INSIGHTS

Get to know air pollution better!

Major Air Pollutants

Factors Affecting Pollution in an Area

    Climate
  • Temperature
  • Prevailing winds
  • Seasonal changes
    Topography
  • Prevailing winds
  • Hills and valleys
  • Dominant vegetation
  • Cities and surfaces
Particulate Matter (PM)

Introduction

Particulate matter is the sum of all solid and liquid particles suspended in air, many of which are hazardous. This complex mixture contains for instance dust, pollen, soot, smoke, and liquid droplets. Particles can either be directly emitted into the air (primary PM) or be formed in the atmosphere from gaseous precursors such as sulfur dioxide, oxides of nitrogen, ammonia and non-methane volatile organic compounds (secondary particles).

Particulate matter goes by many different names. It may be referred to as total suspended particulates, black smoke, breathable particulates or thoracic particulates. Recently, there has been an effort to use more objective features such as the particulate diameter: particles with a diameter less than 10 micrometers are named PM10; particles with a diameter less than 2.5 micrometers are called PM2.5 (or fine particulates) and particles with a diameter less than 0.1 micrometer are called PM0.1 (or ultrafine particulates).

Sources

    Human Activities
  • Agricultural operations
  • Industrial processes
  • Combustion of wood and fossil fuels
  • Construction and demolition activities
  • Entrainment of road dust into the air
    Natural Sources
  • Windblown dust
  • Wildfires and Forest Fires
  • Volcanoes

Health Effects

  • Increased acute respiratory morbidity (pneumonia, asthma)
  • Increased mortality (from all causes)
  • Decreased lung growth and function
  • Decreased birth weights
  • Mortality from cardiovascular and respiratory diseases and from lung cancer

Most Affected

  • Elderly people
  • People with pre-existing heart and lung disease
  • Asthma Patients
  • Socially disadvantaged and poorly educated populations
Ozone (O3)

Introduction

Ozone is a colorless, odorless reactive gas comprised of three oxygen atoms. It is found naturally in the earth’s stratosphere, where it absorbs the ultraviolet component of incoming solar radiation that could be harmful to life on earth. Ozone is also found near the earth’s surface, where pollutants emitted from society’s activities react in the presence of sunlight to form ozone. Principal pollutants involved in these reactions are nitrogen oxides (NOx) and volatile organic compounds (VOCs); carbon monoxide (CO) also participates in the reactions to help form ozone. All of these compounds (NOx, VOCs, and CO) are termed as ozone precursors. Hot sunny weather with stagnant wind conditions favors ozone formation.

Sources

    Natural Causes
  • Forest fires
  • Vegetation
    Human Activities
  • Cars, trucks, and buses
  • Aircraft, locomotive, etc.
  • Construction, agricultural equipment, etc.
  • Cement and power plants
  • Bakeries, paint shops, dry cleaners, etc.
  • Oil and Gas production and drill rigs

Health Effects

  • Difficult to breathe deeply and vigorously
  • Shortness of breath, and pain when taking a deep breath
  • Cause coughing and sore or scratchy throat
  • Inflame and damage the airways
  • Aggravate lung diseases such as asthma, emphysema, and chronic bronchitis
  • Increase the frequency of asthma attacks
  • Make the lungs more susceptible to infection
  • Continue to damage the lungs even when the symptoms have disappeared
  • Cause chronic obstructive pulmonary disease (COPD)

Most Affected

  • Asthma Patients
  • Children
  • Older adults
  • People who are active outdoors, especially outdoor workers
  • People with a pre-existing heart and lung disease
  • Socially disadvantaged and poorly educated populations
  • Pregnant women, exercising women and working women
Sulphur Dioxide (SO2)

Introduction

Sulphur Dioxide is a colorless toxic gas with a pungent and irritating smell. Sulfur dioxide is sometimes used as a preservative for dried apricots, dried figs, and other dried fruits, owing to its antimicrobial properties. As a preservative, it maintains the colorful appearance of the fruit and prevents rotting. Sulfur dioxide was used by the Romans in winemaking when they discovered that burning sulfur candles inside empty wine vessels kept them fresh and free from vinegar smell.

