Nitrogen oxides are gases that contribute to smog and also produce acid rain and its associated effects. This pollutant is produced from “combustion processes” in land vehicles and ships related to power, heat, and running engines.
Carbon Monoxide is produced by the incomplete burning of fossil fuels in vehicles, home heating equipment, and industrial plants, among many other sources, and is a colorless and odorless gas, poisonous to humans and animals when inhaled.
Sulfur dioxide is produced by the burning of sulfur containing fuels like oil and coal, and can cause health issues, especially in those with existing heart or lung conditions.
Lead is emitted into the air by vehicles and industrial sites and by waste burning facilities. Manufacture and recycling of lead-acid batteries, processing of metals, iron and steel, copper, glass, cement, and industrial and institutional boilers are other sources of lead.
Dioxin is present in plastics, and is released during its manufacture and if plastic waste is incinerated
Benzene pollution occurs during some industrial processes and use of products containing petroleum, like plastics. Tobacco smoke exposure is another source.
Some biological pollutants include pollen and mold.
Pollen from trees, weeds and grass can cause allergies and hay fever, and is a health problem even if it is not lethal.
Mold is a problem affecting indoor air quality. Some molds produce toxins that bring on allergies and asthma.