Ambient (outdoor) air pollution consists of a complicated mix of particulate matter (a.k.a. particle pollution), liquids, and gases.
The pollutants that immensely pollute air in many of the world’s cities include the six “criteria” air pollutants (1. particulate matter, 2. ozone [ground level ozone], 3. carbon monoxide, 4. nitrogen oxides, 5. lead, and 6. sulfur dioxide), toxic (hazardous) air pollutants, and greenhouse gas emissions which affect the health of living (human, animals, and plants) and non-living (the environment) things, including the stratospheric ozone layer and various ecosystems.
In particular, the six criteria pollutants listed in the preceding paragraph have been identified by the EPA (Environmental Protection Agency) as “criteria” pollutants because the EPA, itself, regulates them by formulating useful science-based guidelines for setting allowable levels of air pollutants or pollution.
All pollutants are generated from a variety of sources—some general, others specific—and can be influenced or affected by weather and local topographical conditions. The components of air pollution, especially the type in heavily polluted urban air, consist of the following:
Particulate matter can be defined as any small discrete mass of solid or liquid matter that remains dispersed in liquid or gas emissions. Particulate matter is usually regarded as an atmospheric pollutant.
Different types of particulate matter come from different sources and vary in composition and size, and may consist of a large number of chemicals. The variety of particulate matter can cause major visibility problems and be detrimental to the health and growth of agricultural products, depending on the quantities of the particulate matter, and weather conditions.
The liquid components of air pollution come from a variety of chemicals and water and may evaporate into the atmosphere or air in different shapes and sizes of droplets.
The droplets, which have been unknowingly taken deep into the human lungs and body, can cling to particulate matter, reduce visibility, and partake in the formation of acid rain.
The gas component of air pollution (air pollution constituents) come from a variety of different sources and consists of gases such as ozone, carbon monoxide, nitrogen oxides, lead, sulfur dioxide, hydrogen sulphide, volatile organic compounds (VOCs), and various metals that can exist in gaseous form, etc.
Other air pollutants
- Total petroleum hydrocarbons
- Fuel oils and kerosene
- Carbon disulfide
- Synthetic vitreous fibers
- Polycyclic aromatic hydrocarbons (PAHs)