The air was fair on June 26 but foul June 29. It was better July 20 but bad again July 23.
And as August begins it's still anyone's guess when Pittsburgh will have its first clean air day of summer.
This year, for the first time, a coalition of environmental groups launched what it calls the First Clean Air Day of Summer contest, a challenge to Pittsburghers to guess the first day between June 20 and Sept. 21 that will fit its self-written definition of a clean air day.
The contest is being promoted by the Breathe Project, a campaign created last fall by the Heinz Endowments to improve the Pittsburgh region's air quality. It is an initiative of organizations including Clean Water Action, Group Against Smog and Pollution (GASP), Citizens for Pennsylvania's Future, Clean Air Council, Clean Air Task and PA Voice.
"We thought it would be a fun way to engage people about what are good air quality days," said Julie St. John, a program organizer in Clean Water Action's Downtown office.
The summertime -- with its hot temperatures and muggy days -- each year brings warnings about bad air quality days. There's less acknowledgment, Ms. St. John said, of those days when the air quality is good.
The competition opened May 7, and since then about 700 guesses have been made, either by text message or over the group's website, about Pittsburgh's first clean air day. If multiple people guess the same, correct day, a drawing will be conducted to select the winner. First prize is a ride in a hot air balloon over the Pittsburgh region.
So far, there's been a lot of hot air, but no rides. Pittsburgh hasn't yet seen its first clean air day.
To be fair, however, the contest's standard for a clean air day is quite high.
But it is attainable, said John Graham, a senior scientist for the Clean Air Task Force based out of Columbus, Ohio.
"I expect it to happen," he said. His guess would be for a day in September.
When he made the criteria for the contest, he started by looking at air quality figures for the region over the past four years, specifically at Allegheny County ozone monitors in Lawrenceville and Harrison and fine particulate matter monitors in Lawrenceville and Liberty.
He decided that, for a day to be described as a clean air day, the average air quality for the four monitors should be as clean as the best 5 percent of days over the past four years.
Each day and for each monitor, contest organizers calculate a ratio between the day's pollution concentration and the best over the past four years, then average the ratio. An average ratio of one or lower counts as a clean air day.
"This is our own creation, but the motivation is because we do want to highlight that there are days when the air is clean, and not every day is bad," Mr. Graham said.
The point of the contest, said Jamin Bogi, education and outreach coordinator for GASP, is that the story of Pittsburgh's air quality isn't just bad news.
"You can't just be negative all the time," he said. "This is something positive to look forward to."
Indeed, in recent decades, Pittsburgh's air quality has improved substantially, largely because of pollution controls such as decreased emissions from power plants.
In March, Allegheny County officials announced that each of the county's eight monitoring sites met the annual air quality standard for fine particulate matter for the first time. Air quality in Allegheny County "is the best it has been since the industrial revolution began more than 100 years ago," said county air quality program manager Jim Thompson in a news release when the county celebrated the milestone.
"We do want to highlight that we've come a long way," Ms. St. John said.
Still, she said, with Pittsburgh still waiting for its first clean air day of summer, there's room to improve.
Enter the contest at firstcleanair.net or text "AIR" or "burgh" to 877877.