What does this measure?
The percentage of days for which air quality was monitored and found to be good, indicating healthy air both for sensitive groups, such as people with asthma, and for the population as a whole. The Air Quality Index (AQI) summarizes levels of ground-level ozone, particulate matter (soot and other particles), carbon monoxide, sulfur dioxide, and nitrogen dioxide into one measure.
Why is this important?
Exposure to these pollutants can cause short-term health effects such as irritation to the eyes, nose and throat, coughing, sneezing, runny nose, and shortness of breath. Continued exposure can also worsen medical conditions such as asthma and heart disease.
How is Westchester County performing?
In 2023, 88% of days with air quality measurements in Westchester County were good air days, similar to the rate in 2022, and a 14 percentage point increase from 2010. The lowest point in the last two decades was only 66% good air days in 2007. Compared to similar counties, Westchester had the same percentage of good air days in 2022 as Nassau and Rockland Counties; Putnam had the highest at 95%.
Notes about the data
The availability of data depends on the location of EPA monitoring stations.
| 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Westchester County | 81% | 71% | 75% | 81% | 85% | 75% | 79% | 66% | 71% | 77% | 74% | 73% | 80% | 82% | 82% | 79% | 82% | 90% | 87% | 90% | 90% | 89% | 89% | 88% |
| Nassau County | 76% | 74% | 78% | 83% | 84% | 83% | 86% | 63% | 63% | 72% | 72% | 67% | 77% | 80% | 85% | 85% | 92% | 94% | 93% | 95% | 95% | 93% | 97% | 88% |
| Putnam County | 89% | 81% | 78% | 85% | 87% | 84% | 89% | 85% | 88% | 95% | 86% | 94% | 93% | 96% | 95% | 93% | 89% | 94% | 94% | 96% | 98% | 95% | 93% | 95% |
| Rockland County | 86% | 76% | 79% | 81% | 81% | 85% | 80% | 83% | 93% | 88% | 92% | 93% | 92% | 92% | 88% |
Notes: Data were not available for the state or for some counties because they do not have air quality monitoring stations.
| 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Westchester County | 287 | 257 | 261 | 291 | 298 | 272 | 274 | 239 | 260 | 280 | 271 | 263 | 292 | 300 | 299 | 290 | 300 | 327 | 316 | 330 | 327 | 325 | 324 | 322 |
| Nassau County | 276 | 265 | 284 | 295 | 303 | 295 | 312 | 230 | 232 | 263 | 262 | 244 | 276 | 291 | 310 | 310 | 337 | 342 | 340 | 344 | 347 | 337 | 353 | 320 |
| Putnam County | 326 | 294 | 279 | 310 | 316 | 304 | 317 | 311 | 322 | 345 | 315 | 330 | 334 | 351 | 345 | 338 | 322 | 339 | 332 | 348 | 350 | 345 | 311 | 334 |
| Rockland County | 178 | 277 | 270 | 290 | 297 | 311 | 293 | 303 | 340 | 320 | 335 | 340 | 334 | 337 | 320 |
Notes: Data were not available for the state or for some counties because they do not have air quality monitoring stations.
| INDICATORS | TREND | WESTCHESTER |
|---|
