Ozone Action Days

What is ozone?

The ozone layer in the upper atmosphere is beneficial because it prevents harmful ultraviolet radiation from reaching the earth's surface. This ozone in not harmful because it is higher in the atmosphere than the air we breathe. However, high concentrations of ozone at ground level may have harmful effects on many materials we use, vegetation and health.

Ozone is formed when volatile organic compounds (VOC) and nitrogen oxide (NOx) emmissions react in sunlight. Examples of VOC's are emissions from trees, gasoline vapors and paint solvents. NOx is the result of burning fuels such as natural gas, coal, gasoline and wood. Weather is a significant factor in the ozone formation process. During periods of high temperatures, low winds and intense sunlight or little cloud cover, ozone can form at ground levels when there are significant amount of VOCs and NOx present. Air from urban and metropolitan areas transported into our region can contain high levels of ozone or ozone-forming compounds. Ozone levels are highest during daytime hours from April through Ocotober since sunlight and high temperatures are necessary for high ozone levels.

What is an ozone action day?

Some days are more prone to high ozone levels than others, especially summer days when temperatures climb above 90 degrees and the winds are less than 10 miles per hour. When a high ozone level is predicted, an ozone advisory for the next day will be issued to businesses, industry, governmental and media organizations. They, in turn, will then notify their employees and the public that the atmospheric conditions are conducive to the formation of high levels of ozone. On days when ozone advisories are issued, everyone will be asked to take certain actions to reduce emissions. These voluntary actions will help maintain our air quality. The Northeast Texas Air Care Association (NETAC) and local governments are coordinating efforts for public outreach through fax notifications, ozone flag program and a speakers bureau.

What can you do to help?

It may come as a surprise to know that many things we do to keep our homes clean, our yards green and even driving our vehicles contribute to ozone formation. So what can you do to help?

• Drive less. Organize a carpool, walk or ride your bike.
• Don't idle the engine of your vehicle for extended periods.
• Postpone filling your tank on hot, sunny days until late afternoon.
• Keep your car tuned up. Emissions from a poorly maintained vehicle equals that of 25 properly functioning cars.
• Insulate and weather-strip your home.
• Run dishwasher and washing machines only when there are full loads.
• Turn off lights and appliances when not in use.
• Set your thermostat between 76 and 78 degrees in the summer.
• When using a gas mower, wait until late evening to mow the lawn.
• Apply paint with rollers and brushes instead of sprays to cut down on fumes and save paint.

What can industry and local government do to help?

• Implement an Ozone Action Day plan.
• Postpone maintenance activities such as painting, lawn care or tank clean-outs until the Action Day has passed.
• Encourage employees to share rides or carpool.
• Use conference calls to avoid travel.
• Alter production schedules to avoid heavy production on Action Days.
• Coordinate voluntary efforts to reduce emissions through technological advances.
• Delay fleet fueling until late in the day.
• Restrict permits for outdoor burning.
• Publicize Ozone Action Days on government broadcast channels.

Why are People Concerned with Ozone?

Ozone pollution near the ground is the most wide-spread air quality problem in the United States. The public in nearly 100 major cities is periodically exposed to harmful concentrations of ozone.

The biggest concern with high ozone concentrations is the damage it causes to human health and vegetation.

High concentrations of ozone can cause:

• shortness of breath
• coughing or wheezing
• headaches
• nausea
• throat and lung irritation

Who can suffer the effects

Children

Children often play outside for long periods during the summer. Their lungs are still developing, and they breathe more rapidly and inhale more air pollution per pound of body weight than adults. On days when ozone levels are high, these factors put children at increased risk for respiratory problems.

People with lung diseases

People who suffer from lung diseases like bronchitis, pneumonia, emphysema, asthma, and colds have even more trouble breathing when the air is polluted. The effects can be worse for anyone who spends significant periods of time exercising or working outdoors.

Active adults

During exercise or strenuous work we breathe more often and draw air more deeply into the lungs. When we exercise heavily, we may increase our intake of air by as much as 10 times our level at rest.

The interaction between air pollution and exercise is so strong that health scientists typically use exercising volunteers in their research.

The financial toll

Air pollution is costly.

The costs include expenses for:

• increased health care and property damage
• decreased property values and diminished quality of life

Reducing air pollution also is costly. The costs can include expenditures for installing, operating, maintaining, and monitoring emission control systems.

Some of these costs are paid directly by business and industry. Others are paid indirectly through increased production costs and loss of business and economic opportunity.

The One Hour vs. The Eight Hour Ozone Standard

The One Hour Ozone Standard

Under the one-hour standard, ozone concentrations of 0.125 ppm (125 parts per billion) or above are considered to exceed the standard. The standard is not to be exceeded in an area more than three times in three consecutive years at the same monitoring site. If the standard is exceeded four times in three years at one site, then the area is in violation of the standard and no longer in "attainment."

The Eight Hour Ozone Standard

In 1997, the U.S. Environmental Protection Agency (EPA) announced new national ambient air quality standards (NAAQS) for ground-level ozone, the primary constituent of smog. The new standard was challenged in the federal courts. The standard was upheld by the courts in March 2002, but the EPA is required to revise their implementation plan. In the interim, EPA has re-instated the old one-hour standard but has not yet made public it's revised implementation plan.

The new eight-hour standard of 0.08 parts per million (85 parts per billion to exceed the standard) is determined by the fourth highest eight-hour daily maximum at any single monitor in an area, averaged over a three-year period.