dr bhargava

APPROPRIATE INSTRUMENTS AND TECHNIQUES FOR COMPLYING

WITH NEW AMBIENT AIR QUALITY MONITORING STANDARDS

Dr. S. K. Bhargava, Chairman,

State Expert Appraisal Committee, U. P.&

Former Deputy Director & Head, Environmental Monitoring Section,

Indian Institute of Toxicology Research,Lucknow

The presence in outdoor atmosphere, of one or more contaminants such as fumes, dust, gases, mist, grit, odor, smoke, smog or vapors in considerable quantities and of duration which is injurious to human, animal or plant life of which unreasonably interferes with comfortable enjoyment of life and property.”

How Do We Define the Air Pollution ?

Natural SourcesVolcanic

EruptionsForest FiresNatural DecaysMarsh GasesCosmic DustsSoil DebrisPollen GrainsFungal Spores

Anthropogenic SourcesIncrease in

PopulationVehicular PollutionDeforestationBurning of Fossil

Fuels Rapid

IndustrializationAgricultural

ActivitiesWars

Sources of Pollution

Health EffectsPollutants Health Effects

SPM & RSPM Respiratory diseases, reduce visibilitySO2 Irritation of eyes, respiratory system, increased

mucus production, cough and shortness of breath.NOX Irritation of pulmonary tract affecting functioning of

lungs.

CO Reduction in oxygen-carrying capacity of blood, prone to cardiovascular diseases

Hydrocarbons Lung cancer, irritation of mucus membrane.

Pb Cumulative poison, impairment of central nervous system, disruption of pathways of haem synthesis,increase in d-aminolevulinic acid dehydratase activity in red cells/or elevated levels of erythrocyte protoporphyrin

Benzene Leukaemia, Chromosomal damage

Pollutants Health Effects

Ammonia Eye, Nose, Throat irritation, Dyspnea, Bronchospasm, Chest Pain, Pulmonary edema, Pink frothy sputum,Skin burns, vesiculation

Nickel Head verti, nausea, vomit, epigastric, substernal pain, cough, hypernea

Arsenic Ulceration of nasal septum, gastrointestinal disturbances, hyperpigmentation of skin

Benjo(a)Pyrene Carcinogenic

Health Effects

Penetration of RSPM in Respiratory System

Primary and Secondary Pollutants Primary pollutant is an air pollutant emitted directly

from a source. Secondary pollutant is not directly emitted as

such, but forms when other pollutants (primary pollutants) react in the atmosphere.

Examples of a secondary pollutant include ozone, which is formed when hydrocarbons (HC) and nitrogen oxides (NOx) combine in the presence of sunlight; NO2, which is formed as NO combines with oxygen in the air; and acid rain, which is formed when sulfur dioxide or nitrogen oxides react with water.

Objective of Air Monitoring

To assess health hazards and potential damage to property;

To determine the background pollution level for application in industrial zoning, town planning or location of sites for certain types of industries requiring stringent air quality criteria;

To determine the degree of air pollution control required for existing industries;

To identify industrial and other source of pollution;Conti…….

To collect data for formulating and testing air pollution models;

To identify and control pollution from vehicular emission;

To monitor the criteria pollutants depending on the locations;

To determine present air quality status and trend;

To control and regulate pollution from industries and other sources to meet the air quality standards.

Guidelines for carrying out Ambient Air Quality Monitoring developed by CPCB

Site selection criteria;

Quality assurance and quality control in air quality monitoring;

Type of pollutants to be monitored in a city;

Frequency and duration of monitoring; Data reporting and compilation procedures; Measurement methods of various air pollutants

etc.

Site Selection Criteria

The site should be representative of the location being assessed. It should not be unduly influenced by immediate surroundings unless those influences are specifically being measured, for example, near a busy road, a factory stack or a dusty quarry.

The site should not be subject to flooding, and the site classification or situation should not change over time.

National Ambient Air Quality StandardPollutantsPre November 2010

SO2 NOx SPM PM10 Pb Ammonia CO

Post November 2010

SO2 NOx PM10 PM2.5 O3 Pb Carbon Monoxide Ammonia Benzene Benzo(a)pyrene Arsenic Nickel

National Ambient Air Quality StandardArea

Industrial, Residential, Rural& other Areas

Ecologically Sensitive Area

Rotameter and FloatsGas Flow

Rotameter

Floats

Sampling Device

Any gas sampling equipment has three essential component

Suction device Metering device Trapping device to retain the contaminants Equipment with two are even three of the

above component in combination have been designed

Method Prescribed in the standard are:

SO2 Improved West and Gaeke Ultaviolet Florosence

NOx Jacob & Hochheiser (Na-Arsenite) Chemiluminescence's

PM10 & PM 2.5 Gravimetric TOEM Beta attenuation

O3 UV Photometric Chemiluminescence's Chemical Method

Pb AAS/ICP method after sampling on EPM 2000 or equivalent EDXRF Using Teflon filter

CO Non dispersive infrared spectroscopy (NDIR)

NH3

Chemiluminescence's Indophenols Blue Method

Benzene Gas Chromatography based continuous analyzer Adsorption and desorption followed by GC

Benzo (a) pyrene particulate phase only Solvent Extraction followed by HPLC/GC

Arsenic & Nickel AAS/ICP method after sampling on EPM 2000 or equivalent

Types of SamplingSpot sampling Batch Sampling Baseline Sampling

It is for short duration It is for long duration (usually for 24 hours)

It is carried out to determine the quality of ambient for 1-hour and 24‑hour.

