Corinne, an academic research chemist for thirty year who joins our team will post an article every two weeks. We would like to invite people to send questions or topics at corinne@labucketbrigade.org. We cannot promise we can answer all the questions, but we will seek answers from experts if we cannot. The aim is to keep each topic to a page or two, but if you want more information feel free to send an email.

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Issue #1: Six Criteria Air Pollutants

With the Clean Air Act in 1970, the Environmental Protection Agency (EPA) established the National Ambient Air Quality Standards (NAAQS) requiring the monitoring of six criteria pollutants. These are general pollutants which are a good representation of the ambient air quality in the country. The acceptable levels are established by the EPA and regularly reviewed, based on the latest research, to minimize health risk. We will describe each of the pollutants and the health concerns. We will discuss the monitoring of these six pollutants.

Carbon Monoxide (CO) is a colorless gas resulting from fossil fuel burning. It reduces the amount of oxygen transported to critical organs such as the heart (and causes chest pain). Indoor high concentration (amount) can be fatal. Outdoors, the concentration can reach a level of concern for people who are vulnerable, such as those with heart disease.

Lead (Pb) primarily comes from ore/metal processing, incinerators, paints and lead-acid batteries. Lead emission exposure has reduced a lot since the removal of lead in fuel and paint. Lead accumulates in the body after exposure. One major concern is the neurological effect on children’s development.

Sulfur Dioxide (SO2) is a gas which principally comes from burning fossil fuels, part of the sulfur oxides family. It is harmful to the respiratory system and known to trigger asthma attack. It also leads to the formation of particulate matter (PM) (see below).

Nitrogen Dioxide (NO2) is highly reactive gas, representing the nitrogen oxides family. It also comes from burning fossil fuels. Exposure is harmful to the respiratory system. Long exposures may contribute to the development of asthma. It also leads to the formation of particulate matter (PM) (see below).

Ground ozone, also called bad ozone (compared to the good ozone in the upper atmosphere which stops excess UV from reaching earth) is a toxic gas. It is not emitted directly by cars or industry, but it is the result of reaction of nitrogen oxides with Volatile Organic Compound (other pollutants in the air) and sunlight. It is harmful to the respiratory system, leading to difficulty breathing and asthma.

Particulate Matter (PM) is a mixture of solid and liquid droplets in the air. They are so small that we cannot see them. They can go deep into our lungs and even into the bloodstream, particularly the smaller PM2.5 (diameter 25 times smaller than the diameter of a hair). They form from car emission, industrial emission and fires. They can be composed of many chemicals depending on their origin and even carry toxic heavy metal atoms such as chromium, cadmium and nickel. They are generally very harmful to health, targeting the heart and lungs. Their specific toxicity can depend on their composition.

Are these the only pollutants?

No.

Since there are many possible pollutants, a small list was established. They were not chosen because they are the most toxic but because they represent the most common and general pollutants due to fossil fuel burning (cars or industrial) but they are far from the only ones. They are responsible for the smog and acid rain. We will talk about the other toxic pollutants next time.

Are these six pollutants monitored?

Yes, but very little or not all. The air quality cannot be regulated if it is not monitored sufficiently.

In Louisiana, EPA and Louisiana Department of Environmental Quality (LDEQ) have monitors. They do not monitor the six criteria pollutants at each site.

For example: Ascension parish has one monitoring site (same one for EPA and LDEQ), in Dutchtown. It monitors Ozone, Nitrogen Oxide and Volatile Organic Compound (VOC). One monitor for the entire parish is not enough. It is not monitoring the six criteria. How can the EPA decide on attainment with just one monitoring station in a parish?

Where are the monitors located?

Monitors are very often located away from the most polluted area. It does not represent what the population who lives next to the plants gets exposed to. The monitors are not sufficient for the population living next to the plants to know about their air quality.

For example: The only monitoring site in Ascension Parish is two to ten miles away from the major polluting plants, but people live less than a quarter of a mile away from the plants.

Next time: Hazardous Air pollutants, ie other toxic pollutants.

Resources:

1. Environmental Protection agency (EPA): https://www.epa.gov/criteria-air-pollutants
2. Louisiana Department of Environmental Quality (LDEQ): https://www.deq.louisiana.gov/
3. CDC: https://www.cdc.gov/air-quality/pollutants/index.html