Air pollution threatens the health of human beings and other living things on our planet. While often invisible, pollutants in the air create smog and acid rain, cause cancer or other serious health effects, diminish the protective ozone layer in the upper atmosphere, and contribute to the potential for world climate change.

Air pollution can lead to or aggravate respiratory, heart, and other health problems. It can be particularly harmful to people with existing lung or heart disease, the elderly, and the very young. Six of every ten Americans live in areas that fail to meet one or more federal air quality standards during some portion of the year. However, not everyone who lives in such areas will have health problems. Level, extent, and duration of exposure, age, individual susceptibility, and other factors play a significant role in determining whether or not someone will experience pollution-related health problems. Since polluted air can move from one area or region to another, it has the potential to affect virtually all of us.

Pollutants in the air can also reduce visibility, limits the ability of lakes to support aquatic life, may damage trees and plants, and erodes building surfaces and national monuments.

Air pollution has many sources. Some sources are obvious--like industrial smokestacks, chemical plants, automobiles, trucks, and buses. Others are not so obvious--like gasoline stations; dry-cleaners; outboard motors; lawn, garden, farm, and construction equipment engines; certain paints; and various household products. Naturally occurring sources such as windblown dust, and volcanic eruptions, also contribute to air quality problems.

Major Air Pollutants--What They Are, Where They Come From, and Their Potential Effects
For six pollutants--ozone, carbon monoxide, nitrogen dioxide, particulate matter, sulfur dioxide, and lead--EPA has established air quality standards designed to protect the health and welfare of people, plants, and animals, as well as buildings, monuments, water resources, etc. These standards are based on currently available scientific data and health studies. Levels of concern vary from pollutant to pollutant.

The United States Environmental Protection Agency (USEPA) coordinates information about the major pollutants through the AIRNow web site. The web site coordinates real-time ground level ozone and particulate matter monitor readings from across the country and compiles the information into animations and forecast maps. The location of monitoring stations reflects the quantity and accuracy of the data collected.

The EPA has developed an effective way to report air quality called the AQI. The AQI (Air Quality Index) tells you how clean or polluted your air is, and what associated health effects might be a concern for you. The AQI focuses on health effects you may experience within a few hours or days after breathing polluted air. EPA calculates the AQI for five major air pollutants regulated by the Clean Air Act: ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide, and nitrogen dioxide.

How Does the AQI Work?
Think of the AQI as a yardstick that runs from 0 to 500. The higher the AQI value, the greater the level of air pollution and the greater the health concern. For example, an AQI value of 50 represents good air quality with little potential to affect public health, while an AQI value over 300 represents hazardous air quality.
An AQI value of 100 generally corresponds to the national air quality standard for the pollutant, which is the level EPA has set to protect public health. AQI values below 100 are generally thought of as satisfactory. When AQI values are above 100, air quality is considered to be unhealthy—at first for certain sensitive groups of people, then for everyone as AQI values get higher.

Understanding the AQI
The purpose of the AQI is to help you understand what local air quality means to your health. To make it easier to understand, the AQI is divided into six categories: Good; Moderate; Unhealthy for Sensitive Groups; Unhealthy; Very Unhealthy; and Hazardous. EPA has assigned a specific color to each AQI category to make it easier for people to understand quickly whether air pollution is reaching unhealthy levels in their communities. For example, the color orange means that conditions are “unhealthy for sensitive groups,” while red means that conditions may be “unhealthy for everyone,” and so on.

When looking at the Air Quality Map, there are areas of the country that are shaded gray or may not appear to have an air quality problem simply because there may not be any monitoring stations present. The monitors have been placed in areas that have a higher likelihood of diminished air quality. It is not practical to place monitors everywhere due to the high costs (hundreds of thousands of dollars) of each monitor and the maintenance of the monitors once in place.

This portion of the project focuses on general air quality issues and will cover:

• What is air pollution?
• Where does air pollution come from?
• How can air pollution harm me?
• What do I do to contribute to the problem?
• How can I help??

The two other portions of the project focus specifically on ground level ozone and particulate pollution.

Print... | Close