollution of Delhi being
caused by vehicles only. This has resulted in higher air
pollution-related morbidity among its inhabitants.
The study area in Daryaganj is a highly congested
area with heavy traffic density and frequent traffic jams,
resulting in build up of air pollutants in that area. This
ultimately leads to more exposure to people residing
and working in that area. Gazipur on the other hand, is
a rural area situated on the outskirts of Delhi with less
traffic density and consequently less exposure of its
inhabitants.
In the present study, mean levels of pollutant in the study
areas were almost comparable to the study done by
Kamat and others.11,12 In air quality studies, total aerosol
in air is measured as TSPM. Course particles are not
useful except that it reflects the perception of haze in
air and results in diminished visibility. RSPM is the most
important fraction from health point of view.
Total exposure of an individual to pollutants is determined
by the concentration of pollutants and the duration of
exposure. The exposure levels in the study population
were measured by the duration of stay of subjects in the
study area as up to 2 years, 3-5 years and above 5 years.
Sixty-eight percent of the people of HPA and 56% of
LPA were staying in the area for more than 3 years. The
prevalence of airborne diseases was more in HPA as
compared to LPA. This could be due to high levels of
air pollutants in their environment specially the RSPM,
as these particulates tend to deposit in alveoli and slow
down the exchange of oxygen with carbon dioxide in
the blood, causing shortness of breath. The number of
symptoms observed in this study had more frequency of
occurrence in HPA than LPA. The symptoms also vary
with different duration of exposure. The findings reported
in this study and others regarding respiratory morbidity,
lung function and urban air pollutant levels are similar.
According to the Health Care Institute of India, there is
an alarming rise in number of patients in Delhi hospitals
with respiratory problems.13 A study from Cochin also
reported higher prevalence of respiratory symptoms.14
A study conducted by All India Institute of Medical
Sciences and Central Pollution Control Board in Delhi
showed that exposure to higher levels of particulate
matter contributed to respiratory morbidity. It indicated
that the most common symptoms related to air pollution
were irritation of eyes (44%), cough (28.8%), pharyngitis
(16.8%), dyspnea (16%) and nausea (10%).15 A similar
study in Bombay found the prevalence of symptoms and
signs of disease to be around 22.2%.11
In the present study, the PEFR values were found to be
much lower than Clement Clark’s Standard. 83.8% of
the subjects of HPA were having PEFR values less than
normal as compared to 44.1% of the subjects of LPA.
Person with less duration of exposure were found to have
more compromised PEFR as compared to those with more exposure, since it was observed that as duration
increases the acute symptoms subside. Thus, chronic
inhalation of air in Delhi caused decline in lung function in
a significant percentage of inhabitants of the city. Kumar
et al. reported similar findings where the lung functions
such as forced expiratory volume, forced vital capacity
and peak expiratory volume (PEV) were found to be
much lower than normal.15 In a similar study by Kumar
et al., the increased risk of having chronic respiratory
symptoms was 1.5 (95% CI = 1.2, 1.8; P < 0.00) and
that of spirometric ventilatory defects was 2.4 (95%
CI = 2.0, 2.9; P < 0.001) in the study town compared with
the reference population, even after controlling for the
effects of age, gender, education, occupation, income,
ever smoking, passive smoking, type of cooking fuel
and migration.16
In a similar study conducted by Chitranjan Cancer
Research Institute, Kolkata on 1310 individuals from
Kolkata and 200 from rural West Bengal, symptoms
related to problems in the upper respiratory tract were
found in 47.8% of urban people in contrast to 35%
of rural controls. Respiratory symptoms were most
frequent during winter when the pollution level of the
city with respect to respirable particulate matter was the
highest. The percentage of individuals with impaired lung
function (47%) correlated well with the frequency of lower
respiratory symptoms (47.8%) in urban people.17 In
another study that compared the ventilatory functions of
two groups of school children of Kolkata, one within CMA
(study) and another in an area with better ambient air
quality, the observations were indicative of a statistically
significant impairment of lung functions (PEFR) in the
study group exposed to higher concentration of pollutants
in the ambient air.18
In the present study, asthma was observed in 23% of
patients in HPA compared to 9% in LPA. Allergy and
dermatitis was also more in HPA (15.9%) than in LPA
(4.7%) population. Thus, the present study is comparable
to the studies done earlier by Joshi, in which it was found
that lung function was lower in more polluted city zone.
