Air pollution and climate change are closely related
The main sources of CO2 emissions – the extraction and burning of fossil fuels – are not only key drivers of climate change, but also major sources of air pollutants. Furthermore, many air pollutants that are harmful to human health and ecosystems also contribute to climate change by affecting the amount of incoming sunlight that is reflected or absorbed by the atmosphere, with some pollutants warming and others cooling the Earth. These so-called short-lived climate-forcing pollutants (SLCPs) include methane, black carbon, ground-level ozone, and sulfate aerosols. They have significant impacts on the climate; black carbon and methane in particular are among the top contributors to global warming after CO2.
Some air pollutants cause more global warming
Air pollution includes greenhouse gases. One of these is carbon dioxide, a common part of the exhaust from cars and trucks. Greenhouse gases cause global warming by trapping heat from the Sun in the Earth’s atmosphere. Greenhouse gases are a natural part of Earth’s atmosphere, but in the last 150 years or so, the amount in our atmosphere has increased. The increase comes from car exhaust and pollutants released from smokestacks at factories and power plants. The increase in greenhouses gases is the cause of most of the global warming that happened over the past century. Scientists predict that much more warming will likely happen during the next century.
Some air pollutants slow down global warming
Cars, trucks, and smokestacks also release tiny particles into the atmosphere. These tiny particles are called aerosols. They can be made of different things such as mineral dust, sulfates, sea salt, or carbon. Some of these particles get into the atmosphere naturally. They are dust lifted into the atmosphere from deserts, from evaporating droplets from the ocean, released by the smoke from wildfires, and erupting volcanoes. But air pollution released by humans by burning of fossil fuels also adds them to the atmosphere. Aerosols have an impact on climate. While different types of aerosols act differently in the atmosphere, the overall effect of aerosols is cooling.
Greenhouse gases stay in the atmosphere for years and cause warming around the world. Computer models indicate that, worldwide, the tiny aerosols cause about half as much cooling as greenhouse gases cause warming.
By trapping the earth’s heat in the atmosphere, greenhouse gases lead to warmer temperatures and all the hallmarks of climate change: rising sea levels, more extreme weather, heat-related deaths, and increasing transmission of infectious diseases like Lyme. According to a 2014 EPA study, carbon dioxide was responsible for 81 percent of the country’s total greenhouse gas emissions, and methane made up 11 percent.
Carbon dioxide comes from combusting fossil fuels, and methane comes from natural and industrial sources, including the large amounts that are released during oil and gas drilling. We emit far larger amounts of carbon dioxide, but methane is significantly more potent, so it’s also very destructive.
Another class of greenhouse gases, hydrofluorocarbons (HFCs), are thousands of times more powerful than carbon dioxide in their ability to trap heat. In October 2016, more than 140 countries reached an agreement to reduce the use of these chemicals—which are used in air conditioners and refrigerators—and find greener alternatives over time. The director of NRDC’s Climate and Clean Air program, writes, “NRDC estimates that the agreed HFC phase-down will avoid the equivalent of more than 80 billion tons of CO2 over the next 35 years.”
Mold and allergens from trees, weeds, and grass are also carried in the air, are exacerbated by climate change, and can be hazardous to health. They are not regulated by the government and are less directly connected to human actions, but they can be considered air pollution. When homes, schools, or businesses get water damage, mold can grow and can produce allergenic airborne pollutants. Mold exposure can precipitate asthma attacks or an allergic response, and some molds can even produce toxins that would be dangerous for anyone to inhale.
Pollen allergies are worsening because of climate change. Lab and field studies are showing that the more carbon dioxide pollen-producing plants—especially ragweed—are grown in, the bigger they grow and the more pollen they produce. Climate change also extends the pollen production season, and some studies are beginning to suggest that ragweed pollen itself might be becoming a more potent allergen. That means more people will suffer runny noses, fevers, itchy eyes, and other symptoms.
The less gasoline we burn, the better we’re doing to reduce air pollution and harmful effects of climate change. Make good choices about transportation. When you can, walk, ride a bike, or take public transportation. For driving, choose cars that get better miles per gallon of gas or choose an electric car. You can also investigate your power provider options—you may be able to request that your electricity be supplied by wind or solar. Buying your food locally cuts down on the fossil fuels burned in trucking or flying food in from across the country. And perhaps most important, Support leaders who push for clean air and water and responsible steps on climate change.