Resource Guide

Air Pollution Manual

Sources & Pollutants

Pure air is made of nitrogen, oxygen, water vapour, and some other trace elements. Unpolluted air contains dust and other chemicals such as sulphur and phosphorous from natural weathering and chemical and biological processes. Air is considered to be polluted when any chemical, biological or physical contaminant that "normally" would not be there enters the air. Air pollution can cause respiratory and other health problems, limit visibility and damage buildings and public property through corrosion.

There are many sources of air pollutants in the indoor and outdoor environments. Automobiles are a significant mobile source of air pollution. In addition there are many stationary sources of air pollution -- such as oil refineries, chemical plants, power plants, waste dumps, waste water facilities, medical and municipal waste incinerators, construction and demolition sites, auto body shops, dry cleaners.

Air Pollutants fall into one of two groups – Particulate Matter (PM) and Gases.

  1. Particulate Matter: PM 10, dust, heavy metals, lead, soot, other solids

    The term particulate matter covers a wide range of finely divided solids that may be dispersed into the air from combustion process, industrial activities or natural sources. PM can come from incinerator stacks, power plants, road traffic, construction etc. It is usually referred to by the largest particle’s diameter (a micron = 10 –6 m = 1millionth of a meter). So, PM 10 would refer to PM whose largest particle size does not exceed 10 microns. Mechanically generated dust particles are generally larger and do not stay in the air for too long. Particulates are important in relation to health not only because they persist in atmosphere longer than larger particles, but also they are small enough to be inhaled and to penetrate deep into the respiratory tract. Currently there are National standards for Suspended Particulate Matter (SPM) and Respirable Particulate Matter (RPM).

    PM toxicity: articulate pollution generally consists of a mixture of particles of dust, pollen, ash, soot, metals, and various other solid and liquid chemicals found in the atmosphere. The proportions of these components vary widely depending on the source. In and around chemical industries and petrochemical industrial locations, it is generally found that SPM comprises carbon, tray material (hydrocarbons, soluble in organic solvents such as benzene), water-soluble material (such as ammonium sulphate) and insoluble ash (containing small amounts of iron, lead and other wide variety of elements).

    So, in addition to the problems caused by physically invading the respiratory system, PM that is loaded with toxic chemicals may also exert a variety of toxic effects defined by the resident chemicals.

  2. Gases

    Ammonia, chlorine, ozone (smog), NOX, Carbon monoxide, sulphur gases, and volatile organic compounds (VOC) such as benzene, toluene are examples of toxic gases. VOCs are volatile compounds containing carbon and, often, hydrogen. Toxic gases exert a variety of health effects. The terrible tragedy at the Union Carbide factory in Bhopal in 1984 was caused by the release of methyl isocyanate and hydrogen cyanide gases.

National Ambient Air Quality Standards


Industrial Air

Residential, Rural and other areas

Sensitive Areas


Sulphur Dioxide

Annual Average


24 hrs.

80 ug/m3

120 ug/m3

60 ug/m3

80 ug/m3

15 ug/m3

30 ug/m3

Exposure to Sulphur Dioxide primarily affects the mucous glands and the lungs. The most common disorders due to the exposure are wheezing and breathing problems. Long-term exposure could result in Asthma and Bronchitis.

Oxides of Nitrogen (NO2)

Annual Average

24 hrs.


80 ug/m3

120 ug/m3


60 ug/m3

80 ug/m3


15 ug/m3

30 ug/m3

Exposure to Nitrogen Dioxide can cause respiratory ailments, asthma, and it also increases the susceptibility of lungs to infections

Suspended Particulate Matter (SPM)

Annual Average

24 hrs.



360 ug/m3

500 ug/m3



140 ug/m3

200 ug/m3



70 ug/m3

100 ug/m3

SPM contains soot, smoke, products of incomplete combustion of organic matter and dust. Such particles are generally larger than 10 microns in diameter and thus are too large to be inhaled beyond the nasal passage. Children are primarily affected by SPM as they are in the habit of breathing through their mouths thus SPM enters their lungs bypassing the nasal clearance mechanism. It causes breathing troubles, wheezing, asthma and bronchitis.

Respirable Particulate Matter (RPM)

Annual Average

24 hrs.



