Newmarket Real-Time AQI Tracker
What's Actually In Newmarket Air Today?
What High AQI Means for Your Lungs in Newmarket
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?
Live Air Quality Index AQI Map Newmarket, ON Today
TL;DR
Newmarket's official air quality is reported on Canada's Air Quality Health Index (AQHI), a 1 to 10+ health-risk scale, while most apps show a U.S.-style AQI from 0 to 500. Unlike the rest of York Region, Newmarket has a provincial monitoring station in town. Check the live map above for today's reading, then use the action guide below.
Key Takeaways
Newmarket's air is measured in town. Air Quality Ontario station 48006 on Eagle Street West records ozone, fine particulate (PM2.5), and nitrogen dioxide hourly.
It is the only provincial AQHI station in York Region. The nearest others are Toronto North, 29.4 km south, and Barrie, 41.4 km north-northwest.
Canada uses the AQHI, not the AQI. On the AQHI, 1 to 3 is low risk and anything above 10 is very high risk.
Wildfire smoke drives the worst days. In July 2026, northwestern Ontario smoke brought air quality warnings to Newmarket.
Indoor air is the part you control. Health Canada recommends HVAC filters rated MERV 13 or higher during wildfire smoke events.
What Is The Air Quality In Newmarket Today?
Newmarket's current air quality appears in the live map at the top of this page. The official Canadian figure is the AQHI, from 1 to 10+. A reading of 1 to 3 is low risk. At 4 to 6, people with heart or breathing conditions may want to ease off strenuous outdoor activity. A reading of 7 to 10 is high risk, and above 10 is very high risk.
Air Quality Ontario calculates Newmarket's AQHI hourly from the local station, and Environment and Climate Change Canada (ECCC) adds the forecast. For the official reading, open Air Quality Ontario's current AQHI for Newmarket or ECCC's Newmarket AQHI page. Readings change through the day, so check again before afternoon plans.
Newmarket Has A Local Air Monitoring Station, And Most Of York Region Does Not
Newmarket is one of the few communities north of Toronto where the AQHI is measured locally. Air Quality Ontario station 48006 stands at Eagle Street West and McCaffrey Road, west of Yonge Street. It measures exactly the three pollutants the AQHI is built from: ozone, PM2.5, and nitrogen dioxide.
Filterbuy Canada went through Ontario's 38 provincial AQHI stations one by one, expecting a monitor in Markham or Vaughan. There isn't one. Newmarket's is the only station inside York Region. Running the ministry's published coordinates through the haversine formula, we found the nearest alternatives: Toronto North, 29.4 km south, and Barrie, 41.4 km north-northwest. Toronto North and Barrie are 69.5 km apart, with Newmarket between them.
Table 1. Provincial AQHI Stations Nearest Newmarket
Straight-line (haversine) distances from Air Quality Ontario station coordinates.
Then we checked where York Region Public Health sends people. The "Check the Current Air Quality" button on its Outdoor Air Quality page opens ECCC's Newmarket reading. It is the number the health unit points residents to first.
Filterbuy also checked where popular air quality apps get their Newmarket figure. Several name the provincial Newmarket station as their source. So a gap between an app and the government site here usually reflects the scale each one uses.
"On our Richmond Hill, Markham, and Vaughan pages, the local number always came from a station in another town. Here, the monitor is down the road, so the reading is one you can act on."
Filterbuy Canada Indoor Air Quality Team
What The Newmarket Reading Does Not Cover
A local station still has five blind spots:
Pollen and mould spores. Neither is part of the AQHI, so a low-risk day can still be a hard allergy day.
Carbon monoxide and sulphur dioxide. The Newmarket station does not measure them; Toronto North does.
Your street. It is one monitor, west of Yonge. Air near Highway 404 can differ.
Your living room. Cooking smoke and pet dander never reach the station.
Final checks. Hourly readings are automatically polled and not yet verified.