For morbidity, the urban area with high levels of pollution
was the worst, the medium areas slightly better and the
low areas best. The study concluded that most of the
health effects observed could be attributed to multiple
pollutants.4,7 All these findings both from the present
and past studies warrant long-term perspective studies
in view of the possible risk of developing obstructive
lung diseases.
References
- Ghosh MK, Paul R, Banerjee SK. Assessment of the
impacts of the vehicular pollution on urban air quality.
J Environ Sci Engg 2004;46:33-40.
- Yassi A, Kjellstroom T, Kok TD, Guidotti T. Basic Environmental
Health. Oxford University Press: Oxford; 2001.
- Sapru RK. Environmental management in India. Air
Pollution 1987;1:145-7.
- Smith KR. Air pollution and rural biomass in developing
countries: A pilot village study in India and implication
for research and policy. Atmospheric Environ 1993;17:
2343-62.
- David B. Environmental health risks and public policy.
Washington Press: Washington DC; 1994.
- Lercher P, Schitzberger R, Kofler W. Perceived traffic air
pollution, associated behavior and health in an alpine area.
Sci Total Environ 1995;169:71-4.
- Joshi TK. Asbestos related morbidity in India. Int J Occup
Env Health 2003;9:249-53.
- National Ambient Air Quality Monitoring Series, Central
Pollution Control Board Report, Delhi: Ministry of
Environment and Forest, Government of India, 1996-97.
- Pollution Control Acts, Rules and Notification issued there
under, Central Pollution Control Board, New Delhi: Ministry
of Environment and Forest, Government of India, 1998.142-9.
- World Health Organization. World Health Report 2002.
WHO: Geneva; 2002.
- Kamat SR, Godkhindi KD, Shah BW, Mehta AK, Shah VN.
Correlation of health morbidity to air pollution levels in
Bombay city, results of prospective three years survey at
one year. J Postgrad Med 1980;26:45-62.
- Respirable particulate matter and its health effects. Central
Pollution Control Board: New Delhi; 2001.
- Survey for assessing the impact of air pollution on health at
critically polluted areas of Cochin, Clinical Epidemiology Unit,
Medical College, Thiruvananthapuram, New Delhi: Ministry
of Environment and Forest, Government of India, 1992-94.
- Kumar R. Effects of environmental pollution on respiratory
system of auto rickshaw drivers in Delhi. Indian J Occup
Environ Med 1999;3:171-3.
- CPCB. Effects of Kolkata’s air pollution on adult population:
A survey by Chitranjan Cancer Research Institute: Kolkata;
2004. Available from: http://www.cpcb.nic.in.
- Kumar R, Parwana HK, Sharma M, Srivastva A, Thakur JS,
Jindal SK. Association of outdoor air pollution with chronic
respiratory morbidity in an industrial town in northern India.
Arch Environ Health 2004;59:471-7.
- CPCB Newsletter. Available from: http://www.cpcb.nic.in.
- Viegi G. Non-carcinogenic health effects of air pollutants:
A European perspective. J Tuber Lung Dis 1994;75:83-4.
National Institute of Health and Family Welfare, Delhi, and
(1)Department of CHA, National Institute of Health and Family
Welfare, Delhi, India
Correspondence to:
Prof. M. Bhattacharya,
Department of CHA, National Institute of Health and Family Welfare,
New Mehrauli Road, Munirka, New Delhi – 110 067, India.