Its duration varies from less than 30 minutes to several hours.

Batch sampling may be carried out by the chemical absorption or filtration of measured air volumes sequentially in time.

During monitoring there should not be any construction or dust generating activities in the vicinity of the monitoring stations.

It is useful for the random checking of pollution at any point due to some local source.

Particulate matter which is very small ( less than 10 µm) remain suspended in the air for a periods of time and easily inhaled into the deep lungs. Increased death (mortality) and diseases (morbidity). Currently PM10 have been identifying death effects associated with environmental levels of PM10 is significant issue.

Particulate Matter A. Suspended Particulate Matter (<100 µm)

B. Respirable Suspended Particulate Matter (<10 µm)

C. Fine Particles (<2.5 µm).

Particulate Matter is the term used for a mixture of solid particles and liquid droplets found in the air. Coarse particles larger than 10 µm is known as SPM (Suspended Particulate Matter).

Application and Limitation for Sampling Airborne Particulate Matter

As per the new notification it measures PM10, PM2.5 .

A known volume of air is passed through initially weighted glass fibre filter paper (GF/A) of size 8” x 10”.

Centrifugal force acts on the dust particles to separate it into two parts.

Below 10 m collected on filter paper. Particle above 10 m collected in cyclone cap. The difference in initial and final weight of filter

paper and cyclone cap used in calculation to express the result in g/m3.

Instructions for Measurement of Particulate Matter

Conditioning of Filter Paper: Both blank and sampled filters shall be conditioned at

20-250C and relative humidity below 50% for 16 hrs. prior to weighing.

Sampling: Use fresh carbon brush after every 48 hrs of sampling

or use brushless sampler.Handling: Do not bend or fold the filter before collection of

samples. Transport and Storage: Filter papers can be transported in filter paper box.

RSPM sampling by Respirable Dust Sampler as per IS 5182 Part 32 involves the principle of filtering a known volume of air through a glass fiber filter paper of known weight at an average speed of 1.0-1.5 m3 air/min.

RSPM (µg/m3) = (W2-W1) *106

___________________________

Volume of air sampled

Where W1 is initial weight (g) and W2 is final weight (g) of the filter paper

Methods for Sampling Airborne Particulate Matter

PM10

APM 550 for PM10 & 2.5

The APM 550 uses a brush-less pump with a low noise.

Same instrument can be used for PM10 and PM2.5 sampling.

Lower sampling rate of 1m3/hour reduces filter choking even in areas having high FPM levels.

Critical Orifice maintains constant sampling rate of 1m3/hour.

Compact and portable for convenient field operation.

Beta Ray Attenuation Measurement

•This method provides a simple determination of concentration in units of milligrams or micrograms of particulate per cubic meter of air. •A small 14C (Carbon 14) element emits a constant source of high-energy electrons known as beta particles. •These beta particles are detected and counted by a sensitive scintillation detector. •An external pump pulls a measured amount of dust-laden air through a filter tape. •After the filter tape is loaded with ambient dust, it is automatically placed between the source and the detector thereby causing an attenuation of the beta particle signal. •The degree of attenuation of the beta particle signal is used to determine the mass concentration of particulate matter on the filter tape, and hence the volumetric concentration of particulate matter in ambient air.

Particulate Monitor Flow diagram

Hourly tape spots

Step ‑ by step test instruction to be followed for Gaseous Sampling

Install the RDS at a height of 1.5 m.

Switch on the instrument,

Adjust the timer reading for required hours of sampling, Flow rate to be adjusted 0.5 litre per minute at the initial stage. Note the initial and final manometer readings,

Fill the impinger with 10 ml by the absorbing solution,

After 4 / 8 hours of operation transfer the media to plastic bottle (60 ml) and then analyse the sample.

SO2

Improved West and Gaeke Ultraviolet FlorescenceStandard: µg/m3

Industrial, Residential, Ecologically Sensitive Rural& other Areas Areas

Annual Average 50 2024 hr Average 80 80

SO2 Source Natural process 67% Volcanoes Manmade 33% Fuel combustion Coal Biofuel Diesel Removal of Sox from fuel gases Removal of Sulphur from fuel burning and use of low

sulphur fuel Sulphur can be remove by using chemical scrubber in

which gases passes through lime stone.

