Most Recent Four Weeks Quality Assured Air Quality Data

About the Data Sources and When Measurement Data are Posted

The air quality data available through this website have been provided by the contractor responsible for operating and maintaining the air monitoring station where the measurements were made. Each contractor is responsible for reviewing and assuring data quality prior to submitting it for use by this website and the public. No data are posted to this website before they are quality assured. The time required for quality assuring the data varies and affects when data are ready for posting. It depends on the number of chemical compounds measurements being checked and the calibration steps that must be reviewed for each measurement. For all but the auto GC data (46 compounds) and the 6th Day Canister Data, the quality assured data are posted on Friday for all measurements made through the previous Friday. Auto GC data are posted within 90 days of the end of the month the measurements were made. Canister data are posted within 30 days of the end of the month. The air monitoring contractors are listed below by station name.

Air Monitoring Station Contractor
Gregory - Fresnos The University of Texas & Orsat
Portland - Buddy Ganem AECOM
Portland - Broadway AECOM

In posting, making available and storing these data, The University of Texas does not alter the measurement data provided by the contractor in any way. Should you have questions or concerns about the data, please contact David W. Sullivan, Website Data Analyst.


Graphs of the Air Quality Data by Station

The most recent quality assured four weeks measurement data from all three air-monitoring stations are graphed automatically for you and displayed below. Each week on Friday, a new week's data are added and the oldest week's data are removed from these graphs. These data as well as data from any other time period can also be selected, viewed and/or downloaded through the Custom Data Request page. Graphs can be printed and saved in JPEG or PNG image format by selecting the three-line menu icon in the upper-right corner of the graph.

Gregory Fresnos

PM2_5 hourly concentrations from 19th of August 2022 through 18th of September 2022.
Notes:
  1. PM2.5 is a particle pollutant measured by the ratio of the total accumulated fine particle mass in micro-grams to the air volume in cubic meters, abbreviated “µg/m3”.
  2. Hourly concentrations are shown in the graph; however, the level of the NAAQS is based on a daily 24-hour average. Individual elevated one hour values alone do not constitute exceedances of the level of the NAAQS. PM2.5 also has an annual average NAAQS level of 12 µg/m3 averaged over 3 years.
  3. Air pollutant concentrations are always nonnegative. In reality however, measurement inaccuracy can lead to the reporting of small, negative value concentrations.
  4. When data are missing in the graph, this may be indicated by a straight line with no points on it. In other cases it may be represented by an empty gap in the graph. Data are also periodically often missing owing to regular quality assurance and instrument maintenance activities.
  5. The scale on the y-axis (vertical axis) on the left is chosen to represent the range in concentrations often found in ambient air around the state. In several cases the top of the range may be the level of the NAAQS or a value considered to be the highest value likely to be found based past measurements. If a value has been measured that is higher than the default maximum scale value, the scale is automatically adjusted so the value is shown near the top of the graph.

Gregory Fresnos

NO2 hourly concentrations from 19th of August 2022 through 18th of September 2022.
Notes:
  1. NO2 is a gas diluted in the air, and its concentrations are expressed as the ratio of molecules of NO2 to total molecules in the air, and, because concentrations are so low, concentrations are expressed as parts of NO2 per billion parts of air, abbreviated “ppb”.
  2. NO2 has both a one-hour level of the NAAQS at 100 ppb, and an annual mean level at 53 ppb.
  3. Air pollutant concentrations are always nonnegative. In reality however, measurement inaccuracy can lead to the reporting of small, negative value concentrations.
  4. When data are missing in the graph, this may be indicated a straight line with no points on it. In other cases it may be represented by an empty gap in the graph. Data are also periodically missing owing to regular quality assurance and instrument maintenance activities.
  5. The scale on the y-axis (vertical axis) on the left is chosen to represent the range in concentrations often found in ambient air around the state. In several cases the top of the range may be the level of the NAAQS or a value considered to be the highest value likely to be found based past measurements. If a value has been measured that is higher than the default maximum scale value, the scale is automatically adjusted so the value is shown near the top of the graph.

