An
emergency plan called the Graded Response Action Plan has been notified by the
Ministry of Environment, Forest & Climate Change for implementation under
different Air Quality Index (AQI) categories.
The
different AQI categories are Severe, Very poor and Moderate & Poor. The
cut-off levels of PM2.5 or PM10 have been defined for each category as have
been the actions to be implemented and the agency responsible for implementing
the specified actions.
The
actions to be implemented under the Severe or Emergency category defined
as “ambient PM 2.5 or PM 10 concentration values of 300μg/m3 or 500
μg/m3 respectively persist for 48 hours or more” are:
- Stop entry of
truck traffic into Delhi (except essential commodities)
- Stop
construction activities
- Introduce odd
and even scheme for private vehicles based on license plate numbers and
minimize exemptions
- Task Force to
take decision on any additional steps including shutting of schools
The
graded response action plan, as the name suggests, also lists action to be
taken under different categories such as severe, very poor and moderate to poor
(defined as below).
- Severe (ambient
PM2.5or PM10 concentration value is more than 250 μg/m3or 430μg/m3
respectively)
- Very poor
(ambient PM2.5or PM10 concentration value is between 121-250μg/m3or
351-430 μg/m3 respectively)
- Moderate to poor
(ambient PM2.5 or PM10 concentration value is between 61-120 μg/m3 or
101-350 μg/m3 respectively)
What
stands out in this Action Plan is the time period of 48 hours specified only
for the Severe or Emergency category, but not for other
categories.
The
question here is why this time period of 48 hours?
One
cannot wait for 48 hours to declare an emergency. If AQI remains high in the
severe or emergency category, even for a very short period of time, a person
will have suffered the ill-effects. They will not wait for 48 hours to set in.
AQI
in the severe category not only affects those with underlying heart or lung
disease, but also those who are healthy.
Breathing polluted air for even two hours can increase blood
pressure, potentially raising the risk of cardiovascular disease in those
exposed to smog. In susceptible patients, this small increase may actually be
able to trigger a heart attack or stroke. .
Short-term
exposure to air pollutants (both ozone and fine particulate matter) has been
associated with total mortality1 and acute coronary
ischemic events2-5
· In a
case-crossover study of more than 22 million deaths between 2000 and 2012
identified from the United States Medicare population, increased risk of
all-cause mortality was seen with short-term increases in fine particulate
matter (RR increase 1.05 percent for each 10 mcg/m3 increase) and
ozone (RR increase 0.51 percent for each 10 part per billion increase). 1
The increased risk occurred at levels of air pollution that are lower than the
currently suggested air quality standards.
· In a study
of over 12,000 patients living in a defined geographic area, a short-term
increase in fine ambient particulate matter positively correlated with an
increase in acute ischemic coronary events. 2
· In a
systematic review and meta-analysis of data from 34 studies, carbon monoxide,
nitrogen dioxide, sulfur dioxide, and small particulate matter (less than 10
microns and less than 2.5 microns) were all associated with an increased risk
of myocardial infarction (MI), with the overall population attributable risk
ranging from 1 to 5 percent. 6
Possible
mechanisms by which fine particulate air pollution may increase the risk of CVD
include:7
· An
increase in mean resting arterial blood pressure through an increase in
sympathetic tone and/or the modulation of basal systemic vascular
tone8
· An
increase in the likelihood of intravascular thrombosis through transient
increases in plasma viscosity and impaired endothelial dysfunction9
· The
initiation and promotion of atherosclerosis10,11
When
the AQI reaches the level, high enough to be categorized as emergency, the
pre-emptive measures should start automatically by the concerned agency
including us, as individuals.
For
instance, if the AQI is in the emergency category, schools/colleges should stop
all outdoor activities including sports and the school medical officer should
advise closing of the school.
- The odd and even
scheme can be self-implemented in such a situation.
- Walk or cycle
for short distance commutes or to the neighborhood market. Plan and
combine all your errands in one area or close by areas for one trip. Limit
driving and make use of carpool.
- Use public
transport as much as possible for longer distances. If you have to use
your vehicle keep it well maintained for efficient functioning with
regular servicing to reduce harmful exhaust emissions and get pollution
check done as required. Follow speed limits. Avoid buying diesel vehicle.
- Avoid burning
candles dhoop or incense sticks at home or workplace.
- Wet mop the
floors at home or workplace
The
AQI varies from area to area. It may be higher in some parts of Delhi, for
example; at places, it may be lower. Hourly AQIs can be obtained for different
areas of Delhi at http://www.dpccairdata.com/.
Each
of one of us should act, instead of waiting for the government to enforce the
graded action plan after a period of 48 hours.
Check
the daily pollution levels in your area and be proactive in taking precautions.
Self-regulation
is the answer…
References
1. Di Q, Dai L, Wang Y, et al. Association of
short-term exposure to air pollution with mortality in older adults. JAMA
2017;318:2446.
2. Pope CA 3rd, et al. Ischemic heart disease
events triggered by short-term exposure to fine particulate air pollution.
Circulation 2006;114:2443.
3. Ruidavets JB, Cournot M, Cassadou S, et al.
Ozone air pollution is associated with acute myocardial infarction. Circulation
2005; 111:563.
4. Tonne C, Wilkinson P. Long-term exposure to
air pollution is associated with survival following acute coronary syndrome.
Eur Heart J 2013;34:1306.
5. Sinharay R, Gong J, Barratt B, et al.
Respiratory and cardiovascular responses to walking down a traffic-polluted
road compared with walking in a traffic-free area in participants aged 60 years
and older with chronic lung or heart disease and age-matched healthy controls:
a randomised, crossover study. Lancet 2018;391:339.
6. Mustafic H, Jabre P, Caussin C, et al. Main
air pollutants and myocardial infarction: a systematic review and
meta-analysis. JAMA 2012;307:713.
7. Newby DE, Mannucci PM, Tell GS, et al. Expert
position paper on air pollution and cardiovascular disease. Eur Heart J
2015;36:83.
8. Brook RD, Brook JR, Urch B, et al. Inhalation
of fine particulate air pollution and ozone causes acute arterial
vasoconstriction in healthy adults. Circulation 2002;105:1534.
9. Pekkanen J, Peters A, Hoek G, et al.
Particulate air pollution and risk of ST-segment depression during repeated
submaximal exercise tests among subjects with coronary heart disease: the
Exposure and Risk Assessment for Fine and Ultrafine Particles in Ambient Air
(ULTRA) study. Circulation 2002;106:933.
10. Sun
Q, Hong X, Wold LE. Cardiovascular effects of ambient particulate air pollution
exposure. Circulation 2010; 121:2755.
11. Bauer
M, Moebus S, Möhlenkamp S, et al. Urban particulate matter air pollution is
associated with subclinical atherosclerosis: results from the HNR (Heinz
Nixdorf Recall) study. J Am Coll Cardiol 2010;56:1803.
Padma
Shri Awardee
President Elect Confederation of Medical Associations
in Asia and Oceania (CMAAO)
Group
Editor-in-Chief IJCP Publications
President
Heart Care Foundation of India
Immediate Past National President IMA
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