When it comes to air quality, everyone thinks of CO2. Which is certainly a problem. But it is only one side of the coin. Or rather, of the prism.
CO2 is a problem, but not the only one
Global attention on air quality has grown exponentially, largely due to global warming and climate change induced greenhouse gas emissions. Although CO2 is often the focus of discussions, it is time to clarify that air pollution is a complex and multifaceted phenomenon.
In this article, we would like to clarify a misconception. We’re going to explain why not only CO2 plays a role in the complex picture of air quality, but also other greenhouse gases such as methane, fine particles and even biological contaminants, typically viruses and bacteria.
The (entire!) family of greenhouse gasses
Greenhouse gasses are substances in the Earth's atmosphere that trap heat, leading to the warming of the planet. While some greenhouse gasses are natural and necessary for maintaining a habitable climate, human activities have significantly increased the concentrations of certain greenhouse gasses, contributing to climate change.
The key 7 direct greenhouse gases - beyond CO2
Here are the key seven direct greenhouse gases under the Kyoto Protocol:
Carbon dioxide (CO2)
Nitrous oxide (N2O)
Sulfur hexafluoride (SF6)
Nitrogen trifluoride (NF3)
These gasses contribute directly to climate change owing to their positive radiative forcing effect.
Brief review: how GHG affect global warming
Greenhouse gasses trap heat in the Earth's atmosphere, leading to a warming effect known as the greenhouse effect. Human activities, especially the burning of fossil fuels and the manufacturing of consumer goods, have significantly increased the concentrations of these gasses, contributing to global warming and climate change. The consequences include rising temperatures, more frequent and severe weather events, sea level rise, and disruptions to ecosystems. Addressing the reduction of greenhouse gas emissions is a critical component of global efforts to mitigate climate change.
As a consequence of this paragraph, an effective clean air and anti-pollution strategy should address the removal of other substances, not only CO2. Let’s see some examples.
Methane, your enemy #2
Methane is also a global enemy .Per unit of mass, the impact of methane on climate change over 20 years is 86 times greater than CO2; over a 100-year period, it is 28 times greater.
As reported on Active Sustainability, in 2019, atmospheric concentrations of methane reached record levels in our atmosphere, with 2.5x more methane than there used to be in the pre-industrial era. Because its atmospheric lifetime is so short in relation to CO2, reducing methane emissions is an effective way to curb climate change.
Methane also contributes to the formation of ozone, a type of air pollutant that makes air quality worse and reduces crop yields.
Humans contribute around 60% of methane emissions through fossil fuels, agriculture and waste, while the other 40% comes from natural sources. Agriculture forms the leading source of methane production globally. While all ruminant animals (hoofed herbivores that graze) can produce this gas, cows produce the most methane, releasing up to 500 litres of it into the atmosphere each day, according to the EC stats.
On December 4, 2023, during the COP28 Global Methane Pledge (GMP) Ministerial, Ministers expressed appreciation for the national initiatives and significant grant funding unveiled at COP28, aiming to achieve a minimum 30% reduction in methane emissions by 2030. GMP collaborators disclosed the allocation of over $1 billion in fresh grant funding for methane-related initiatives, a figure surpassing three times the current amount. This funding is expected to leverage billions in investments dedicated to mitigating methane emissions.
Fine dust - a silent killer
But what we should really worry about is the PM, to such an extent that a new report from the National Academies of Sciences, Engineering, and Medicine recommends public health officials and other local and regional agencies take action to mitigate exposure to fine particulate matter indoors.
Fine dust or atmospheric particulate matter (PM10 and PM2.5) is a very fine material that can include substances harmful to health such as heavy metals, sulphates and nitrates.
These dust particles are so light that they can remain suspended in the air and be breathed in. They are also able to absorb polluting gases and toxic vapours that reach the lungs.
It is so light that it can easily remain suspended in the air and therefore be breathed in.
Fine dust is divided into two categories, depending on the average particle size.
PM10 - Coarse particulate matter: this consists of particles, dust, pollen and spores with a diameter greater than 10 µm (microns), the so-called PM10. A micron is equal to a millionth of a metre, or a thousandth of a millimetre.
PM2.5 - Fine or fine particulate matter: this is dust with a size of around 2.5 microns, i.e. PM2.5.
Ultra-fine or respirable dust: these are those dusts with a size between 1 and 0.1 microns. Below these sizes, we speak of nanopowders.
Ultrafine particles are those who ventilation systems hardly capture. That’s why a clean air strategy should not rely on a single solution, but rather on a protocol that combine different technologies with different features.
Viruses and bacteria, the unspoken side of air quality
Venice. Early 15th century. Thick fog, high humidity, gloomy days. The republican institutions determined that all ships had to undergo a period of 40 days of isolation to ensure they weren’t carrying disease.
600 years later, we still battle against pathogens and bacteria present in the air, on surfaces, and on our skin. Cross-contamination – which is when pathogens are transferred from one surface or person to another – is no longer a problem that occurs in hospitals. Cross contamination is everywhere, as the pandemic showed.
There are several reasons why it's important to combat viruses and bacteria as part of a clean air strategy:
Respiratory Health: Combating viruses and bacteria reduces respiratory infections and promotes healthier air quality.
Indoor Air Quality: Controlling indoor infectious agents improves indoor air quality.
Preventing Pandemics: Controls the potential for virus-driven pandemics that impact public health and air quality.
Reducing Hospitalizations: Limits severe infections, decreasing hospitalizations and strain on healthcare systems.
Community Well-being: Healthier communities experience improved productivity and quality of life.
Airborne Transmission: Mitigating airborne transmission minimizes the risk of respiratory infections in public spaces.
Reducing Antibiotic Resistance: Combating bacterial infections helps preserve antibiotic effectiveness.
Environmental Impact: Proper waste disposal in combating infectious agents contributes to environmental protection and indirectly impacts air quality.
Conclusion: the imperative of a holistic approach to air quality
Hopefully we have cleared up a misconception. While addressing CO2 is crucial, particularly concerning global warming, it's imperative to emphasize that air quality transcends climate change. It's an urgent, present health emergency demanding immediate attention.
Taking a holistic approach to air quality involves not only reducing emissions and absorbing CO2 but also actively purifying the air of various contaminants. Only through comprehensive efforts can we effectively mitigate negative impacts on human health, the environment, and the economy.