For months at a time, Fresno's air is as polluted as a firework show, according to a Fresnoland analysis. Photo credit: Eric Thayer/Reuters

What's at stake?

South Fresno, the part of Fresno earmarked for the next big box warehouse boom, has poor air quality for months at a time.

How bad? Like the evening of the Fourth of July.

Each year, under the fog of burnt fireworks, the Fourth of July triggers the worst day for air pollution across much of the United States.

Last year, the San Joaquin Valley Air Pollution Control District said festive fireworks turned Fresno into a “war zone.”

On the night of the Fourth of July in Fresno last week, air pollution climbed to levels far too unhealthy to host a baseball practice, play recess, or go for a walk.

But in southcentral Fresno, one of the most polluted neighborhoods in the state, Independence Day is just another toxic day.

For months at a time, central Fresno faces air quality as poor as the dirtiest hours of the Fourth of July, a Fresnoland analysis shows.

“(The) fireworks simulate, for a single night, what we are forced to breathe for months on end in the Valley during the wintertime,” said Kevin Hamilton, executive director of the Central California Asthma Collaborative.

Fresnoland compared long-term air pollution data from the area around Roosevelt High School to the pollution sensors in Fresno reporting the dirtiest air on the Fourth of July, which was acquired from the Central California Asthma Collaborative.

Months-long stretches of dirty air at Roosevelt High School in 2020, 2021, and 2022 rival the pollution figures taken during the most recent Fourth of July evening. The average Air Quality Index at Roosevelt, measured over the span of months, was nearly the same as the peak hours of firework pollution in Clovis, from 8 p.m. to midnight.

And before heavy winter rains cleaned up the dirty air earlier this year, 2023 was on track to have similar problems too.

In south Fresno, average air quality rivals other areas’ worst night.

On the morning of July 4, air quality sensors across Fresno registered an Air Quality Index of 20. Below 50 is considered “healthy;” above 100 is “unhealthy for sensitive groups,” and children and older adults are advised to avoid outdoor exercise; above 150 is “unhealthy,” and high school sports are typically canceled; between 200 and 300 is “very unhealthy.” Anything above 300 is considered “hazardous.”

As the sun went down that night, pollution levels exploded well above 150. Between 8 p.m. and midnight on July 4, the area’s top firework shows at the suburban fringes of Fresno caused air sensors across the city to spike as high as around 500.

That’s over five times higher than the World Health Organization’s pollution limit.

Across the Fresno area’s 57 air pollution sensors, the average air pollution peaked around 10 p.m. at an AQI of 120, considered unhealthy for sensitive groups.

The highest pollution read-outs of the night came from the suburban fringe in Clovis, at the corner of Barstow and Leonard, near the new Bonadelle Neighborhoods subdivision.

Pollution in that neighborhood peaked at 490.

The second highest? Another suburban fringe, in southwest Fresno. Air pollution readings at McKinley and Polk hovered above unhealthy levels between 8 and 10 p.m., and stayed elevated through the night.

But at Roosevelt High School in the winter of 2021-2022, the school’s average AQI for the whole month of January was 122 – higher than Fresno’s dirtiest hour on the Fourth and nearly identical to the two sensors on the evening of the Fourth of July. A similar result was found at Edison High School.

Roosevelt’s peak AQI during the winter months over the last few years was also similar: 215 in 2020, 374 in 2021, and 359 in 2022. Before the rains this winter, one southcentral Fresno air quality sensor registered an AQI that rivaled a firework show: 451.

Much of the valley’s unhealthy winter air is caused by heavy-duty diesel trucks, ammonia from mega-dairies, and residential wood smoke, according to the Valley Air District.

Ivanka Saunders, a regional policy manager at Leadership Counsel, said the data confirms what communities in south central Fresno have been saying for years about racist land use patterns in the area.

“This data shows that the toll of highways and industrial parks on south Fresno is already massive,” she said. “The neighborhoods singled out by the city and county for the next big-box warehouse park already have air that is unsafe to breathe for months at a time.

“It confirms that the city and county are hyper-focused on economic growth, no matter the sky-high costs to existing communities.”

Air district spokesperson Jaime Holt said it was fortunate that the high firework pollution on the Fourth cleared out, regardless of the weather patterns. 

“Historically, air quality levels drop significantly once the fireworks cease, around midnight,” she said. “We have not seen elevated levels linger much into July 5th, regardless of the weather pattern in place.”

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Gregory Weaver is a staff writer for Fresnoland who covers the environment, air quality, and development.

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