SO2 by Improved West and Gaeke Method

Principle

Sulphur Dioxide is absorbed from air in a solution of Sodium/Potassium Tetra Chloromercurate (TCM)

Ambient SO2 react with it and forms a stable dichlorosulphitomercurate complex

The amount of SO2 then estimated by colour produced when p-rosaalinie is added to the solution.

Range and Sensitivity

This method can measure concentration over an approximate range of 0.005 to 5.0 ppm with an accuracy of ±10% (including sampling and analysis at the lower end of the range and ±5% at the upper end with the precision of about 2%.

Take the 10 ml portion of Sample.

Then add 2 ml sulphamic acid + 2 ml of formaldehyde + 1 ml p-rosaniline.

After 20 min., read the absorbance at 560 nm in a spectrometer with the blank as reference.

Methodology for Analysis of SO2

(West & Gaeke Method)

Reaction Mechanism HgCl4-2+SO2+ H2O =HgCl2SO3

-2 +2H+2Cl-

SO2+H2O+HCHO=HOCH2-SO3H

C6H4-NH3

NH3-C6H4-C-C6H4-NH3 + HOCH2-SO3H= p-rosaline

methyle Clsulphonic acid

Equipments used A midget impinger contains absorbing

solution A pump suitable to desire flow rate of

0.2-1.0 lpm A volume meter with thermometer,

manometer and timer.

Chemicals RequiredAbsorbent 0.1 M Sodium –tetra chloromercurate (Na2HgCl4) (27.2 g

HgCl2 and 11.7 g NaCl in 1000 ml D.W.)

Rosaaniline hydrochloride(0.04%) 0.2 gm of dye in 100 ml of DDW, after 48 hrs filter the

solution (This is stable for three month if kept in dark)---(A) Take 20 ml of (A) in 100 ml flask add 6ml conc. HCl and

after five min fill up to the mark with DDW. (stable 2 week if refrigerated)

Formaldehyde (0.2%) 5ml of 40% in 1000ml DDW

Standard Solution Calibration-0.0123 N Sodium Metabisulphite

(1ml=150 µl SO2)(Dissolve 640 mg of metabisulphite (65%.5)as SO2

in 1 liter of DDW standardized with iodine using starch as indicator)

0.01 Iodine- (Dissolve 12.69 of resublimed iodine in 25 ml of solution made with 15 gm iodate-free KI, Dilute to 1 liter, pipette 100 into 1000ml flask, fill to mark with 1.5%KI, check the normality by standard thiosulphate)

Standardization of metabisulphie

Follow the following steps: Standardize sodium thiosulphate with

potassium dichromate Standardize iodine with standard thiosulphate Standardize metabisulphite with standard

iodine and finally make the solution of 0.0123N

Dilute 2ml of this in 100 ml with absorbing reagent, this is equivalent to 3µl of SO2

per ml

Procedure 10 ml absorbing in midget impinger Bubble known volume of air through any gas

collecting device. (This is stable up to three days)

Adjust volume to 10 ml with D.W. (If any evaporation loss occurs)

Add 1ml each of complexing reagent and mix. Prepared a blank in same manner. After 20 min read absorbance at 560 nm. Calculate ppm or µg/m3 of SO2. 1ppm=1µl of SO2

/liter of air

SO2

Ultraviolet Fluorescent Sulphur dioxide absorbs UV energy at

190nm-230nm free from interference and come to the exited state, producing fluorescence, which is measured by PMT.

The fluorescence reaction impinging up on the PMT is directly proportional to to the concentration of SO2.

Optical measurement theory

Exhaust air is scrubbed with a charcoal scrubber to eliminate Hydrocarbons and SO2. This air is then ideal for use in the hydrocarbon kicker to remove hydrocarbons from sample air.

SampleInlet

SO2 + photon

ParticulateFilter

FluorescenceCell PMT

Microprocessor

SO2 Outputs

exhaust

SO2 *

Hydrocarbonkicker

Opticalfilter

UV lampSO2 + UV

SO2 Analyzer Flow diagram

Oxides of Nitrogen (as NO2) Jacob & Hochheiser (Na-Arsenite) Chemiluminescence'sStandard: (µg/m3)


Annual Average 50 2024 hr Average 80 80

Source Combustion of Coal, Oil, Natural gas and

Gasoline Average residence time in atmosphere is 4

days. At traffic rush time (6-8am) level of NO

increases. At mid morning level of NO2 increases due

to conversion of NO to NO2 by UV rays.

Jacob & Hochheiser (Na-Arsenite)

Principle

Nitrogen oxides as nitrogen dioxide are collected by bubbling air through a sodium hydroxide solution to form a stable solution of sodium nitrite. The nitrite ion produced during sampling is determined colorimetrically by reacting the exposed absorbing reagent with phosphoric acid, sulphanilam ide and N (1‑napthyl) ethylenediamine dihydrochloride at 540nm

.

Range Range of the method is 20-740 µg/m3(0.01 to 0.4

ppm) nitrogen dioxide in a 50 ml absorbing reagent with a sampling rate of 200ml/min for 24 hr.

