At first glance, "environmental protection" sounds like a worn-out phrase. But just how environmentally conscious are we, really?
If I were to paint a vivid picture, I'd think of those moments when you catch a choking whiff of exhaust from a passing scooter. When people describe something as foul-smelling, they're often thinking of ammonia compounds from animal waste — things like manure. But to me, scooter exhaust is something different: synthetic, inorganic, almost industrial. A diluted poison that won't kill you on the spot, but a poison nonetheless.
Sunlight, Air, Water
That thought leads me to the three basic elements of life: sunlight, air, and water. When scientists consider human colonization of other planets, these are the first three conditions they examine. And the scooter example strikes right at the second one — air.
The list of things that pollute our air is long. From vehicles to power plants, if you've made it this far in the article, you're probably already familiar with most of them. Worth clarifying, though: the toxic, nauseating smell I described earlier is not carbon dioxide. CO₂ is odorless. What makes exhaust unbearable is the incompletely burned carbon compounds and other components — sulfur, for instance.
Solid, Liquid, Gas: The Purity Problem with Fossil Fuels
The three main fossil fuels — coal, oil, and natural gas — exist in solid, liquid, and gaseous states respectively. From a purity standpoint, solids are the most impure and gases the most refined. This means coal contains more impurities, and burning it creates more byproducts to deal with.
The problem here isn't carbon dioxide. Coal-fired power plants have to manage sulfur compounds as byproducts, along with enormous quantities of coal ash. Gas-fired plants may also produce some sulfur compounds, but in far smaller amounts — and no ash.
Next time you pass a gas-fired power plant, take a look at what's coming out of the smokestacks. If you spot a faint yellowish tinge, ask yourself: CO₂ is colorless — so where is that color coming from?
CO₂ Isn't Actually What You're Smelling
Sharp readers may have noticed that carbon dioxide isn't something most people can actually detect. In fact, every one of us produces CO₂ — it's part of being alive. Like many problems in life, CO₂ is fundamentally a question of balance.
Air pollution doesn't come from carbon dioxide itself, but from the other substances that accompany fossil fuel combustion. The mainstream scientific view holds that excess CO₂ depletes the ozone layer, allowing more ultraviolet radiation to penetrate the atmosphere and accelerating global warming (the higher the frequency of light, the more energy it carries).
Setting aside the climate debate — for the average person on the street, the answer is simple: just crank the air conditioning up.
And therein lies the trap: the more we need energy to keep cool, the more CO₂ we produce — assuming the grid still runs on fossil fuels. Like so many things in life, it's a vicious cycle. And just like scooter exhaust, most of us quietly assume there's nothing we can do about it.
Where Do Renewables and Hydrogen Fit In?
This is precisely why advocates of renewable energy champion solar, wind, hydropower, and geothermal generation — and why some go further, proposing hydrogen produced from renewables as a zero-carbon energy carrier. For a deeper look at renewables and hydrogen energy, feel free to revisit the earlier articles in this series.
This article was published by the Tellus Materials editorial team. Tellus Materials specializes in hydrogen energy and energy storage solutions, dedicated to driving Taiwan's energy transition forward.
