Case Study: How PurpleAir Helps Monitor New York Air Quality

Clear view of air quality in New York
  • Topic: New York Air Quality 
  • Industry: Air Quality, Air Quality Technology 
  • Author: Adrian Dybwad 
  • Website: 


While you can’t control the air, you can gather data on your air quality. That way, you can take informed measures to minimize your exposure to air pollution. This is what Cornell Cooperative Extension aimed to do when it expanded New York’s air quality network with PurpleAir Flex. It distributed one air quality monitor to each of the 28 counties that don’t have an air quality monitoring system for particle pollution.  

In this air quality case study, we dive into the history of air quality in New York and its present air quality achievements. We’re also covering Conrnell’s PurpleAir project to empower New Yorkers to take data-driven action on their air quality. 

 View of New York City’s Smog 1953

The Hazy History of Air Quality in New York 

While New York is now known as the Big Apple, it was once the most polluted city in the United States.  

In the 1950s, New York air quality was so toxic that it was often compared to the Great London Smog, which caused thousands of deaths. It also led the state government to establish the country’s first air pollution control laws and the creation of the Air Pollution Control Board.  

However, New York City again experienced hazardous levels of air pollution in 1962-1963 and 1966. The air pollution in 1966 was notably the worst, gaining the nickname “killer smog.” Residents alive during this period remember that they had to wash the pollution from their bodies just after a few minutes of staying outside. They also recall how a dusty haze enveloped the city and limited visibility.  

The U.S. Department of Health estimated that the 1966 killer smog increased the death rate by 24 deaths per day. Additionally, the New York Times linked 168 deaths to the event. Prompted by these events, the U.S. government passed the Air Quality Act in 1967 and the Clean Air Act in 1970.  

On the state level, New York State set air quality standards in 1964, setting limits on the air pollutants:   

  • Particle pollution  
  • Sulfur dioxide  
  • Carbon monoxide  
  • Oxidants  
  • Hydrogen sulfide  
  • Fluoride, beryllium   
  • Sulfuric acid mist  

It also installed an air quality monitoring station at the Harlem Courthouse in 1966. 

 A map of the manufacturing industries in New York City circa 1922


What Caused the Air Pollution in New York? 

After World War II, New York and the rest of America experienced a population and economic boom. In the 1940s, the State of New York only had 13,479,142 residents. By the 1960s, this number soared to 16,782,304—a 24% increase. This meant that there was a greater demand for resources, like electricity, that was mainly from coal-burning power plants 

Additionally, automobiles were skyrocketing at that time, as car sales quadrupled between the 1940s and 1950s. By 1965, there were 11.1 million new cars, trucks, and buses in the country. However, there were no air quality regulations in place. As such, these vehicles emitted hydrocarbons, nitrogen oxides, carbon monoxides, and other toxic gases, depending on the make, model, and fuel.  

Worse, New York was a major manufacturing center during this period, producing anything from sugar and oil to pharmaceutical drugs and machines. This also meant high levels of hazardous aerosols and deadly substances.  

In addition to this, New York was experiencing temperature inversion during the 1960s killer smog. Consequently, air pollution from all the sources listed above was trapped for longer periods of time, worsening the air quality. 

Air Quality in New York Today 

New York air quality today has improved by leaps and bounds. According to the New York City Community Air Survey, the following air pollutants have decreased since 2009: 

  • Fine particulate matter (PM2.5) by 40% 
  • Nitrogen dioxide by 38% 
  • Nitric Oxide by 58% 
  • Sulfur dioxide by 97% 
  • Black carbon by 45% 

Additionally, the American Lung Association has awarded the majority of the counties under the New York State with air quality monitoring stations a passing grade: 

  • 75% of the counties with Ozone monitors have either an A or B grade 
  • 56% of the counties with particle pollution monitors have a passing grade 

Despite the New York air quality progress today, much still needs to be done. The American Lung Association notes that out of the 62 counties in the State of New York, only 14 are tracking particle pollution.   

More than that, New York City still faces problems from its primary sources of air pollution: 

  • Commercial cooking 
  • Construction/industrial emissions 
  • Transportation  
  • Building boilers/heating 
  • Wood burning 
  • Electric energy generation 

How Cornell University is Helping New York Air Quality with PurpleAir Air Quality Monitors 

When Canada’s wildfire painted the New York skyline yellow last June 2023, many realized that we still needed to continue fighting against air pollution. And Cornell University was one of the institutions that rose to the occasion. 

The Cornell Cooperative Extension (CCE) is a part of Cornell University that aims to implement lessons learned inside the classroom into real-world situations. It does this by connecting students and educators with communities across the state of New York. In doing so, they hope to help improve lives, local businesses, towns, and cities. 

As such, when it discovered that 28 of the 62 New York counties didn’t have an air quality monitor that tracked PM2.5, it established an air quality program to provide each county with one PurpleAir Flex. 

PurpleAir air quality monitors are widely recognized in the scientific community for their hyper local and highly accurate air quality data. Not only that, but they also have one of the most comprehensive air quality networks that can easily be accessed through its free online air quality map.  

With it, individuals and communities can make data-driven decisions that can reduce their exposure to air pollution. In fact, an air quality study on wildfires found that people are more likely to take preventive action against wildfire smoke when they have easy access to the air quality data in the area.  

Another benefit of the PurpleAir air quality monitors is that the Environmental Protection Agency uses their air quality data for the Fire and Smoke Map. The map serves as a vital resource for areas affected by wildfire smoke. 

By providing the 28 counties with a PurpleAir Flex monitor, CCE aims to strengthen New York’s air quality network. At the same time, they hope to provide New Yorkers with real-time information, so they can make timely data-driven decisions. 

To date, CCE has installed PurpleAir Flex in all 28 counties: Allegany, Cattaraugus, Chemung, Chenango, Clinton, Columbia, Delaware, Franklin, Fulton, Genesee, Herkimer, Jefferson, Livingston, Madison, Montgomery, Orleans, Oswego, Otsego, Saratoga, Schenectady, Schoharie, Schuyler, Seneca, Tioga, Washington, Wayne, Wyoming, and Yates. 

They have also connected the air quality monitors to the AirNow Fire and Smoke Map. 

The CCE air quality project was developed with the help of Ecosystem Health in College of Veterinary Medicine, the Cornell Atkinson Center for Sustainability, and the New York State Association for County Health Organizations. 

“The next time we have wildfires and smoke – and it will happen again – all of us will be very glad that these sensors are in place. Now, we’ll get more localized, tangible, complete and readily accessible information,” explains Keith Tidball, assistant director of CCE and a senior extension associate. 

About PurpleAir 

Since being founded in 2018, PurpleAir has dedicated itself to providing highly precise air quality monitors that track hyper-local air quality levels in real time. In doing this, PurpleAir is empowering community scientists and helping to facilitate social change through accessible air quality data for all. By working together, everyone is more informed and able to make changes in their local communities.