120 ug/m3

150 ug/m3



60 ug/m3

100 ug/m3



50 ug/m3

75 ug/m3

Particulate matter less than 10 microns in diameter are respirable particulate matter. These can easily enter the lungs of both adults and children and is known to cause breathing problems and lung disorders.

Lead (Pb)

Annual Average

24 hrs.

1.0 ug/m3

1.5 ug/m3

0.75 ug/m3

1.0 ug/m3

0.5 ug/m3

0.75 ug/m3

Lead is a heavy metal found in paints and industrial facilities involved in battery recycling. Lead can enter the human body by inhalation or through lead-contaminated drinking water.

Lead interferes with the Central Nervous System and the kidneys. Exposure to even small amounts can cause neurological damages and renal failure in adults. Exposure to lead can affect the thyroid forming ability among the children. Children are particularly susceptible to lead poisoning and health effects due to lead exposure. Lead exposure among children is linked to reduced Intelligence Quotients (IQ) and behavioural abnormalities.

Ammonia (NH3)

Annual Average

24 hrs.

0.1 mg/m3

0.4 mg/m3

0.1 mg/m3

0.4 mg/m3

0.1 mg/m3

0.4 mg/m3

Ammonia is one of the most common gases used for industrial purposes. Ammonia causes severe irritation to the eyes, nose, lungs and throat. Symptoms include burning sensation, headache, dizziness, wheezing, shortness of breath and nausea. Over exposure could lead to damage in the central nervous system resulting in unconsciousness and convulsions. Intense ammonia exposure can also cause death.

Carbon Monoxide (CO)

8 hrs.

1 hour


5.0 mg/m3

10.0 mg/m3


2.0 mg/m3

4.0 mg/m3


1.0 mg/m3

2.0 mg/m3

Carbon Monoxide is a colourless, odourless, tasteless toxic gas, which is a product of incomplete carbon combustion. CO reduces the oxygen carrying capacity of the blood thus creating a deficiency of oxygen in the organs and tissues.

Symptoms of exposure could vary from - headache, weakness, dizziness, nausea and vomiting to coma and death (in case of prolonged and intense exposure). Children and pregnant women are most susceptible to CO toxicity.

#Sensitive areas are locations like hospitals, schools etc.

Other common air pollutants:

Heavy Metals: Heavy metals like lead; cadmium and chromium etc. are the most common contaminants of the air. The most important sources of heavy metals emissions are combustion of fossil fuels and waste.

Lead: See table above

Chromium and Cadmium: They are used in metal alloys and pigments for paints, cement, paper, rubber, and other materials. Low level exposure to these metals can irritate the skin and cause ulceration while long term exposure could cause kidney and liver damage, bone deformation and high blood pressure.

Dioxins and Furans: Dioxins and furans are inevitable byproducts of combustion involving chlorinated material. They are persistent, bioaccumulative and are capable of exerting transgenerational effects. They are known human carcinogens, and their effects target virtually every system in the human body. However, contaminated food rather than inhalation of polluted air is the most significant route of exposure to dioxins and furans.

Sulphur compounds: The primary source of sulphur dioxide is from burning coal; thus major emitters of sulphur dioxide include coal-fired power plants, smelters, and pulp and paper mills. Sulphuric acid aerosol is formed in the atmosphere from oxidation of sulphur dioxide in the presence of moisture. Industries that either use or manufacture the acid can also emit sulphuric acid. Hydrogen sulfide (gas with a characteristic rotten egg odour) is emitted from a variety of industrial processes, including oil refining, wood pulp production and wastewater treatment.

Exposure to sulphur dioxide could lead to lung dysfunction, wheezing and breathing problems, asthma and bronchitis; Hydrogen sulphide can cause irritation of eyes and respiratory system, coma, convulsion, conjunctivitis, eye pain, lacrimation (tears to eyes), photophobia, dizziness, headache, weakness and exhaustion, irritation, insomnia, gastrointestinal disturbances.

Sources of air pollution within the industries:

Stack or vent emissions are often identified as the most significant sources of emissions in a factory. In reality, however, fugitive emissions from storage tanks, cooling tanks, pipe connectors, valves, equipment leaks, flanges, pumps, compressors, pressure release devices etc are capable of violating the ambient air quality standards and even exceeding the stack emissions.

