New York, New York vs Philadelphia, Pennsylvania Air Quality

Side-by-Side Analysis

New York, New York outperforms Philadelphia, Pennsylvania on overall air quality with a Grade B (70/100) versus C (59/100). New York, New York's 5-year median AQI of 44 sits in the "Good" range, while Philadelphia, Pennsylvania averages 52 ("Moderate") — a 8-point gap that shows up consistently in year-over-year readings, not just in a single year.

Both cities are on improving trajectories — New York, New York at roughly 1.2 AQI/yr cleaner and Philadelphia, Pennsylvania at 0.5 AQI/yr cleaner. That mirrors the broader U.S. pattern of falling pollution as cleaner vehicles, cleaner power generation, and tighter emissions standards take effect.

What's in the Air

Both cities share the same dominant pollutant: Fine Particulate Matter (PM2.5). These cities' dominant issue is fine particulate matter — typically driven by combustion (vehicles, wildfire smoke, industry, residential wood burning). PM2.5 is the air pollutant most strongly linked to long-term cardiovascular and respiratory disease because the particles penetrate the bloodstream.

Health Implications

Over a 5-year window, New York, New York averages roughly 4 unhealthy air days per year (AQI above 100, where sensitive groups should limit outdoor exertion) versus 8 for Philadelphia, Pennsylvania. The two cities offer comparable counts of unhealthy days, suggesting that day-to-day exposure planning would look similar for residents of either. For long-term residents, the cleaner-air city is associated with measurably better outcomes on respiratory disease, cardiovascular events, and life expectancy — Harvard cohort research consistently finds 0.5 to 1.0 years of additional life expectancy for each 10-µg/m³ reduction in long-term PM2.5 exposure.