Reagents Absorbing reagent(4.0gm NaOH + 1 gm sodium arsenite in 1000 ml D.W.)

Sulphanilamide: 20gm in700ml D.W. NEDA: 0.5 gm of N (1-Napthyle) ethylene diamine

dihydrochloride

Equipment used Respirable Dust Sampler along with

gaseous attachment. Gaseous attachment contains 4 (2 for SO2 and 2 for NOX) midget impingers containing the absorbing solution.

Flow rate of gas in the midget impinger is to be adjusted through manometer of the gaseous attachment

Methodology for Analysis of NOx

Pipette 10 ml of the collected sample into a test tube.

Add 1 ml of H2O2, 10.0 of sulphanilamide solution and 1.4 ml of NEDA solution with thorough mixing after the addition of each reagent.

After a 10-minute colour‑development interval, measure the absorbance at 540 nm against the blank. Read g NO2 /ml from the standard curve.

CalculationFor calibration the amount of Potassium/Sodium Nitrate used can be

calculated:G=(1.500/A)x100

Where:G=Amount of Sodium Nitrate1.500=Gravimetric FactorA=Assay, percent

Mass NO2 in µg/m3 = (µg NO2/ml)/(V x 0.82)

Where: V=Volume of Air Sampled

NOx by Chemiluminescence's Emission of light from electrically exited

species due to the chemical reaction. NO+O3=NO2

* + O2

NO2*=NO2+hv

In this process light energy produce is directly proportional to the NO concentration.

NO is associated with NO2 therefore it is

necessary to convert NO2 to NO before

analysis

Sample air is drawn into the reaction cell via two separate (alternating) channels the NO and NOX. The NOX channel travels through a delay coil enabling the same sample of air to be sampled for NO, NO2 and NOX.

The NOX channel passes through an NO2 to NO converter, NO2 is converted to NO

Sample air (NO & NOX channels) enter the measurement cell where NO reacts

with Ozone in the following reaction NO + O3 -> NO2* + O2 Equation 1 Chemiluminescence reaction

Chemiluminescence

This reaction releases energy in the form of Chemiluminescence radiation (1100nm), which is filtered by the optical band pass filter and detected by the Photomultiplier tube (PMT)

The level of Chemiluminescence detected is directly proportionally to the NO in sample NO2 is calculated by subtracting the NO measurement from NOX measurement NOX = NO + NO2 or NO2 = NOX – NO

SampleInlet

NO + photon

3-waysolenoid valve

ParticulateFilter

Molycon

OzoneGenerator

ReactionCell

PMT

Microprocessor

NO,NO2,NOx

Outputs

exhaust

room airPermeation

Dryer

NO2 NO

NO + O3 NO2 *

NOx Analyzer Flow diagram

Ammonia (NH3) Chemiluminescence's Indophenols Blue MethodStandard: (µg/m3)


Annual Average: 100 10024 hr. Average 400 400

Principle• Ammonia in the atmosphere is collected by

bubbling of measured amount of air through a dilute solution of sulfuric acid to form ammonium sulphate.

• The ammonium sulfate formed in the sample is analysed colorimetric by reaction with phenol and alkaline sodium hypochlorite to produces Indophenols a blue dye.

• Sodium nitropruside accelerated the reaction as an catalyst.

Range & Sensitivity With a sampling rate of 1-2 lit/mina conc.

range of 200-700µg/m3. of air may be determine with the sampling time of one hr.

The limit of detection of the analysis is 0.02µNH3/ml.

Reagents

Ammonia free D.D.W.Absorbing Solution (0.1 N)

(2.3 ml of conc. H2SO4(18M) in 1lit.DDW.)

Sodium Nitropruside:(2g in 100ml of DDW)(Stable for two months in refrigerator)

Sodium Hydroxide(6.75M)(270g in 1lit.)

Buffer: 50g Na3PO4.12H2O in and 74ml of 6.75 NaOH in DDW.

Working Hypochloride: Mix 30ml of 0.1NSodium hypochloride+30ml of 6.75 M

NaOH in 100ml DDW. Working Phenol: 20ml of 45% phenol in 1ml of 2%sodium nitropruside

and dilute to 100ml) (Prepare fresh every at

4hrsAmmonia: Dissolve 3.18gm of NH4Cl in 1lit.DDW.(Stable for two

month when preserve with CHCl3)

Procedure Bubble air through any gas sampling device to 10 ml

of absorbing reagent. The sampling rate should be 1-2 lit/min for adequate

sampling time. Transfer the sample in 25ml glass stoppred flask. Add 2ml of Buffer. Add 5ml of working phenol solution mix and then

add 2.5 ml of working hypochloride solution with rapid mixing.

Dilute to 25 ml and keep it in dark for 30 min. Measure developed blue colour at 630nm

Calibration Pipet 0.5,1,0,1.5 of working standard in

25ml flask and make 10 ml with absorbing and then proceed as in sample.

