Woods Hole Research Center

Who hasn’t spent time on their back gazing up at floating clouds, run ahead of a kite on a string, taken a deep breath of fresh air after a spring rain shower, or peered through an airplane window at the passing geography of Earth far below? Mention the word ‘air’ to many, and depending on where they live and how they grew up, it may also conjure up images of smog or smokestacks. But what is air, and do air quality and global warming have anything in common?

The Earth’s atmosphere consists of a layer of gases surrounding the planet. The atmosphere nourishes all life on earth with essential gases needed for photosynthesis and respiration, and with water vapor that falls as rain and snow. It also protects life by absorbing harmful ultraviolet radiation from the sun, warms the Earth by retaining heat, and dampens daily temperature extremes. The air that is mixed freely in the atmosphere, which we breath and which plants use for photosynthesis, consists of roughly 78% nitrogen, 21% oxygen, 0.93% argon and 0.039% carbon dioxide. And the atmosphere not only provides oxygen for all humans, plants and animals, but it also cycles carbon and nitrogen and is part of the Earth’s water cycle.

+ Read More...

Air quality is generally defined as a measure of the condition of air relative to the needs of humans or other species. An index of air quality allows countries to monitor their air for the following pollutants that are known contributors to respiratory disease: ground-level ozone, dirty particles, sulfur dioxide, carbon monoxide and nitrogen dioxide. Notice that carbon dioxide at levels found in the atmosphere is not dangerous to breathe. However, it is a heat trapping gas that causes climate change, as do methane and nitrous oxide. The majority of greenhouse gases come from burning gas, coal, and oil for transportation, industry, heating, and electricity generation. Deforestation and agriculture are also important sources of greenhouse gases.

Human-caused climate change is occurring because excessive amounts of heat-trapping gases are accumulating in our atmosphere. Climate change not only means higher average temperatures (global warming), but also more extreme weather events such as droughts and intense storms. The economic, ecological, and human health consequences already being experienced include lower crop yields in many parts of the world, water shortages, flooding, heat waves, higher insurance costs, more frequent and widespread forest fires, losses of plant and animal species, spread of human disease vectors like mosquitos and ticks, and more frequent poor air quality days.

Although the Earth’s climate has changed naturally throughout geologic history science has demonstrated that the current rate of climate change cannot be explained by any of those natural processes and can only be explained by human burning of fossil fuels. Moreover, the climate is rapidly changing beyond the envelope of natural variation that has been experienced since humans invented agriculture and civilization about 10,000 years ago. The relative stability of climate that has made our civilization possible is now in jeopardy.

Advancing Science. Informing Solutions.

• WHRC is studying how the rapid change in climate in the Arctic is affecting the release of more greenhouse gases into the air from the region’s wetlands and permafrost soils, thus accelerating the rate of human-caused climate change.
• WHRC has led scientific assessments of nitrogen in air pollution, including industrial and transportation sources of nitrogen oxides and agricultural sources of the heat trapping gas, nitrous oxide.
• WHRC has also researched the chemical characteristics of soot found on remote glaciers in order to identify the sources of this air pollution. This dark-colored soot is causing the glaciers to melt more rapidly and may also be affecting food webs in the rivers and oceans receiving the glacial meltwater.