Sources

    Natural Causes
  • Volcanoes
    Human Activities
  • Industrial processes, smelting of sulfur-containing ores
  • Generation of electricity from coal, oil or gas
  • Processing of sulphur-containing mineral ores
  • Motor vehicle emissions

Health Effects

  • Difficulty in breathing
  • Wheezing and cough
  • Heart failure
  • Skin defects due to acid rain
  • Decrease in lung function
  • Asthma and bronchitis
  • Eye irritation

Most Affected

  • Infants
  • Elderly
  • People with chronic symptoms of asthma and bronchitis
  • Children
  • Women
  • Workers and laborers working in refrigeration units, sprays and chemical units or aerosol units
  • Firemen and dye makers
Carbon Monoxide (CO)

Introduction

Carbon monoxide (CO) is a colorless, odorless, and tasteless gas that is slightly less dense than air. It is often called the “Silent Killer” because of its ability to take lives quickly and quietly when its victims never even knew they were at risk.

Sources

  • Incomplete combustion of gasoline, natural gas, oil, coal, and wood
  • Motor-vehicle emissions
  • Furnaces or boilers
  • Gas stoves and ovens
  • Water heaters
  • Clothes dryers
  • Wood stoves
  • Power generators

Health Effects

  • Breathing air with a high concentration of CO reduces the amount of oxygen that can be transported in the blood stream to critical organs like the heart and brain.
  • At very high levels, CO can cause dizziness, confusion, unconsciousness and death.
  • At higher risk: children with anemia, heart disease or chronic lung disease, fetuses and people with some types of heart disease.

Most Affected

  • Infants
  • Children
  • Children with existing pulmonary or hematological illnesses
  • Pregnant women
Nitrogen Oxides (NOx)

Introduction

Nitrogen oxides are a group of gases that are composed of nitrogen and oxygen. Two of the most common nitrogen oxides are nitric oxide (NO) and nitrogen dioxide (NO2). They are produced from the reaction among nitrogen, oxygen and even hydrocarbons (during combustion), especially at high temperatures.

Sources

    Natural Causes
  • Lightning
  • Thunderstorms
    Human Activities
  • Agriculture fertilization
  • Use of nitrogen-fixing plants
  • Combustion of natural gas, coal
  • Working of rotary kilns, boilers

Health Effects

  • Inflammation of the airways at high levels
  • Decrease in lung function
  • Increase in the risk of respiratory conditions
  • Increases the response to allergens

Most Affected

  • Children
  • Elderly
  • Newborn
  • People with cardio-respiratory disease or diabetes
  • People spending considerable time outdoors
  • Asthma patients

SUMMARY

PollutantSourcesHealth Effects
Particulate Matter
Automobile
Bus and truck exhaust
Fuel burning (wood stoves, fireplaces)
Industry
Construction
Increased infant respiratory mortality
Decreased lung function
Decreased lung growth
Increased symptoms in asthmatics
Ozone
Cars, trucks, and buses
Aircraft, locomotive, etc.
Construction, agricultural equipment, etc.
Cement and power plants
Bakeries, paint shops, dry cleaners, etc.
Oil and Gas production and drill rigs
Forest Fires and Wildfires
Vegetation
Decreased lung growth
Increased asthma exacerbations
Increased respiratory hospitalization
Increased asthma hospitalization
Increased school absence for respiratory illness
Nitrogen Oxides
Agriculture fertilization
Use of nitrogen-fixing plants
Combustion of natural gas, coal
Working of rotary kilns, boilers
Volcanoes
Thunderstorms
Increased symptoms in asthmatics
Decreased lung growth
Carbon Monoxide
Incomplete combustion of gasoline, natural gas, oil, coal, and wood
Motor-vehicle emissions
Furnaces or boilers
Gas stoves and ovens
Water heaters
Clothes dryers
Wood stoves
Power generators
Increased asthma hospitalization
Increased clinic visits for lower respiratory tract disease
Headache
Sulphur Dioxide
Industrial processes, smelting of sulfur-containing ores
Generation of electricity from coal, oil or gas
Processing of sulphur-containing mineral ores
Motor vehicle emissions
Increased asthma hospitalization clinic
Increased visits for heart attacks, chronic bronchitis, eye irritation and skin defects