Air Pollution: All you need to know!

What is Air Pollution?

air pollution

The most common air pollution definition is the introduction of harmful or excessive quantities of substances (such as chemicals, airborne particles and biological molecules) into the atmosphere, at levels that organisms in danger.

However, air composition in its natural state contains Nitrogen (78%), Oxygen (21%) and other gases (0.9%) like Argon or Neon. Therefore, any other foreign element is considered a pollutant, either if these have origin on natural processes or human activity.

It is well known that air pollution cause diseases, allergies, health problems or even death to humans, specially on sensitive groups like elders, kids or asthmatics and others). Still, air pollution has many effects on the environment and living organisms. Here below you can discover all the causes, effects, pollutants, most affected areas in the world, solutions and ways to measure air pollution.

Air Pollution Causes

There are several air pollution sources everyone knows, for example exhaust fumes or industrial pollution. But what really causes air pollution? Which of them are more harmful to the population?

Air pollution causes can be divided in the following two groups (Do not hesitate to use the listings below to know everything about them!):

  • Natural causes: if you think that humans are the only ones who create air pollution you are mistaken, there are natural processes on our world and environment, and some of them are in our everyday lives.
  • Anthropogenic causes: you are right if you still think humans create way more air pollution than natural processes. Moreover, it seems we are far from solving this problem because in 2018 we may not reach the climate change goals within the Paris Agreement.

Air Pollution Effects

Air pollution has many effects on humans, animals, plants, microorganisms and the environment. We are not really aware of the real impact of air pollution, as it is well known as the invisible killer.

Air pollution effects are branched in two groups:

  • Health Effects: breathing polluted air increases the probability of suffering lungs and heart diseases, or even the probability of death. Unfortunately, apart from these major problems there are many short and long term health effects of air pollution, as the average adult inhales and exhales 11.000 litres of air per day.
  • Effects on wildlife and environment: impacts of air pollution do not only affect humans, but also the environment. Phenomenons like acid rain or the eutrophication destroy the ecosystems and its flora and fauna.

To know all the air pollution effects, check out the listing below:

Air Pollutants: PM10, PM2.5, Ozone and others

Gases and particles are all contribute to pollute the air and they can be produced by humans or naturally. There is a big amount of air pollutants, however we will focus only into criteria pollutants, and some others that play an important role on their creation. These 6 pollutants are considered to be the most harmful for the health and environment, this is why, those have been regulated with standards and are used as indicators of air quality. Likewise, you can find detailed information about each one of them, and other related pollutants, on the following posts or you can take a look to the brief summary below:

  • Particles: Particle pollution, also called Particulate Matter or PM, are solid material (usually) that float in the air. Depending on how small they are, those airborne particles can be classified as: coarse particles (PM10), fine particles (PM2.5) or ultra fine particles (UFPs).
  • Nitrogen dioxide (NO2): Nitrogen Dioxide is one of a group of highly reactive gases known as oxides of nitrogen or nitrogen oxides (NOx). Those gases are produced by human activity 99% of the times, and produced during thunderstorms by electric discharge the other 1%. Acid rain is formed by the interaction of NO2 or others NOx with water, oxygen and other chemicals in the atmosphere.
  • Ozone (O3): This harmful gas that can cause serious health issues when it is inhaled in high concentration, is also protecting us through the Ozone Shield from UV radiation. This is why, we can divide Ozone into the “Good Ozone” (Ozone Shield) and “Bad Ozone” (Ground Level Ozone). Ground Level Ozone is the main component for smog and it is formatted by a combination of gases (VOCs + NOx + Heat) and the Sunlight.
  • Carbon monoxide (CO): Carbon Monoxide is an odorless, tasteless and toxic gas when reached levels higher than 35 ppm. Breathing air with a high concentration of CO reduces the amount of oxygen that can be transported in the bloodstream to critical organs like the heart and brain. Most common symptoms are weakness, headache, dizziness, confusion, fatigue, nausea or even death.
  • Sulfur dioxide (SO2): SO2 is the component of greatest concern and is used as the indicator for the larger group of gaseous sulfur oxides (SOx). It is invisible and has a nasty, sharp smell and it reacts easily with other substances to form harmful compounds. About the 99% is  produced by industrial activities such as generation of electricity from coal, oil or gas that contains sulfur. It can also be produced naturally by volcanoes.
  • Lead (Pb): Lead is a naturally occurring heavy metal that is found in the Earth’s crust. Major sources of lead in the air are mining and metal manufacturing and piston-engine aircraft operating on leaded aviation fuel, among others. The lead effects most commonly encountered in current populations are neurological effects in children and cardiovascular effects (high blood pressure and heart disease, for example) in adults.

