CO2, GHGs, and PM2.5. Oh My!


by Carter Harrison

With each passing year, the discussion about climate change and pollution becomes more intense and direct. Some scientists and legislators have gone as far as toplace a deadline of 12 years before human-caused changes to the climate are irreconcilable. In addition, recent talk in Washington DC includes the creation of a “climate crisis” committee and legislation like the Green New Deal proposingpruposing a fight to combat the issue of rising temperatures. In the midst of all these discussions, it can be hard to distinguish between the effects of emissions that are harmful to the world’s climate and emissions that are harmful to us.

Carbon Dioxide

Climate change and greenhouse gases are almost synonymous. These are gases that act much like actual greenhouses used to trap energy from the sun to keep temperatures warm. The most infamous of these gases is Carbon dioxide (CO2). Carbon dioxide (CO2) is a natural compound that exists within our planet’s atmosphere. You and I exhale carbon dioxide each time we take a breath, and plants use carbon dioxide in the process of photosynthesis. The purpose of carbon dioxide is to keep the planet warm enough for all of us to inhabit at it’s natural CO2 levels. It is the increasing amount of carbon dioxide in the atmosphere that concerns climate change scientists because it tends to stay in the atmosphere for long periods of time. In fact, most scientists believe carbon dioxide levels must be reduced in order to maintain climate stabilization. It takes very high levels of CO2 to produce any negative health effects like drowsiness or shortness of breath.

Short-lived Pollutants

Short-lived pollutants are gases and particles that are also powerful climate influences. The primary issue with Carbon dioxide is that it stays in the atmosphere for long periods of time. This fact is used as primary evidence regarding the importance of decreasing CO2 emissions. Short-lived pollutants have “life spans” far shorter than Carbon dioxide and act as both a greenhouse gas and a harmful pollutant. These pollutants include; black soot, tropospheric ozone, hydrofluorocarbons (HFCs), and methane. When combined together with other organic compounds, these gases form harmful particles and toxic smogs like PM 2.5 and ground level ozone that put us at risk of heart and lung conditions.

Short-lived pollutants, although related, are much different than CO2 but still present a danger. Some scientists believe that, because of the increased role they play in rising temperatures and harming human health, short-lived pollutants are an opportunity for quick action. The benefits of which would materialize much quicker in the near term.


Climate change is a real issue that will impact the world’s economies and communities if not dealt with. Although, those things which contribute to climate change and those thing which pollute the air aren’t always the same. Understanding the major contributing factors to the unique challenges of climate change and air pollution may help us reduce the impact of those factors.

Strata is committed to finding innovative solutions to important environmental issues such as air quality and climate change. To learn more about how policy aimed at tackling even the most difficult of environmental problems we face, check out these Strata research projects