Air Quality in Concord, California — Live
Live readings from PurpleAir sensors across Concord — with free alerts the moment the air turns.
AQI 18 from 5 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Concord, California is AQI 18 — Good and falling — with PM2.5 at 3.2 µg/m³, the median of 5 live PurpleAir sensors reading 5 to 30. Canairy's verdict: Breathe easy.
For scale, that PM2.5 reading is below the World Health Organization's 24-hour guideline of 15 µg/m³. The WHO figure is a daily average and this is a live reading, so read it as a sense of magnitude rather than a formal exceedance — a brief spike and a bad day are not the same thing. More on the WHO guidelines
Pollen today in Concord: weeds pollen is the strongest of the three at a moderate level, from Google's pollen forecast. Canairy shows the tree, grass and weed forecast beside the air reading on every plan, including the free one.
Free to download · Live data from PurpleAir & public monitors
Live PurpleAir sensor map for Concord and Pleasant Hill, Walnut Creek, Martinez, Clayton. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Concord
The sensors Canairy reads in Concord agree right now — all 5 sit in the Good band, a 25-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 1.0 mi SSW | 30 | Good |
| 3.4 mi W | 8 | Good |
| 4.1 mi W | 18 | Good |
| 6.2 mi SSW | 19 | Good |
| 6.3 mi SE | 5 | Good |
Concord sits inland in central Contra Costa County, behind the hills at the foot of Mount Diablo, and that inland position cuts both ways. Summers are hot — average July highs run near 88°F, and the city hit 113°F on 1 September 2017 — and heat is what makes ozone. Winters bring cold, still nights when wood smoke settles into the valley instead of blowing out of it. And a few miles northwest, along the Carquinez Strait, is the refinery corridor, with Martinez Refining Company essentially next door. Most days none of that shows up and the air is simply Good; the point of watching is the days it doesn't.
What Canairy does for Concord
A clear verdict
Not just a number — a plain-English call for Concord: open the windows, or keep them shut.
Smoke alerts
A push or text the moment the air crosses your threshold — and again when it clears.
A heads-up before it's bad
Trend alerts catch the air turning, so you can close up the house before the smoke settles in.
Every place you care about
Home, work, the kids' school — across Concord or across the country, on one screen.
The refineries are just over the hill
The one that matters most to Concord is Martinez Refining Company, immediately northwest of the city. On 24 and 25 November 2022 it released up to 24 tons of metal-laden spent catalyst over the surrounding community, and did not activate the Community Warning System or notify Contra Costa Health as the law requires. The county commissioned a root cause analysis and a community risk assessment with soil sampling; the contractor found metals in the soil samples within the range typically seen across California and not in the ratios found in the catalyst dust. The failure to warn anyone is what drove years of county oversight afterwards.
On 1 February 2025 an explosion and fire at the same refinery injured six workers. Contra Costa Health sent a shelter-in-place alert at 4:49pm for neighbourhoods near the plant, covering parts of Martinez, Pacheco and Clyde — Clyde sits just north of Concord — and lifted it around 9pm, keeping a public health advisory in place for people with respiratory sensitivities until the fire was out. Smaller Level 1 community awareness messages for flaring come through more routinely. The refinery publishes fenceline air measurements at fenceline.org/martinez. Further west, Phillips 66's Rodeo plant has converted to renewable fuels and now makes about 27,000 barrels a day of renewable diesel.
Can I use the fireplace tonight?
On cold, still winter nights, wood smoke is the single largest source of air pollution in the Bay Area — the Air District puts it at roughly a third of fine particulate pollution. When PM2.5 is forecast above the Air District's Wood Burning Rule threshold, a winter Spare the Air alert is issued and burning wood, manufactured logs or any other solid fuel becomes illegal for that day across all nine Bay Area counties, indoors and outdoors alike. Natural gas, propane and electric heat are fine.
The rule got stricter on 1 October 2025, when the forecast level that triggers an alert dropped from 35 to 25 micrograms per cubic metre of PM2.5 — so alerts now fire on more nights than they used to. A first violation can be cleared by taking a wood smoke awareness course, or a $100 ticket if you would rather not; a second is $500, rising from there. An open-hearth fireplace no longer qualifies for the sole-source-of-heat exemption. Complaints go to 1-877-4NO-BURN.
