Monitoring & Technical Services Division

Ambient Air Quality Section

58.14 Report

for

The Decommissioning ofPM10Sampling at the

Kearny Villa Rd. & Chula Vista Stations

February 16, 2018

Authors:

David N. Shina

Senior Chemist, Ambient Air Quality Section

Adam Canter

Associate Meteorologist, Meteorology and Modeling Section

Monitoring & Technical Services Division, Ambient Air Quality Section 10124 Old Grove Rd., San Diego CA 92131

San Diego APCD Formal Request to Decommission PM10 sampling at the Kearny Villa Rd. and Chula Vista Stations

Request:

The San Diego Air Pollution Control District (District) is requesting the decommissioning of the PM10 samplersat the Kearny Villa Road (KVR) and Chula Vista (CVA) stationsthat are designated to measure ambient levels of particulate air pollution.

Reason(s):

  1. The measured levels of PM10concentrations at these locations are less than 80% of the NAAQS.
  2. According to the 40 CFR Part 58, Appendix D, “Network Design Criteria for Ambient Air Quality Monitoring,” Section 4, “Pollutant-Specific Design Criteria for SLAMS Sites,” part 4.6 “Particulate Matter (PM10) Design Criteria,” the District is only required to operate the following PM10 samplers (See Table 1PM10 Minimum Monitoring Requirements-Summary).
  3. For KVR, the grounds surrounding the station are an open field. This adversely influences the true measured concentrations (the District cannot pave any area, due to proximity to vernal pools).
  4. For KVR, the EPA recommended decommissioning during the 2017 Technical Systems Audit, based on items 1-3.

Monitor/Station Decommissioning Requirements

  • Monitors are eligible based on 40 CFR 58.14 (c)(1)
  • No longer needed/measure concentrations well below the NAAQS - 40 CFR 58.14(c).

Other Information

Table 1 PM10 Minimum Monitoring Requirements - Summary

MSA / County / Population
Estimated from
2010 Census / Is the Design Value Site
Low/Medium/High Concentration? / Number of
PM10Samplers
Required / Number of PM10Samplers
Active / Number of PM10Samplers
Needed
(name) / (name) / (#) / (#) / (#) / (#)
San Diego / San Diego / 3.3
million / Low / 2 - 4 / 4 / None

At the time for the writing of this report, the District has four (4) active PM10 samplers located at:

  1. Donovan (the Design Value site)
  2. Lexington Elementary School (NCore)
  3. Chula Vista
  4. Kearny Villa Rd.

By late-2018/2019, two more stations, Escondido and Sherman Elementary School, should be active and they will have PM10 samplers, bringing the total to six (6) stations, including KVR and CVA. If the PM10 samplers from KVR and CVA are allowed to be decommissioned, the total will be at the EPA minimum of two (2) stations with PM10 samplers. Once the Escondido and Sherman Elementary School stations become active, the total will be the EPA maximum of four (4) stations. Please note: the District will continue to operate the KVR and CVA PM10 samplers until EPA makes an official ruling.

Calculation Information

An accounting of the last five (5) years of data for the monitors/samplers that are regulatory and can be compared to the NAAQS.

  • All data are from AQS
  • Student’s t-value for n-1 degrees of freedom at 90% confidence interval

(5 trials-1=4) at 90% confidence interval= 2.132

  • Probability of less than 10% of exceeding 80%

Average +{[(Student’s t-value for n-1 degrees of freedom at 90% confidence interval)*Standard deviation)] ÷ (Sqrt (n))}

Sampler Decommission Applicability for KVR

An accounting of the last five (5) years of data for the samplers that are regulatory and can be compared to the NAAQS are in Tables 3a-3b.

Sampler Decommission Applicability for CVA

An accounting of the last five (5) years of data for the samplers that are regulatory and can be compared to the NAAQS are in Tables 4a-4b.