In 2007, the New York City Department of Health and Mental Hygiene (Health Department) established the New York City Community Air Survey (NYCCAS), the largest ongoing urban air monitoring program of any U.S. City.  NYCCAS, which began collecting data in December 2008, is a collaboration between the Health Department and Queens College of the City University of New York and provides data to:

• Help inform OneNYC, the City’s sustainability plan
• Track changes in air quality over time
• Estimate exposures for health research
• Inform the public about local topics, such as: air quality in the time of COVID-19, recent air quality improvements, car-free zones, changes in the sources of air pollution, unique studies conducted in New York City and differences in air quality and health impacts across NYC neighborhoods.

This report:

• Provides a summary of key findings, the air monitoring program, monitoring site selection, and descriptions of the pollutants measured
• Describes the trends in air pollutant levels from more than a decade of data between winter 2008-2009 through fall 2020 for fine particulate matter (PM_2.5), nitrogen dioxide (NO₂), nitric oxide (NO), black carbon (BC), wintertime sulfur dioxide (SO₂) and summertime ozone (O₃)
• Presents maps of neighborhood air pollution levels by year
• Identifies the local sources that contribute to high levels of these pollutants in New York City neighborhoods

Fine Particles

Fine particles (PM_2.5) are tiny airborne solid and liquid particles less than 2.5 microns in diameter. PM_2.5 is the most harmful urban air pollutant. It is small enough to penetrate deep into the lungs and enter the bloodstream, which can worsen lung and heart disease and lead to hospital admissions and premature deaths. 

PM_2.5 can either be directly emitted or formed in the atmosphere from other pollutants. Fuel combustion in vehicles, boilers in buildings, power plants, construction equipment, marine vessels and commercial cooking are all common sources of PM_2.5. Up to 40% of the PM_2.5 in New York City's air comes from sources in areas upwind from the city, such as coal-burning power plants in the Midwest.

 

Black Carbon

Black carbon (BC) is one type of PM_2.5 and is the sooty black material emitted from gas and diesel engines, coal-fired power plants, and other sources that burn fossil fuels. It comprises up to 20% of fine particulate matter in New York City. Unlike other fine particles, BC is primarily from local sources. Inhalation of BC is associated with health problems, including respiratory and cardiovascular disease, cancer and birth defects. BC also contributes to climate change by altering the patterns of rain and clouds.

 

Nitrogen Dioxide and Nitric Oxide

Nitrogen dioxide (NO₂) and nitric oxide (NO) are part of a group of pollutants called “oxides of nitrogen” (NO_X). Exposures to NO_X are linked to increased emergency department visits and hospitalizations for respiratory conditions, particularly asthma. NO_X also reacts with other compounds in the atmosphere to form PM_2.5 and O₃. A variety of combustion sources produce NO_X in New York City, including motor vehicles, buildings, marine vessels and construction equipment.

 

Ozone

Ozone (O₃) forms at ground level when NO_X emissions combine with sunlight and other airborne pollutants. Measured O₃ concentrations are often highest in the summer and downwind from areas with high NO_X emissions, such as places with high traffic density. In areas with heavy traffic, NO_X reacts with any ground-level O₃ to reduce O₃ concentrations. As a result, NYCCAS has measured lower O₃ levels near roadways, in city centers and in other areas of high NO_X emissions density. Higher levels of O₃ are seen in areas away from dense traffic and building emissions.

 

Sulfur Dioxide

Sulfur dioxide (SO₂) is produced mainly by burning oils with high sulfur content, such as No. 4 and No. 6 oil (also known as residual fuel oil), or high-sulfur No. 2 oil. The primary use of fuel oil in NYC is to heat buildings and water, which is why we only monitor it in the winter. Some high-sulfur oil is also used to generate electricity and power marine vessels. SO₂ exposures can worsen lung diseases, causing hospitalizations and emergency department visits for asthma and other respiratory conditions. SO₂ also contributes to the formation of PM_2.5 in the atmosphere, resulting in PM_2.5 exposures downwind of SO₂ emissions.