Gregory Fresnos

SO2 hourly concentrations from 19th of August 2022 through 18th of September 2022.
Notes:
  1. SO2 is a gas diluted in the air, and its concentrations are expressed as the ratio of molecules of SO2 to total molecules in the air, and, because concentrations are so low, concentrations are expressed as parts of SO2 per billion parts of air, abbreviated “ppb”.
  2. SO2 has a one-hour level of the NAAQS at 75 ppb.
  3. Air pollutant concentrations are always nonnegative. In reality however, measurement inaccuracy can lead to the reporting of small, negative value concentrations. This is especially important to note for SO2, as concentrations tend to be very close to 0.0 ppb.
  4. When data are missing in the graph, this may be indicated a straight line with no points on it. In other cases it may be represented by an empty gap in the graph. Data are also periodically missing owing to regular quality assurance and instrument maintenance activities.
  5. The scale on the y-axis (vertical axis) on the left is chosen to represent the range in concentrations often found in ambient air around the state. In several cases the top of the range may be the level of the NAAQS or a value considered to be the highest value likely to be found based past measurements. If a value has been measured that is higher than the default maximum scale value, the scale is automatically adjusted so the value is shown near the top of the graph.

Gregory Fresnos

1,3-Butadiene hourly concentrations from 1st of July 2022 through 31st of July 2022.
Notes:
  1. Graphs for Benzene and 1,3-Butadiene are shown owing to long-term health concerns associated with these chemicals. For more information, see the TCEQ website.
  2. Because of the complexity associated with measuring hydrocarbons, the data validation process takes longer. Data for Benzene, 1,3-Butadiene, and other hydrocarbons are reported on this Website within 90 days of the end of the month the measurements were made.
  3. Benzene and 1,3-Butadiene are hydrocarbon compound that may be diluted in ambient air. Concentrations can be expressed based as the ratio of the number of molecules of the compound to the number of molecules of air in a fixed volume, or in terms of the number of carbon atoms in the compound's molecule to the number of molecules of air. The former approach uses units of “parts per billion volume”, while the second approach uses units of “parts per billion carbon”, abbreviated “ppbC” or “ppb-C” and sometimes “PPBC”. This latter approach is valuable since most hydrocarbons are larger than the vast majority of molecules making up the air. Graphs for hydrocarbon compounds for this project are expressed in ppbC.
  4. Air pollutant concentrations are always nonnegative. In reality however, measurement inaccuracy can lead to the reporting of small, negative value concentrations.
  5. When data are missing in the graph, this may be indicated a straight line with no points on it. In other cases it may be represented by an empty gap in the graph. Data are also periodically missing owing to regular quality assurance and instrument maintenance activities.
  6. The scale on the y-axis (vertical axis) on the left is chosen to represent the range in concentrations often found in ambient air around the state. In several cases the top of the range may be a value considered to be the highest value likely to be found based past measurements. If a value has been measured that is higher than the default maximum scale value, the scale is automatically adjusted so the value is shown near the top of the graph.

Gregory Fresnos

Benzene hourly concentrations from 1st of July 2022 through 31st of July 2022.
Notes:
  1. Graphs for Benzene and 1,3-Butadiene are shown owing to long-term health concerns associated with these chemicals. For more information, see the TCEQ website.
  2. Because of the complexity associated with measuring hydrocarbons, the data validation process takes longer. Data for Benzene, 1,3-Butadiene, and other hydrocarbons are reported on this Website within 90 days of the end of the month the measurements were made.
  3. Benzene and 1,3-Butadiene are hydrocarbon compound that may be diluted in ambient air. Concentrations can be expressed based as the ratio of the number of molecules of the compound to the number of molecules of air in a fixed volume, or in terms of the number of carbon atoms in the compound's molecule to the number of molecules of air. The former approach uses units of “parts per billion volume”, while the second approach uses units of “parts per billion carbon”, abbreviated “ppbC” or “ppb-C” and sometimes “PPBC”. This latter approach is valuable since most hydrocarbons are larger than the vast majority of molecules making up the air. Graphs for hydrocarbon compounds for this project are expressed in ppbC.
  4. Air pollutant concentrations are always nonnegative. In reality however, measurement inaccuracy can lead to the reporting of small, negative value concentrations.
  5. When data are missing in the graph, this may be indicated a straight line with no points on it. In other cases it may be represented by an empty gap in the graph. Data are also periodically missing owing to regular quality assurance and instrument maintenance activities.
  6. The scale on the y-axis (vertical axis) on the left is chosen to represent the range in concentrations often found in ambient air around the state. In several cases the top of the range may be a value considered to be the highest value likely to be found based past measurements. If a value has been measured that is higher than the default maximum scale value, the scale is automatically adjusted so the value is shown near the top of the graph.

