What are the National Ambient Air Quality Standards (NAAQS)?

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National Ambient Air Quality Standards (NAAQS) are a set of standards for six air pollutants, known as criteria pollutants: particulate matter ground level ozone carbon monoxide sulfur dioxide nitrogen dioxide lead Criteria pollutants are common air pollutants that are found worldwide at varying levels and can be harmful to human health and the environment. The NAAQS are established by the U.S. Environmental Protection Agency (EPA) under the Clean Air Act. … Continued

What are the sources of air pollution in Houston?

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Air pollutants may exist as solid particles, liquid droplets or gases and may originate from: 1 – large stationary sources – refineries, power plants, smelters, boilers, and smaller sources such as dry cleaners and degreasing operations 2 – mobile sources – cars, construction equipment, buses, planes, trucks, marine vessels and trains 3 – naturally occurring sources – wildfires [link to blog post on haze/smoke], wind-blown dust, some tree species, and … Continued

Is Houston’s air quality getting better or worse?

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Houston’s air quality has dramatically improved since the late 1980s, and it’s no accident. Despite hot, humid summer weather that makes for ideal ground level ozone formation and being home to the largest concentration of petrochemical and refining facilities in the nation, Houston remains compliant with five out of the six federal health-based standards for common air pollutants. Furthermore, since 2010, the Houston region has added more than 736,000 residents, … Continued

Ozone Levels in 2015: What Can We Learn from the Data?

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The greater Houston region has been working for many years to meet EPA’s health-based standard for ozone. Over the past 15 years, we have seen significant decreases in both ozone levels and the number of days that the standard was exceeded in Houston. In fact, 2014 was our cleanest year on record.

Ozone Levels in 2015

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The greater Houston region has been working for many years to meet EPA’s health-based standard for ozone. Over the past 15 years, we have seen significant decreases in both ozone levels and the number of days that the standard was exceeded in Houston.

Ozone Levels in 2015: Did Wildfires Play A Role?

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Scientists are still working to understand the reason for the higher ozone. We know that weather is a key factor that drives ozone formation. Some years have more days with hot, dry, stagnant weather that can contribute to more days with high ozone.

Ozone Pollution Standards for Houston’s Air

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This graph illustrates the changes to the National Ambient Air Quality Standard for ozone pollution over the past 26 years and Houston’s compliance with this standard.

Sulfur Dioxide

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What is Sulfur Dioxide? Sulfur dioxide (SO2) is one of a group of highly reactive gasses known as “oxides of sulfur.”  Short-term exposures to SO2 can harm the human respiratory system and make breathing difficult. Children, the elderly, and those who suffer from asthma are particularly sensitive to effects of SO2. Where is Sulfur Dioxide Found? The largest sources of SO2 emissions are from fossil fuel combustion at power plants (73%) and … Continued