 

Since it is impossible to sample the air in every location in New York City, we monitor representative sites to determine how pollution levels vary in relation to traffic, buildings, trees and other neighborhood factors. We use NYCCAS monitoring data along with data on land use, traffic, building emissions and other neighborhood factors around the monitors to build a land-use regression (LUR) model. We then used the associations from these models to estimate the seasonal average air pollution levels at locations across the city, including places where no NYCCAS measurements were collected. For more details on emission source data, see Appendix 1 (PDF). For more details on the analysis methods, see NYCCAS Scientific Publications.

In the maps below, you can select a pollutant to see how air pollution is distributed throughout the city and how it has changed over time. The City's air quality changed significantly during the spring and summer of 2020 and resulted in lower annual average values, especially for PM_2.5, as can be seen in the maps below. Winter and summer average maps for BC, NO₂, NO and PM_2.5 are available in Appendix 2 (PDF). 

Since monitoring began in winter 2008-2009 in New York City, we have seen a decrease in most of the air pollutants we measure. However, the concentrations of NO₂, NO and PM_2.5 continue to be higher in industrial zones with more diesel truck traffic, neighborhoods with large numbers of restaurants, and areas of higher traffic and building density. Air pollution changes not only by neighborhood, but also by season. Some pollutants are highest in certain seasons of the year because of either weather patterns or emissions sources. For example, O₃ is produced when NO_X and other airborne pollutants react in the presence of heat and sunlight. Therefore, we only monitor O₃ in the summer when direct sunlight is highest and days are longer.

The figure below illustrates how the levels of each air pollutant change by season from winter 2008-2009 to fall 2020.  We break out locations with high, medium and low densities of the most common sources of each. Since winter 2017-18 there have been too few sites with SO₂ values above the detection limit for us to include it in this chart. SO₂ levels have gone down dramatically since Local Law 43 of 2010 prohibited the burning of heavy fuel oil (No. 6) in New York City buildings.

NYCCAS data were analyzed using a land-use regression (LUR) model. LUR models estimate associations among pollution levels, average traffic, building emissions, land use and other neighborhood factors around the monitoring sites. The pollution sources that contribute most to differences in concentrations of NO, NO₂, BC, and PM_2.5 across NYC are listed in the table below.  SO₂ is now so low in NYC that it is not possible to build a LUR model for the most recent years of data.  

Fuel used to provide heat and hot water in buildings has become significantly cleaner under state and local regulations requiring use of cleaner burning fuels. As a result, commercial charbroiling and grilling operations have become a more important source of PM_2.5 emissions over the past several years due to state and local regulations mandating cleaner burning fuels for building heat and hot water. The number of commercial cooking charbroilers and grills in an area now explains PM_2.5 differences among neighborhoods better than building emissions. For more information on these changes, please see Tracking changes in New York City's sources of air pollution.

This report underscores the importance of emissions reduction efforts over the past decade and highlights the continued need to reduce emissions citywide. The City’s sustainability plan, OneNYC, and its roadmap to reduce greenhouse gas emissions, 80x50, have already and will continue to improve air quality, providing important public health benefits to all New Yorkers. These strategies and measures include:

• Transitioning the City's fleet to more efficient, less polluting heavy-duty vehicles, such as trash trucks and school buses
• Reducing motor vehicle use by shifting to more sustainable modes of transportation
• Creating more efficient freight networks and expanding truck retrofit and replacement programs
• Continuing to reduce fossil fuel combustion in buildings

Additionally, reducing emissions from other widely distributed sources of pollution, such as BC and PM_2.5 from commercial charbroiling, will contribute to improved air quality in the future.

More Information:

• Appendix 1 (PDF) : Sampling Methodology and Data Sources for Emissions Indicators.
• Appendix 2 (PDF) : Seasonal Average Pollutant Maps. 
• Appendix 3 (PDF) : Community District Average Pollution Levels 
• NYCCAS Air Quality Data Hub
• Environment & Health Data Portal : Neighborhood-level data and neighborhood air quality reports
• The Public Health Impacts of PM_2.5 from Traffic Air Pollution data story. 
• NYCCAS Air Pollution Rasters on NYC OpenData.
• New York Community Air Survey: past reports