Allentown Real-Time AQI Tracker
Get Alerts For Unhealthy AQI In Your Area
When air quality in your area reaches unhealthy levels, we'll send you a quick alert, along with expert tips on how to reduce your exposure.
What's Actually In Allentown Air Today?
What High AQI Means for Your Lungs in Allentown
How to Read AQI
The Air Quality Index (AQI) measures how polluted the air is and how it may affect your health.
0–50 (Good): Air quality is satisfactory.
51–100 (Moderate): Acceptable, but some pollutants may pose minor concerns.
101–150 (Unhealthy for Sensitive Groups)
151–200 (Unhealthy)
201–300 (Very Unhealthy)
301+ (Hazardous)
Moderate
Still okay for most, but if you have asthma or allergies, take it easy and avoid long outdoor workouts.
Shop MERV 11 filters→What's the Right Filter for Your AQI Level?
Check Today's Live Real Time Air Quality Index AQI Map in Allentown, PA Now
TL;DR
The live map above shows Allentown's Air Quality Index (AQI) right now and the pollutant behind it. Most days stay under 100, but summer ozone and wildfire smoke push the Lehigh Valley into unhealthy air a few times a year. At Filterbuy, AQI 100 is our action line: MERV 13 in the HVAC, the thermostat fan set to On, a portable HEPA cleaner in each occupied room and the house closed up.
Key Takeaways
Summer ozone and PM2.5, the fine particles in smoke and exhaust, drive Allentown's AQI.
The American Lung Association's 2026 report gave the Allentown metro an F for short-term particle pollution and a C for ozone.
At AQI 100, Filterbuy recommends two separate layers: MERV 13 in the HVAC and a portable HEPA cleaner in each occupied room.
Reading the Live Allentown Air Quality Map
Each marker on the map above is a monitoring station, colored by EPA's AQI categories. Tap the one nearest you to see its reading and the pollutant driving it.
Official readings come from two Pennsylvania DEP stations, in East Allentown and Freemansburg. For street-level detail, the Filterbuy team also leans on Lehigh Valley Breathes, a county project that placed 40 PurpleAir sensors around the valley from 2023 to 2025.
What Each AQI Color Means for Your Day in Allentown
At orange, children, older adults and people with heart or lung disease should take it easier; at red, everyone should. Filterbuy acts at AQI 100, the top of Moderate: MERV 13 in the HVAC, the fan on, a portable HEPA cleaner in each occupied room and the house closed up. Match the map's color below or see the full Filterbuy AQI color chart.
| AQI Range | Category | In Allentown, Usually | What to Do |
|---|---|---|---|
| 0–50 | Good (green) | Clean air after a breezy front clears the valley | Normal routine; open the windows |
| 51–100 | Moderate (yellow) | Warm summer afternoons, calm winter mornings | Unusually sensitive people ease off; stage MERV 13 and spares |
| 101–150 | Unhealthy for Sensitive Groups (orange) | A summer ozone day or light smoke; a DEP Code Orange day | Sensitive groups limit hard exertion; MERV 13, fan On, HEPA in occupied rooms, house closed |
| 151–200 | Unhealthy (red) | Wildfire smoke or a strong ozone episode | Everyone cuts back; same steps, and inspect the filter more often |
| 201–300 | Very Unhealthy (purple) | Rare; smoke reached this range in June 2023 | Follow AirNow and local guidance first; keep a clean room running |
| 301–500 | Hazardous (maroon) | Emergency-level smoke | Official guidance first; filtration is one layer |
Categories follow EPA AirNow guidance. Filterbuy's action line starts at 100, the top of Moderate.
Why the Allentown Reading Can Lag What You Smell
Hourly readings use EPA's NowCast, a weighted average of recent hours, so fast-moving smoke can outrun the number by an hour. In 2024 Lehigh Valley Breathes data, a busy Allentown road south of American Parkway peaked near 54 micrograms per cubic meter (µg/m³) at morning rush, while a rural Portland site stayed at background levels.
If you smell smoke before the number moves, trust your nose and trace where the smoky smell is coming from.
Is Allentown's Air Safe to Breathe Right Now?