Gregory Fresnos

Wind speed and direction from 19th of August 2022 through 18th of September 2022.
Notes:
  1. In measuring directions in terms of degrees, North is both “0” and “360”, East is “90”, South is “180”, and West is “270”. In the graphs, when the wind is from the north, the points for wind direction frequently can jump from top of the graph in one hour to the bottom of the graph in the next hour, or bottom to top.
  2. Note that when wind speeds are low (less than 2 miles per hour), wind directions may be “variable”, meaning the directions can change rapidly and seemingly at random.
  3. Often, near the ocean (or gulf) coast, overnight and morning surface wind directions tend to blow from land to sea, and reverse directions later in the day. However, larger scale weather factors lead to southeasterly winds being the most common overall year-round, with many northerly winds in the winter months.
  4. When data are missing in the graph, this may be indicated a straight line with no points on it. In other cases it may be represented by an empty gap in the graph. Data are also periodically missing owing to regular quality assurance and instrument maintenance activities.

Portland Buddy Ganem

PM2_5 hourly concentrations from 19th of August 2022 through 18th of September 2022.
Notes:
  1. PM2.5 is a particle pollutant measured by the ratio of the total accumulated fine particle mass in micro-grams to the air volume in cubic meters, abbreviated “µg/m3”.
  2. Hourly concentrations are shown in the graph; however, the level of the NAAQS is based on a daily 24-hour average. Individual elevated one hour values alone do not constitute exceedances of the level of the NAAQS. PM2.5 also has an annual average NAAQS level of 12 µg/m3 averaged over 3 years.
  3. Air pollutant concentrations are always nonnegative. In reality however, measurement inaccuracy can lead to the reporting of small, negative value concentrations.
  4. When data are missing in the graph, this may be indicated by a straight line with no points on it. In other cases it may be represented by an empty gap in the graph. Data are also periodically often missing owing to regular quality assurance and instrument maintenance activities.
  5. The scale on the y-axis (vertical axis) on the left is chosen to represent the range in concentrations often found in ambient air around the state. In several cases the top of the range may be the level of the NAAQS or a value considered to be the highest value likely to be found based past measurements. If a value has been measured that is higher than the default maximum scale value, the scale is automatically adjusted so the value is shown near the top of the graph.

Portland Buddy Ganem

1,3-Butadiene hourly concentrations from 1st of July 2022 through 31st of July 2022.
Notes:
  1. Graphs for Benzene and 1,3-Butadiene are shown owing to long-term health concerns associated with these chemicals. For more information, see the TCEQ website.
  2. Because of the complexity associated with measuring hydrocarbons, the data validation process takes longer. Data for Benzene, 1,3-Butadiene, and other hydrocarbons are reported on this Website within 90 days of the end of the month the measurements were made.
  3. Benzene and 1,3-Butadiene are hydrocarbon compound that may be diluted in ambient air. Concentrations can be expressed based as the ratio of the number of molecules of the compound to the number of molecules of air in a fixed volume, or in terms of the number of carbon atoms in the compound's molecule to the number of molecules of air. The former approach uses units of “parts per billion volume”, while the second approach uses units of “parts per billion carbon”, abbreviated “ppbC” or “ppb-C” and sometimes “PPBC”. This latter approach is valuable since most hydrocarbons are larger than the vast majority of molecules making up the air. Graphs for hydrocarbon compounds for this project are expressed in ppbC.
  4. Air pollutant concentrations are always nonnegative. In reality however, measurement inaccuracy can lead to the reporting of small, negative value concentrations.
  5. When data are missing in the graph, this may be indicated a straight line with no points on it. In other cases it may be represented by an empty gap in the graph. Data are also periodically missing owing to regular quality assurance and instrument maintenance activities.
  6. The scale on the y-axis (vertical axis) on the left is chosen to represent the range in concentrations often found in ambient air around the state. In several cases the top of the range may be a value considered to be the highest value likely to be found based past measurements. If a value has been measured that is higher than the default maximum scale value, the scale is automatically adjusted so the value is shown near the top of the graph.