Documenting Air pollution

Most commonly, air pollution is noticed through a change in the smell of the air one breathes. If it smells different, in all likelihood, the air is not "normal." Although, the nose cannot identify each chemical individually, it is the cheapest tool for monitoring air pollution. Community monitoring of air pollution should, therefore, include chemical odour incident monitoring using the nose as a tool.

Chemical Odour Incident Monitoring:

The sense of smell, hearing, sight and feeling can form the basis for documenting air pollution. International agencies, including the US EPA, and several community groups in South Africa, U.S.A. and the Philippines use chemical odour incident monitoring to document air pollution.

Daily Chemical Odour Monitoring is really quite simple.

  • Organise a village meeting, or a meeting of youth or women in the pollution-impacted community;
  • Ask them to describe the odours they experience, and list them.
  • Ask them to describe some of the immediate health effects or symptoms experienced by them as a result of the odours, and list them.
  • Ask them to maintain records of the most intense odours throughout the day, using the questionnaire provided in Annexure 1 below.
  • In the event of major incidents – serious emissions or soot deposit from plants etc – a letter may be written to the regulatory authorities enclosing the incident monitoring form.

How to rate the smell: The intensity of the smell can be rated as "high," "low" or "No smell." To get a degree of standardization among the monitors, a simple rule of thumb can be followed. If the odour is overpowering, easily perceptible and/or induces noticeable symptoms, the odour can be rated "high intensity." If the odour is perceptible or just barely so, rate the odour "low intensity." It helps to do a group rating of different smells at different locations in an industrial estate to check the standardization.

The power of the chemical odour incident monitoring, when conducted systematically, lies in its ability to yield trend data to answer questions such as these:

  1. Are chemical odours present day-long?
  2. Does their intensity vary with the time of day?
  3. What kinds of smells are common? Which sources are they associated with?
  4. What kinds of immediate health symptoms are associated with each smell?
  5. What is the geographical spread of the odours?

What incidents need to be closely monitored?

    • Any incident of intense smell, which may or may not have resulted in immediate health effects.
    • Any visible sign of air pollution – black smoke, coloured smoke, dust
    • Any gas leak or explosion inside the factory or around it, including chemical tanker lorry incidents
    • Any unusual hissing sound in the factory, indicating a gas leak
    • Any situation of perceptible physical reaction in the absence of smell, noise or any other visible pollution

Laboratory analysis of air toxics:

High Volume Sampling:

A high volume sampler has an air suction machine that pulls the air through a special filter paper. While the sample air is being pulled through, the flow rate can be adjusted and the sample can be taken over a specific period of time. This determines the volume of the sample taken. Any material deposited on the filter paper and is analysed further. High volume sampling gives a quantitative analysis of the pollutants presents in the air.

Buckets Samplers:
Community activists in the United States have developed a well-tested tool called the "bucket" to allow communities to sample the air they breathe. The sampler is a plastic bucket with a detachable bag inside it. To sample the air, the valve on the nozzle of the bucket is opened. This operates a pump that sucks in the air and fills up the bag. Once filled, the bag can be detached and couriered to the analytical laboratory.

Several community groups in North America, South Africa and the Philippines are currently successfully using the bucket. The analytical protocols are standardized and allow communities to choose from one or more of several analytical categories that test for different air pollutants with known toxicological profiles.

The advantage of the bucket is that it is a low-cost, but physically and scientifically robust tool, that can be deployed by the community as and when they sense intense air pollution. More importantly, it builds capacity within the community, particularly among the youth, engages them in a meaningful way in the struggle against pollution and strengthens their struggle.

What’s the worth of buckets?

The buckets can be used to measure the everyday pollution levels or to respond to accidental releases at the chemical factory in your area. The Buckets take "grab" samples at nose-level and can give you a snapshot of what you are breathing. Buckets have proven to be a valuable tool to keep polluters in line and challenge their baseless claims that emissions are within permissible limits.

The government agencies too are more likely to begin monitoring and publish the results once they know that communities are taking regular samples and monitoring the state of the environment.