It depends on the live map color. At orange, sensitive groups and outdoor workers should cut back on strenuous activity; at red, everyone should. Smoke works its way indoors, so on smoky days keep the windows closed. Anyone with asthma, COPD or a heart condition should follow their clinician and official guidance.
Lehigh Valley Air Quality Forecasts and Action Days
Pennsylvania DEP issues daily Lehigh Valley air quality forecasts, linked from DEP's Air Program page and shown on AirNow. A Code Orange forecast triggers an Air Quality Action Day, as on July 30, 2025 and July 8, 2024 for ozone. Check official guidance first, then use the Filterbuy checklist for what to do at home during an air quality alert.
What Shapes Allentown's Air: Ozone, Particles and the Valley
Ozone in summer and PM2.5 all year drive most readings. The valley sits between Blue Mountain and South Mountain, with freight moving on I-78, US 22 and the Turnpike's Northeast Extension (I-476).
Ozone forms when sunlight reacts with emissions, and some drifts in from the Philadelphia and I-95 corridor, which is why DEP often pairs the two regions in alerts. More on ground-level ozone and indoor air.
Fine particles come largely from diesel trucks serving the valley's warehouses and from industry. A Lehigh Valley Breathes sensor near a Bath cement plant peaked near 78 µg/m³, about double the warehouse sites.
Weather sets the timing. Lehigh University researchers tied January 2023 PM2.5 peaks to low wind, and a January 24, 2020 Code Orange alert traced back to a strong temperature inversion.
Filterbuy pulled those patterns into a seasonal calendar:
| Season | What Drives the AQI | Our Advice |
|---|---|---|
| Winter (Dec–Feb) | Inversions trap PM2.5 on calm mornings | Check the map before early outdoor plans |
| Spring (Mar–May) | Tree and grass pollen; fewer alert days | Measure your filter size; stock a spare |
| Summer (Jun–Aug) | Code Orange ozone days and Canadian smoke risk | Move exercise to mornings; seal and filter on smoke days |
| Fall (Sep–Nov) | Ozone fades; inversions return | Swap the filter before the furnace starts |
Our summary of PA DEP alerts and Lehigh Valley Breathes findings.
How Air Quality Shifts Across Allentown Neighborhoods
Distance from traffic matters as much as distance from a monitor. Start with the nearest station, then consider what's nearby:
Center City (18101, 18102): dense blocks on busy bus routes.
East Side (18109): near US 22 and Lehigh Valley International Airport.
South Side (18103): closest to I-78 truck traffic.
West End (18104): more trees, fewer freight routes.
How the Lehigh Valley's Air Ranks Nationally
The American Lung Association's 2026 State of the Air report, based on 2022–2024 data, gave the Allentown-Bethlehem-East Stroudsburg metro an F for short-term particle pollution, 52nd worst nationally, and a C for ozone. Compare the Philadelphia air quality map, Pittsburgh air quality map and statewide Pennsylvania AQI map.
Wildfire Smoke Is Allentown's Biggest Short-Term Air Risk
Canadian wildfire smoke is the event most likely to push Allentown into the red or purple range. On June 7, 2023, Quebec smoke drove Lehigh Valley readings into the very unhealthy range under a Code Red alert.
When smoke is forecast, check AirNow and Pennsylvania DEP guidance first, then the Allentown wildfire smoke map. At AQI 100, Filterbuy's steps, in order:
MERV 13 in the HVAC, the whole-home layer.
Thermostat fan to On, so the system filters continuously instead of just while heating or cooling.
A portable HEPA cleaner in each occupied room, bedrooms first.
Close the house up: windows shut, system on recirculate, and no candles, frying, smoking or unsealed vacuuming.
EPA recommends a high-efficiency filter rated MERV 13 or higher in the central system during smoke events and notes that most furnaces and HVAC systems can accommodate MERV 13 when the filter is replaced often. The AQI 100 trigger and room-by-room HEPA advice are Filterbuy's own. At purple or maroon, official guidance comes first; filtration is one layer.
No Ductwork? Filtering the Air in Allentown's Older Homes
Many Allentown rowhouses and twins heat with radiators and cool with window units. No ducts, no filter slot. Here, portable HEPA cleaners are the primary defense, one per occupied room, bedrooms first. EPA's sizing rule is a smoke CADR of at least two-thirds of the room's square footage, about 200 for a 300-square-foot bedroom, and EPA advises against ozone-producing cleaners.
