Air Pollution Alert: New York's Unhealthy Air Quality

New York City, the most populous city in the United States, has relatively clean air on average. However, the air quality in the city can sometimes be unhealthy, especially for sensitive groups. While particle pollution meets annual attainment levels, it still contributes to thousands of deaths and hospital visits annually. The primary sources of this pollution include transport exhaust, particularly from cars, heavy-duty trucks, ships, and planes, as well as industrial businesses on the city outskirts and residential buildings that burn residual fuel oil. The most common cause of unhealthy air quality in New York City is high ozone levels, which are among the most dangerous gaseous pollutants and a critical component of smog.

Ozone pollution

Ozone (O3) is a highly reactive gas that forms at ground level through the interaction of nitrogen oxides (NOx) emissions and other airborne pollutants in the presence of sunlight. This process is exacerbated during the summer months when temperatures exceed 80 degrees Fahrenheit, leading to increased concentrations of ozone in the atmosphere. While ozone naturally occurs in the Earth's upper atmosphere, providing a protective layer against harmful ultraviolet (UV) radiation, ground-level ozone is a harmful pollutant.

New York City's dense population, heavy vehicle traffic, and industrial activities contribute to the elevated levels of ozone pollution. Despite stringent emission controls, the city's unique challenges make tackling ozone pollution particularly difficult. The State of the Air Report by the American Lung Association gave New York City an "F" for ozone pollution due to several high pollution episodes. In 2019, the city experienced five and a half days where ozone levels exceeded the national 8-hour standard of 70 parts per billion (ppb).

The health impacts of ozone pollution are significant. A 2011 analysis attributed approximately 10% of hospital visits for asthma in New York City to ozone pollution. Additionally, areas like Staten Island, Southern Brooklyn, Central Queens, and the Northwest Bronx have the highest ozone-related death rates. The New York Health Department estimates that fine particle pollution, including ozone, contributes to more than 3,000 deaths and 2,000 hospital admissions for coronary and respiratory conditions annually.

To address ozone pollution, New York City has implemented various measures. These include stricter emission controls, legislation for cleaner mass transport, and reductions in heating oil emissions. While these efforts have led to some improvements, more needs to be done to mitigate the health risks associated with ozone pollution. Achieving cleaner air in New York City will require continued efforts to reduce emissions, improve air quality monitoring, and prioritize the well-being of residents, especially those in lower-income neighbourhoods that are disproportionately affected by air pollution.

PM2.5 pollution

PM2.5, or fine particulate matter, is a dangerous and prevalent air pollutant in New York, widely regarded as one of the most harmful to human health. The New York Health Department estimates that PM2.5 pollution contributes to more than 3,000 deaths and 2,000 hospital admissions for coronary and respiratory conditions annually. Long-term exposure to PM2.5 is responsible for an estimated 2,000 excess deaths from lung and heart disease each year in NYC, with short-term exposure contributing to asthma incidents requiring emergency treatment.

Despite being the most populous city in the United States, New York has relatively clean air on average. For 2017, 2018, and 2019, New York's air quality index (AQI) was less than 50, or "good", as defined by the US Environmental Protection Agency (EPA). The EPA defines "good" air quality as air that poses little to no risk to health. However, the World Health Organization (WHO) uses a more stringent threshold for PM2.5 levels than the US EPA ( <10 μg/m3). Since 2017, New York's air quality has consistently met this target, with 2017, 2018, and 2019 averaging 6.8, 7, and 7 μg/m3 respectively.

However, there are still concerns about air pollution in New York City. The city's high population density and heavy vehicle traffic pose significant challenges to tackling air pollution. While particle pollution meets annual "attainment" levels established by the US EPA, it still contributes to thousands of deaths and hospital visits annually. The majority of fine particles in New York City's air originate from outside the city, with local sources accounting for differences within the city. Primary sources include transport exhaust, particularly from cars, heavy-duty trucks, ships, and planes, industrial businesses on the city outskirts, and residential buildings burning residual fuel oil.

New York has implemented stricter emission controls and legislation for "cleaner" mass transport to reduce traffic congestion and further lower emissions. The city has also mandated reductions in heating oil emissions and lowered pollution from construction vehicles, school buses, ferries, and private trucks. During the COVID-19 lockdown in March 2020, New York observed a 25% reduction in fine particle pollution (PM2.5) compared to the same period in 2019. This brief period provided valuable insights into the potential benefits of a shift towards more electric or clean transport and reduced or cleaner industry.

Overall, while New York has made significant progress in improving air quality and reducing PM2.5 levels, it continues to be a critical issue, particularly for lower-income neighbourhoods, with health risks including heart and lung complications. Further reductions in PM2.5 levels could provide opportunities to save more lives and equalize the health of New York residents across income levels.

