Saturday, September 26, 2015

Air Pollution Tag on Pinterest

Pinterest is a big social media platform and we want to look at air pollution tag on pinterest.
Here you can reach air pollution documents from Pinterest;

Tuesday, November 05, 2013


There are many SO2 analysis and measurement techniques in this research I will mention about four main analysis and measurement techniques.

1  The Flame Photometric Detector (FPD)

An integrated gas sample is extracted from the stack. The SO2 is removed selectively from the sample using a citrate buffer solution. The TRS compounds are then thermally oxidized to SO2 and analyzed as SO2 by gas chromatography (GC) using flame photometric detection (FPD).

Emission of radiation can be stimulated thermal-chemically by a gas/hydrogen-flame chemiluminescent interaction. The emission can be detected by photometric techniques. If sulfur compounds (SO2, H2S, CS2, CH3SH) were introduced into the hydrogen flame, a emission between 300 to 420 nm wavelength can be detected. Total sulfur can be measured and combined with GC provides the capability to separate and measure each sulfur compound. It has a highly sensitive, 1 - 10 ppb.

FDP is still the most commonly used physiochemical transducer for gaseous sulfur-containing compounds despite its notable limitations. Various FPD response optimization studies have been performed, but problems with regard to detectability, response time, selectivity and misunderstanding of its exponential response remain. FPD designs include fast response burners a dual flame burner and a catalytic, nonflame device. Other reported sulfur-selective transducers are a dc plasma, the electrolitic conductivity detector, ozone-sulfide chemiluminescence and F2-induced chemiluminescence.

Sulfur Dioxide (SO2) is a colorless, nonflammable gas that has a strong suffocating odor.  SO2 originates from fuel containing sulfur (mainly coal and oil) burned at power plants and during metal smelting and other industrial processes.  High levels of SO2 can result in temporary breathing impairment for asthmatic children and adults who are active outdoors.  Long-term exposure to high levels of SO2, in the presence of high levels of particulate matter, may aggravate existing cardiovascular disease and respiratory illness.

The Teledyne-Advanced Pollution Instrumentation (T-API) model 100AS combines proven detection technology for the determination of trace levels of SO2.   This SOP will detail the operation, preventive maintenance, cautions and health warnings.

The Detection Limit (DL) for a non-trace level SO2 analyzer is 10 parts per billion (ppb) (Code of Federal Regulations, Volume 40, Part 53.23c, or, in the shortened format used hereafter, 40 CFR 53.23c)3.    However, the T-API model 100AS has an estimated DL of 100 parts per trillion (ppt), which is accomplished by an increased detector sensitivity, as well as increasing the length of the standard instrument’s optics bench.  This document will discuss the Trace Level (TL) operating procedures in detail.

The Model 100AS Trace Level operating principle is based on measuring the emitted fluorescence of SO2 produced by the absorption of ultraviolet (UV) light.  The UV lamp emits ultraviolet radiation which passes through a 214 nm band pass filter, excites the SO2 molecules, producing fluorescence which is measured by a photomultiplier tube (PMT) with a second UV band pass filter.  SO2 absorbs in the 190 nm – 230 nm region free of quenching by air and relatively free of other interferences.  The equations describing the above reactions are as follows:

            SO2 + hν1 Ia → SO2*

The excitation ultraviolet light at any point in the system is given by:

            Ia =I0[1-exp(-ax(SO2))]


            I0 = UV light intensity,
            a  = the absorption coefficient of SO2
            x  = the path length
            SO2 = concentration of SO2

The excited SO2 decays back to the ground state emitting a characteristic fluorescence:

            SO2* kF→ SO2 + hν2
When the SO2 concentration is relatively low, the path length of exciting light is short and the background is air, the above expression reduces to:

            F = k(SO2)


            F = amount of fluorescent light given off
            k = rate at which SO2* decays into SO2
The 100AS instrument operates in the following fashion:
In sample mode, the sample is drawn into the analyzer through the SAMPLE bulkhead.  The sample flows through a hydrocarbon “kicker,” which operates on a selective permeation principle, allowing only hydrocarbon molecules to pass through the tube wall.  The driving force for the hydrocarbon removal is the differential partial pressure across the wall.  This differential pressure is produced within the instrument by passing the sample gas through a capillary tube to reduce its pressure and feeding it into the shell side of the hydrocarbon kicker.  The SO2 molecules pass through the hydrocarbon “kicker” unaffected.

