Editor’s note: This letter was sent to the editor by Emily Brandt in response to her question below to the San Joaquin Valley Air Pollution Control District.
I am looking at the areas that are covered in the up-to-date pollution levels and I do not see southwest Fresno covered. I wonder why as this area is clearly the most seriously impacted by industry (animal rendering plant, poultry and agricultural chemicals). It would seem to be the most in need of close monitoring to protect the residents who live there. Please explain this with proper documentation.
We received your email and thank you for your questions. First, let me start off by thanking you for utilizing RAAN, it’s a great tool to utilize when making decisions on whether current air conditions are acceptable for outdoor activities.
With regard to where a monitor is placed, it’s a complex process with criteria dictated by the EPA to ensure monitoring data that is representative of the most people possible. Depending on the location, monitors may be placed close together or farther apart. You can learn more about the District’s air monitoring stations and the requirements set forth by the EPA by reviewing our most recent monitoring plan located here: https://www.valleyair.org/aqinfo/Docs/2016-Air- Monitoring-Network-Plan.pdf
In the case of Southwest Fresno, ozone data is recovered by the Southeast Fresno site and PM 2.5 by the Central Fresno site. The most representative, nearest air monitoring site was assigned to Southwest Fresno using complex modeling and calculations. You are correct, there are a lot of facilities in Southwest Fresno, but the way the wind blows, that area is better served to have its monitor downwind to truly capture accurate pollution data.
Generally, the area west of Highway 99 has better air quality than east of the highway. In Fresno County, as you travel west and get closer to Kerman, the air quality improves significantly. (By “significantly,” I mean that there can be a difference in the category of pollution expected. For example, if the highest reading in the county is forecast as “unhealthy for sensitive groups,” the actual pollution level west of 99 can be in the “moderate” range, etc.). But do note, that areas in close proximity—within 1/2 mile—to highways pose their own increased risks due to diesel exhaust.
According to the air monitoring siting regulations, there are sufficient monitoring sites in Fresno County at this time. But as in any case in any county, if you notice localized conditions, such as fire or disturbed dust event, please take precautions to protect yourself. Finally, with the recent passage of Assembly Bill 617, we can expect additional community monitoring to be coming in the next several months.
Thank you for your inquiry. If you have further questions, please do not hesitate.
Cassandra Melching Outreach & Communications Representative San Joaquin Valley Air Pollution Control District 1990 E. Gettysburg Ave., Fresno, CA 93726 cassandra.melching@valleyair. org Phone: 559-230-5901