These correspond to 5,10 and 15 µg ammonia /25ml of sample.

Calculation

µg/m3 NH3=W/V0

Where: W=µgNH3 in 25 ml from standard

V= Volume of Air sampled

Ozone (O3) UV Photometric Chemiluminescence's Chemical MethodStandard: (µg/m3)


8 hr. Average: 100 1001 hr. Average 180 180

Ozone: Chemical Method Principle Air containing Ozone is drown through a

midget impinger containing 10 ml of 1% potassium iodide in a neutral (pH 6.8)buffer composed of 0.1M disodium hydrogen phosphate and 0.1M potassium dihydregen phosphate.

The iodine librated in the absorbing reagent is determined spectrophotometrically at 352 nm.

Chemical Reaction

O3+3KI+H2O=KI3+2KOH+O2

The analysis must be completed within 30 min to 1hrs after sampling.

Range and sensitivity The range extend from 0.01ppm to about 10

ppm. The sensitivity of method is depend on the

volume of air sampled.

Precision and Accuracy The Precision of the method within the

recommended range is about ±5%deviation from the mean.

The accuracy of this method has not been established. Calibration is based on the assumed stoichiometry of the reaction with the absorbing solution.

Chemicals Required Potassium dihydrogen phosphate ( KH2PO4 ), Bisodium hydrogen phosphate ( Na2NH4 ) Potassium iodide Sodium hydroxide

Reagents Dissolve 14 g of potassium dihydrogen

phosphate( KH2PO4 ), 14.20 g of disodium hydrogen phosphate ( Na2NH4 ) and 10 g of potassium iodide successively and dilute the mixture to 1 litre with distilled water. Age at room temperature for at least 1 day before use.

Measure the pH and adjust to 6.8 with sodium hydroxide or potassium dihydrogen phosphate solution. This absorbing solution may be stored for several weeks in a glass stoppered brown bottle in the refrigerator and for shorter periods at room temperature without deterioration.

The absorbing solution should not be exposed to sunlight.

Standard Iodine Solution

Dissolve 16 g of potassium iodide and 3.173 g of iodine successively and dilute the mixture with distilled water to exactly 500 ml to make a 0.05N solution. Age at room temperature least one day before use.

Sampling Pipette exactly 10 ml of the absorbing solution

into the bubbler. Sample at a rate of 0.5 to 3 litres/min for up to 30

minutes. The flow rate and time of sampling should be

adjusted to obtain a sufficiently large concentration of oxidant in the absorbing solution.

Approximately 2 µg of ozone may be obtained in the absorbing solution at an atmospheric concentration of 0.01 ppm by sampling for 30 minutes at 3 litres/min.

Calibration Prepare a 0.0025 N iodine solution by pipetting exactly 5

ml of the 0.05 N standard solution ( normality should be checked before use ) into a 100 ml volumetric flask and diluting to the mark with absorbing solution.

Prepare four or more standard solutions in 25 ml

volumetric fasks by pipetting 0.1 to 1 ml portions of the 0.0025 N iodine solution into the flasks, diluting to the mark with absorbing solution and mixing.

Immediately after preparation of this series, read the absorbance of each at 352 nm. The solutions should cover the 0.1to 1 unit

Procedure If significant evaporation of solution occurs, add double

distilled water to bring the liquid volume to 10 ml. Read the absorbance at 352 nm against double distilled water within a 30 to 60-minute period after collection in a I-cm cuvette or tube.

Ozone liberates iodine through both a fast and a slow set of reactions. Some of the organic oxidants also have been shown to cause slow formation of iodine.

Some indication of the presence of such oxidants and of gradual fading due to reductants may be obtained by taking several readings during an extended period of time.

Determine the blank correction (to be subtracted from sample absorbance) every few days by reading the absorbance of unexposed reagent.

Calculations Subtract the absorbance of the blank from the

absorbance of the standards. Plot corrected absorbance's against the normality's of the standardized solutions.

From the line of the best fit the normality corresponding

to an absorbance of exactly one shall be determined. To obtain a value, M, representing microlitres of ozone

required by 10 m.l of absorbing solution to produce an absorbance of one, multip!y this normality by the factor 1.224 X 103.

Calculations continued……

For I-cm cells, M should be approximately 9.6

Results for air samples may be computed from equation:

Oxidant ( as O3), ppm = AM/V

where A = corrected absorbance, and v = volume of air sample in litres ) per 10 ml of absorbing solution

corrected to 25°C and 760 mmHg (correction is ordinarily small and may be omitted).

