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Does air pollution cause climate change?

/ 3 May 2024 / 0 Comments

The overwhelming scientific consensus according to more than 99.9 percent of peer-reviewed studies is clear – climate change is real and man-made. Climate change results in increased flooding, record heatwaves, stronger hurricanes, and longer, more extreme wildfire seasons that all directly affect our welfare.

Climate change is predicted to have devastating long-term effects on human health and safety. Regional impacts provided by the Intergovernmental Panel on Climate Change include:

  • abrupt ecosystem shifts
  • species extinction
  • reduced snow cover
  • greater risk of flash flooding
  • reduced agricultural output for a growing population
  • more intense, prolonged heatwaves
  • increased droughts

The key driver of climate change is air pollution caused by methane emissions and fossil fuel burning, gas-phase air pollution. These two environmental hazards are deeply intertwined and must be addressed together.

The consequences of climate change are dire and the need for mitigating action is urgent. Because the connection between air pollution and climate change is well-established, it’s critical to understand the complex interaction between pollutants and our environment, how that leads to climate change, and what can be done about it.

Key pollutants affecting poor air quality and climate change

Air pollutants comes in two physical states: solid, particulate matter and gas-phase pollutants. Gas-phase pollutants, such as greenhouse gases (GHGs) consist of methane, nitrous oxides, and carbon dioxide. These pollutants enter the Earth’s atmosphere in unprecedented concentrations, causing our planet’s climate system to change.

When greenhouse gases absorb radiation, they also trap the sun’s heat and stop them from entering space. This creates a greenhouse effect, gradually raising the Earth’s temperature.

Notably, many significant air pollutants like PM2.5 aren’t gases – they’re particles. PM2.5 are particle pollutants measuring 2.5 microns in diameter or less. The chemistry surrounding PM2.5 is not as dynamic and volatile as gas-phase pollutants. Nevertheless, particulate pollution can deeply harm human health. In fact, over 7 million people die every year due to mainly particulate matter pollution, as it is linked to increased heart and lung illnesses and other serious health effects.

Because of these differences, most government write laws and develop policy separating greenhouse gas emissions (also known as gas-phase air pollution) and particulate matter air pollution.

Hotter temperatures impact heatwave length and intensity, wildfire frequency, and increase air pollution. Increased heat and sunlight generate higher concentrations of ozone, a gas which forms through a combination of volatile organic compounds (VOCs) and nitrogen oxides chemically interacting with sunlight. Ground-level ozone is also called smog. This is not to be confused with the “ozone layer,” the protective shield in the Earth’s stratosphere that protects us from the sun’s radiation.

While ground ozone by itself is a pollutant, heat has the added impact of increasing particle pollutants. By drying out plants and soil, high heat increases dust circulation and creates conditions favorable for wildfires. A careless camper in a back country forest or lightning strikes can spark massive infernos, which then carry smoke for hundreds or thousands of miles.

Can air pollution affect the weather (meteorology)?

There are many ways in which air pollution directly impacts the weather.

Higher concentrations of particle pollution can affect cloud formation. When there are moderate concentrations of particle pollutants, water condenses onto the particles. Clouds become taller, creating more intense rainfall, thunderstorms, and lightning. This can also alter traditional rainfall patterns, with significant potential consequences.

For example, when an area has experienced long periods of drought and vegetation is dry, storms can ignite brush. It’s often lightning strikes that spark wildfires, which leads to noxious wildfire smoke and particulate matter.

If there is an extreme concentration of particle pollution – as may be found in smoke – those concentrations can block sunlight and cool the earth’s surface. This inhibits cloud formation and growth, preventing rainfall.

Particulate matter itself can affect global warming in various ways, depending on its composition. In general, light-colored particles will reflect sunlight away from and cool the earth. Dark particles absorb heat, having a warming effect. Sulphates and nitrates are light particles which cool; black carbon absorbs heat. Black carbon can have a particularly negative effect when it settles on Arctic ice, which accelerates melting.

In a similar way, the more Arctic ice that melts, the less white space exists to reflect sunlight and heat away from Earth – so this contributes doubly toward global warming.

Both black carbon and ozone trap heat in the atmosphere, resulting in warmer global temperatures.

Solutions for air pollution and climate change

The stakes are high in reducing air pollution and mitigating climate change. Air pollution directly impacts our ability to breathe and live healthy lives. Reducing climate change severity is the key to maintaining a sustainable planet for future generations. The science connecting these environmental issues demands an approach that addresses both problems at the same time.

Often, air pollution and greenhouse gas emissions come from many of the same sources. Significant contributors to both include carbon-based fuel combustion, combustion that results in vehicle and industrial emissions.

Both issues can often be combated simultaneously by reducing harmful emissions and lowering our carbon footprint.

We can reduce our carbon footprint on a personal level and through advocacy for national and international cooperation in reducing carbon emissions.

Many countries have pledged to meet goals in reducing emissions through international treaties like the 2015 Paris Agreement. But we also know that no country in the world is meeting the World Health Organization’s recently updated guidance to reduce their annual average PM2.5 concentrations to 5 µg/m3 or less (micrograms per cubic meter air).

Until countries set their national policies with that goal in mind, particle pollutant levels will remain above safe levels for human health – and will continue to have an impact on climate change.

We can each pledge to take meaningful steps to lower our personal carbon footprint in many ways:

  • When possible, walk to stores and restaurants rather than taking the car.
  • When buying a new vehicle, choose a fuel-efficient, hybrid, or electric vehicle.
  • Install solar power energy for your home or business.

You can play an active role in raising air pollution awareness by providing your community with a low-cost air quality monitor. Air quality monitors can notify you and anyone following your station when air quality falls below safe standards, empowering you take immediate action like closing windows, wearing a mask outdoors, or running a high-efficiency air purifier.

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