Air quality in Onondaga County, NY

Includes Syracuse · EPA monitor readings, 2021 to 2025 · 477,000 people

A few bad days a yearMostly summer smoke
Bad-air days a year
3
days with an AQI over 100

13 bad-air days in 5 years of readings, 2021 to 2025. That's down from about 12 a year in the early 2000s. Onondaga County has the 12th most bad-air days of the 27 New York counties with monitors.

<1day unhealthy for everyoneAQI over 150, a year
37AQI on a typical dayGood: fine for everyone
May to Julworst monthsSmoke and particles in summer and fall
258worst day since 2016Jun 7, 2023, fine particles
How to read the AQIThe EPA's air score runs from 0 to 500. Higher is worse. Over 100 counts as a bad-air day.
Typical day 37 (Good)Worst day 258 (Very unhealthy)
Good0 to 50Moderate51 to 100Sensitive groups101 to 150Unhealthy151 to 200Very unhealthy201 to 300Hazardous301 to 500

When bad air happens in Onondaga County

Average bad-air days in each month, from 10 years of daily readings since 2016. Most fall in May, June and July.

Jan0
Feb0
Mar0
Apr0.1
May0.4
Jun0.6
Jul0.3
Aug0.3
Sep0
Oct0
Nov0
Dec0
012JanFebMarAprMayJunJulAugSepOctNovDecSMOKE012JFMAMJJASONDSMOKE
Fine particles (smoke, soot)Ozone (smog)Bars stack in that order, from the bottom.
See the numbers by month
Average bad-air days a year in each month in Onondaga County, from 10 years of daily readings
MonthOzoneFine particlesAll
January000
February000
March000
April0.100.1
May0.400.4
June00.60.6
July00.30.3
August00.30.3
September000
October000
November000
December000

The worst day since 2016 was June 7, 2023: AQI 258, from fine particles.

What causes it

The pollutant that pushed the AQI over 100 on each of the 17 bad-air days since 2016.

71%particles
29%Ozone: smog that forms in sunlight on hot days
71%Fine particles: smoke and soot

Most bad days here are fine-particle days in summer and fall, the months when wildfire smoke drives particle pollution.

CDC estimates by month, 2001 to 2022

The CDC's model counts bad-air days at the county's worst spot, from monitors and satellites. Particles (brown) fill the inside of the ring and ozone (blue) the outside.

January: 0.1 smoky days a yearJFMarch: 0.0 ozone days a yearMApril: 0.6 ozone days a yearAMay: 0.9 ozone days a yearMJune: 0.3 smoky days a yearJune: 1.6 ozone days a yearJJuly: 0.4 smoky days a yearJuly: 0.8 ozone days a yearJAugust: 0.3 smoky days a yearAugust: 0.8 ozone days a yearASeptember: 0.1 smoky days a yearSeptember: 0.5 ozone days a yearSONDbad daysby month
See the numbers by month
CDC estimated bad-air days a year in each month in Onondaga County, 2001 to 2022
MonthFine particlesOzone
January0.10
February00
March00
April00.6
May00.9
June0.31.6
July0.40.8
August0.30.8
September0.10.5
October00
November00
December00

What helps in Onondaga County

Most bad days here are smoke and other fine particles. Filtering the air at home helps most.

Keep one room clean on smoky days

Shut the windows and run an air purifier sized for the room.

Choosing a purifier →

Upgrade the furnace filter

Use MERV 13 if your system can take it, and run the fan on smoky days.

Furnace filters →

Wear an N95 outside on smoky days

A well-fitted N95 helps. Cloth and surgical masks do little against smoke.

Wildfire smoke guide →

For today's reading and tomorrow's forecast, check AirNow by ZIP code. Its fire and smoke map adds smoke plumes.

Purifiers with a verified smoke rating

For a clean room on smoky days. Each has a smoke CADR tested by AHAM's independent program and is certified by California as a mechanical cleaner, so it makes no ozone.

Bedroom or small room

Levoit Vital 100S-P

143 smoke CADR

Everyday
up to 222 sq ft
Heavy smoke
up to 143 sq ft
Filters
about $40 a year

The cheapest unit we found with a verified smoke rating. Enough for a bedroom clean room.

$119.99 at Levoit
Best value for smoke

Levoit Vital 200S-P

250 smoke CADR

Everyday
up to 388 sq ft
Heavy smoke
up to 250 sq ft
Filters
about $50 a year

The most verified smoke cleaning per dollar of any qualifying model: 75% more than the 100S-P for $50 more.

$169.99 at Levoit
Living room or open floor

Levoit Core 600S-P

391 smoke CADR

Everyday
up to 606 sq ft
Heavy smoke
up to 391 sq ft
Filters
$60 to $120 a year

For a big room or a small apartment. Buy the LAP-C601S-WUS version, which CARB lists as mechanical.

$299.99 at Levoit

Why all 3 are Levoit: of the models we checked that pass both tests, these give the most verified smoke cleaning per dollar at each room size. Medify's MA-25 and MA-40 also pass but cost more for the same cleaning.

Ratings from the AHAM Verifide directory and CARB's certified list. Prices from Levoit's site, checked November 7, 2026; they change. We don't earn anything from these links. How to pick a purifier

Every year since 2000

Bad-air days each year. The striped part is days unhealthy for everyone, over AQI 150. The worst recent year was 2023, with 8 bad-air days.

0510152025302000262005201020152020202540510152025302000262010202020254
Unhealthy for sensitive groups (101 to 150)Unhealthy or worse (over 150)
See the numbers by year
Bad-air days each year in Onondaga County
YearBad-air daysOver 150
200091
2001193
2002268
200362
200410
2005152
200640
2007151
200830
200910
201050
201120
201280
201300
201400
201500
201620
201700
201820
201900
202000
202110
202200
202384
202400
202540

Onondaga County and its neighbors

Bad-air days a year, 2021 to 2025. New York counties with monitors averaged about 4 bad-air days a year, weighted by population.

Onondaga County3
Oswego County<1

Nearest counties with a full report: Oneida County, NY (1 bad-air day a year), Jefferson County, NY (under 1 bad-air days a year).

Questions people ask about air in Onondaga County

How often is the air bad in Onondaga County?

From 2021 to 2025, monitors in Onondaga County recorded about 3 bad-air days a year with an AQI above 100, which is unhealthy for sensitive groups or worse. The worst year in that stretch was 2023, with 8 bad-air days.

What causes bad air in Onondaga County?

Most bad days here are fine-particle days in summer and fall, the months when wildfire smoke drives particle pollution. Bad days cluster in May, June and July.

Where can I see today's air quality in Onondaga County?

AirNow, run by the EPA and its partners, shows the current AQI and tomorrow's forecast for your ZIP code. Its fire and smoke map adds smoke plumes. On a typical day the AQI in Onondaga County is about 37, which is good, fine for everyone. Check it most in May, June and July, when bad days here cluster.

About these numbers

Day counts come from the EPA's county air quality summaries, which take the worst reading across a county's monitors each day. Monitors here reported on about 363 days a year from 2021 to 2025. A county is large, and your street can be cleaner or worse. CDC's model, which estimates every county from monitors and satellites, gives the worst spot in Onondaga County almost no high-particle days and almost no high-ozone days a year from 2018 to 2022.

Sources: EPA AirData county AQI summaries (2000 to 2025) and daily county AQI (2016 to 2025); CDC Environmental Public Health Tracking Network modeled PM2.5 and ozone (2001 to 2022). Updated November 8, 2026.