E-mail: cha_nihfw(at)yahoo.co.in
Received: 28.04.06
Accepted: 15.10.07
ISSN No. 0970-0218
A Sagar, M Bhattacharya1, Vinod Joon1
Abstract
Background: Vehicular pollution is increasing in Indian cities, which may lead to increased number of patients with diseases related to air pollution. Present study was undertaken to assess the pattern of morbidity in two areas of Delhi, one highly polluted area (HPA) and the other low polluted area (LPA). Materials and Methods: Subjects were interviewed regarding socioeconomic status and exposure history. Symptoms during the last month were recorded in a questionnaire and weight, height and peak expiratory flow rate (PEFR) were measured. Air pollution data were obtained from the monitoring stations of Central Pollution Control Board (CPCB). Results: A total of 640 subjects participated in the study. Majority of the patients in both the areas were educated till primary but 24% in HPA and 13% in LPA were graduates. Current levels of all pollutants (except SO2 and NOx) were above the safety levels prescribed by CPCB in both the areas, but the values were much higher in HPA. The values of PEFR amongst study population were more compromised in HPA. The difference in mean PEFR values among the populations in LPA and HPA were found to be statistically significant (P < 0.05). The mean number of symptoms experienced by subjects of HPA was more as compared to LPA (P < 0.05). Frequency of occurrence of symptoms varied with duration of stay in the study area. Children were affected more than the adults. Conclusion: Air pollution has a deleterious effect on various systems of the body.
Keywords: Air pollution, exposure, health effects, peak expiratory flow rate, vehicular emissions
Air quality is deteriorating especially in metropolitan cities, mainly due to vehicular emissions. There is good evidence that the health of 900 million urban people over the world is deteriorating daily because of high levels of ambient air pollutants.1 The toxicology of air pollution is exceedingly complex as there are different types of pollutants affecting individual differently.2
The pollutants in air namely SO2, NOx and suspended particulate matter (SPM) damage the human respiratory and cardio respiratory systems in various ways. The elderly, children, smokers and those with chronic respiratory diseases are most vulnerable.3 It has been reported that high levels of pollution affect mental and emotional health too. Amongst the symptoms, feeling of fatigue, exhaustion, low mood, nervousness, irritation of eyes and stomach aches have shown a significant association with air quality. Inhalation of fumes is associated with recurrent colds, chronic bronchitis and hyperactive airways.4 Elevated lead levels in children have been associated with impaired neurological development as measured by lowered IQ, poor school performance and behavioural difficulties.3
Environmentalists claim that living in an Indian metropolitan city is like smoking 10-20 cigarettes every day. More than 40,000 people die pre-maturely every year because of air pollution, says a World Bank report, of which Delhi’s share is the highest (19%).5 The estimates of disease burden due to urban air pollution are based on the impact of air pollution on mortality. The impact of air pollution on morbidity could not be included in the calculations due to lack of reliable epidemiological data. Few studies have been conducted on the health effects of air pollution in the general population of Delhi. This study is an effort to identify the adverse health impacts due to air pollution on communities residing in areas of high and low ambient pollution levels.
Materials and Methods
This descriptive study was carried out in Delhi, the capital of India. The study areas were taken up randomly from among the areas already identified by the central pollution control board. Daryaganj was identified as highly polluted area (HPA) and Gazipur as low polluted area (LPA). The mean level of pollutants during the previous 1 year was recorded. Two population groups, one from HPA and other from LPA were selected for this study.
A sample of 320 people each was taken up from both LPA and HPA. The sample size was based on the prevalence of symptoms and signs in the studies done earlier, which had found the frequency of mucosal irritation as 39.7% and eye symptoms as 26.9%6 with 10% error. Inclusion criteria for the study was that the person should be living and working in the selected areas for more than 6 months, be below 45 years (to rule out respiratory symptoms associated with old age) and be a non-smoker. The study population was disaggregated into four age groups. The age groups were: 0-5 years, 6-13 years, 14-22 years and 23-45 years, with a sample size of 80 subjects in each age group. Males outnumbered females in both the areas. In HPA, 78% and in LPA, 75% subjects were males.
A pre-coded structured interview schedule was prepared to collect the data. Past history of relevant illness was obtained from the medical records of individuals. Medical examination and certain measurements like weight, height, blood pressure and peak expiratory flow rate (PEFR) were carried out on the spot for each study subject. The levels of pollutants namely SPM [respirable suspended particulate matter (RSPM) and total suspended particulate matter (TSPM)], NO2, SO2 and lead as measured by CPCB were obtained by the investigators. The adverse health effects of pollutants were based on the list of symptoms prepared by the Society for Environment and Health.7 The data were analysed with SPSS and appropriate statistical tests like chi-square test, odds ratio and standard error of mean were used.
