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Ultimate Guide to Air Pollutants

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Table of Contents

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What is Air Pollution?

Air pollution is caused by a variety of sources, both natural and man-made. Air pollution is caused by solid and liquid particles and certain gases that are suspended in the air. These particles and gases can be bad for our health and the environment, making it important to understand how to minimize exposure.

Woman blowing her nose in public.

Potential Health Risks of Air Pollution

While air pollution is invisible, it can cause a lot of unknown harm. The health effects from air pollution varies depending on the type of air pollutant and the level of exposure. Air pollutants are everywhere, informing yourself and others on the causes and how to limit exposure is essential to lowering the potential health effects they cause.

Short-term Effects

  • Irritation of the eyes, nose and throat
  • Wheezing, coughing, chest tightness, and breathing difficulties
  • Worsening of existing lung and heart problems, such as asthma
  • Increased risk of heart attack

Long-term Effects

  • Damage to the immune, neurological, reproductive and respiratory systems
  • Respiratory or cardiovascular disease
  • Cancer
  • In extreme cases, premature death

A smokey forest.

Environmental Effects

Not only do air pollutants have the potential to cause harm to human health, but they effect the environment in numerous ways.

  • Acid Rain

Acid rain or acid deposition, includes any form of precipitation with acidic components. Acid rain can be either wet or dry, including rain, snow, fog, hail or dust. Acid rain is made up of sulfur dioxide and nitrogen oxides. Small amounts of these chemicals can come from natural sources such as volcanoes, but most comes from the burning of fossil fuels.

  • Eutrophication

Eutrophication occurs when excessive nutrients enrich the environment. The excess in nutrients sets off a chain reaction in the ecosystem, starting with an overabundance of algae and plants, dead zones, fish kills, and loss of plant and animal diversity.

  • Haze

Haze is caused when sunlight encounters tiny pollution particles in the air.  Haze reduces the clarity and color of what we see, especially during humid conditions. Some haze-causing particles are directly emitted to the air, while others are formed when gases emitted to the air form particles.

  • Effects on Wildlife

Like humans, wildlife may also experience health effects from air pollution.  Wildlife can be exposed to air pollutants in three different ways: inhalation, ingestion, or absorption through the skin.

  • Ozone Depletion

Ozone occurs both in the Earth’s upper atmosphere and at ground-level. Ozone that occurs naturally in the upper atmosphere is known as stratospheric ozone. This “good” ozone shields us from the sun’s harmful ultraviolet (UV) rays. Stratospheric ozone is gradually thinning due to man-made chemicals referred to as ozone-depleting substances, including chlorofluorocarbons, hydrochlorofluorocarbons, and halons. Thinning of the protective layer of ozone can cause increased levels of UV radiation and damage or reduction of sensitive crops.

  • Crop and Forest Damage

Crop and forest damage can be caused by ozone depletion and increased UV, ground-level ozone, or acid rain. Ozone depletion, leading to increased UV, affects sensitive crops, such as soybean, leaving them damaged or reduces the crop yields. Ground-level ozone can lead to reductions in crop and forest yields, reduced growth and survivability or tree seedlings, and increase plan susceptibility to disease, pests, and other environmental stresses. Acid rain may damage trees and causes soils and water bodies to acidify, making the water unsuitable.

Criteria Air Pollutants

The Clean Air Act required the Environmental Protection Agency (EPA) to set six common air pollutants, also known as “criteria air pollutants”. These pollutants include ground-level ozone, particulate matter, carbon monoxide, lead, sulfur dioxide and nitrogen dioxide.

  • Ground-level Ozone

The harmful air pollutant ozone, otherwise known as ground-level ozone, is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOCs). This happens when pollutants chemically react in the presence of sunlight.

Read more on ozone here.

  • Particulate Matter (PM)

Particulate matter, also known as particle pollution or PM, are extremely small solid particles and liquid droplets suspended in air. Particulate matter can be made up of a variety of components and have both short term and long-term potential health effects.

Read more on particulate matter here.

  • Lead (Pb)

Lead is a naturally occurring metal found in small amounts in the Earth’s crust. Although lead can be found in all parts of the environment, most of it comes from human activities. Depending on the level of exposure, lead can affect several systems throughout the human body such as neurological and renal.

  • Carbon Monoxide (CO)

Carbon Monoxide or “CO” is an odorless, colorless gas that forms when carbon in fuels do not completely burn. CO may cause harmful effects on the body’s organs due to the reduction of oxygen reaching them.

Read more on carbon monoxide here. 

  • Sulfur Dioxide (SO2)

Sulfur dioxide or “SO2” is a colorless gas with pungent odor. This gas is formed by fossil fuel combustion from activities like burning of coal and oil at power plants or from copper smelting. Naturally, SO2 can be released into the air by volcanic eruptions.

Read more on sulfur dioxide here. 

  • Nitrogen Dioxide (NO2)

Nitrogen dioxide or “N02”  is formed by emissions from motor vehicles, industry, unfluted gas-heaters and gas stove tops. NO2 is one of a group of highly reactive gases known as oxides of nitrogen or nitrogen oxides (NOx).

