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Air Quality Monitoring

NYS' Program to Track Air Quality

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To protect human health and the environment from harm, DEC measures levels of outdoor air pollution. DEC reports these measurements to EPA's Air Quality System (AQS) API (leaves DEC website). DEC also provides an Air Quality Index (AQI) forecast for some pollutants that can be harmful to human health and current air quality measurement data for New York State. Air Quality alerts are also available through DEC Delivers and other broadcast media. EPA's AirNow (leaves DEC website) offers air quality data by zip code. Along with measuring and reporting air quality data, DEC also writes reports and network assessments for the public and technical community.

DEC measures air pollutants at more than 50 sites across the State using continuous and/or manual instrumentation. These sites are a mix of federally-mandated and supplemental monitoring networks. Real-time direct reading measurements include:

  • criteria pollutants (ozone (O3), sulfur dioxide (SO2), oxides of nitrogen (NOx), carbon monoxide (CO)),
  • PM2.5 and PM 10 (fine particulate with diameter less than 2.5 or 10 microns),
  • black carbon
  • ultrafine particle (UFP) count
  • meteorological data.

Filter-based PM2.5, PM10, lead, elements, acid and mercury deposition samples are collected manually and shipped to a laboratory for analysis.

Monitoring the air for pollution is a complex technical task requiring:


Locations of these sites and more are available on the DECinfo Locator Map. DECinfo Locator is an interactive map that lets you access DEC documents and public data about the environmental quality of specific sites in the State, as well as outdoor recreation information. The Air Quality Monitoring Sites layer can be found under DEC Information Layers > Environmental Monitoring > Air Quality Monitoring Sites.

Monitoring Programs

DEC works with many national networks, universities, and regional programs. These partnerships allow not only for a robust and consistent dataset, but they help the State lead with the latest technology and methods. Some of these networks include:

  • State and Local Air Monitoring Stations (SLAMS)
    • Sites track ambient air quality for the main purpose of comparison to the National Ambient Air Quality Standards (NAAQS) for Criteria Air Pollutants (links leave DEC website)
    • Monitoring aspects are found in the Code of Federal Regulations, Title 40, Parts 50, 53 and 58.
    • Approved Federal Reference Method (FRM) or Federal Equivalent Method (FEM) must be used for ambient pollutant levels to be compared to the NAAQS.
  • National Core (NCore) Network
    • Monitors for all gases, except for O3, are more sensitive than standard FRM/FEM monitors to measure concentrations that are well below the respective NAAQS. This data is important to study the formation of O3 and particles.
    • Monitoring includes PM2.5, speciated PM2.5, PM10-2.5, speciated PM10-2.5, O3, SO2, CO, nitrogen oxides (NO/NO2/NOy), and basic meteorology.
    • Data provide support for modeling and long-term health assessments that contribute to ongoing reviews of the NAAQS.
  • Photochemical Assessment Monitoring Stations (PAMS)
    • Monitors NOx and volatile organic compounds (VOC) during the summer ozone season.
    • The data assist air pollution control agencies in evaluating, tracking the progress of, and refining control strategies for attaining the O3 NAAQS.
    • Provides local, current meteorological and ambient data to feed into photochemical grid models. These data can later be used as a baseline for model evaluation.
  • National Air Toxics Trends Station (NATTS) Network
    DEC Engineer Santosh Mahat performing a routine audit on ground level Ozone analyzer at Queens Ncore Site
    DEC Engineer Santosh Mahat
    performing a routine audit on ground level
    Ozone analyzer at Queens Ncore Site.
    • Supplies long-term monitoring data and shows trends for certain priority air toxics across the country.
    • There are 23 NATTS established in 22 cities across the country. The two New York NATTS sites are in Bronx and Rochester.
      • Outside of the NATTS program, the State has been operating a toxics monitoring network since 1990. There are 13 sites statewide collecting 24-hour canister samples for VOC analysis on a 1-in-6 day interval.
    • Both NATTS and independent sites measure 42 VOCs and 12 carbonyl species. Data from these sites are submitted quarterly to EPA's AQS system.
  • Near-Road NO2 Network
    • Measures peak ambient PM2.5, CO and NO2 concentrations from motor vehicles alongside busy roadways.
    • DEC operates three sites in Rochester, Buffalo, and Queens.
    • Data are used to advance research on the impact of motor vehicles on the environment and public health.
  • National Acid Deposition Program (leaves DEC website)
    • Samples are collected weekly to determine the long-term trends in acids, nutrients, base cations and mercury in rain water.
  • Special Studies
    • In addition to working within the above programs, DEC leads and assists with special studies, as resources allow. Historical information about completed studies is available in the New York State Archives and by request.