The sample flows into the fluorescence chamber, where UV light is focused through a narrow 214 nm band pass filter into the reaction chamber, exciting the SO2 molecules; the molecules then give off their characteristic decay radiation.  A second filter allows only the decay radiation to fall on the PMT.  The PMT transfers the light energy into the electrical signal which is directly proportional to the light energy in the sample stream being analyzed.  The preamp board converts this signal into a voltage which is further conditioned by the signal processing electronics.

The UV light source is measured by a UV detector.  Software calculates the ratio of the PMT output and the UV detector in order to compensate for variations in the UV light energy.  Stray light is the background light produced with zero ppb SO2.  Once this background light is subtracted, the CPU will convert this electrical signal into the SO2 concentration which is directly proportional to the number of SO2 molecules.

SO2 + hv1 = SO2*

SO2* = SO2 + hv2 (by fluorescence)

SO2* + M = SO2 + M (by quenching)

SO2* = SO + O (by dissociation)

This method is sensitive, specific and has a wide linear range. It is good for detecting ambient and industrial sources. The emission analyzers can measure from 0 - 5000 ppm. Ambient atmospheric analyzers can go down to 0 - 0.5 ppm. The detection limit is around 0.02 ppm. This method needs calibration gas to perform a multi-point calibration.

2  Gas Chromatographic Method

Gases migrate differentially in a porus sorptive medium(consist of an absorption column and a detection unit). Air sample is aspirated into the sample loop of a gas sampling valve. The valve is then switched to inject the sample on to a GC column where SO2 is separated from other gaseous compounds. The effluent passes into a FPD (flame photometric detector) and the detector signal amplified and recorded. Minimum detection limit is 5 -10 ppb.


To prepare mercury stabilizing solution, mercuric chloride (27.2 g) and sodium chloride (11.7 g) were dissolved in water and made up to 1 L. Sodium bisulfite stock solution was made by dissolving 10 g of sodium bisulfite (AR grade) in water and making up to 1 L. The solution was assayed iodimetrically for SO2 content (1) and further diluted to contain 300 mg/ L SCh. The concentrated stock solution is stable and lasts for at least a week. The 300 mg/L SCh solution must be prepared daily before use. Sample Preparation Free SCh was prepared by taking beer (20 ml in a 100-ml volumetric flask) and adding 11.0 ml of phosphoric acid. This was mixed and subsequently brought to volume with distilled water. Total SCh was measured in 10 mi-samples of beer to which was added 2 ml of mercury-stabilizing solution. This was mixed well in the 100-ml volumetric flask, and 15.0 ml of 0.10 NaOH was pipetted into the flask. The contents were swirled for sufficient mixing and subsequently allowed to stand for at least 1 min.
Phosporic acid (11.0 ml of 85%) was added and the contents brought to volume with distilled water.


To a series of nine 100-ml volumetric flasks each containing 2 ml of mercury stabilizing solution, 0-0.8 ml aliquots of sodium bisulfite stock solution were added in 0.1-ml increments. The solutions were acidified with 11 ml phosporic acid and made up to volume with distilled water. The resulting SCh concentrations ranged from 0 to 2.4 mg/L, respectively.

Chromatographic Determination;

For headspace analysis, a 50-ml test sample was placed in a 100-ml vial and sealed with a butyl rubber septum. Equilibration was achieved by shaking the vial for 1 5 min on a wrist action shaker and standing 10 min at room temperature. The headspace sample (5.0 ml) was withdrawn using a gas-tight syringe, and it was injected into the gas chromatograph. The chromatography conditions were as follows: instrument, Tracer with flame photometric detector; column, glass (2 m X 4 mm i.d.) packed with Carbopak B HT 100, 60/80 mesh. Temperatures were injector 100°C, detector 175°C, and column isothermal at 45° C; gas flow rates were hydrogen 55 ml/min, air 100 ml/min, and nitrogen 50 ml/min.