Air Quality Standards

Until now, you have learned a lot about air pollution, but maybe you can ask yourself: What is my country doing to improve our air quality? Am I in danger? What are the levels recommended by World Health Organization (WHO)?

Here, the AirGO team has summarised which are the United States and European Union concentration standards for most harmful pollutants for human health and public welfare protection. You can easily compare them with WHO recommendations and check if your region is taking action according to these guidelines.

PollutantsAveraging periodNAAQSEU Air Quality DirectiveWHO guidelines
StandardFormStandardFormConcentrationForm
PM2.524 hours35 μg/m398th percentile, averaged over 3 years25 µg/m399th percentile (3 days/year)
1 year12.0 μg/m3Annual mean, averaged over 3 years25 µg/m3Not to be exceeded10 µg/m3
PM1024 hours150 μg/m3Not to be exceeded more than once per year on average over 3 years50 µg/m3Not to be exceeded more than 35 times per year50 µg/m399th percentile (3 days/year)
1 year40 µg/m3Not to be exceeded20 µg/m3
O3Maximum daily 8 hour mean0.070 ppm (140 μg/m³)Annual fourth-highest daily maximum 8-hour concentration, averaged over 3 years120 µg/m3Not to be exceeded more than 25 days averaged over 3 years100 µg/m3
NO21 hour0.1 ppm98th percentile of 1-hour daily maximum concentrations, averaged over 3 years200 µg/m3Not to be exceeded more than 18 times per year200 µg/m3
1 year0.053 ppm (100 μg/m³)Annual Mean40 µg/m3Not to be exceeded40 µg/m3
Differences between NAAQS, European Directive and World Health Organization guidelines about air pollutants.

The table is based only in 4 pollutants (the most important according to WHO), however every region/country takes into account also other relevant pollutants. If you would like to know more details about National Ambient Air Quality Standards (NAAQS) for USA or about European Union Air Quality Directive for each individual pollutant, you can check our posts in “Pollutants” category.

Air Quality Index

At this point you must be wondering where you can look for the pollution levels in your city. Well, this chapter is made for it! The most common website to look for the pollution levels in your city is Worldwide Air Quality. However, if you search “air quality index” in Google you will find an snipped with pollution levels in your location.

Air Pollution in the World 2018

air pollution in china

The World Health Organisation estimated this May 2018 that 9 out of 10 people breathe polluted air in the world, which is a clear signal that this type of pollution is affecting almost everyone. Unfortunately, the poor countries bear the brunt of this issue, and more than 3.000 women and children are highly exposed to air pollution in their own homes.

The WHO estimates that 7 million people die every year due to particulate matter exposure. This particulates get deep into our lungs and induce diseases like cerebrovascular accidents, heart disease, lung cancer, chronic obstructive pulmonary disease and respiratory infections.

The higher levels of air pollution in the world are registered, the worst air quality there will be in the Eastern Mediterranean Region and South-East Asia, where the levels multiply by five the limits established by the WHO. However, these rates aren’t accurate because there is a lack of data in Africa and Western Pacific. On the list of the 10 most polluted cities we have cities from Iran, India, China, Saudi Arabia and Cameroon.

The good news that governments are increasing policies in these areas, monitoring, controlling and taking actions based on the air pollution levels. On the other hand, the WHO considers these measures insufficient and is planned the first World Conference on Air Pollution and Health, which toke place between October 30 2018 and November 1 2018.