Results
The mean values of all pollutants (except SO2 and NO2) exceeded the recommended National Ambient Air Quality Standards (NAAQS) prescribed for residential areas in both Daryaganj and Gazipur, but the values were much lower in Gazipur (LPA).8 The levels of TSPM, RSPM and lead were much above the safety limits prescribed for residential areas by the Central Pollution Control Board for both the study areas.9 The TSPM levels were 683 and 235 μg/m3 for HPA and LPA, respectively.
Fifty-two percent of people in HPA and 47.2% of people in LPA had 3-5 years of stay in their respective areas, and 32.2% of subjects of HPA and 44% of subjects of LPA have been living in that area for nearly 2 years.
As shown in Table 1, majority of subjects in both HPA and LPA were educated till primary. The percentage of graduates was more in HPA than in LPA. In HPA, 84.4% and in LPA, 79.4% of the subjects had knowledge about air pollution as a hazard to health.
Table 2 shows that the values of PEFR were less in HPA as compared to LPA. The PEFR is the indicator of lung function, which is affected as a result of exposure to air pollution.
When the differences in mean number of symptoms experienced by the individuals of HPA and LPA were compared, it was found that the symptoms were more likely to occur in HPA population than in the subjects residing in the LPA. Table 3 shows that higher percentage of subjects of HPA suffered from different symptoms like irritation of nose and eyes, watering of eyes and nose, respiratory infections, breathlessness, ringing in ears and headaches. When the differences between various symptoms experienced by the subjects from HPA and LPA areas were compared, it was found that the symptoms were statistically significant except for a few symptoms like febrile conditions and common cold.
The individual symptoms were analyzed for different age groups and it was observed that the subjects residing in HPA, irrespective of age were likely to have 1.7 to 3.37 times more chances of suffering with the symptoms related to pollution, compared to the subjects residing in LPA. Further, when we compared the symptoms among different age groups, it was found that the age group 14-22 years had the lowest probability of occurrence of various symptoms amongst all the age groups, while the age group 6-13 years had the highest chance of developing various symptoms.
Table 1: Educational status of the study subjects
| Educational status |
High pollution area, No. (%) |
Low pollution area, No. (%) |
Total, No. (%) |
|---|---|---|---|
| Illiterate | 24 (7.5) | 35 (10.9) | 59 (9.2) |
| Primary | 110 (34.3) | 108 (33.7) | 218 (34.0) |
| Middle | 47 (14.6) | 49 (15.3) | 96 (15) |
| Matric | 22 (6.8) | 35 (10.9) | 57 (8.9) |
| Senior Secondary |
44 (3.7) | 52 (16.2) | 96 (15) |
| Graduate | 73 (23.1) | 41 (13.0) | 114 (17.9) |
| Total | 320 | 320 | 640 |
P = 0.01
Table 2: Mean peak expiratory flow rates by duration of exposure
| Duration of stay | High pollution area | Low pollution area | ||||
|---|---|---|---|---|---|---|
| Mean | S.D. | Total | Mean | S.D. | Total | |
| Up to 2 years | 231.9 | 150.8 | 103 | 281.7 | 157.4 | 141 |
| 3-5 years | 414.4 | 147.3 | 165 | 507.6 | 138.7 | 151 |
| More than 5 years | 527.3 | 57.2 | 52 | 590.4 | 51.4 | 28 |
P < 0.05
Table 3: Symptoms during previous 1 year
| Symptoms | High pollution area, No. (%) | Low pollution area, No. (%) | P-value |
|---|---|---|---|
| Burning eyes | 124 (38.8) | 57 (17.8) | <0.001 |
| Irritation of eyes | 111 (34.7) | 53 (16.6) | <0.001 |
| Irritation of Nose | 134 (41.9) | 54 (16.9) | <0.001 |
| Irritation of throat | 136 (42.5) | 50 (15.6) | <0.001 |
| Watering of eyes | 125 (39.1) | 66 (20.6) | <0.001 |
| Watering of nose | 170 (53.1) | 130 (40.6) | <0.001 |
| Respiratory infection | 86 (26.9) | 36 (11.3) | <0.001 |
| Black sputum | 45 (14.1) | 31 (9.7) | 0.08 |
| Cough | 220 (68.8) | 212 (66.3) | 0.4 |
| Breathlessness | 112 (35) | 48 (15) | <0.001 |
| Chest pain | 40 (12.5) | 23 (7.2) | <0.02 |
| Sneezing | 168 (52.5) | 135 (42.2) | 0.008 |
| Common cold | 158 (49.4) | 113 (35.3) | 0.0003 |
| Febrile condition | 11 (3.4) | 14 (4.4) | 0.5 |
| Suffocation | 17 (5.3) | 9 (2.8) | 0.1 |
| Ringing in ears | 80 (25) | 38 (11.9) | 0.00001 |
| Nausea | 11 (3.4) | 14 (4.4) | 0.5 |
| Headache | 142 (44.4) | 98 (30.6) | 0.0003 |
| Vomiting | 45 (14.1) | 98 (30.6) | <0.001 |
| Total | 320 | 320 |
