The San Joaquin Valley has the country’s worst air quality. Here’s what that means for Merced

by Rachel Livina l April 25, 2024

No place in the U.S. has worse particle pollution year round than San Joaquin Valley, according to a new American Lung Association report.

This year the report found the highest levels of hazardous air pollution in 25 years. Nationwide, 131 million people live in areas with unhealthy air, according to the most recent data used by the association from 2020-22.

In the Valley, the Bakersfield, Visalia and the Fresno region ranked in the top five for the most ozone pollution and in the top three for particle pollution. 

Merced County wasn’t out of the woods, receiving an “F” grade for both ozone and particle pollution air quality.  The report found the Merced area saw a total of 74 orange air quality days and 19 red days – orange represents air that is unhealthy for sensitive groups and red represents air that is unhealthy for all. 

Kern County, on the other hand, saw 331 orange days, and 74 red days in particle and ozone pollution combined. Bakersfield, the largest city in the county, saw the highest particle pollution year round as well as in the short term in the country. 

Levels of particle pollution, also known as soot, are often caused by wildfires, wood burning stoves or diesel engines. 

The San Joaquin Valley has been plagued by bad air for decades. Recent wildfires have also increased the number of bad air days in the region.  

Particle pollution is dangerous for people, according to health experts, because particles are sometimes too small to see and can enter the bloodstream. It can result in asthma attacks, heart attacks or even lung cancer. 

In Merced County, roughly 17,000 adults have asthma, compared to more than 4,000 children. Rates of asthma are much higher in Fresno and Kern counties.  

While the Los Angeles area ranked at the top for ozone pollution, Tulare, Kern, and Fresno counties ranked right behind. 

Ozone is an odorless, colorless gas. If inhaled, it can cause asthma attacks, shortness of breath or may shorten a person’s lifespan overtime. 

While some progress has been made to improve air quality, the American Lung Association report found 4 in 10 people in the U.S. live in areas with a failing grade on pollution.