Data generated by the bucket gives information about the levels of several gases, some of them with known toxicological properties. The analytical data thus generated combined with regularly maintained chemical odour incident records provides a fair picture of air quality in an area. It would also alert us to the need, if any, for precautionary action to protect health.

Are the results credible?

Grab Sampling is a well-established technique in the environmental monitoring industry. The bucket employs the same principles and techniques as the US Environmental Protection Agency and other industries do to take samples. Indeed, the Bucket was co-developed as a community tool by the US EPA. Bucket samples that were analysed alongside samples taken simultaneously by well-established techniques yielded similar results. Quality assurance and quality control measures provide additional scientific information and increase the credibility of the bucket samples. Currently, Columbia Analytical Services, a US EPA-certified laboratory in California performs the sample analyses. The laboratory is placed among the top 10 laboratories in the U.S.

Are the buckets difficult to use?

The bucket design is well suited for community use. Sturdy and easy to use, the buckets provide a less expensive way of obtaining the comprehensive information relating to toxic gases in the air. This information can help you ask informed questions and express legitimate documented concerns. The buckets represent sound science, and can provide the data-backing required to corroborate community concerns about pollution and related health effects.

How does the bucket take an air sample?

The plastic bucket serves as a rugged enclosure for a standard "Tedlar" sampling bag and for the equipment needed to fill the bag with outside air. A small vacuum sucks air out of the bucket. When you open the valve attached to the sampling bag, air rushes in to fill the bag. After taking a sample, a trained person, like the bucket coordinator, removes the sampling bag and sends it for analysis. The bucket coordinator puts a new bag and then you are ready to take another sample.

What buckets Do and Do-not Do?

The laboratory can only analyze the bucket sample for gases.

  • Buckets cannot measure for PM, including heavy metals, soot, dust, and other solids.
  • Buckets cannot measure for toxins that normally attach themselves to particles, such as dioxins.
  • Buckets cannot measure for acid rain or radiation.

What pollutants can be tested for using bucket samples?

For testing around chemical plants and oil refineries, two common analytical procedures are requested for, they are – a) VOC’s (Volatile Organic compounds) and inorganic gases and b) sulphur compounds.

Volatile Organic Compounds

With bucket samples, the lab can detect many of these compounds at parts per billion (ppb) levels. Some of the measured VOCs include – Benzene, Toluene, 3 types of Xylenes, Methylene Chloride, Tetrachloroethane, Acetone etc.

Sulphur Compounds

Sulphur compounds can also be detected at levels below 1 ppb. Some of the sulphur compounds are – Hydrogen Sulphide, Carbonyl Sulphide, Carbon Disulphide, 7 types of Mercaptans and 5 types of Thiophenes.

Bucket samples are currently being sent to a USEPA-certified laboratory in the US for analyses, because labs in India don’t have one essential component required for the analyses.

How are the results interpreted?

Laboratories report the amount of chemicals in the air as a "concentration." Our air is made up of many different gases all mixed together. Nitrogen gas constitutes 70% of air. Other chemicals are present in very small amounts. A concentration describes how much of a certain chemical exists in a given amount of air. Concentration can be expressed as PPM or PPB (parts per million or billion) and mg/m3 or ug/m3 (milli- or micro-grams per meter cubed)

Parts Per Billion:

A chemical present in air at 1ppb concentration represents one molecule of contaminant in 1 billion molecules of air.

ug/m3 Micrograms Per Meter Cubed:

This defines how much a chemical weighs per volume of air. If a chemical contaminant is present at 2 ug/m3, that means that the total weight of that contaminant in a cubic meter or air totals 2 ug or 2 millionth of a gram.

What do all these numbers mean?

The bucket results tell how much of a certain chemical was present at the time of sampling. However, these numbers are meaningless without a reference or benchmark.

Background concentration:
"Background concentration" of a chemical is the normal concentration of the chemical in unpolluted air or normal air. See the National Ambient Air Quality Standards for more information.

Health effects: For unpolluted air, chemical contaminants should not be in excess of background levels. These chemicals can exert varying toxic effects on the health of people depending upon the toxicity of chemical contaminants and their concentration in excess of background levels. Very large deviations above background concentration should be closely studied because these chemicals could adversely affect public health. While standards exist for some of the toxic gases measured by the Bucket, it is always preferable to keep all contaminants within background levels of concentration. That is because the toxicity and method of action of many of these poisons is not known. Emerging evidence also indicates that the effects of chemical poisons may magnify if the victim is exposed to a cocktail of poisons.

