Learn More - Concentration
The increase in the concentration of air pollutants will have an increasingly significant impact on human health, vegetation and visibility.
Where does the air pollution come from?
Air pollution comes from several sources. However cars, trucks, buses, boats, planes and trains are considered the largest contributors to poor air quality and produce millions of pounds of pollutants every day.
The haze that can spoil the visibility by sooty particles in the air as well as smog-forming ground level ozone. Tons of airborne particles are produced by fires, both unplanned and planned.
What do the weather and shape of the land have to do with air quality?
The normal circulation of air can help reduce the build up of air pollutants at ground level. Normal circulation will take pollutants higher in the atmosphere where they can disperse.
Sometimes a layer of warm can can trap cooler air close to the ground, this is called a thermal inversion. Not only is the cooler air trapped, but the normal circulation is disrupted, so it prevents the air pollutants from escaping. If the thermal inversion stays in place for several days, the trapped air pollutants can accumulate and reach significantly high levels.
The area topography (shape of the land) can have a role in creating poor air quality. Stagnant weather conditions can trap air in valleys and canyons which can create haze-filled inversions that decrease the distance we can see.
What can elevated levels of air pollutants such as ozone or particulate affect?
1) Aggravate asthma and other medical conditions
Ground-level ozone and airborne particles are the two pollutants that pose the greatest threat to human health in this country. Ozone, also known as smog, can irritate your respiratory system, causing coughing, irritation in your throat or a burning sensation in your airways. It can reduce lung function, so that you may have feelings of chest tightness, wheezing, or shortness of breath. Ozone can aggravate asthma and trigger asthma attacks. People at greater risk from ground-level ozone are people with lung diseases, such as asthma, and children and adults who are active outdoors.
Particle pollution, also known as particulate matter, is composed of microscopic solids or liquid droplets that are so small that they can get deep into the lungs and cause serious health problems. When exposed to these small particles, people with heart or lung diseases and older adults are more at risk of hospital and emergency room visits or, in some cases, even death from heart or lung disease. Even if you are healthy, you may experience temporary symptoms from exposure to elevated levels of particles. Symptoms may include: irritation of the eyes, nose and throat; coughing; phlegm; chest tightness; and shortness of breath. At greatest risk from particle pollution are people with heart or lung disease, older adults (possibly because they may have undiagnosed heart or lung disease), and children.
2) Decrease visibility
Visibility or visual range can be seriously reduced by polluting gases and fine particles called aerosols that absorb or scatter light. Some light scattering and absorption is natural--the sky is blue because of the scattering effect of naturally-occurring gases. But, human activities also create fine organic particles as well as tiny nitrate, sulfate, and nitrogen dioxide particles that are very efficient at reducing visibility.
Some human-created air pollutants form acids which come down either as dry fallout, or as rain, snow, fog and cloud water. This fallout raises the acidity level of lakes, streams and soils, injuring life in the water and causing chemical imbalances in plants.
3) Injure or kill vegetation
Acid rain does not usually kill trees directly. Instead, it is more likely to weaken trees by damaging their leaves, thereby limiting the nutrients available to them. This loss of nutrients in their foliage makes trees more susceptible to damage by other environmental factors, particularly cold winter weather. Acid rain can harm other plants in the same way it harms trees.