NOTE - 1 mg/litre = 509 ppm of ozone at 25°C and 760 mmHg

UV Absorption The UV photometer determines the concentration of Ozone (O3) in a sample gas at ambientpressure by detecting the absorption of UV radiation in a glass absorption tube. • Ozone shows strong absorption of UV light at 254nm• Sample air is passed into the glass absorption tube (measurement cell)• Within the measurement cell a single beam of UV radiation passes through the sample and is absorbed by the O3• The Solar blind vacuum photodiode detects any UV that is not absorbed• The strength of the UV signal being detected is proportional to the amount of UV light being absorbed by O3• The analyzer uses the Beer-Lambert relationship to calculate the ozone concentration

SampleInlet

ParticulateFilter

Absorption(Measurement Cell)

Detector

Microprocessor

O3 Output

exhaust

UV source

O3 Analyzer Flow diagram

•O3 is not the only gas that absorbs UV (254nm), SO2 and aromatic compounds also absorb radiation at this wavelength•To eliminate these interferences a second cycle is performed where sample air is passed through an ozone scrubber which allows all interfering gases through but eliminates ozone thereby accurately measuring interfering gases effects on signal and removing them from the sample measurement signal

Benzene Gas Chromatography based continuous

analyzer Adsorption and desorption followed by GC

Standard:(µg/m3)Industrial, Residential, Ecologically

Sensitive Rural& other Areas Areas

Annual Average: 5 5

Principle of the Method•A known volume of air is drawn through a charcoal tube to trap the organic vapors present.

•The charcoal in the tube is transferred to a small, graduated test tube and desorbed with carbon disulphide.

•An aliquot of the desorbed sample is injected into a gas chromatograph.

•The area of the resulting peak is determined and compared with areas obtained from the injection of standards.

Interferences • When the amount of water in air is so great that

condensation actually occurs in the tube, organic vapors will not be trapped. High humidity severely decreases the breakthrough volume.

• When two or more solvents are known or suspected to be presenting the air, such information (including their suspected identities), should be transmitted with the sample, since with differences in polarity, one may displace another from charcoal.

• It must be emphasized that any compound which has the same retention time as the specific compound under study at the operating condition described in this method is an interference.

Advantages of the Method

•The sampling device is:–small, –portable and –involves no liquids.

•The tubes are analyzed by means of a quick, instrumental method.

•The method can also be used for the simultaneous analysis of

two or more solvents suspected to be present in the same sample by simply changing gas chromatographic conditions.

Disadvantages of the Method

One disadvantage of the method is that the amount of sample, which can be taken, is limited by the number of milligrams that the tube will hold before overloading. When the sample value obtained for the backup section of the charcoal tube exceeds 25% of that found on the front section, the possibility of sample loss exists. During sample storage, the most volatile compounds will migrate throughout the tube until equilibrium is reached (33% of the sample on the backup section).

Apparatus

Suction device

• For personal sampling : personal sampler • For an area sample : any vacuum pump

Trapping device to retain the contaminants

Charcoal tubes

7cm long and 6 mmO.D.and 4mm I.D. ontaining 2 sections of 20/40 mesh activated charcoal separated by 2mm portion of urethane foam.

Instrumentation Gas Chromatograph with a Flame

Ionization Detector

Column (20ft X 1/8”) with 10% FFAP stationary phase on 80/100meshes, acid- washed DMCS chromosorb W solid support

A mechanical or electronic integrator or a recorder and some method for determining peak area.

Micro centrifuge tubes, 2.5 ml, graduated.

Hamilton syringes: 10l and convenient sizes for making standards.

Pipettes: 0.5ml delivery pipettes or 1.0 ml type graduated in 0.1ml increments.

Volumetric flasks: 10ml or convenient sizes for making standard solutions.

Each personal pump must be calibrated with a representative charcoal tube in a line.

This will minimize error associated with uncertainties in the sample volume.

In Rotameter, float reading should be in proper place as directed in figure.

Calibration Of Sampling Pump

•Spectroquality Carbondisulfide

•Sample of Specific Compound Under Study

•Grade A Helium gas

•Purified Hydrogen

•Filtered Compressed Air

Reagents

Procedure •Glass ware: detergent washed and thoroughly rinsed with distilled water

•Calibrate the personal pump

•Immediately before sampling break the tube to provide an opening

•Place the charcoal tube in a vertical direction

•Air being sampled should not be pass through any hose or tubing before entering the charcoal tube

Analysis Of Sample•The Charcoal in the first section is transferred to the small stoppered tube.

•The separating section of foam is removed.

•The second section is transferred to another test tube.

•These two section are analyzed separately.

•Now in each tube add 0.5 ml of carbon disulfide.

•Carbon disulfide is toxic therefore all work should be performed in hood.

•The de-sorption time should not exceed 3 hours.

•Condition the GC as per the type of instrument.

•Inject the aliquot of the sample in GC.

•The de-sorption time should not exceed 3 hours.

•Condition the GC as per the type of instrument.

•Inject the aliquot of the sample in GC.