Some Common VOCs and Their Toxic Effects



Symptoms and Target Organs

1,1,1- Trichloroethane

Used as a dry cleaning agent, a vapour degreasing agent and as a propellant

Symptoms: irritation of eyes, skin, weakness and exhaustion, restlessness, irregular respiration, muscle fatigue; in animals: liver changes

Target organs: eyes, skin, CNS, liver

1,4 – Dichlorobenzene

Used as an air deodorant and as insecticide

Symptoms: irritation of eyes, skin, nose, throat, respiratory system, bronchitis, hypochromic anemia, headache, drowsiness, weakness and exhaustion, dizziness, nausea, incoherence, vomiting, confusion, chemical pneumonia

Target organs: eyes, skin, respiratory system, CNS, blood

2 – Butanone

Used as a solvent and in the surface coating industry, in manufacturing synthetic resin

Symptoms Irritation eyes, skin, nose; headache; dizziness; vomiting; dermatitis

Target Organs Eyes, skin, respiratory system, central nervous system


Used as a solvent, in the production of lubricating oils and as an intermediate in pharmaceuticals and pesticides.

Symptoms Irritation eyes, nose, throat; headache, dizziness, central nervous system depression; dermatitis

Target Organs Eyes, skin, respiratory system, central nervous system


Constituent in motor fuels, solvent for fats, inks, oils, paints, plastics and rubber. Also use din manufacturing of detergents, pharmaceutical, explosives and dyestuff.

Symptoms Irritation eyes, skin, nose, respiratory system; dizziness; headache, nausea, staggered gait; anorexia, lassitude (weakness, exhaustion); dermatitis; bone marrow depression; [potential occupational carcinogen]

Target Organs Eyes, skin, respiratory system, blood, central nervous system, bone marrow
Cancer Site [leukemia]


Used in the manufacture of dyestuffs and pesticides

Symptoms Irritation eyes, skin, nose; drowsiness, incoordination; central nervous system depression; in animals: liver, lung, kidney injury

Target Organs Eyes, skin, respiratory system, central nervous system, liver


Used as a solvent – widely distributed in atmosphere and water

Symptoms Irritation eyes, skin; dizziness, mental dullness, nausea, confusion; headache, lassitude (weakness, exhaustion); anesthesia; enlarged liver; [potential occupational carcinogen]

Target Organs Liver, kidneys, heart, eyes, skin, central nervous system


Used as a solvent and in the manufacture of styrene related products

Symptoms Irritation eyes, nose, respiratory system; headache, lassitude (weakness, exhaustion), dizziness, confusion, malaise (vague feeling of discomfort), drowsiness, unsteady gait; narcosis; defatting dermatitis; possible liver injury; reproductive effects

Target Organs Eyes, skin, respiratory system, central nervous system, liver, reproductive system


Use din particle board, insulation

Symptoms Irritation eyes, nose, throat, respiratory system; lacrimation (discharge of tears); cough; wheezing; [potential occupational carcinogen]

Target Organs Eyes, respiratory system
Cancer Site [nasal cancer]

m-/p-Xylene and o-Xylene

Used as a solvent, as constituents of paint, lacquers, varnishes, inks, dyes, adhesive, cement, and aviation fluid. Also used in manufacture of perfumes, insect repellent, pharmaceuticals and the leather industry.

Symptoms Irritation eyes, skin, nose, throat; dizziness, excitement, drowsiness, incoordination, staggering gait; corneal vacuolization; anorexia, nausea, vomiting, abdominal pain; dermatitis

Target Organs Eyes, skin, respiratory system, central nervous system, gastrointestinal tract, blood, liver, kidneys


Used in dry cleaning

Symptoms Irritation eyes, skin, nose, throat, respiratory system; nausea; flush face, neck; dizziness, incoordination; headache, drowsiness; skin erythema (skin redness); liver damage; [potential occupational carcinogen

Target Organs Eyes, skin, respiratory system, liver, kidneys, central nervous system
Cancer Site [in animals: liver tumors]


