Ozone Monitoring: Where To Find Daily Data

The ozone layer is a layer of gas in the Earth's atmosphere that protects life on the planet by absorbing harmful ultraviolet B (UV-B) radiation from the sun. Ozone-depleting substances (ODS) emitted by human activity have adversely affected the amount of ozone in the atmosphere, most notably causing an annual ozone hole over the Antarctic region. The ozone hole is caused by complex meteorological and chemical processes and is monitored by various organizations, including NASA and the US EPA. NASA's Aura satellite, launched in 2004, measures ozone levels from the Earth's surface to the top of the atmosphere, and this data is available to the public. The US EPA's Clean Air Status and Trends Network (CASTNET) program measures ground-level ozone at more than 85 locations across the United States, and this data is also available online.

Ozone Monitoring Instrument (OMI)

The Ozone Monitoring Instrument (OMI) is a nadir-viewing visual and ultraviolet spectrometer that uses hyperspectral imaging to observe solar-backscatter radiation. It is a key instrument on the Aura satellite, which was launched in 2004 and has been collecting data since August 9, 2004. The OMI project is a collaboration between the Netherlands Agency for Aerospace Programmes (NIVR), the Finnish Meteorological Institute (FMI), and the National Aeronautics and Space Agency (NASA).

OMI measures ozone from the Earth's surface to the top of the atmosphere, as well as other pollutants such as nitrogen dioxide (NO2), sulfur dioxide (SO2), bromine oxide (BrO), formaldehyde (HCHO), OClO, and aerosols. It can distinguish between different types of aerosols, such as smoke, dust, and sulfates, and measures cloud pressure and coverage. These measurements are important for monitoring air quality, industrial pollution, biomass burning, and aircraft safety.

OMI data is available through NASA's Land, Atmosphere Near-real-time Capability for Earth Observation (LANCE) platform, generally within 100 to 165 minutes after a satellite observation. To access the data, users must register for an Earthdata Login and download the files using the provided instructions. The data has a wide range of applications, including monitoring the recovery of the ozone layer, assessing the effectiveness of international protocols like the Montreal Protocol, and providing information on absorbing aerosol levels and tropospheric ozone levels.

Copernicus Programme

The Copernicus Programme is a European Union initiative for environmental monitoring. It includes the Copernicus Sentinel-5P satellite, which is dedicated to monitoring the Earth's atmosphere. The satellite carries an advanced multispectral imaging spectrometer called Tropomi, which can detect a wide range of pollutants at a higher spatial resolution than ever before.

The Copernicus Atmosphere Monitoring Service (CAMS) is a vital part of the Copernicus Programme. CAMS is implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the European Union. It plays a crucial role in monitoring, forecasting, and understanding the behaviour of ozone in the atmosphere. CAMS collects data on air quality, greenhouse gases, and climate forcing from various sensors, making this information accessible worldwide through its Atmosphere Data Store.

CAMS provides valuable information on both the beneficial ozone in the stratosphere, which shields the Earth from harmful ultraviolet (UV) radiation, and the ground-level ozone that can cause respiratory issues. The service records past trends, offers current snapshots, and forecasts future ozone concentrations to support research, policymaking, and individual actions for a healthier planet.

CAMS has a unique capacity to simultaneously utilise measurements from different wavelengths of light reflected or emitted by the Earth's surface or atmosphere. It combines data from multiple satellite sources to provide uninterrupted, high-quality ozone monitoring. Additionally, CAMS uses measurements from balloon sondes to verify the accuracy of its forecasts.

CAMS is one of the few services globally that can produce high-resolution 'total column' forecasts, making it a leader in three-dimensional ozone monitoring. Its analyses and forecasts are widely used by policymakers, scientists, and organisations. For example, CAMS data is essential for calculating UV radiation levels and is used by healthcare professionals and policymakers in Australia for UV forecasts and public advice.

US EPA's CASTNET

The Clean Air Status and Trends Network (CASTNET) is a national monitoring network established by the US Environmental Protection Agency (EPA) to assess trends in pollutant concentrations, atmospheric deposition, and ecological effects due to changes in air pollutant emissions. CASTNET provides air quality information to rural and tribal communities that often lack other sources of ambient data. The network consists of over 90 sites, including locations in Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Florida, Georgia, Idaho, Illinois, Indiana, Kansas, Kentucky, Maine, Maryland, Michigan, Minnesota, Mississippi, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, and Wyoming.