Vehicle emissions

New York City has relatively clean air on average. For three consecutive years (2017, 2018, and 2019), the city's air quality index (AQI) remained below 50, or "good." However, vehicle emissions remain a significant contributor to air pollution in the city.

The transportation sector in New York is responsible for the largest share of the state's total annual carbon dioxide (CO2) emissions. Motor gasoline accounts for the highest share of transportation-related emissions. While total emissions from motor gasoline declined from 51.2 million metric tons (MMT) of CO2 in 1990 to 41.6 MMT in 2015, this trend reversed, rising to 44.2 MMT in 2018, even as vehicle miles travelled (VMT) decreased. This recent increase in motor gasoline emissions is likely due to changes in the composition of vehicles used in the state, with a slight decrease in VMT being offset by an increase in fuel usage per vehicle.

Diesel-powered vehicles, particularly those with a gross vehicle weight rating (GVWR) greater than 8,500 pounds, are also a significant source of vehicle emissions in New York. While emissions from diesel-powered vehicles have slightly decreased, this reduction has been offset by an increase in aviation-related emissions. Passenger aviation has rapidly increased over the past two decades, with a 47% rise in passenger enplanements across the state from 2000 to 2018. This increase in air travel has contributed to a significant rise in aviation-related emissions.

To address these issues, New York has implemented several measures. The state conducts a Vehicle Safety/Emissions Inspection Program to ensure that registered vehicles meet minimum standards for safe operation and reduce air pollution. Most vehicles are subject to an emissions inspection, and those that fail may not be eligible for registration or renewal. New York is also mandating reductions in heating oil emissions and lowering pollution from construction vehicles, school buses, ferries, and private trucks. Additionally, the state has set ambitious goals under the Climate Leadership and Community Protection Act (CLCPA) of 2019 to reduce statewide greenhouse gas (GHG) emissions by 40% from 1990 levels by 2030 and by 85% by 2050.

Wildfires

New York City has relatively clean air on average. For instance, in 2017, 2018, and 2019, New York's air quality index (AQI) remained less than 50, or "good". However, the city's high population density and heavy vehicle traffic pose significant challenges to maintaining good air quality. While particle pollution meets annual "attainment" levels, it still contributes to thousands of deaths and hospital visits annually. The majority of fine particles in New York City's air originate from outside the city, with transport exhaust, industrial businesses on the outskirts, and residential buildings burning residual fuel oil being primary sources.

Wildfire smoke contains a mix of gases, particles, and chemicals, which can cause various health issues when inhaled. People with heart or respiratory conditions, such as asthma, are particularly vulnerable to the health effects of smoke exposure. During periods of poor air quality due to wildfires, it is recommended to stay indoors with windows and doors closed if temperatures allow. Using a portable air cleaner or ensuring window AC units have correctly installed filters can also help reduce indoor smoke levels.

New York experiences wildfire seasons from April through October, and the impact of wildfires on the city's air quality can be unpredictable. For example, in April 2025, smoke from wildfires in New Jersey triggered air quality alerts in New York City, with the air quality index climbing above 100, indicating unhealthy air for sensitive groups.

Overall, while New York City generally maintains good air quality, it is susceptible to periods of unhealthy air pollution due to wildfires, highlighting the importance of monitoring air quality and taking appropriate measures to protect public health.

Industrial businesses

New York City, despite being the most populous city in the United States, has relatively clean air on average. For instance, in the years 2017, 2018, and 2019, New York's air quality index (AQI) remained less than 50, or "good." The US Environmental Protection Agency (EPA) defines "good" air quality as air that poses little to no risk to health.

However, New York's high population density and heavy vehicle traffic pose significant challenges to maintaining and improving air quality. While the city has implemented relatively strict emission controls, certain industrial businesses on the outskirts of the city contribute to air pollution.

In 1988, eight factories were responsible for producing most of New York City's industrial air pollution, according to the Consumer Policy Institute. These eight factories, out of 66 companies, accounted for about two-thirds of the total pollution. The biggest toxic chemical emitter among them was the Ulano Corporation, a producer of photographic chemicals in Brooklyn, which accounted for about 17% of the city's toxic air pollution in 1988.

Today, industrial businesses on the city outskirts continue to be a source of fine particle pollution, along with transport exhaust from vehicles, ships, and planes, as well as residential buildings burning residual fuel oil.

New York City has been taking steps toward cleaner mass transport and industry, and the lockdown period during the COVID-19 outbreak in 2020 provided a glimpse of what could be achieved. During that time, New York observed a 25% reduction in fine particle pollution (PM2.5) compared to the same period in 2019. This brief period of improved air quality was attributed to reduced industrial activity and cleaner transportation options.

While the city has made progress in certain areas, such as lowering pollution from construction vehicles, school buses, ferries, and private trucks, more comprehensive efforts are needed to address the impact of industrial businesses on air quality.

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