4 Things You Should Know About the Main Air Pollutants (Part I)

If someone on the street suddenly asked you what you know about the main air pollutants, what would you answer?

You might recognize the names of some air pollutants such as nitrogen oxides or carbon monoxide. But would you be able to explain the consequences of air pollution on your health and that of your family? What are the risk groups and what precautions should they take? What sources of information do you have available to learn firsthand about air quality and how to act when pollutant emissions are high? In these two articles, we will try to clarify all these doubts in a simple way.

The worst of the worst in air pollution

Before listing the main air pollutants, you should know that they are divided into:

  • Primary pollutants, which are directly emitted from natural sources (wildfires, volcanoes, etc.) or anthropogenic sources (cars, industry, agriculture, etc.), and
  • Secondary pollutants, which are the result of a series of transformations that primary pollutants undergo in the atmosphere.

The following image will help you understand this differentiation better.

Source: Agencia Europea de Medio Ambiente CC BY 2.5 DK (1)

Once this difference has been clarified, let’s point out the main atmospheric pollutants, substances that you can monitor in real-time with the air quality devices we offer at Arantec.

Nitrogen Oxides (NOx)

In the group of NOx, nitrogen dioxide (NO2) and nitric oxide (NO) stand out. The main sources of pollution are motor vehicles, volcanoes, and wildfires. It is a primary pollutant, but when it mixes with water vapor in the atmosphere, it can transform into nitric acid, a secondary substance that contributes to acid rain. It also contributes to the formation of tropospheric ozone.

Carbon Monoxide (CO)

This gas is produced by incomplete combustion (flameless smoke could be a sign) of carbon-based fuels such as gasoline or wood. It is also a primary pollutant, but once released, like NOx, it contributes to the formation of tropospheric ozone or bad ozone.

Sulfur Dioxide (SO2)

Sulfur dioxide is produced by burning organic fuels such as oil or coal. When it combines with water in the atmosphere, it transforms into sulfuric acid, another substance that contributes to acid rain.

Particulate Matter

The particulate matter present in the atmosphere is also known as PM10, PM2.5, and PM0.1. In this designation, the number refers to the size of the particle in micrometers. The smaller the value, the greater the potential toxicity, as a smaller diameter allows them to be even absorbed into the circulatory system once inhaled. Examples of particulate matter include pollen, ash, dust, and even substances resulting from tire wear.

The following image shows the size relationship of different particles.

Fuente: United States Environmental Protection Agency (US EPA). Imagen traducida (2)

Ozone (O3)

Ozone is one of the primary secondary pollutants formed by the photochemical reaction between NOx, CO, and other compounds in the presence of sunlight. As you may already know, this gas is essential as it protects us from the sun’s ultraviolet rays.

However, it also has a dark side: when it remains near the Earth’s surface (up to a height of about 10 km, in the troposphere), it leads to the appearance of smog, a characteristic type of fog in cities that can be seen from a distance due to its brown color.

Consequences of air pollution: When breathing becomes a challenge

In some countries like China, it is common to check the air quality before going outside or opening windows to ventilate homes. The reason is the consequences that air pollution has on health, which organizations like the World Health Organization (WHO) (2) continuously emphasize.

The degree of impact of air pollution on health varies depending on factors such as pre-existing health conditions, concentration, and duration of exposure. However, there are certain vulnerable groups for whom precautions need to be taken when it comes to air pollution and health:

  • Children
  • Elderly individuals
  • People with pre-existing illnesses
  • Pregnant women

Considering these factors and how air pollution affects the health of you and your loved ones, the main effects can be summarized as follows:

ContaminantePrincipales efectos sobre la salud con niveles de exposición muy altos
NO2, SO2 y O3Irritation of the respiratory tract, which can cause coughing and wheezing. Symptoms are more pronounced in individuals with lung diseases.
Particulate MatterSmaller particles can penetrate deep into the respiratory system. Depending on their nature, they can have different effects (acting as a kind of Trojan horse, in short). In vulnerable individuals, they can cause inflammation and exacerbate heart and lung diseases.
COIt reduces the amount of oxygen carried by the blood, which can pose a serious risk for individuals with heart diseases.
Sources consulted: Department for Environment, Food & Rural Affairs – DEFRA (3) / Balali-Mood et al., 2016.

A tip: don’t miss the second part of this article. We will explain what you can do to reduce the effects of pollution and where to find information about air quality.

Sources consulted:

  • (1) Agencia Europea de Medio Ambiente. (2016). Air pollution: from emissions to exposure. https://www.eea.europa.eu/media/infographics/air-pollution-from-emissions-to-exposure/view
  • (2) US EPA. Particulate Matter (PM) Basics | US EPA. https://www.epa.gov/pm-pollution/particulate-matter-pm-basics
  • (3) Organización Mundial de la Salud / OMS. (2018). Calidad del aire ambiente (exterior) y salud. https://www.who.int/es/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health
  • (4) DEFRA UK. Effects of air pollution. https://uk-air.defra.gov.uk/air-pollution/effects
  • Balali-Mood, M., Ghorani-Azam, A., & Riahi-Zanjani, B. (2016). Effects of air pollution on human health and practical measures for prevention in Iran. Journal Of Research In Medical Sciences, 21(1), 65. doi:10.4103/1735-1995.189646

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