CASTNET was established to address the need for a comprehensive monitoring network to assess the status and trends of air quality in the United States. The network collects data on a variety of pollutants, including ozone, fine particulate matter, nitrogen oxides, sulfur dioxide, carbon monoxide, and mercury. The data collected by CASTNET helps the EPA and other organizations to track changes in air quality over time, identify areas of concern, and develop strategies to improve air quality.

The EPA maintains and operates CASTNET sites in collaboration with state and local partners. The sites are equipped with state-of-the-art instruments and technologies to measure air quality parameters. Data from CASTNET sites are typically made available to the public through online platforms and databases. The EPA also produces reports, fact sheets, and other publications based on CASTNET data to inform policymakers, researchers, and the general public about air quality trends and issues.

In addition to its core monitoring functions, CASTNET also serves as a platform for research and innovation. The EPA collaborates with academic institutions, government agencies, and private sector organizations to conduct research and develop new technologies for air quality monitoring. CASTNET data has been used in numerous scientific studies and has contributed to a better understanding of atmospheric processes, pollutant transport, and the impacts of air pollution on human health and the environment.

Overall, CASTNET plays a crucial role in the EPA's efforts to protect and improve air quality in the United States. By providing timely and accurate data on a wide range of pollutants, CASTNET informs policy decisions, drives regulatory actions, and helps track the effectiveness of air quality management strategies.

NASA Ozone Watch

The NASA Ozone Watch website provides the latest status of the ozone layer over the Antarctic, with a focus on the ozone hole. The site also provides a movie of the daily progression through a season or the annual progression of the means for a month. A table of all ozone movies is available in the multimedia section.

The Dobson Unit (DU) is the unit of measure for total ozone. If you were to take all the ozone in a column of air stretching from the surface of the earth to space, and bring all that ozone to standard temperature (0 °Celsius) and pressure (1013.25 millibars, or one atmosphere, or “atm”), the column would be about 0.3 centimetres thick. Thus, the total ozone would be 0.3 atm-cm. To make the units easier to work with, the “Dobson Unit” is defined as 0.001 atm-cm.

The ozone hole is a region of the southern polar region where ozone is destroyed rapidly and severely due to chemical reactions involving chlorine and bromine. The area of the ozone hole is determined from a map of total column ozone. It is calculated from the area on the Earth that is enclosed by a line with a constant value of 220 Dobson Units. This value is chosen because total ozone values of less than 220 Dobson Units were not found in the historic observations over Antarctica prior to 1979.

The Aura Mission is a NASA project that closely monitors the ozone layer. The Ozone Monitoring Instrument (OMI) aboard NASA's Aura satellite (launched in 2004) measures ozone from Earth's surface to the top of the atmosphere. OMI also measures sulfur dioxide (SO2), aerosols, and cloud top pressure. Near-real-time (NRT) OMI data is available through NASA's Land, Atmosphere Near-real-time Capability for Earth Observation (LANCE) generally within 100 to 165 minutes after a satellite observation.

Air Quality System (AQS)

The Air Quality System (AQS) is the national database for ambient air quality monitoring data in the United States. It is managed by the Environmental Protection Agency (EPA) and contains data collected by the EPA, state, local, and tribal air pollution control agencies from thousands of monitors. The data is used to determine compliance with clean air standards, assess the nature of air pollution, and understand human exposure to airborne pollutants.

The AQS database includes ambient air pollution data, meteorological data, descriptive information about each monitoring station (including its location and operator), and data quality assurance/quality control information. The data is available to partners through the Exchange Network, which enables the sharing of real-time air quality data.

The AQS data is consolidated at the AirData website, which offers pre-generated files of extracted AQS data at the annual, daily, and hourly level. The website also features reports, graphs, and maps that can be generated based on specific selections, as well as an API (REST query interface) that allows users to query raw AQS data. For those seeking real-time data, the AirNow Gateway/API page is the recommended source.

Frequently asked questions