Breathe easy: NYC's air quality is improving

The air we breathe can have a major effect on our health — air pollution can make asthma worse and can cause heart disease, lung disease, strokes, and even cancer.

Fortunately, New York City has made great strides in recent years to improve air quality. Let’s take a look.

An air quality advisory day happens when air pollution builds up to dangerous levels. It means that people who are sensitive to air pollution (like people with respiratory or heart problems) should spend less time outside and avoid outdoor exercise. If the air quality is bad enough, then most people will be affected by it.

Over the years, though, the number of advisory days has gone down. That’s good news for everyone who breathes.

What’s behind this improvement?

Since the winter of 2008/2009, the Health Department has been measuring air quality through the NYC Community Air Survey (NYCCAS). It’s the largest urban air monitoring program in the USA, and measures six different kinds of air pollution at about 100 locations around the city.

Because of NYCCAS, we’ve been able to measure improvements in air quality that are, in part, due to City regulations and policies. For example:

• Efforts by the City to phase out residual heating oil (the dirtiest kind) have helped wintertime levels of sulfur dioxide go down by 96 percent.
• Citywide average levels for 4 other pollutants have gone down by between 26 and 44 percent.

A closer look at PM2.5 in the air

One major component of air pollution? Fine particles in the air, called PM2.5. We breathe them in and they enter our lungs and bloodstream, where they can cause health problems.

In New York City, the current PM2.5 levels contribute to an estimated 2,300 deaths from lung and heart disease each year. That means about 1 out of every 20 deaths in New York City is due to this type of air pollution.

So it’s good news that since monitoring neighborhood-level air pollution began in 2009, the levels of PM2.5 have steadily gone down — which you can see in the chart below.

By burning heating oil, New York City’s buildings are responsible for about 22 percent of the city’s PM2.5 emissions—and traffic is responsible for another 17 percent (see a data story on the Public Health Impacts of PM2.5 from Traffic Air Pollution). That means that reducing traffic and working to make sure that buildings burn cleaner fuel are great ways to clean up the air and help keep our air cleaner - and both are important parts of OneNYC, the city’s sustainability plan.

But since 20 to 30 percent of PM2.5 in NYC comes from outside the city, rollbacks of federal regulations like the Clean Power Plan will also affect the quality of our air. The City is providing comments to the Environmental Protection Agency in support of stricter emissions standards for power plants, cars, and trucks so that NYC’s air quality continues to improve.

PM2.5 is only one piece of the puzzle

While NYCCAS has let us see ways that air quality has improved, it also identifies areas where we can make better progress. For example, we’ve learned that:

Average ozone levels in the summer haven’t changed in the past 10 years There are higher levels of pollutants in areas of higher traffic density, building density, and in industrial areas Measuring air quality means we can track improvements and challenges, and push for changes in our city and the nation that will reduce air pollution and keep New Yorkers healthy.

Here at the Health Department, we’ll continue monitoring air quality — just as we measure levels of asthma, heart disease, and lung disease that can be attributed in part to air pollution. As air quality improves, we expect decreases in disease rates: good news for us all.