Take a deep breath in and out. Your lungs swelled with approximately 25 sextillion molecules in that single breath, ranging from compounds created only days ago to those developed billions of years ago.
Many of the molecules you’re inhaling were undoubtedly exhaled by ancient cultures and countless humans since then. But what are we all breathing, exactly?
Nitrogen generated by volcanic activity deep beneath the planet’s crust accounts for roughly 78 percent of the planet’s atmosphere. The second most important component is oxygen, which makes up 21% of the world’s air.
Although oxygen molecules have existed for as long as the Earth’s oceans, oxygen gas was not discovered until ocean-dwelling microbes developed the ability to generate it.
Finally, argon, a molecule created by the radioactive decay of potassium in Earth’s atmosphere, crust, and heart, makes up .93 percent of our air. All of these dry gases combine to make up 99.93 percent of any breath you take. Water vapour can be present in the air depending on when and where you are.
However, the remaining is much more variable.
07 percent, which is brimming with possibilities. Pollen, fungal spores, and liquid droplets, as well as trace gases like methane and carbon dioxide, make up this thin slice of air.
The exact mix of natural and man-made substances varies significantly from one location to the next. But, regardless of where you are, Man-made pollutants are likely present in 7% of your breath, including toxic compounds that can cause lung disease, cancer, and even DNA damage.
There are several different types of contaminants, but they all fall into one of two groups. The first form of pollutant is primary pollution.
These poisonous compounds are released directly from a man-made or natural source. They don’t necessarily come from the usual suspects, though. Water vapour is mainly generated by some large factories, with only minor amounts of contaminants mixed in.
Burning wood or dung, on the other hand, produces polycyclic aromatic hydrocarbons, which have been linked to a variety of cancers as well as long-term DNA damage.
Pollutants deal with regional weather conditions and topography in both situations, which can hold compounds local or disperse them over hundreds of kilometres.
As these molecules pass through the air, they undergo a transformation. Pollutants are broken down by natural compounds called oxidants, which are produced by oxygen and sunlight.
These reactions can also make contaminants more quickly washed away by rain. In certain cases, however, they produce even more toxic secondary contaminants. When factories burn coal, for example, high levels of sulphur oxides are released.
These molecules oxidise to form sulphates, which condense with airborne water vapour to form a blanket of fine particles that reduce visibility and cause serious lung damage.
This so-called sulphurous smog was well-known in early twentieth-century London and continues to afflict cities such as Beijing. Another secondary pollutant has risen to prominence since the invention of automobiles.
Nitrogen oxides and hydrocarbons are released from fossil fuel-burning vehicles’ exhaust, which react to form ozone. Although some ozone in the upper atmosphere protects us from ultraviolet rays, it may form alongside secondary particles on the ground, resulting in photochemical smog.
This brown fog is common in densely populated towns, making visibility difficult and breathing dangerous. By trapping heat in the atmosphere, it also leads to climate change.
Industrial activity has led to a massive increase in various trace gas emissions in recent decades, dramatically altering the air we all breathe.
Counter-measures have also been taken in a number of countries. Catalytic converters, which minimise carbon monoxide and nitrogen oxide emissions, are standard equipment on most cars manufactured since the 1980s.
Today, cities such as Beijing are combating smog by electrifying their energy grids and banning vehicle pollution entirely.
Although it is important to move away from fossil fuels, there is no universal solution to air pollution.
Different regions will need to reply with their own set of regulations that take into account local contaminants. And we all breathe the same air, no matter where we live.