SCV’s Summer of Smog

Katharine Lotze/The Signal


The long hot summer of 2017 is now Santa Clarita Valley’s long hot summer of smog as air monitoring officials record more days yielding air that exceeds federal health standards than not.

In July, 20 days out of 31 were found to have air that exceeded federal health standards, a spokesman for the South Coast Air Quality Management District said Wednesday.

In June, almost half the days that month were also found to have air quality diminished to the point of being deemed unsafe to breathe by federal standards, SCAQM spokesman Sam Atwood said.

“The pollution we’re talking about is at the ozone ground level,” he told The Signal Wednesday.

“The ozone at this level can damage and kill lung cells,” he said. “It increases hospital admissions and hospital visits.”

“We have seen an increase in pollution specifically this summer and last summer,” he said.

Comparing air quality in Los Angeles County from July last year to July this year, the air-monitoring experts reported 87 days of “unhealthy” air quality across the county.

Air quality measured July 2015 to July 2016 was found to be “unhealthy” on 84 days, Atwood said, and the air monitored 2014 to 2015 revealed 61 such days.

A number of factors contribute to smog levels but the strongest of those factors this summer has been the number of days SCV experienced triple digit heat.


In a nutshell, extreme heat cooks the ozone pollutants trapped under a “lid” of heat inversion created by a high pressure system.

“Heat is a factor,” Atwood said. “It will speed up the reaction or formation of ozone in the atmosphere.”

On days when the SCAQM data exceeds federal health standards, officials with the Los Angeles County Department of Public Health issue health advisories.

This past week, two dozen other days this summer, smog in the Santa Clarita Valley has prompted county public health officials to issue an air quality advisory.

Officials with the Los Angeles County Department of Public Health issued an air quality advisory Monday urging those with respiratory conditions to limit their time outside.

The advisory was called due to poor air quality deemed unhealthy for “sensitive individuals in Santa Clarita Valley” and in the East San Gabriel Valley.

Similar warnings were issued on June 5, June 24 and Aug. 4.

According to the South Coast Air Quality Management District, air quality was considered unhealthy for sensitive individuals in the Santa Clarita Valley on those days.

Los Angeles County Interim Health Officer, Jeffrey Gunzenhauser, MD, advised people living or working in the Santa Clarita Valley area with heart disease, asthma or other respiratory diseases to minimize outdoor activities.

Schools with children who have sensitive conditions, including heart disease, asthma, and other chronic respiratory diseases, should not participate in outdoor physical activity and should stay indoors as much as possible.

Air quality officials, however, caution against SCV residents fearing that the “sky is falling” as the sky gets darker with smog.

“This summer and last summer we had an above average number of unhealthy days – all weather related and specifically due to high temperatures and a strong inversion layer,” Atwood said.

“The weather is the dominant factor in smog produced,” he said. “However, because of the many programs and controls in place emissions are reduced.”

Atwood was referring to programs such as mandatory smog checks required in renewing motor vehicle licenses.

“The emissions decrease every year,” he said.

“We have more than 11 million vehicles in the (Los Angeles) basin but the newer vehicles undergo tougher standards now,” he said. “As older vehicles are replaced with newer ones, emissions are going down each year.”

Atwood adds: “We still have a long way to go, however.”

The Department of Public Health issues warnings about poor air quality as part of its mandate to protect and improve the health of more than 10 million residents of Los Angeles County.

Through a variety of programs, community partnerships and services, public health officials oversee environmental health, disease control, and community and family health.

Nationally accredited by the Public Health Accreditation Board, the Los Angeles County Department of Public Health comprises nearly 4,000 employees and has an annual budget exceeding $900 million.

Anyone wanting to know more about the Los Angeles County Public Health, is urged to visit, and follow LA County Public Health on social media at,, and

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