At high temperature becomes a plastic; used in manufacture of resins, polyesters, insulators, and in drug manufacturing

Symptoms Irritation eyes, nose, respiratory system; headache, lassitude (weakness, exhaustion), dizziness, confusion, malaise (vague feeling of discomfort), drowsiness, unsteady gait; narcosis; defatting dermatitis; possible liver injury; reproductive effects

Target Organs Eyes, skin, respiratory system, central nervous system, liver, reproductive system


Used as a solvent in degreasing and dry cleaning

Symptoms Irritation eyes, skin, nose, throat, respiratory system; nausea; flush face, neck; dizziness, incoordination; headache, drowsiness; skin erythema (skin redness); liver damage; [potential occupational carcinogen

Target Organs Eyes, skin, respiratory system, liver, kidneys, central nervous system
Cancer Site [in animals: liver tumors]


Used in manufacture of Benzene, as a solvent for paints and coatings or as a component of car and aviation fuels.

Symptoms Irritation eyes, nose; lassitude (weakness, exhaustion), confusion, euphoria, dizziness, headache; dilated pupils, lacrimation (discharge of tears); anxiety, muscle fatigue, insomnia; paresthesia; dermatitis; liver, kidney damage

Target Organs Eyes, skin, respiratory system, central nervous system, liver, kidneys


Used as a solvent in vapour degreasing. Used as an intermediate in production in pesticides, waxes, gums, resins, tars, and paints.

Symptoms Irritation eyes, skin; headache, visual disturbance, lassitude (weakness, exhaustion), dizziness, tremor, drowsiness, nausea, vomiting; dermatitis; cardiac arrhythmias, paresthesia; liver injury; [potential occupational carcinogen]

Target Organs Eyes, skin, respiratory system, heart, liver, kidneys, central nervous system
Cancer Site [in animals: liver & kidney cancer]

[Volatile Organic Compounds: Exposure to VOCs primarily occurs through inhalation, affecting the mucous membranes of eyes, nose, throat and respiratory tract. Prolonged exposures to VOCs are known for causing various types of cancer. These chemicals are also known as endocrine disrupters as they imitate or disrupt the action of naturally occurring hormones in the human body. Whatever little we know about the toxics effects of VOCs, indicates that these chemicals are serious concerns to human health]

Annexure 1

Name of the monitor:
Date of the incident
Time of the incident

Location of the source of the emission:
Name of the unit
(Please specify if the emissions/ leak was from any particular point of the unit)

Describe the wind flow during the leak:
From the plant – gusty, steady, strong, light, none

What was the usual direction of the wind for the area at that time

Identify the smell

Rotten eggs
Acid like
Gasoline/ kerosene/ oil
Nail paint/ paint
Any other

What is the immediate health effect of the leak
makes feel nauseous
gives a headache
eyes burning
throat closing
difficulty in breathing
any other

How does the emission look like:
vapour clouds

Was there any flare? If yes then what was the colour of the smoke from the flare?

--------------------------Answer the additional questions in case of Accidents -----------------

Has the incident been reported to the local authorities?
By whom?
What was the response of the local authorities (visit by officials, action taken against polluter, compensation paid, samples taken etc)

Was there any human injury as a result of the leak/ emissions? If yes, please answer the following:
How many people were affected?
How did they came in contact with the air/ gas?
Was complaint filed with police, PCB? If yes, provide copy of complaint. If not, file complaint with copies to local group and relevant Panchayat.

Please fill out their personal details:
Type of injury
Extent of injury
Date/time of injury
Any medical treatment taken? Describe with name of doctor, doctor’s report/prescription etc
Any loss of workdays. If yes, how many?

Has there been any death due to the exposure?
Address of the deceased.

Describe incident leading to death –
Where was the victim at te time of exposure?
What was the victim doing at the time of exposure?
Was death immediate?
What symptoms?

Cattle Animal Injury/Death
Number of animals affected? Kind of animal
Describe injury, cause of injury.
Was a veterinarian consulted? If yes please attach details of diagnosis, prescription, tests performed?
Was complaint filed with police, PCB? If yes, provide copy of complaint. If not, file complaint with copies to local group and relevant Panchayat.