Portland Buddy Ganem

Benzene hourly concentrations from 1st of July 2022 through 31st of July 2022.
Notes:
  1. Graphs for Benzene and 1,3-Butadiene are shown owing to long-term health concerns associated with these chemicals. For more information, see the TCEQ website.
  2. Because of the complexity associated with measuring hydrocarbons, the data validation process takes longer. Data for Benzene, 1,3-Butadiene, and other hydrocarbons are reported on this Website within 90 days of the end of the month the measurements were made.
  3. Benzene and 1,3-Butadiene are hydrocarbon compound that may be diluted in ambient air. Concentrations can be expressed based as the ratio of the number of molecules of the compound to the number of molecules of air in a fixed volume, or in terms of the number of carbon atoms in the compound's molecule to the number of molecules of air. The former approach uses units of “parts per billion volume”, while the second approach uses units of “parts per billion carbon”, abbreviated “ppbC” or “ppb-C” and sometimes “PPBC”. This latter approach is valuable since most hydrocarbons are larger than the vast majority of molecules making up the air. Graphs for hydrocarbon compounds for this project are expressed in ppbC.
  4. Air pollutant concentrations are always nonnegative. In reality however, measurement inaccuracy can lead to the reporting of small, negative value concentrations.
  5. When data are missing in the graph, this may be indicated a straight line with no points on it. In other cases it may be represented by an empty gap in the graph. Data are also periodically missing owing to regular quality assurance and instrument maintenance activities.
  6. The scale on the y-axis (vertical axis) on the left is chosen to represent the range in concentrations often found in ambient air around the state. In several cases the top of the range may be a value considered to be the highest value likely to be found based past measurements. If a value has been measured that is higher than the default maximum scale value, the scale is automatically adjusted so the value is shown near the top of the graph.

Portland Buddy Ganem

Ethylene Oxide in 6th Day Canisters, 24-hr Average concentrations from 28th of June 2022 through 28th of July 2022.
Notes:
  1. 24-hour air samples are collected every 6th day and analyzed for Ethylene Oxide concentration owing to the long-term health concerns associated with this chemical. For more information, see the TCEQ website.
  2. Because of the complexity associated with measuring Ethylene Oxide, the sample analysis and data validation process takes longer. Data for Ethylene Oxide will be reported on this website 30 days after the end of the month of sample collection.
  3. Ethylene Oxide is a hydrocarbon compound that may be diluted in ambient air. Concentrations can be expressed based as the ratio of the number of molecules of the compound to the number of molecules of air in a fixed volume, or in terms of the number of carbon atoms in the compound's molecule to the number of molecules of air. The former approach uses units of “parts per billion volume”, while the second approach uses units of “parts per billion carbon”, abbreviated “ppbC” or “ppb-C” and sometimes “PPBC”. This latter approach is valuable since most hydrocarbons are larger than the vast majority of molecules making up the air. On this website, graphs for all hydrocarbon compounds, except Ethylene Oxide are expressed in ppbC. Graphs for Ethylene Oxide are expressed in both ppbC and ppbV. You will see regulatory agencies use one or both of these units of measurement depending on the measurement's application.
  4. Air samples are collected in canisters every 6th day for 24 hours for analysis of the concentration of Ethylene Oxide in the air sample. Hence there will be only one data point, I.e., average concentration for the 24 hours of sample collection every six days.
  5. The scale on the y-axis (vertical axis) on the left is chosen to represent the range in concentrations often found in ambient air around the state. In several cases the top of the range may be a value considered to be the highest value likely to be found based past measurements. If a value has been measured that is higher than the default maximum scale value, the scale is automatically adjusted so the value is shown near the top of the graph.