Discussion
According to the World Health Report 2002, analyses based on particulate matter estimates report that ambient air pollution causes about 5% of trachea, bronchus and lung cancer, 2% of cardio-respiratory mortality and about 1% of respiratory infections mortality globally. This amounts to about 1.4% (0.8 million) deaths and 0.8% (7.9 million) of disability-adjusted life years. The adverse effects of air pollution are more pronounced in developing countries.10 The problem of air pollution is increasing at an alarming rate in Delhi. It is India’s most polluted metropolitan city with 70% air pollution of Delhi being caused by vehicles only. This has resulted in higher air pollution-related morbidity among its inhabitants.
The study area in Daryaganj is a highly congested area with heavy traffic density and frequent traffic jams, resulting in build up of air pollutants in that area. This ultimately leads to more exposure to people residing and working in that area. Gazipur on the other hand, is a rural area situated on the outskirts of Delhi with less traffic density and consequently less exposure of its inhabitants.
In the present study, mean levels of pollutant in the study areas were almost comparable to the study done by Kamat and others.11,12 In air quality studies, total aerosol in air is measured as TSPM. Course particles are not useful except that it reflects the perception of haze in air and results in diminished visibility. RSPM is the most important fraction from health point of view.
Total exposure of an individual to pollutants is determined by the concentration of pollutants and the duration of exposure. The exposure levels in the study population were measured by the duration of stay of subjects in the study area as up to 2 years, 3-5 years and above 5 years. Sixty-eight percent of the people of HPA and 56% of LPA were staying in the area for more than 3 years. The prevalence of airborne diseases was more in HPA as compared to LPA. This could be due to high levels of air pollutants in their environment specially the RSPM, as these particulates tend to deposit in alveoli and slow down the exchange of oxygen with carbon dioxide in the blood, causing shortness of breath. The number of symptoms observed in this study had more frequency of occurrence in HPA than LPA. The symptoms also vary with different duration of exposure. The findings reported in this study and others regarding respiratory morbidity, lung function and urban air pollutant levels are similar. According to the Health Care Institute of India, there is an alarming rise in number of patients in Delhi hospitals with respiratory problems.13 A study from Cochin also reported higher prevalence of respiratory symptoms.14
A study conducted by All India Institute of Medical Sciences and Central Pollution Control Board in Delhi showed that exposure to higher levels of particulate matter contributed to respiratory morbidity. It indicated that the most common symptoms related to air pollution were irritation of eyes (44%), cough (28.8%), pharyngitis (16.8%), dyspnea (16%) and nausea (10%).15 A similar study in Bombay found the prevalence of symptoms and signs of disease to be around 22.2%.11
In the present study, the PEFR values were found to be much lower than Clement Clark’s Standard. 83.8% of the subjects of HPA were having PEFR values less than normal as compared to 44.1% of the subjects of LPA. Person with less duration of exposure were found to have more compromised PEFR as compared to those with more exposure, since it was observed that as duration increases the acute symptoms subside. Thus, chronic inhalation of air in Delhi caused decline in lung function in a significant percentage of inhabitants of the city. Kumar et al. reported similar findings where the lung functions such as forced expiratory volume, forced vital capacity and peak expiratory volume (PEV) were found to be much lower than normal.15 In a similar study by Kumar et al., the increased risk of having chronic respiratory symptoms was 1.5 (95% CI = 1.2, 1.8; P < 0.00) and that of spirometric ventilatory defects was 2.4 (95% CI = 2.0, 2.9; P < 0.001) in the study town compared with the reference population, even after controlling for the effects of age, gender, education, occupation, income, ever smoking, passive smoking, type of cooking fuel and migration.16