Ozone Exceedances

Ground level ozone (leaves DEC website) (O3) is not emitted directly into the air, but is created in the air itself by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC). Ozone forms on hot, sunny days when pollution from cars, power plants, consumer products and other sources react with sunlight. It is most likely to reach harmful levels in urban areas on hot, sunny days. Ozone, and the chemicals that form ozone, can be blown long distances. So, even areas outside of cities can experience high levels of ozone.

High Ozone Level Warnings

Public health officials caution against strenuous outdoor activity when ozone levels are high. To help people decide when to curtail activity, DEC forecasts ozone pollution and, in cooperation with the New York State Department of Health, posts warnings if dangerous conditions are expected to occur. These warnings are also aired through the media and are available online from the Air Quality Forecast webpage or toll-free New York State Air Quality Hotline: 1-800-535-1345. You can also sign up for AQI alerts sent through the GovDelivery system.

Please see the ozone exceedance pages below. Last update: 9/7/2023

2023 High Ozone Values (PDF)
2022 High Ozone Values (PDF)
2021 High Ozone Values (PDF)
2020 High Ozone Values (PDF)

NYS Ambient Air Quality Reports

Summary tables of air pollution data are organized by DEC Region. Data is available for the traditional air pollutants. These tables will generally indicate the number of observations, maximum values, and a comparison with the NAAQS. Annual averages for 2021 and past years are available below.

All network data are submitted to EPA and can be accessed via the EPA Air Quality System (AQS) API (leaves DEC website) in standard units. Summary information for the criteria pollutants is available from EPA using the Monitor Values Report service (leaves DEC website). For more information, contact

2022 Ambient Air Quality Report (PDF)
2021 Ambient Air Quality Report (PDF)

2020 Ambient Air Quality Report (PDF)

Monitoring Program Network Assessment (June 2020)

The NYS Ambient Air Monitoring Program Network Assessment (PDF) was prepared as part of the requirements specified in the Monitoring Regulations 40 CFR Parts 53 and 58. As required by §58.10(d), "the State, or where applicable, local agency shall perform and submit to the EPA Regional Administrator an assessment of the air quality surveillance system every 5 years to determine, at a minimum, if the network meets the monitoring objectives defined in Appendix D to this Part, whether new sites are needed, whether existing sites are no longer needed and can be terminated, and whether new technologies are appropriate for incorporation into the ambient air monitoring network." All monitoring networks operated by the Bureau of Air Quality Surveillance, Division of Air Resources (DAR) were evaluated to determine if they meet the monitoring objectives as defined by the regulations. Considerations were given to: population and geographical coverage; air quality trends; attainment classification; emissions inventory; parameters monitored; special purpose monitors; health-related and scientific research; external data users; new and proposed regulations; quality assurance; technology; personnel and training.

As a whole, the State has one of the most comprehensive and robust ambient air monitoring programs in the nation. The State meets or exceeds current monitoring requirements in nearly all instances. There are adequate monitoring stations in populated areas, including where sensitive subgroups reside. Networks for criteria and non-criteria pollutants meet specified monitoring objectives. The toxics analytical laboratory has proven to be one of the best in the country, as demonstrated by data produced for the School Air Toxics Monitoring Initiative (leaves DEC website) and the South Albany Community Air Study. New York is among the first to deploy new monitoring technology in the network. Staff routinely communicate findings via publication in peer reviewed scientific journals as well as presenting these data at technical conferences.

2023 Monitoring Network Plan

Federal regulations require DEC to prepare an annual plan which describes in detail the specifics of the monitoring network. This plan includes an annual review of the existing monitoring network to determine the adequacy of the network and to propose any modifications. The proposed plan must be available for public review for a 30-day period prior to submittal to EPA. The 2023 Monitoring Network Plan (PDF) is available as a downloadable PDF.

DEC has reviewed the current ambient air monitoring network and has proposed to change the PM2.5 Federal Reference Method (FRM) sampling frequency from 1-in-3 to 1-in-6 at IS-52, Albany County Health Department, East Syracuse and Buffalo. These FRM monitors are collocated with FEMs which can provide hourly and daily averages for use in comparison to the NAAQS. The 1-in-6 FRM data are adequate to monitor the performance of the Federal Equivalent Methods (FEM) over time. The NYSDEC has also proposed to formally close the Susan Wagner site. Data generation for the sites was discontinued in 2017 due to roof work, and the new building configuration will no longer allow for the site to reopen.

