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Important Pollutants and Greenhouse Gases other than Ozone:

Criteria Pollutants: CO, Pb, O3, PM, NO2, SO2


Oxides of nitrogen (NOX), such as Nitric Oxide and Nitrogen Dioxide, are emissions that are released into the air and can be harmful air pollutants. NOX is a key component for the formation of ozone, smog, and acid rain. Numerous programs over the years have been aimed at reducing these emissions into the atmosphere. NOX is harmful due to these byproducts and their effect on public health, and the troposphere.


Volatile Organic Compounds (VOCs) are an aggregation of organic chemicals/compounds that have a high vapor pressure (volatile) and low water solubility. VOCs are another precursor for ozone, a harmful criteria pollutant controlled by the EPA and a pollutant that our region is in nonattainment for and are common air and ground-water pollutants. VOCs come from many sources, especially anthropogenic (man-made), such as paints, aerosol sprays, petroleum fuels, disinfectants, perfume, and many others.


Nitrogen Dioxide (NO2) is a highly reactive gas that is one of the gases grouped to collectively make up Nitrogen Oxides (NOX). NO2 is one of EPA’s six criteria pollutants listed in the National Ambient Air Quality Standard (NAAQS) and is heavily regulated. Primarily emitted from burning fuel, exposure to high concentrations of NO2 emissions are very unhealthy to the respiratory system through both acute and prolonged time periods. NO2 is a major component in creating harmful secondary pollutants.


Particulate Matter (PM) is microscopic particle pollution of solids/liquids that can cause or exacerbate serious health problems. These particles are very small and can damage people’s lungs and throat when inhaled. PM pollution comes from things being burned, construction, mining, factories, vehicles, power plants, and many others.


Sulfur Dioxide (SO2) is a pollutant harmful to the respiratory system. Emission sources are fossil fuel combustion through anthropogenic uses, and natural phenomena such as volcanoes. SO2, like NO2, contributes to acid rain, smog formation, and particle pollution – all of which are harmful and unwanted conditions.


Carbon Dioxide (CO2) is a colorless gas that is heavily emitted through anthropogenic activities, such as the usage of fossil fuels. The buildup in concentrations of CO2 is contributing to global warming, and the EPA has been setting standards to increasingly reduce carbon pollution for decades.


Carbon Monoxide (CO) is a colorless, flammable, and toxic gas that is one of the six criteria pollutants. At very high levels, CO is toxic (and fatal) to humans and animals. This is because it binds to hemoglobin in the bloodstream, which normally carries oxygen, and therefore eventually will replace the oxygen with CO and deprive the organism of the necessary oxygen to function or survive with prolonged exposure. CO is slightly denser than air, so it is typically found and tested for close to the floor, though it can be moved through numerous means. High CO emissions in enclosed environments are typically due to burning charcoal, gasoline, wood, or other fuels indoors and with improper ventilation.


Historically, lead (Pb) pollution was much more problematic due to the high concentrations and low regulation. Lead pollution primarily comes from anthropogenic sources and uses. According to the EPA, from 1980 through 2014, regulatory efforts have reduced lead concentrations in the air by 98 percent. This is important, as part of our region was in nonattainment for lead concentration back in 2015. Lead pollution is very harmful to people, especially children, as it affects many critical systems and functions that allow for a normal, healthy life and early/prolonged exposure are linked to many adverse physical and cognitive impacts.

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