Area Sample- Area blank•De-sorption efficiency=

Area Standard

Convert the volume of air sampled to standard condition of 250 and 760 Torr

The concentration of organic solvent in the air sampled

Total mg x 1000mg/m3 =

Volume of air

CALCULATION

Conversion ppm to mg• Another method of expressing concentration is

ppm (corrected to standard conditions of 25oC and 760 mm Hg).

ppm = [(mg/m3) x (24.45/MW) x (760/P) x ((T+273)/298]

where: • P = pressure (mm Hg) of air sampled • T = temperature (oC) of air sampled • 24.45 = molar volume (liter/mole) at 25'Cand

760 mm Hg • MW = molecular weight • 760 = standard pressure (mm Hg) • 298 = standard temperature (oK)

Benzo(a)pyrene

Solvent Extraction followed by HPLC/GC

Standard: ng/m3


Annual Average 01 01

Benzo(a)pyrene Polycyclic aromatic hydrocarbons (PAHs)

have received increased attention in recent years in air pollution studies because some of these compounds are highly carcinogenic or mutagenic.

In particular, benzo[a]pyrene (B[a]P) has been identified as being highly carcinogenic.

This method is designed to collect particulate phase PAHs in ambient air and fugitive emissions and to determine individual PAH compounds.

It is based on high volume (- 1.2 m3/min) sampling method capable of detecting sub ng/m3 concentration of PAH with a total sample volume -480 m3/ of air over a period of 8 h with same filter.

It involves collection from air particulate on a fine particle (glass-fibre) filter using high volume sampler for total suspended particulatematter (TSPM) or respirable dust sampler for respirable suspended particulate matter (RSPM or PM1O) and subsequent analysis by Gas Chromatograph (GC) using Flame Ionization Detector (FID).

If sampling period is extended to 24 h without changing the filter, it may enhance sample loss due to volatility or reactions of PAHs on collection media.

PRINCIPLE

INTERFERENCES The panicle phase PAH maybe lost from particle fiIter

during sampling due to resorption and volatilization especially during summer months at ambient temperature of 30°C and above.

The method interference may be caused by contaminations in low grade filter, solvent, and reagent, if used.

Glassware shall be properly cleaned (acid-washed) followed by solvent rinsing prior to use.

Matrix interferences may be caused by contaminants, that is, hydrocarbons and other organics that are co-extracted from sample. In this organics that are co-extracted from sample.

In this case clean-up by column chromatography shall be required besides identification and confirmation of individual analyte followed by mass-spectrometer.

DETECTION LIMIT

The minimum detectable concentration in term of BaP for a sampling period of 8 h (with about 480 m3 of air passed) will be 2 ng per cubic meter assuming 0.5 ml as the final volume of sample extract after clean-up and detectable concentration of 2 ng/pl of that sample extract. High resolution mass-spectrometry or high pressure liquid chromatography can improve sensitivity down to 1 ng/m3.

REAGENTS All solvents to be used should be of reagent

grade. Toluene, ultra-residue grade. Cyclohexane, ultra-residue grade. Tri-phenyl Benzene, ultra-residue grade. Solid PAHs Compounds, high purity to

prepare the standard PAH solution. Activated Silica Gel (60-100

meshes),chromatography grade.

APPARATUS

Ultrasonicator, with compact tank/bath of 4.5 litre capacity and producing -40 kHz frequency for extraction.

Rotary Evaporator, buchi-type. Silica-Gel Column, 200 mm length, 5 mm internal diameter with teflon stopcock. GC-FID with Capillary Column Syringes, 1 @to 10 ~1. Flask and Beakers, 5-ml, lo-ml, 25-ml, 50-ml and 250-ml capacity. Variable Volume Micro-Pipettes, 0.5 ml and 1.0 ml capacity.

PROCEDURE Collect sample through a high volume-

sampler (HVS) using glass fibre (EPM — 2000) filter paper perferably Whatmart or equivalent) at a flow rate of -1.2 m3/min over an extended period of time usually 8 h for ambient air.

Sample Processing and Extraction Cut/punched at least 30 percent of total sample of the

exposed filter paper or measured fraction of it into small strips/circtrlar pieces in a beaker/flask of 250-ml capacity.

Add tri-phenyl benzene, an internal standard at this stage for recovery test. Add about 100 ml of toluene for extraction and keep beakers in ultrasonic bath for 30 min (or for 6 using Soxhlet extraction apparatus).

Filter the extracts into evaporative flask of 250 ml with

the help of Whatrnan filter paper No. 20 or filter-disc. Repeat the extraction twice and combine extractants.

Sample Processing and Extraction Cut/punched at least 30 percent of total sample of the

exposed filter paper or measured fraction of it into small strips/circtrlar pieces in a beaker/flask of 250-ml capacity.

Add tri-phenyl benzene, an internal standard at this stage for

recovery test. Add about 100 ml of toluene for extraction and keep beakers

in ultrasonic bath for 30 min (or for 6 using Soxhlet extraction apparatus).

Filter the extracts into evaporative flask of 250 ml with the help of Whatrnan filter paper No. 20 or filter-disc. Repeat the extraction twice and combine extractants.

Sample Concentration Evaporate the toluene extracts using rotary evaporator with

water bath as cool as possible (temperature not exceeding 40”C).

