Amidst the bustling streets of New York City, a transformation has been taking place, altering the very makeup of the city’s air. During the summer of 2022, a team of scientists investigated summer air quality in Manhattan and Queens, uncovering a surprising shift in the composition of pollution which they recently published in a new ACS ES&T Air study.
While measuring air particles across the city as part of the NYC-METS (New York City metropolitan Measurements of Emissions and TransformationS) field campaign, the scientists recognized a remarkable change in the types of pollutants present in the atmosphere. Instead of the expected mix of chemicals, they found that a staggering 80-83% of the summer pollution consisted of organic aerosols – compounds formed from natural and man-made emissions reacting in the air.
This revelation marks a significant departure from past research, which had long focused on other pollutants like sulfates and nitrates emitted from various sources like vehicle emissions and industrial processes. Now, organic aerosols reign supreme, posing new challenges for air quality management in the city.
But what exactly are these organic aerosols, and where do they come from? Through sophisticated analysis, the researchers traced the origins of these particles. They found that a large portion resulted from chemical reactions happening in the atmosphere, rather than direct emissions from vehicles or factories. This means that controlling their presence in the air will require a deeper understanding of atmospheric chemistry and weather patterns.
Moreover, the team uncovered a curious relationship between temperature and pollution levels. As summer temperatures rise, so too does the concentration of organic aerosols, presenting a troubling trend for hot summer days in the city. With climate change expected to bring more frequent heatwaves, this finding underscores the urgent need for action to mitigate air pollution and protect public health.
Overall, this research sheds light on a previously overlooked aspect of New York City’s air quality, highlighting the complex interplay between human activity, atmospheric processes, and environmental conditions. The authors suggest possible steps to mitigate these challenges, like improved modeling, organic aerosol monitoring capabilities, further research on health impacts of the new air quality composition, and science-informed emissions policies. As cities around the world grapple with similar pollution challenges, the lessons learned from this study could prove invaluable in shaping future policies and strategies for cleaner, healthier urban environments. CPO’s Atmospheric Chemistry, Carbon Cycle and Climate (AC4) Program supported this project to work toward an initiative to understand the chemical composition of urban atmospheres. This work contributed to a large-scale coordinated measurement effort in 2022 and 2023, as part of the NOAA-led AEROMMA field campaign, and its interagency umbrella, AGES+ (AEROMMA+CUPiDS, GOTHAAM, EPCAPE, STAQS).
For more information, contact Clara Deck.
Image credit: Drew Gentner, Yale University
