About

Air Quality problems are some of the most complicated environmental issues we face in North Central Texas. The Office of Environmental Quality’s Air Quality Program aims to promote healthy outdoor air for all residents by addressing the impact of City operations and actions on air quality. The two key air quality issues facing the City of Dallas are ground level ozone and the emission of greenhouse gases that effect global climate change.

The DFW region meets the standard for five of the six criteria air pollutants defined by the EPA: carbon monoxide, lead, nitrogen dioxides (a precursor to ozone), particulate matter, and sulfur dioxide (a component of acid rain). Ozone, the sixth criteria pollutant, is the only air pollutant for which we do not meet the National Ambient Air Quality Standards (NAAQS). The City of Dallas, along with many other cities across the United States and around the world, recognize the impact that smog and ozone formation have on our health and economic well-being.

El PasoWhile the Dallas/Fort Worth region is still in non-attainment for ozone, there has been a steady improvement measured across the area in recent years. Emission reductions have been achieved by implementing more stringent controls at stationary sources (stacks), by driving cleaner cars, using cleaner energy options, and by utilizing cleaner construction equipment.

What are the challenges?

Air Pollution

The photos seen here are from an usually warm October morning in 2015.

North Texas is bustling. Most of the vehicles on Dallas roads emit greenhouse gases and other air pollutants, including nitrogen oxide (a precursor to ozone), that contribute to declining respiratory health and smoggy views. Additionally, homes and businesses in North Texas use electricity and burn natural gas, creating more emissions here and across Texas that choke the air.

The Environmental Protection Agency (EPA), recognizing that ozone and other pollutants are potentially harmful to human health, created the National Ambient Air Quality Standards (NAAQS). These standards set the maximum safe concentrations for ozone, carbon monoxide, nitrogen dioxide, lead, sulfur dioxide, and particulates. If the maximum concentration is exceeded in a region, the region is designated in non-attainment for that pollutant. Currently, the North Central Texas area is in non-attainment for ozone. If progress is not made toward reducing ozone, the area can face sanctions and will spend more financial resources on addressing the health impacts of unsafe air.

Ozone: Good Up High, Bad Nearby

Ozone can be good or bad, depending on where it is in the atmosphere. “Good” ozone occurs naturally at the upper reaches of Earth’s atmosphere where it protects the planet from ultraviolet rays and moderates the climate; “bad” ozone accumulates within a few hundred feet of the ground and is the main component of smog that forms when pollutants emitted by cars, power plants, industry, and other sources react chemically in the presence of sunlight. Specifically, nitrogen oxides (NOX) and volatile organic compounds (VOCs) combine and “cook” in the sun. Regional data confirms that automobiles account for the majority of ozone-forming emissions released within North Central Texas.

Ozone pollution is a larger problem during warmer months, when weather conditions necessary to form ground-level ozone normally occur. Pollution from traffic, industry, and other sources, combined with high temperatures and stagnant air conditions of the summer months, make North Central Texas an ideal incubator for ground-level ozone. When ozone concentrations exceed safe levels, based on the Air Quality Index, an Ozone Action Day is called.

Cities throughout the region have taken action to curb the emission of the chemical precursors of ozone, and therefore steadily reduce ozone formation in the region. It is important that Dallas continue to reduce ozone, as the EPA lowered the NAAQS for ozone in 2015 from 75 ppb (parts per billion) to 70 ppb, based on the health risks associated with higher concentrations in the atmosphere.

For more information on ozone in the region, and to sign up for Ozone Action Day alerts, visit Air North Texas.

Impacts

Asthma_inhalerElevated levels of ozone can lead to increased respiratory ailments, especially in young children, the elderly, asthma sufferers, and those with chronic conditions. Evidence also indicates a strong correlation between chronic obstructive pulmonary disease (COPD) and ozone in the environment. Other health effects of high levels of ozone include:

• Difficulty breathing
• Shortness of breath
• Increased susceptibility to respiratory infection
• Chronic coughing and sore throat
• Aggravation of existing conditions such as bronchitis and emphysema

In addition to affecting the health and well-being of the residents of Dallas, high levels of ozone or any other pollutant can damage vegetation and building facades. It can also impact local business and industry: failure to attain the NAAQS carries potential sanctions that could have an impact on business and industry that could limit activities and prevent new businesses from locating in Dallas or the region. The resulting economic losses would be shouldered by the regional economy and the residents of North Texas and Dallas; reaching attainment to all the NAAQS standards will help ensure the economic vitality of the region and the health of Texans.