Importance of National Ambient Air Quality Standards
Air
Pollutant includes any substance in solid, liquid or gaseous form
present in the atmosphere in concentrations which may tend to be
injurious to all living creatures, property and environment. Various
contaminants in different forms from both man-made and natural sources
perpetually enter our environment and contaminate it causing toxicity,
diseases and environmental decay. Recent industrialization and increased
number of potent air polluting sources like automobiles, landfills,
etc. has gushed into the atmosphere toxic materials which not only harm
human health but are also a threat to the ecosystem in general. In order
to arrest the deteriorating air quality, Government of India enacted
Environment (Protection) Act, 1986, which was an umbrella act for the
protection of all aspects of the environment. The government had also
enacted the Air (Prevention and Control of Pollution) Act, 1981 with the
aim of ensuring moderated pollution concentrations and hence safe
ambient air quality.
Also read- Vehicular Pollution and Emission Standards in India
Air
pollution is a global concern. One can not merely abstain themselves
from pollution at an individual level because unlike water whose purity
can be ensured before consumption, air has to be taken up in the form
that it is present. Air pollution is known to cause a lot of premature
deaths, chronic asthma, decreased fertility, deteriorated property and
may lead to the hazardous acid rains too. It is hence imperative that
the air pollutant concentrations are regularly monitored and a proper
inventory is maintained so that one can predict unforeseen disasters
like The Great Smog of 1952 in London. With the aim of proper monitoring
of the pollutant concentrations, the Central Pollution Control Board
(CPCB) in1984-1985 launched the National Ambient Air Quality Monitoring
network which was later renamed as National Air Monitoring Programme
(N.A.M.P.). The objectives of N.A.M.P. can be enlisted as follows-
- To determine the trend and status of the ambient air quality.
- To ascertain that the prescribed levels are being met or not
- To identify the cities where the pollution concentration is higher than the prescribed levels.
- To understand and obtain knowledge for the development of preventive and corrective measures.
- To understand the ongoing natural processes of cleansing like dispersion, dilution, dry deposition, wind-based movements, chemical transformation and precipitation.
The objective of National Ambient Air Quality Standards (NAAQS) is-
- To indicate necessary air quality levels and appropriate margins required to ensure the protection of vegetation, health and property.
- To provide assistance in the establishment of priorities for abatement and control of pollution.
- To provide a uniform yardstick for assessment of air quality at the national level.
- To indicate the extent and need of monitoring programme.
The NAAQS notified as on November 2009 is tabulated below-
Sr. No | Pollutants | Time Weighted Average | Concentration in Ambient Air | Methods of Measurement | |
Industrial, Residential, Rural and other Areas | Ecologically Sensitive Area (notified by Central Government) | ||||
1 | Sulphur Dioxide (SO2 ), µg/m3 | Annual* | 50 | 20 | 1. Improved West and Gaeke2. Ultraviolet Fluorescence |
24 Hours** | 80 | 80 | |||
2 | Nitrogen Dioxide (NO2 ), µg/m3 | Annual* | 40 | 30 | 1. Modified Jacob & Hochheiser (Na-Arsenite)2. Chemiluminescence |
24 Hours** | 80 | 80 | |||
3 | Particulate Matter (Size <10 µm) or PM10 µg/m3 | Annual* | 60 | 60 | 1. Gravimetric2. TEOM 3. Beta attenuation |
24 Hours** | 100 | 100 | |||
4 | Particulate Matter (Size<2.5 µm) or PM2.5 µg/m3 | Annual* | 40 | 40 | 1. Gravimetric2. TEOM 3. Beta attenuation |
24 Hours** | 60 | 60 | |||
5 | Ozone (O3 ), µg/m3 | 8 hours** | 100 | 100 | 1. UV photometric2. Chemiluminescence 3. Chemical Method |
1 hours ** | 180 | 180 | |||
6 | Lead (Pb), µg/m3 | Annual* | 0.50 | 0.50 | 1. AAS/ICP Method after sampling using EPM 2000 or equivalent filter paper2. ED-XRF using Teflon filter |
24 Hours** | 1.0 | 1.0 | |||
7 | Carbon Monoxide (CO), mg/m3 | 8 hours** | 02 | 02 | Non dispersive Infra Red (NDIR) Spectroscopy |
1 hours ** | 04 | 04 | |||
8 | Ammonia (NH3 ), µg/m3 | Annual* | 100 | 100 | 1. Chemiluminescence2. Indophernol blue method |
24 Hours** | 400 | 400 | |||
9 | Benzene (C6 H6 ) , µg/m3 | Annual* | 05 | 05 | 1. Gas chromatography based continuous analyzer2. Adsorption and Desorption followed by GC analysis |
10 | Benzo(a)Pyrene (BaP)- particulate phase only, ng/m3 | Annual* | 01 | 01 | Solvent extraction followed by HPLC/GC analysis |
11 | Arsenic (As), ng/m3 | Annual* | 06 | 06 | AAS/ICP method after sampling on EPM 2000 or equivalent filter paper |
12 | Nickel (Ni), ng/m3 | Annual* | 20 | 20 | AAS/ICP method after sampling on EPM 2000 or equivalent filter paper |
*Annual
Arithmetic mean of minimum 104 measurements in a year at a particular
site taken twice a week 24 hourly at a uniform interval.
