Air Quality Monitoring

NYS' Program to Track Air Quality

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. 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 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 (NO_x), carbon monoxide (CO)),
• PM_2.5 and PM ₁₀ (fine particulate with diameter less than 2.5 or 10 microns),
• black carbon
• ultrafine particle (UFP) count
• meteorological data.

Filter-based PM_2.5, 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:

• direct measurement of pollutants,
• comparison against National Institute of Standards and Technology (NIST) and EPA measurement standards,
• external and internal quality assurance,
• co-location of instrumentation to ensure intra-system consistency between two of the same instruments,
• replicate analysis to ensure analytical consistency,
• continuous review of measured data and diagnostic information to ensure data are as accurate, precise, and complete as possible.

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.

Ozone Exceedances

Ground level ozone (O₃) is not emitted directly into the air, but is created in the air itself by chemical reactions between oxides of nitrogen (NO_x) 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.

Monitoring Program Network Assessment (May 2025)

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 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.

The New York State Department of Environmental Conservation (NYSDEC), Division of Air Resources operates an ambient air monitoring network for various air contaminants within the State. As required by federal regulations, NYSDEC prepares an annual monitoring network plan, which describes in detail the specifics of the monitoring network, that reviews the network data in relation to data quality objectives and measurement quality objectives. These documents include review of the existing monitoring network to determine the adequacy of the network and to propose any network modifications. 

2026 Monitoring Network Plan

The New York State Department of Environmental Conservation (NYSDEC), Division of Air Resources operates an ambient air monitoring network for various air contaminants within the State. As required by federal regulations, NYSDEC prepares an annual monitoring network plan, which describes in detail the specifics of the monitoring network. These documents include review of the existing monitoring network to determine the adequacy of the network and to propose any network modifications. The proposed annual monitoring network plan and five year assessment must be available for public review for a 30-day period prior to submittal to EPA.

This notice is intended to afford interested parties the opportunity to comment on the proposed plans. 

NYSDEC has reviewed the current ambient air monitoring network and is proposing to discontinue the source-oriented lead monitoring site located in Wallkill, Orange County, New York, associated with Ecobat Resources New York LLC, formerly Revere Smelting & Refining Corp., located at 65 Ballard Road in Middletown, Town of Wallkill. The facility operates a secondary lead (Pb) smelter that processes primarily used lead-acid batteries, and its principal emission-generating activities include kiln drying of lead-containing material, smelting, slag casting, refining kettles, and material handling and storage.

Since 2015, there have been no calculated rolling 3-month averages exceeding 50 percent of the Pb NAAQS. These long-term monitoring results, together with current facility emissions information showing reported air releases of lead compounds well below the 0.50 tons/year source-oriented monitoring threshold, support NYSDEC’s proposal to discontinue the Wallkill Pb monitor, pending EPA  Region 2 approval. NYSDEC will continue to evaluate Pb emissions information for Ecobat Resources New York LLC through applicable emissions inventory, permitting, compliance, and network assessment processes. NYSDEC will reassess monitoring needs if future emissions information, facility changes, modeling, or other information indicates a renewed potential for ambient Pb impacts requiring source-oriented monitoring.

The 2026 Network Monitoring Plan (PDF) can be accessed from the NYSDEC website for viewing and downloading.

Written comments on this plan should be forwarded to the Department by June 19th, 2026 and addressed to: NYSDEC, Division of Air Resources, Bureau of Air Quality Surveillance, 625 Broadway – 11th Floor, Albany, NY 12233-3256, Attn: Mr. Michael Miliani, P.E.
 

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 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) 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 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.

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 in standard units. Summary information for the HAPs are available from EPA using the Monitor Values Report - Hazardous Air Pollutants 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, NO_x 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) 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.