Other Air Pollutants

While the criteria air pollutants have been marked as the most prevalent, there are many others. Below, we’ve listed other solid particles and gasses that pollute the air.

  • Ammonia (NH3)

Ammonia or “NH3” is a colorless alkaline gas with a distinct odor. The odor may be a familiar scent due to ammonia’s use in smelling salts, and many household and industrial cleaners. It is both manufactured and produced naturally.

  • Volatile Organic Compounds (VOCs)

Volatile organic compounds or “VOCs” are emitted as gases from certain solids or liquids. Sources of VOCs include paints, pesticides, disinfectants, building materials, craft materials and so on. These chemicals are widely used as ingredients in household products.

  • Acrolein

Acrolein is a colorless or yellow liquid with unpleasant odor. Acrolein is used as a pesticide and can be formed when trees, tobacco, gasoline and more is burned.

  • Biological Pollutants

Biological pollutants come from various sources including pollens, viruses, mold, animal dander, and so on. Sources of biological contaminants include living things and what they produce. Thankfully, there are preventative measures that can be taken against these pollutants including keeping humidity low or proper ventilation.

  • Formaldehyde

Formaldehyde is a colorless gas with a strong scent that can be both inhaled or absorbed through the skin. Formaldehyde levels may be higher where there is tobacco smoke, products with new manufactured wood, some fabrics, and so on.  

  • Radon (Rn)

Radon or “Rn” is a radioactive gas that forms naturally when certain radioactive metals break down in rocks, soil and groundwater. Since it comes from the ground naturally, total avoidance may be unavoidable.

  • Asbestos

The term asbestos refers to a class of minerals that naturally form long, thin, very strong fibers. Asbestos occurs both naturally from the environment and from the breakdown or disposal of old asbestos products.

  • Benzene

Benzene is a colorless liquid with a sweet odor that is used to make some types of plastics, resins, rubbers, lubricants dyes, pesticides and so on. In addition to being used by some industries for production, it is also naturally part of crude oil, gasoline and cigarette smoke.

  • Carbon Disulfide

In its pure form, carbon disulfide is a colorless liquid with a pleasant odor. Impure carbon disulfide is a yellowish liquid with an unpleasant odor. In nature, small amounts of carbon disulfide are found when gases are released like volcanic eruptions or over marshes.

  • Creosote

The term creosote is used to describe a variety of products. These products are mixtures of many chemicals ranging in color, texture and use. Creosote can end up in disinfectants, laxatives, medicines, roofing, animal repellants, and so on.

  • Fuel Oils

Fuel oils can be used for many common products like engines, stoves and furnaces. Fuel oils include kerosene, diesel fuel and home heating oil. Different types of fuel oil can range in color from yellowish to light brown.

  • Polycyclic Aromatic Hydrocarbons (PAHs)

Polycyclic aromatic hydrocarbons or “PAHs” are a group of over 100 different chemicals that are formed during the incomplete burning of certain materials. Some PAHs are manufactured for use in products.

  • Synthetic Vitreous Fibers (SVFs)

Synthetic vitreous fibers or “SVFs” are a class of materials. The fibers are produced by melting various rocks, clay and more, then blowing or extruding them into fibers of particular properties. Synthetic vitreous fibers never occur naturally in the environment and may affect the respiratory system.

  • Total Petroleum Hydrocarbons

The term total petroleum hydrocarbons or “TPH” is used to describe a large family of several hundred chemical compounds that originally come from crude oil. Due to the large number of chemical compounds under this term, it has been more efficient to measure the total amount of TPH together. Although TPH is a mixture, it is generally mostly made up of hydrogen and carbon, known as hydrocarbons.

Two TruSens Air Purifiers on the floor of a home.

How to Reduce or Prevent Exposure to Air Pollution

Reducing or preventing exposure to air pollution may vary based on which pollutants you are concerned about and the level of exposure you are experiencing.

  • Air Quality Index (AQI)

The air quality index or “AQI”  is an index for reporting daily air quality.  Knowing the AQI both outdoors and indoors allows you to take measures to reduce or prevent air pollutants. The AQI is calculated for four major air pollutants regulated by the Clean Air Act. These air pollutants include ground-level ozone, particle pollution, carbon monoxide, and sulfur dioxide.

  • Managing Indoor Air Quality (IAQ)

Managing indoor air can be done in a variety of ways including managing sources of air pollutants, improved ventilation, investing in air cleaning technology, avoiding high indoor temperatures or humidity, and regularly changing filters in the products you use.

Investing in an air purifier is a great way to manage your IAQ. Depending on the air purifier, they have the capability to provide an AQI value to your indoor air and help remove a variety of pollutants such as mold spores, pollen, and VOCs.


  • Reducing Activities that Cause Air Pollution

Depending on the source of the pollutant, pollutants can be man-made and caused by household, industrial or other human activity. Reducing the use of products with these pollutants will also limit the amounts you are exposed to.