Do not evaporate up to total dryness.

It should be stopped at near dryness (less than 1 ml,visible). Add 2.0 ml of toluene to rinse the wall of evaporation flask and transfer extract into a beaker of5 ml capacity.

NOTE — Samples extraction should preferably be carried out within a month of sampling.

It is performed using silica gel column having length 200” mm, and inner diameter (ID) 0.5 cm. Pour a slurry of 3 g deactivated silica gel (60-100 mesh size) in cyclohexane into the column.

Eltrte toluene followed by cyclohexane through the column for

conditioning.

Now introduce sample extract (concentrated, 2.0 or 3.0 ml) at the top of silica column.

Collect the PAH fraction with about 5 ml of cyclohexane. Collect all the eluants into a rotary evaporator flask.

Add another 30 ml of cyclohexane to the column to elute all organics of interest. Collect all fractions into the flask and reduce to about 1 ml.

Finally transfer into 5 ml capacity beaker/vials, dry and store in a dark and cool place.

Clean-Up and Enrichment

Gas Chromatography Conditions Gas chromatography equipped with percent ionization detector

(FID), a split injector and capillary column (Phase cross linked 5 percent phenyl,methyl-silicone) :25 m length, 0.2 mm inner diameter

GC conditions:

Injection — Port — Temperature : 320°C FID — Temperature : 320”C Oven — Temperature — Programme : Initial temperature

140°C, hold for 3 min Deg/min “c min Ramp A 6 250 6 Ramp B 10 300 5 Total run time :36 min

CALCULATION Calculate the concentration in (rig/@) of each

identified analyte in the sample extract (CJ asfollows:cs = (AS Xcis)/(Al$X RF)

whereA, = area count of characteristic analyte sample/peak being measured,Ais = area count of characteristic internal standardlpeak, and C,, = concentration of internal standard.

Calculate the air volume from the periodic flowreading taken during sampling using the following equation:

V = Average flow rate of sampling, m3/min x Twhere

v = total sample volume at ambient conditions, in m3; andT = elapsed sampling time, in min.

The volume of air sampled (VS) may optionally be converted to standard conditions of temperature

and pressure (25°C and 101 kpa) using the following equation:

V,= VX (P. / 101)X [298/(273+ T.)]where

v= total sample volume under ambientPa =conditions, in m3;T, = ambient pressure, in kPa; andambient temperature, in “C.

Solvent Extraction followed by HPLC/GC

Soxhlet Appratus GC, Capillary Column

Water In

Water Out

Condenser

Flask

sSample

Solvent

MetalsPb AAS/ICP method after sampling on EPM 2000 or equivalent EDXRF Using Teflon filterStandard:(µg/m3) Industrial, Residential, Ecologically Sensitive Rural&

other Areas AreasAnnual Average: 0.5 0.524 hr. Average 1.0 1.0Arsenic & NickelAAS/ICP method after sampling on EPM 2000 or equivalentStandard:(ng/m3)


Annual Average: (As) 6.0 6.0Annual Average: (Ni) 20.0 20.0

Sample Collection and Analysis Metals are associated mainly with the particulate

matter therefore collected on EPM-2000 cellulose membrane filter paper by any dust collecting device.

Calculate the dust collecting area of filter. This filter will be digested with digestion mixture (6:1

of nitric acid and perchloric acid) and digested at 1000C.

Digested samples will be filtered through Whatman filter paper (Grade No1)

Make the volume up to 25 ml with double distilled water and analyzed for Pb, Hg, Cu, Cd, Zn and Ni using AAS.

Calculation

Metal Concentration (µg/m3)

= (Concentration in sample- Blank) x Area of filter Volume of air sampled

Carbon MonoxideNon dispersive infrared spectroscopy (NDIR)

Standard: mg/m3


8 hr.Average 02 021 hr.Average 04 04

Carbon Monoxide Non dispersive Infrared Gas filter Correlation The measurement of Carbon Monoxide is completed via the following principles and measurement techniques:

Measurement cell theory

•CO absorbs infrared radiation (IR) at a wavelength near 4.7 microns•IR radiation (at 4.7 microns) is passed through a 5 meter path length through sample air•The strength of the signal received is proportional to the amount of CO in the sample as shown in the Beer Lambert Law •A band pass filter is fitted to the signal detector to ensure only light near 4.7 microns wavelength is detected

SampleInlet

ParticulateFilter

Absorption(Measurement Cell)

IR Detector

MicroprocessorCO Output

exhaust

IR sourceGas Filter

WheelCO Analyzer Flow diagram

•A gas filter correlation wheel is combined with this system in the light path.•This wheel contains 3 parts to increase measurement accuracy, CO, N2 and the mask•The CO window contains a saturation of CO which acts as a reference beam•The N2 window does not absorb IR at 4.7 microns and is used during normal CO measurement•The mask totally blocks the light source and is used to determine background signals and the strength of other signals relative to each other and the background