VOCs and Carbonyls

New York State's ambient air toxics monitoring program was first established in 1985 as part of the Governor's Air Monitoring Modernization Capital Budget Program. This monitoring network measures VOCs across the State. The initial development of the network and analytical capabilities was part of a joint Staten Island/New Jersey Urban Air Toxics Assessment Project (leaves DEC website) coordinated with EPA Region II from 1987 through 1989. The network expanded in 1990 to a statewide network.

The State's toxics network comprises of 12 monitoring sites, including two National Air Toxics Trends Station (NAATS) (leaves DEC website) sites, covering industrial, urban and rural areas. Composite 24-hour canister samples are collected on an every-sixth-day schedule. Whole air samples are routinely analyzed using a modified version of the EPA Method TO-15 (leaves DEC website) for 42 VOCs using gas chromatography with a mass spectrometer detector. Carbonyls are sampled using cartridge containing 2,4-dinitrophenylhydrazine and analyzed with high performance liquid chromatography according to EPA Method TO-11a (leaves DEC website).

The NATTS Network was developed by EPA to fulfill the need for long-term hazardous air pollutants (HAPs) monitoring data of consistent quality. Among the principle objectives are assessing trends and emission reduction program effectiveness, assessing and verifying air quality models (e.g., exposure assessments, emission control strategy development, etc.), and as direct input to source-receptor models. The State's two NATTS sites, located in the Bronx (IS 52) and Rochester, are among 27 sites nationwide funded by EPA.

All network data are submitted to the EPA and can be accessed via EPA's Air Quality System (AQS) API (leaves DEC website) in standard units. Summary information for the HAPs are available from EPA using the Monitor Values Report - Hazardous Air Pollutants (leaves DEC website) service.

Quality Assurance

Ambient air is the air we all breathe; it may be affected by nearby or far-off emissions. DAR calibrates and checks the accuracy of ambient air monitors and maintains calibration standards used for data collected by air monitors. This work is organized so that the staff who oversee the quality of the monitoring systems are not managed by staff who operate systems. That independence allows impartial reviews of the installations and data, which is a defining feature of quality assurance.

Monitors are calibrated by measuring standard samples with known properties to confirm the monitor provides correct results. Their accuracy is checked by comparing the monitors' readings to readings from a standard device known to be accurate. These samples and devices are primary standards certified by NIST. Field operators may use "transfer standards" certified by comparison with primary standards at DAR's laboratory.

DAR keeps primary standards for:

  • temperature;
  • pressure;
  • time;
  • flow rates; and
  • concentrations of gases CO, SO2, NOx and ozone

To assure the quality of ambient air monitoring operations, DAR reports whether the State's monitors are properly maintained and whether the data collected are valid. DAR also conducts independent audits of monitors run by the State, public organizations, and permit-holders. (Permits often require sites to operate air monitors.)

There are two main types of audit:

  • Performance audits use DAR's calibration standards to check the accuracy of equipment.
  • Systems audits make sure ambient air monitors are useful by checking that:
    • monitoring programs use appropriate procedures, techniques, and schedules;
    • databases are well-organized and the data are valid; and
    • the supervising engineers are thorough when reviewing on-site log books.

Emissions Monitoring & Stack Tests

DAR also reviews stack test protocols and designs for continuous monitoring systems, and may review reports generated by those tests and systems. These reviews support work done in DEC's regional offices and allow DAR to respond to inquiries from facilities, consultants, and engineers.

Stack tests collect samples from emission streams to test the efficiency of equipment that captures or destroys pollutants. Some applicants must run tests before getting a permit, and some sites must run tests as a condition of their permit.

DAR also uses its own calibration standards to evaluate devices that are permanently installed, and can take measurements at any time. For example:

  • Continuous Emissions Monitoring Systems (CEMS) (leaves DEC website) analyze emissions to find concentrations of nitrogen oxides, sulfur dioxide, and some other pollutants. DEC uses that data and data about the rate of emissions to calculate compliance with laws like the limits that reduced acid rain in NY.
  • Continuous opacity monitors measure how much light a stream of particles blocks to determine if permit conditions are being met.

Stack tests, CEMS, and opacity analysis all use methods approved by EPA (leaves DEC website).