Share this. What is ozone? VOCs: Carbon-containing compounds that easily evaporate at room temperature and enter the surrounding air. Many VOCs are emitted naturally by plants. Others come from human-made sources, including products such as paints, pesticides, solvents, and processes such as fuel production and combustion.
Gas-powered lawn equipment and older-model cars emit particularly high levels of VOCs. Until relatively recently, car emissions were the largest source of VOCs in most cities. However, the catalytic converter almost completely eliminates these emissions in modern vehicles. Nitrogen oxides: A family of gases that cause pollution and are harmful to human health.
Trucks and automobiles are responsible for about half of all nitrogen oxide emissions, with electric power plants and other industrial sources contributing most of the rest.
In addition to smog, nitrogen oxides are converted in the atmosphere to nitric acid, a component of acid rain. What is particulate matter? How do ozone and particulate matter affect human health? If no button appears, you cannot download or save the media. Text on this page is printable and can be used according to our Terms of Service.
Any interactives on this page can only be played while you are visiting our website. You cannot download interactives. Humans impact the physical environment in many ways: overpopulation, pollution, burning fossil fuels, and deforestation.
Changes like these have triggered climate change, soil erosion, poor air quality, and undrinkable water. These negative impacts can affect human behavior and can prompt mass migrations or battles over clean water. Help your students understand the impact humans have on the physical environment with these classroom resources. An atmosphere is the layers of gases surrounding a planet or other celestial body.
These gases are found in layers troposphere, stratosphere, mesosphere, thermosphere, and exosphere defined by unique features such as temperature and pressure. The atmosphere protects life on earth by shielding it from incoming ultraviolet UV radiation, keeping the planet warm through insulation, and preventing extremes between day and night temperatures.
The sun heats layers of the atmosphere causing it to convect driving air movement and weather patterns around the world. Teach your students about the Earth's atmosphere with the resources in this collection. Pollution is the introduction of harmful materials into the environment. These harmful materials are called pollutants.
Air pollution consists of chemicals or particles in the air that can harm the health of humans, animals, and plants. It also damages buildings. Non-renewable energy comes from sources that will eventually run out, such as oil and coal. Join our community of educators and receive the latest information on National Geographic's resources for you and your students.
Skip to content. Twitter Facebook Pinterest Google Classroom. Encyclopedic Entry Vocabulary. Everyone can do their part to reduce smog by changing a few behaviors, such as: Drive less. Walk, bike, carpool , and use public transportation whenever possible. Take care of cars. Getting regular tune-up s, changing oil on schedule, and inflating tires to the proper level can improve gas mileage and reduce emissions.
Fuel up during the cooler hours of the day—night or early morning. This prevents gas fumes from heating up and producing ozone. Avoid products that release high levels of VOCs. JavaScript appears to be disabled on this computer. Please click here to see any active alerts. The term "smog" was first used around to describe the combination of smoke and fog in London. Today, it refers to a mixture of pollutants made up mostly of ground level ozone.
Air pollution emitted from transportation contributes to smog, and to poor air quality, which has negative impacts on the health and welfare of U. Pollutants that contribute to poor air quality include particulate matter PM , nitrogen oxides NO x , and volatile organic compounds VOCs. The transportation sector also contributes to emissions of air toxics, which are compounds that are known or suspected to cause cancer or other serious health and environmental effects.
Examples of mobile source air toxics include benzene, formaldehyde, and diesel particulate matter. EPA implements national programs and standards for fuels and vehicles that reduce air pollution including smog, soot, and toxic pollutants, and spur investments in clean vehicle and engine technology. EPA programs to reduce emissions from transportation sources have resulted in less smog and soot, significantly better air quality and better health for Americans.
By , EPA air quality emissions standards for vehicles are projected to annually prevent:. Passenger vehicles are regulated by EPA under light duty vehicle programs. EPA set stringent emissions standards for passenger vehicles, as well as limits on the amount sulfur, a naturally occurring contaminant, in gasoline. Limiting sulfur in gasoline allows emissions reductions technologies like catalysts to be significantly more effective in reducing nitrogen oxides and other pollutants.
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