With the aid of a microcomputer statistical software program, a second-order regression equation was obtained by plotting the square root of the peak area (or peak height) against the SO2 concentration of the standards. Using this equation, the free and total SO2 concentrations in the treated test samples were calculated. Taking into account the dilutions in preparation of the test samples, free and total SO: in the original beer sample were determined.

3  West-Gaeke colorimetric analysis

West-Geake Method for SO2 showed no significant NH3 interference. Dasgupta et al. have described another method that uses a 0.02% solution of formaldehyde at a pH of 4 to absorb and stablize SO2 as hydroxymethane sulfonate. A fluorometric technique or a more conventional colorimetric technique can be used with this latter SO2 method.

The divices contains a rechargeable battery and a constant volume adjustable air pump.
An air sample is continuously drawn into the unit and any formaldehyde present is
scrubbed with a sodium tetrachloromercurate solution that contains a fixed quantity of
sodium sulfite. Acid bleached pararosaniline is added and the intensity of the resultant
color is measured at 550 nm by a colorimeter and displayed on a digital readout. A recorder
output is also provided and both formaldehyde in air and liquid samples can be analyzed.

4  Fluorescent Analyzers

Fluorescent Analyzers is a popular method which is conducted for SO2 determination. Several such commercial instruments are avaliable for this method. Certain design of fluorescent SO2 analyzers have interference from aromatic hydrocarbons and water vapor. Because of this response to aromatic hydrocarbons, devices called cutters were added to these fluorescent SO2 analyzers to reduce this interference. Smith and Buckman examined the performance of these cutters and suggested that their test procedure should be employed on a routine basis to verify effective cutter operation. Interferences due to water are minimized by the use of discrete line source or gas drying via Nafion permeation dryers.

Other SO2 methods include oxidation-induced chemiluminescence, ion chromatography and ultraviolet (UV) absorption spectrometry.

Monday, October 07, 2013


Bag filters can be used for collection of particles if the gas temperature is lower than 200 C.

Sometimes bag filters are more economical than the ESP.

Venturi scrubbers are used for particulate removal as well as the gas cleanup. If gases
contain some acidic gases like HCl or HF or even SO2, these can be removed by the basic liquid or water used in the scrubber together with the Particulates.


• ESP is used for collecting particles < 5 micron in diameter
• Electrostatic force is used to collect the particles instead of the gravitational force
• The basic idea is to give the particles a (-) charge around the CORONA and collect them on (+) ly charged plates.

Air Pollution During Pregnancy

Air pollution is a well-known problem that give harm to humankind. Columbia University's Mailman School of Public Health conducted a survey on causes of air pollution during pregrnancy.

Maternal psychological distress combined with exposure to air pollution during pregnancy have an adverse impact on the child's behavioral development, according to researchers at the Columbia Center for Children's Environmental Health at the Mailman School of Public Health.

The study, which appears in the journal Pediatrics, reports that maternal demoralization, a measure of psychological distress capable of affecting a mother's ability to cope with stressful situations, was linked with a number of behavioral problems, including anxiety, depression, attention problems, rule-breaking, externalizing problems, and aggressive behavior. The effects of demoralization were greatest among children with higher levels of prenatal exposure to polycyclic aromatic hydrocarbons (PAH) in air pollution.

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Saturday, May 21, 2011

Particulate Control

There are 3 main system to particulate control. These are cyclones, ESP (Electrostatik Precipitator) and bag filters.

The oldest system is cyclones, it is only used particles bigger than 50 microns. For smaller particles ESP or bag filters must be used.

Sunday, March 07, 2010

Air Pollution Photos

50 years after the industrial revolution people started to get sick from air pollution. Today millions of the factories, automobiles and vehicles continuosly release hazardous gases to athmosphere.

In this post we air pollution control blog want to display some photos of air pollution.