In a similar study conducted by Chitranjan Cancer Research Institute, Kolkata on 1310 individuals from Kolkata and 200 from rural West Bengal, symptoms related to problems in the upper respiratory tract were found in 47.8% of urban people in contrast to 35% of rural controls. Respiratory symptoms were most frequent during winter when the pollution level of the city with respect to respirable particulate matter was the highest. The percentage of individuals with impaired lung function (47%) correlated well with the frequency of lower respiratory symptoms (47.8%) in urban people.17 In another study that compared the ventilatory functions of two groups of school children of Kolkata, one within CMA (study) and another in an area with better ambient air quality, the observations were indicative of a statistically significant impairment of lung functions (PEFR) in the study group exposed to higher concentration of pollutants in the ambient air.18
In the present study, asthma was observed in 23% of patients in HPA compared to 9% in LPA. Allergy and dermatitis was also more in HPA (15.9%) than in LPA (4.7%) population. Thus, the present study is comparable to the studies done earlier by Joshi, in which it was found that lung function was lower in more polluted city zone. For morbidity, the urban area with high levels of pollution was the worst, the medium areas slightly better and the low areas best. The study concluded that most of the health effects observed could be attributed to multiple pollutants.4,7 All these findings both from the present and past studies warrant long-term perspective studies in view of the possible risk of developing obstructive lung diseases.
References
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- Yassi A, Kjellstroom T, Kok TD, Guidotti T. Basic Environmental Health. Oxford University Press: Oxford; 2001.
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- Smith KR. Air pollution and rural biomass in developing countries: A pilot village study in India and implication for research and policy. Atmospheric Environ 1993;17: 2343-62.
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- Lercher P, Schitzberger R, Kofler W. Perceived traffic air pollution, associated behavior and health in an alpine area. Sci Total Environ 1995;169:71-4.
- Joshi TK. Asbestos related morbidity in India. Int J Occup Env Health 2003;9:249-53.
- National Ambient Air Quality Monitoring Series, Central Pollution Control Board Report, Delhi: Ministry of Environment and Forest, Government of India, 1996-97.
- Pollution Control Acts, Rules and Notification issued there under, Central Pollution Control Board, New Delhi: Ministry of Environment and Forest, Government of India, 1998.142-9.
- World Health Organization. World Health Report 2002. WHO: Geneva; 2002.
- Kamat SR, Godkhindi KD, Shah BW, Mehta AK, Shah VN. Correlation of health morbidity to air pollution levels in Bombay city, results of prospective three years survey at one year. J Postgrad Med 1980;26:45-62.
- Respirable particulate matter and its health effects. Central Pollution Control Board: New Delhi; 2001.
- Survey for assessing the impact of air pollution on health at critically polluted areas of Cochin, Clinical Epidemiology Unit, Medical College, Thiruvananthapuram, New Delhi: Ministry of Environment and Forest, Government of India, 1992-94.
- Kumar R. Effects of environmental pollution on respiratory system of auto rickshaw drivers in Delhi. Indian J Occup Environ Med 1999;3:171-3.
- CPCB. Effects of Kolkata’s air pollution on adult population: A survey by Chitranjan Cancer Research Institute: Kolkata; 2004. Available from: http://www.cpcb.nic.in.
- Kumar R, Parwana HK, Sharma M, Srivastva A, Thakur JS, Jindal SK. Association of outdoor air pollution with chronic respiratory morbidity in an industrial town in northern India. Arch Environ Health 2004;59:471-7.
- CPCB Newsletter. Available from: http://www.cpcb.nic.in.
- Viegi G. Non-carcinogenic health effects of air pollutants: A European perspective. J Tuber Lung Dis 1994;75:83-4.
National Institute of Health and Family Welfare, Delhi, and
(1)Department of CHA, National Institute of Health and Family
Welfare, Delhi, India
Correspondence to:
Prof. M. Bhattacharya,
Department of CHA, National Institute of Health and Family Welfare,
New Mehrauli Road, Munirka, New Delhi – 110 067, India.
E-mail: cha_nihfw(at)yahoo.co.in
Received: 28.04.06
Accepted: 15.10.07
