Air Quality in Concord, California — Live

Live readings from PurpleAir sensors across Concord — with free alerts the moment the air turns.

Live Concord AQI from nearby PurpleAir sensors loads when this page opens in a browser, along with a live sensor map covering Concord and Pleasant Hill, Walnut Creek, Martinez, Clayton.

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.

Canairy watches the sensors around your home, your kids' school, and everywhere else you care about, and tells you in plain English when the air changes enough to matter.

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

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.

What is the air quality in Concord right now?

This page shows the current AQI for Concord, calculated from PurpleAir sensors across the city and updated continuously. Concord is spread out between the Diablo foothills and the flats toward Pacheco and Clyde, and on a still night those can read differently — wood smoke pools in the low ground. The map below shows every live sensor so you can pick the one closest to your street.

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 AQI level is unhealthy?

Under the US EPA scale, AQI 0–50 is Good and 51–100 is Moderate. From 101 the air is Unhealthy for Sensitive Groups — kids, older adults, and people with asthma or heart conditions — and above 150 it's Unhealthy for everyone. Canairy translates these numbers into a plain-English verdict, like whether to close the windows or move a workout indoors.

Is Canairy free?

Yes. The Canairy app is free to download and includes live air quality for all your saved places, plain-English verdicts, and free push alerts when the air crosses your threshold. A paid plan adds extras like SMS text alerts.

Get Canairy free on Google Play.