AQHI Or AQI? Why Newmarket Can Show Two Different Numbers
Newmarket can show two numbers because Canada and the United States measure different things. The U.S. AQI converts the single worst pollutant into a value from 0 to 500. Canada's AQHI combines ozone, nitrogen dioxide, and PM2.5 into one health-risk score from 1 to 10+. The scales are not directly convertible, but their action thresholds line up for everyday decisions.
Table 2. AQHI Risk Categories And Approximate U.S. AQI Ranges
Approximate alignment for orientation only; not an official conversion. AQHI categories: ECCC.
How To Read Newmarket's Station Like A Local
Building this Filterbuy Canada page around the station's public data, three habits stood out for smoke season.
Watch hourly PM2.5 when smoke moves in. The AQHI blends three pollutants using three-hour averages, so during a fast-moving plume it can lag behind what you are breathing. Air Quality Ontario publishes the hourly PM2.5 chart for the Newmarket station. On a smoky day, that line moves first. One thing the Filterbuy team noticed: the chart can open on an older date range, so check the dates above the graph.
Compare Newmarket with Barrie and Toronto North. Check Barrie's live air quality page alongside this one. The three stations sit roughly on a north-south line. A rise at Barrie first suggests air arriving from the north; a rise at Toronto North first suggests it is moving up from the city.
Sign up for warnings. Air Quality Ontario's free air quality alert sign-up emails you when a warning is issued. When Filterbuy tested the form, the region that covers Newmarket was York - Durham. ECCC warnings for the Newmarket - Georgina - Northern York Region area are yellow at a forecast AQHI of 7 to 10 and orange at 10+. Recorded readings: 1-800-387-7768.
What Drives Newmarket's Air Quality Through The Year
Summer (June to September). Wildfire smoke is the biggest swing factor. In mid-July 2026, smoke from fires in northwestern Ontario brought ECCC air quality warnings to Newmarket and northern York Region, including an orange warning on 17 July, when the hourly forecast for Newmarket reached 10. Follow active fires and plumes on the live Ontario wildfire and smoke map from Filterbuy Canada. Hot, still days also build ground-level ozone.
Autumn and winter (October to April). Furnaces run six to eight months a year with windows shut, so dust, pet dander, cooking odours, and mould spores recirculate.
Year-round. Traffic on Highway 404, Yonge Street, and Davis Drive adds nitrogen dioxide and fine particulate near the roads.
What To Do At Each AQHI Level
Follow any ECCC warning or York Region Public Health advice first. Then use these home steps.
AQHI 1 to 3 (low). Enjoy your usual outdoor activities. Indoors, keep the furnace filter on its normal schedule.
AQHI 4 to 6 (moderate). People at higher risk should consider reducing strenuous activity if they have symptoms. Indoors, get ready: a MERV 13 in the furnace and a spare on hand before smoke arrives.
AQHI 7 to 10 (high). People at higher risk should reduce or reschedule strenuous activity. Indoors, switch to a MERV 13 filter, set the thermostat fan to On, run a portable HEPA air cleaner in each occupied room (bedrooms first), and close up the house. Skip candles, frying, and smoking while smoke is in.
AQHI above 10 (very high). Official guidance comes first. People at higher risk should avoid strenuous activity; everyone else should reduce it. Keep the same indoor steps and check the filter often. Filtration is one layer of the response.
Outdoor guidance follows ECCC AQHI health messages; indoor steps draw on Health Canada and York Region Public Health. The HEPA-in-each-room step goes beyond official guidance. Not medical advice.
People with heart or lung conditions should follow their health care provider's advice. For health questions, York Region Public Health directs residents to 811; seek medical attention for serious symptoms.
How To Protect Indoor Air In A Newmarket Home
A furnace filter is the only whole-home air cleaner most Newmarket houses already have. Health Canada's guidance for cleaner air spaces recommends HVAC filters rated MERV 13 or higher during wildfire smoke. During smoke, EPA advises replacing it sooner, when it looks dark brown or black.
Most furnaces can take a MERV 13 without equipment problems if the filter is replaced often, the EPA guide to air cleaners notes. Check the fit like you check the size.
No ducted system? In apartments and homes without central HVAC, a portable HEPA air cleaner is the main defence. Size it to the room: a smoke CADR of at least two-thirds of the floor area, so about 200 for a 300 sq ft bedroom. Avoid cleaners that produce ozone.