Monday, May 25, 2009

Ultimate Fate of Pollutants

If possible, we prevent the formation of pollutants, if we cannot, we capture them and put them to some good use.

If the pollutants will burn, we often destroy them by burning. In designing any air pollution control system, one should plan for the ultimate disposal of any wastes produced.

Sunday, May 25, 2008

Air Pollution Measurements

• Immission measurements (Ambient Air Monitoring)
– Concentration of the pollutants in the air the public breaths

• Emission Measurements (Stack Gas Monitoring)
– concentrations and/or emission rates from air pollution sources

General Ideas in Air Pollution Control

• Improve Dispersion
– Tall stacks
– Intermittent control schemes
– Relocate the plant

Thursday, February 28, 2008

Particulate Matter PM Control Technologies - Summary

1- Cyclones
A cyclon can collect about 25 micron particles by using centrifugal force.
It has advantages for instance, it is easy to control and cheap.

2- Electro Static Precipitation
Electro Static Precipitation is used for to collect very fine particles. It has 99% efficiency.

3- Bag Filters
It is also very efficient method of PM Control.

4- Co-Flow Venturi Scrubbers
Venturi Sucrubbers have disadvantages. This method cause Water Pollution because of the main idea of washing gas with water.
If this method projected, the plant must have a waste water treatment plant

Wednesday, September 05, 2007

Thermal Oxidation for VOC Control

Volatile organic compounds generally are fuels that are easily combustible.Through combustion, which is synomonous with thermal oxidation and incineration , the organic compounds are oxidised to CO2 and water, while trace elements such as sulfur and chlorine are oxidised to species such as SO2 and HCL.
Three combustion processes that control vapor emisions by destroying collected vapors to prevent release to the environment are
1. thermal oxidation - flares
2. thermal oxidation and incineration
3. catalytic oxidation.
Each of these procecses has unique advantages and disadvantages tha require deep considiration for proper method.As an illustration, flares are designed for infrequent large volumes of concentrated hydocarbon emissions.On the other hand thermal oxidizers are designed for high - efficiency treatment of contınuous.mixed-hydrocarbon gas streams.The design of the basics processes can be modified for specific applications,resulting in the overlap of the distinctions between processes.

Saturday, August 04, 2007

Nitrogen Dioxide

Measurement of Nitrogen Dioxide

For measuring nitrogen dioxide concentration in ambient air the chemiluminesence method is used primarly.Nitrongen dioxide concentrationas are determined indirectly from the difference between the NO and NOX concentrations in the atmosphere.These concentrations are determined by measuring tje light emitted from the chemiluminesece reaction of NO with O3 and the light output is proportional to NO present in the ambient air stream.

Reaction in the Atmosphere

NO is a colorless gas that has some harmful effects on human health , but these effects are substantially less than those of an equivalent of Nitrogen Dioxide.In the atmosphere NO reacts with O2 to form nitrogen dioxide , a brown- coloured gas that is a serious repspiartory irritant.Its brown color is strong enoughtaht is often possible to see a distinct brown colr emerging from a power plant stack or from the vent of any process using nitric acid,which realese NO2.

Methods for measuring Ozone

The principal method used for measuring ozone is based on chemiluminescence.When ozone and ethylen react chemically,products are formed which are in exited electronic state.These products fluoresence,relasing light.The principal components are a cocstant source of ethylen,an inlet sample line for ambient air,a reaction chamber, a photomultuplier tube , and signal processesing circuitry.The rate at which light is recieved by the photomultipler tube is dependent on the ozone conentration and the ethylene.If the concentration of ethylene is made much higher than the ozone concentration to be measured, the light emitted is proportional only to concentration of ozone.

Carbon Monoxide Measurement Technique

The primary method used for measuring carbon monoxide in US is based on nondispersive infrared photometry (NDIR).The analyser has a hot filament sorce of infrared radiation, a chopper , a sample cell, reference cell and a detector.The reference cell is filled with a non- infrared- absorbing gas,and the sample cellis continuously flushed with ambient air containnig unknown amount of CO.The detector cell is divided into two compartments by a flexible membrane, with each filled with CO.Movement of the membrane causes a change in elektrical capacidance in control circuit whose signal is processed and fed to recorder.