Portland Buddy Ganem

Wind speed and direction from 19th of August 2022 through 18th of September 2022.
Notes:
  1. In measuring directions in terms of degrees, North is both “0” and “360”, East is “90”, South is “180”, and West is “270”. In the graphs, when the wind is from the north, the points for wind direction frequently can jump from top of the graph in one hour to the bottom of the graph in the next hour, or bottom to top.
  2. Note that when wind speeds are low (less than 2 miles per hour), wind directions may be “variable”, meaning the directions can change rapidly and seemingly at random.
  3. Often, near the ocean (or gulf) coast, overnight and morning surface wind directions tend to blow from land to sea, and reverse directions later in the day. However, larger scale weather factors lead to southeasterly winds being the most common overall year-round, with many northerly winds in the winter months.
  4. When data are missing in the graph, this may be indicated a straight line with no points on it. In other cases it may be represented by an empty gap in the graph. Data are also periodically missing owing to regular quality assurance and instrument maintenance activities.

Portland Broadway

PM2_5 hourly concentrations from 19th of August 2022 through 18th of September 2022.
Notes:
  1. PM2.5 is a particle pollutant measured by the ratio of the total accumulated fine particle mass in micro-grams to the air volume in cubic meters, abbreviated “µg/m3”.
  2. Hourly concentrations are shown in the graph; however, the level of the NAAQS is based on a daily 24-hour average. Individual elevated one hour values alone do not constitute exceedances of the level of the NAAQS. PM2.5 also has an annual average NAAQS level of 12 µg/m3 averaged over 3 years.
  3. Air pollutant concentrations are always nonnegative. In reality however, measurement inaccuracy can lead to the reporting of small, negative value concentrations.
  4. When data are missing in the graph, this may be indicated by a straight line with no points on it. In other cases it may be represented by an empty gap in the graph. Data are also periodically often missing owing to regular quality assurance and instrument maintenance activities.
  5. The scale on the y-axis (vertical axis) on the left is chosen to represent the range in concentrations often found in ambient air around the state. In several cases the top of the range may be the level of the NAAQS or a value considered to be the highest value likely to be found based past measurements. If a value has been measured that is higher than the default maximum scale value, the scale is automatically adjusted so the value is shown near the top of the graph.

Portland Broadway

1,3-Butadiene hourly concentrations from 1st of July 2022 through 31st of July 2022.
Notes:
  1. Graphs for Benzene and 1,3-Butadiene are shown owing to long-term health concerns associated with these chemicals. For more information, see the TCEQ website.
  2. Because of the complexity associated with measuring hydrocarbons, the data validation process takes longer. Data for Benzene, 1,3-Butadiene, and other hydrocarbons are reported on this Website within 90 days of the end of the month the measurements were made.
  3. Benzene and 1,3-Butadiene are hydrocarbon compound that may be diluted in ambient air. Concentrations can be expressed based as the ratio of the number of molecules of the compound to the number of molecules of air in a fixed volume, or in terms of the number of carbon atoms in the compound's molecule to the number of molecules of air. The former approach uses units of “parts per billion volume”, while the second approach uses units of “parts per billion carbon”, abbreviated “ppbC” or “ppb-C” and sometimes “PPBC”. This latter approach is valuable since most hydrocarbons are larger than the vast majority of molecules making up the air. Graphs for hydrocarbon compounds for this project are expressed in ppbC.
  4. Air pollutant concentrations are always nonnegative. In reality however, measurement inaccuracy can lead to the reporting of small, negative value concentrations.
  5. When data are missing in the graph, this may be indicated a straight line with no points on it. In other cases it may be represented by an empty gap in the graph. Data are also periodically missing owing to regular quality assurance and instrument maintenance activities.
  6. The scale on the y-axis (vertical axis) on the left is chosen to represent the range in concentrations often found in ambient air around the state. In several cases the top of the range may be a value considered to be the highest value likely to be found based past measurements. If a value has been measured that is higher than the default maximum scale value, the scale is automatically adjusted so the value is shown near the top of the graph.