A DIY box fan with a MERV 13 filter is a fair stopgap, not a replacement for a certified cleaner. Use a fan made since 2012 with a UL or ETL logo, and never leave it running unattended. Filterbuy makes HVAC filters, and we'd still point a radiator-heated home to HEPA first.
Our Take: What Allentown's Air Data Means for Your Filter
Filterbuy has made air filters in the USA for over a decade and shipped millions of them. Our read on Allentown: its air problem is episodic, so the real work is getting ready before the bad days. At AQI 100 the four steps apply whatever the pollutant. On an ozone day, move outdoor time to the morning, since ozone breaks down indoors. On a smoke day, stay closed up around the clock.
"AQI 100 is the line I give people: MERV 13 in, fan on, and a HEPA cleaner in every room you are using. Then read the map pollutant-first. And sort out your filter size on a clear spring day, not the morning the sky turns hazy."
Michelle Wan, Brand Manager & Copywriter, Filterbuy
Which Filter Allentown's AQI Calls For
This is how Filterbuy matches MERV 8, MERV 11 and MERV 13 filters to Allentown's air:
| Air Condition | Best Fit | Why |
|---|---|---|
| Good days, pollen season | MERV 8 | Catches everyday dust and pollen |
| Allergies and pets | MERV 11 | Adds finer particles such as pet dander |
| Moderate, ahead of smoke season | MERV 13 staged, spares on hand | Get it in before smoke arrives |
| AQI 100 or higher | MERV 13, fan On, HEPA in occupied rooms | Filterbuy's action line: two separate layers |
| No central HVAC | Portable HEPA in each occupied room | Your primary layer, sized to the room |
Confirm size and fit before switching tiers.
Fitting MERV 13 is a normal check, like confirming your size. Filterbuy stocks 600+ sizes plus custom air filters, with fast and free 2-day delivery to most US states. During smoke, check the filter often and replace it when it looks dark brown or black, which can be well before the normal interval. Keep a spare; auto-delivery makes that easy. Compare MERV 13 vs. HEPA for wildfire smoke.
Supporting Statistics
F grade: Allentown metro, short-term particle pollution, 2026 report. Source: American Lung Association
About 90% indoors: some pollutants run 2–5x higher inside. Source: U.S. EPA
Two-thirds rule: smoke CADR at least two-thirds of a room's square footage. Source: U.S. EPA
Frequently Asked Questions
What is the air quality in Allentown today?
Today's Allentown AQI is on the live map above, updated hourly from Pennsylvania DEP stations. Green or yellow is fine for most people; at orange or higher, sensitive groups should limit hard outdoor activity.
Is the air quality bad in Allentown today?
Look at the map color. Above 100 is unhealthy for sensitive groups, and above 150 is unhealthy for everyone. Pennsylvania DEP declares a Lehigh Valley Action Day when it forecasts Code Orange.
How do I check Allentown PM2.5 today?
Tap a station on the live map for its PM2.5 reading. The Filterbuy guide to EPA air quality standards explains the federal limits.
Why is Allentown's air worse in summer?
Heat and sun turn emissions into ozone, some of it drifting in from Philadelphia, and recent Code Orange alerts came in June and July. See how air quality changes with the seasons.
What MERV rating do I need in Allentown?
MERV 13 is the tier Filterbuy recommends for wildfire smoke and for any day the AQI reaches 100. MERV 8 handles everyday dust, and MERV 11 suits allergies and pets. Homes without ducts should use portable HEPA cleaners. More in MERV ratings for high-AQI days.
Glossary
Air Quality Index (AQI): EPA's daily air quality scale. It runs from 0 to 500, and 100 matches the federal standard.
PM2.5: Fine particles 2.5 micrometers or smaller, found in smoke and diesel exhaust.
Air Quality Action Day: A DEP alert for forecast Code Orange days.
Temperature inversion: Warm air aloft trapping cooler, polluted air near the ground.
MERV: Minimum Efficiency Reporting Value, a 1 to 16 filter efficiency rating.
HEPA: Filtration used in portable air cleaners, never in a home HVAC slot.