Analysis and Measurement of Gaseous Pollutants

The two major goals for air pollutants are identification and quantification of a sample of ambient air.
Hundreds of chemicals are present in the urban atmospheres.The gaseous air pollutantsmost commonly monitored are CO,OZONE,NO2,SO2 and nonvolatile organic ompounds(NMVOCs).

Monitoring Systems

Ambient air quality data may be obtained through the use of mobile or fixed sampling networks and the use of integrated samplers or continuous monitors.Decisions regarding these monitoring techniques constitude the first important steps in design a monitoring network.

Fixed VS Mobile Sampling

In fixed sampling systems , staions are permanent or at least long term instalations.In a mobile sampling network, the monitoring instuments are rotated on schedule among selected locations.
An advantage of fixed sampling is that measurements are made concurrently at all sites, providing directly comparable information, which is particularly important in determining relationship of polluting source to local air quality and in tracing dispersion of pollutants troughout area.The chif advantage of mobile sampling is that air quality measurements can be made at many sites - far more than wopuld be feasible in a fixed sampling program.

Continuous vs İntegrated Sampling

Continuous monitoring is conducted with devices that operate as both sampler and analyser.Pollutant concntrations are instantaneously displayed on a meter, continuously recorded on a chart, magnetic tape or a disk.Integrated sampling is done with devices that collect a sample over some specified time interval after which sample is sent to a laboratory for analysis.This is an olderly techniquce and limited use currently.

Friday, August 03, 2007

Ambient Air Quality Sampling Program

Air pollution monitoring is conducted to determine either emission concentration or ambient air quality.The range of emission concentrations,temperature and pressures encountered is sometimes different than found in tha ambient air sampling situations.For that reason sampling and analysis technuques and equipment are different for each case.


The object would be to measure the amount of gaseous and particulate matter at enough locations to make the data statistically significant.It is not uncommon to find each tation in a network equipped with simple, unsophisticated grab sampling devises.However quite afew complicated devises have been developed which contains continuous monitors with telemetry and computer control.Meterological variables are also monitored and corelated with the concentration data.The information is then used;

1.To establish and evaluate control measure
2.To evaluate atmosphric-diffusion model paremeters
3.To determine areas and time periods when hazardous levels of pollution occurs in the atmosphere
4.for emergecncy warning systems

Best Available Control Technology of Air Pollution

The Federal New Source Review program requires that Best Avaible Control Technology(BACT) be appiled to major new sources and mjor modifications in attainment areas.Many local agencies also require that BACT be applied to smaller new sources of air pollution.
BACT is a technology-based standard that can be met by available technology.Typically it is specified in an air permit as a maximum emission rate or concentration that can be monitored and verified.
The EPA has adopted a " top down" methodology for determining BACT.This means that the control technology with the highest degree of pollutant reduction must be evaluated first.İf that technology meets all the criteria for feasibility,cost effectiveness ,air quality impacts and other impacts, it is determined to be BACT for the proposed new source and analysis ends.İf not, the next most effective control technology is evaluated for BACT.
As a minimum level, BACT must at least meet the emission limitations of New Source Performance Standards(NSPS).Established NSPS have already been based on a thorough technology and economic evaluation.But as control technology improves , BACT may become more stringent than NSPS.

Effects of Air Pollution on Human Health

In Bhopal, India, in December 1984, a release of methly isocyanate from a pessticide plant killed about 2500 people. Similar leakages of hydrogen sulfide from natural gas processing plants have killed houndreds of people. These tragic events attract wide attention.

Their effects dont result from a single exposure these gases but from repeated exposure to low concentration for long periods.

If we wish to establish the dose-response curve for a pollutant gas, we have 3 possible approaches; animal experiments, loboratory experiments with humans and epidomiological studies of human populations.

Wednesday, November 22, 2006

Air Pollution Control Techniques

This blog aims to inform the people about air pollution control techniques.