**
24 hourly 08 hourly or 01 hourly monitored values, as applicable shall
be complied with 98% of the time in a year. 2% of the time, they may
exceed the limits but not on two consecutive days of monitoring.
The air quality is categorized under 4 broad categories based on Exceedance Factor.
The four air quality categories are:
- Critical pollution (C): when EF is > 1.5;
- High pollution (H): when the EF is between 1.0 – < 0.5;
- Moderate pollution (M) : when the EF between 0.5 – <1.0;
- Low pollution (L): when the EF is < 0.5.
Pollution level | Annual Mean Concentration Range (µg/m3 ) | |||||
Industrial, Residential, Rural & others areas | Ecologically Sensitive Area | |||||
SO2 | NO2 | PM10 | SO2 | NO2 | PM10 | |
Low (L) | 0-25 | 0-20 | 0-30 | 0-10 | 0-15 | 0-30 |
Moderate (M) | 26-50 | 21-40 | 31-60 | 11-20 | 16-30 | 31-60 |
High (H) | 51-75 | 41-60 | 61-90 | 21-30 | 31-45 | 61-90 |
Critical (C) | >75 | >60 | >90 | >30 | >45 | >90 |
The
US EPA identifies two types of NAAQS as per The Clean Air Act, namely,
the primary standards for the protection of public health and that of
sensitive populations such as children, elderly people and asthmatics.
Secondary standards provide for the public welfare protection which
includes a safeguard against reduced visibility and damage to crops,
animals, vegetation and buildings.
Pollutant [links to historical tables of NAAQS reviews] | Primary/ Secondary | Averaging Time | Level | Form |
Carbon Monoxide (CO) | primary | 8 hours | 9 ppm | Not to be exceeded more than once per year |
1-hour | 35 ppm | |||
Lead (Pb) | primary and secondary | Rolling 3 month period | 0.15 μg/m3 | Not to be exceeded |
Nitrogen Dioxide (NO2) | primary | 1-hour | 100 ppb | 98th percentile of 1-hour daily maximum concentrations, averaged over 3 years |
primary and secondary | 1 year | 53 ppb | Annual Mean | |
Ozone (O3) | primary and secondary | 8 hours | 0.070 ppm | Annual fourth-highest daily maximum 8-hour concentration, averaged over 3 years |
PM2.5 | primary | 1 year | 12.0 μg/m3 | annual mean, averaged over 3 years |
secondary | 1 year | 15.0 μg/m3 | annual mean, averaged over 3 years | |
primary and secondary | 24 hours | 35 μg/m3 | 98th percentile, averaged over 3 years | |
PM10 | primary and secondary | 24 hours | 150 μg/m3 | Not to be exceeded more than once per year on average over 3 years |
Sulfur Dioxide (SO2) | primary | 1-hour | 75 ppb | 99th percentile of 1-hour daily maximum concentrations, averaged over 3 years |
secondary | 3 hours | 0.5 ppm | Not to be exceeded more than once per year |
The European Union set Air Quality Limit Values (AQLVs) in 1980 and guide values for SO2 and
suspended particulates. They later incorporated lead, nitrogen dioxide
and ozone. The Air Quality Framework Directive (AQFD) of 1996 and its
progenies aim for the establishment of harmonized structure for the
assessment and management of air quality throughout the European Union.
International comparison of Ambient Air Quality Standards in compared to
WHO recommendations-
Pollutant | WHO | European Union | Australia | United States | Canada |
Ozone8 hour, ppb | 50 | 60 | 80 | 80 | 65 |
Fine particulate24 hour, μg/m3 | 25 | 50 | 25 | 65 | 30 |
SO224 hour, ppb | 8 | 48 | 80 | 140 | 115 |
NO2annual, ppb | 21 | 21 | 30 | 53 | 53 |
CO8 hour, ppm | 9 | 9 | 9 | 9 | 13 |
Leadμg/m3 | – | 0.5 | 0.5 | 1.5 | – |
http://www.aeroqual.com/air-quality-standards
It
is hence evident that all countries have a proper inventory of air
pollutant monitored concentrations and also yardsticks that need to be
met. It is important to ensure sustainable development and also to
figure out the loopholes in the system as to why the criteria are not
being met. Each country has their own norms and standards and it is
imperative for the state to manage and work in a way to ascertain that
the air pollutant concentrations are way below the maximum level and
hence safe to breathe because we don’t have an alternative option to
supply us with oxygen which is of essence in ensuring our survival on
this planet.
http://cpcb.nic.in/upload/NewItems/NewItem_104_airquality17cities-package-.pdf
http://www.cpcb.nic.in/15-44.pdf
http://ec.europa.eu/environment/archives/cafe/activities/pdf/case_study2.pdf
No comments:
Post a Comment