Portland Broadway

Benzene hourly concentrations from 1st of July 2022 through 31st of July 2022.
Notes:
  1. Graphs for Benzene and 1,3-Butadiene are shown owing to long-term health concerns associated with these chemicals. For more information, see the TCEQ website.
  2. Because of the complexity associated with measuring hydrocarbons, the data validation process takes longer. Data for Benzene, 1,3-Butadiene, and other hydrocarbons are reported on this Website within 90 days of the end of the month the measurements were made.
  3. Benzene and 1,3-Butadiene are hydrocarbon compound that may be diluted in ambient air. Concentrations can be expressed based as the ratio of the number of molecules of the compound to the number of molecules of air in a fixed volume, or in terms of the number of carbon atoms in the compound's molecule to the number of molecules of air. The former approach uses units of “parts per billion volume”, while the second approach uses units of “parts per billion carbon”, abbreviated “ppbC” or “ppb-C” and sometimes “PPBC”. This latter approach is valuable since most hydrocarbons are larger than the vast majority of molecules making up the air. Graphs for hydrocarbon compounds for this project are expressed in ppbC.
  4. Air pollutant concentrations are always nonnegative. In reality however, measurement inaccuracy can lead to the reporting of small, negative value concentrations.
  5. When data are missing in the graph, this may be indicated a straight line with no points on it. In other cases it may be represented by an empty gap in the graph. Data are also periodically missing owing to regular quality assurance and instrument maintenance activities.
  6. The scale on the y-axis (vertical axis) on the left is chosen to represent the range in concentrations often found in ambient air around the state. In several cases the top of the range may be a value considered to be the highest value likely to be found based past measurements. If a value has been measured that is higher than the default maximum scale value, the scale is automatically adjusted so the value is shown near the top of the graph.

Portland Broadway

Ethylene Oxide in 6th Day Canisters, 24-hr Average concentrations from 28th of June 2022 through 28th of July 2022.
Notes:
  1. 24-hour air samples are collected every 6th day and analyzed for Ethylene Oxide concentration owing to the long-term health concerns associated with this chemical. For more information, see the TCEQ website.
  2. Because of the complexity associated with measuring Ethylene Oxide, the sample analysis and data validation process takes longer. Data for Ethylene Oxide will be reported on this website 30 days after the end of the month of sample collection.
  3. Ethylene Oxide is a hydrocarbon compound that may be diluted in ambient air. Concentrations can be expressed based as the ratio of the number of molecules of the compound to the number of molecules of air in a fixed volume, or in terms of the number of carbon atoms in the compound's molecule to the number of molecules of air. The former approach uses units of “parts per billion volume”, while the second approach uses units of “parts per billion carbon”, abbreviated “ppbC” or “ppb-C” and sometimes “PPBC”. This latter approach is valuable since most hydrocarbons are larger than the vast majority of molecules making up the air. On this website, graphs for all hydrocarbon compounds, except Ethylene Oxide are expressed in ppbC. On this website, graphs for all hydrocarbon compounds, except Ethylene Oxide are expressed in ppbC. Graphs for Ethylene Oxide are expressed in both ppbC and ppbV. You will see regulatory agencies use one or both of these units of measurement depending on the measurement's application.”
  4. Air samples are collected in canisters every 6th day for 24 hours for analysis of the concentration of Ethylene Oxide in the air sample. Hence there will be only one data point, I.e., average concentration for the 24 hours of sample collection every six days.
  5. The scale on the y-axis (vertical axis) on the left is chosen to represent the range in concentrations often found in ambient air around the state. In several cases the top of the range may be a value considered to be the highest value likely to be found based past measurements. If a value has been measured that is higher than the default maximum scale value, the scale is automatically adjusted so the value is shown near the top of the graph.

Portland Broadway

Wind speed and direction from 19th of August 2022 through 18th of September 2022.
Notes:
  1. In measuring directions in terms of degrees, North is both “0” and “360”, East is “90”, South is “180”, and West is “270”. In the graphs, when the wind is from the north, the points for wind direction frequently can jump from top of the graph in one hour to the bottom of the graph in the next hour, or bottom to top.
  2. Note that when wind speeds are low (less than 2 miles per hour), wind directions may be “variable”, meaning the directions can change rapidly and seemingly at random.
  3. Often, near the ocean (or gulf) coast, overnight and morning surface wind directions tend to blow from land to sea, and reverse directions later in the day. However, larger scale weather factors lead to southeasterly winds being the most common overall year-round, with many northerly winds in the winter months.
  4. When data are missing in the graph, this may be indicated a straight line with no points on it. In other cases it may be represented by an empty gap in the graph. Data are also periodically missing owing to regular quality assurance and instrument maintenance activities.