Filterbuy Canada's colour-coded MERV system makes the choice quick, and our guide to MERV ratings explains the scale in more detail.
MERV 8 (Standard). Captures 90% of Airborne Particles. For everyday dust and pollen.
MERV 11 (Superior). Captures 95% of Airborne Particles. For pet dander, mould spores, and allergy season.
MERV 13 (Optimal). Captures 98% of Airborne Particles. The tier Filterbuy recommends for smoke.
Odour Eliminator (carbon-infused). Captures 95% of Airborne Particles. For lingering cooking and pet odours.
Capture rates per Filterbuy product specifications.
Filterbuy Canada's take: with heating from October to April and smoke from June to September, a Newmarket filter rarely gets a break. We built a simple filter calendar around local dates:
Canadian Thanksgiving weekend. Fresh filter as the furnace starts.
Mid-January. Mid-winter check; replace if the media looks dark.
Victoria Day weekend. Spring change ahead of pollen season.
Early June. MERV 13 in, plus one spare on the shelf, before smoke season.
A Filterbuy Canada subscription timed that way keeps a fresh filter on hand, and you can edit, skip, or cancel anytime. Filterbuy Canada carries over 600 sizes, including custom air filters, with free shipping to Canada and no minimum purchase.
Essential Resources For Newmarket Air Quality
Supporting Statistics
Wildfire smoke drives emergency visits.
17% more asthma emergency visits on 19 smoke days in 2023.
Biggest jumps after back-to-back smoke days.
Source: CDC, Morbidity and Mortality Weekly Report, August 2023
A furnace filter only works while the fan runs.
Heating and cooling systems usually run less than 25% of the time in season.
A 300 sq ft room needs a portable cleaner CADR of at least 195.
No air cleaner or filter removes every pollutant in a home.
Filter plus fan beats closed windows.
Windows closed only: 55% to 60% of outdoor PM2.5 still gets in.
Low-efficiency filter, fan on: about 24% less indoor PM2.5.
High-efficiency filter, fan on: about 50% less.
Frequently Asked Questions
Is the air quality bad in Newmarket today?
Check the live map at the top of this page or the official AQHI from Air Quality Ontario. An AQHI of 1 to 3 is low risk, 4 to 6 moderate, 7 to 10 high, and above 10 very high.
What is the PM2.5 level in Newmarket today?
The Newmarket station reports PM2.5 hourly. Air Quality Ontario's hourly chart shows the current value and trend, the fastest way to spot arriving smoke.
Is there a live air quality map for Newmarket?
Yes. The live map at the top of this Filterbuy.ca page shows current conditions; ECCC's FireWork maps forecast smoke.
How often should I change my furnace filter in Newmarket?
Every three months, says York Region Public Health. During smoke, replace it once it looks dark brown or black.
Glossary
AQHI (Air Quality Health Index): Canada's official 1 to 10+ health-risk scale.
AQI (Air Quality Index): The U.S. 0 to 500 scale.
PM2.5: Fine particles 2.5 micrometres or smaller; the main pollutant in wildfire smoke.
Ozone (O3): A gas that forms near the ground on hot, sunny days.
Nitrogen dioxide (NO2): A gas produced mainly by vehicle exhaust.
Air Quality Ontario: Ontario's provincial air monitoring network, which operates the Newmarket station.
ECCC (Environment and Climate Change Canada): The federal department that forecasts the AQHI and issues warnings.
York Region Public Health: The public health unit serving Newmarket.
Air quality warning: A colour-coded ECCC alert: yellow for a forecast AQHI of 7 to 10, orange for 10+.
FireWork: ECCC's wildfire smoke forecast maps.
MERV (Minimum Efficiency Reporting Value): A filter efficiency rating; higher numbers capture smaller particles.
Haversine formula: A way to measure straight-line distance across the globe.
HEPA: High-efficiency filtration used in portable air cleaners, not furnaces.
CADR (clean air delivery rate): How much filtered air a portable cleaner delivers.