Hot inland summers, and a mountain that burns
The Air District describes Contra Costa as split down the middle. In the west, close to the bay, temperatures stay moderate and ozone and PM2.5 infrequently exceed health standards. In the east, summer afternoons frequently approach triple digits and ozone goes over the line, while winter PM2.5 drifting in from the Central Valley adds to local wood smoke. Concord sits inland of the hills, closer to that eastern pattern than the western one, which is why a hot August afternoon here is a different proposition than the same afternoon in Richmond.
Mount Diablo burns too. In August 2020 the Deer Zone fires — the Contra Costa arm of the SCU Lightning Complex — started in dry lightning and ran east from the northeastern face of the mountain through Morgan Territory and Round Valley, reaching 3,104 acres and forcing about 150 homes to evacuate along Marsh Creek Road and Morgan Territory Road. That was the fire you could see. The smoke that actually wrecked Concord's air that month came from the whole ring of Northern California fires burning at once, with a Spare the Air alert running through 23 August.
Concord air quality FAQ
What is the air quality in Concord right now?
As of September 10, 2026 at 5:09 AM PDT, the air quality in Concord, California is AQI 18 — Good — with PM2.5 at 3.2 µg/m³, the median of 5 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why is there smoke in Concord today?
In late summer and autumn it is usually drift from a fire elsewhere in Northern California rather than anything local — August 2020 was the extreme case, with a Spare the Air alert extended through the 23rd while hundreds of lightning fires burned around the Bay Area. Closer to home, the Diablo Range east of the mountain has burned before, as it did in the Deer Zone fires that August. In winter, smoke on a cold still evening is far more likely to be fireplaces and wood stoves in the valley than anything burning outdoors. And a sharp chemical smell rather than woodsmoke is worth checking against Contra Costa Health's alerts for the Martinez refinery.
Can I smell the refinery from Concord?
It happens. Contra Costa Health has repeatedly investigated complaints of strong odours in the greater Martinez area during flaring events at Martinez Refining Company, and its hazmat team does air monitoring in response. When something more serious occurs, the county's Community Warning System is supposed to issue an alert — which is precisely what did not happen in the November 2022 catalyst release. Worth being clear: neighbourhood sensors measure fine particles, so they will pick up smoke and haze but not the specific gases behind a refinery odour. For those, the county's alerts and the refinery's published fenceline monitoring are the right sources.
Is Concord's air actually bad?
Mostly, no. Across its whole network in 2023, the Air District recorded four days over the national 8-hour ozone standard and three days over the national 24-hour PM2.5 standard for the entire Bay Area. The Bay Area is still classified nonattainment for both pollutants, so there is real work left, but the honest picture for Concord is a lot of Good days punctuated by a handful that matter — a hot summer afternoon, a cold winter night, a smoke episode, or an incident up the road. Those are the days worth an alert.
What the AQI numbers mean
| AQI | Category | What it means for you |
|---|---|---|
| 0–50 | Good | Open the windows. Great for outdoor activity. |
| 51–100 | Moderate | Sensitive groups may want to take it slower outside. |
| 101–150 | Unhealthy for Sensitive Groups | Kids, elderly, and respiratory conditions stay closer to home. |
| 151–200 | Unhealthy | Skip outdoor exercise. Close windows. |
| 201–300 | Very Unhealthy | Limit time outside. N95 if you must go. |
| 301+ | Hazardous | Health emergency. Stay inside, run filtration if you have it. |
Canairy lets you tighten these bands if you’re more sensitive than the EPA default, so an alert can fire before the official category changes. How to read the Air Quality Index
Where these readings come from
The AQI at the top of this page is the median of the 5 curated PurpleAir sensors Canairy tracks in and around Concord, with outliers set aside so that one sensor brought indoors — or parked beside a barbecue — cannot set the number for a whole city. Every sensor behind it is listed above with its distance and bearing from the city center. There is no black box here.
In the app, a place you save resolves the same way first. When no neighborhood sensor is reporting it falls back to the nearest EPA AirNow monitor, and anything modeled rather than measured is labelled a regional estimate rather than passed off as a sensor reading. How low-cost sensors compare to regulatory monitors
About Canairy
Canairy is free to download. The free plan covers one saved place with live readings, a plain-English verdict, and push alerts when the air crosses a threshold you choose. Paid plans add more places, faster refreshes, and SMS alerts. It is built by two parents in Sonoma County, California, who got tired of guessing whether it was safe to send the kids outside. Why we built it
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Air quality near Concord
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