Compliance · South Coast Air Quality Management District
SCAQMD Rule 1180: refinery fenceline and community air monitoring
Ambient air: refinery fenceline notification (South Coast AQMD, California)
South Coast Air Quality Management District Rule 1180 (most recently amended January 5, 2024) requires petroleum refineries and related facilities in the district to run real-time fenceline air monitoring under an approved Fenceline Air Monitoring Plan, publish the data on the web, and send a public notification when a pollutant exceeds its notification threshold. The thresholds, set in the rule's Table 1 and based on a 1-hour average unless noted, include SO₂ 75 ppb, H₂S 30 ppb, benzene 8 ppb, formaldehyde 44 ppb, ammonia 4,507 ppb, hydrogen fluoride 289 ppb, PM2.5 35 µg/m³ and PM10 50 µg/m³ (24-hour), and an information-based 730 ppb for total VOCs as non-methane hydrocarbons.
The standard
What Rule 1180 Is
The table also lists oxides of nitrogen (100 ppb), toluene (1,300 ppb), xylenes (5,000 ppb), 1,3-butadiene, acrolein, acetaldehyde, styrene, manganese, nickel, carbonyl sulfide, and hydrogen cyanide, and names further pollutants to be addressed without a numeric threshold.
Limit values
SCAQMD 1180 Limit Values
Every value South Coast Air Quality Management District publishes for the 9 parameters below, with its averaging period, as the standard states it.
Who it applies to
Who It Applies to
Petroleum refineries and specified related facilities in the South Coast district (Los Angeles, Orange, and parts of Riverside and San Bernardino counties). Each operator installs and runs the fenceline system described in its plan, and refineries also fund community air monitoring nearby.
Monitoring
How Monitoring Demonstrates Compliance
Rule 1180 is a continuous monitoring rule. Open-path and point instruments along the fence report in real time, and the notification program automatically compares their readings with the Table 1 thresholds, issuing follow-up notices while an exceedance lasts. The record that matters is the time series, its completeness, and the notifications sent. Wind direction alongside each reading is what lets the facility and the public tell a fenceline release from a passing regional plume.
Recommended
best match-
Industrial monitor for indoor and outdoor sites. Built-in sensors cover the essentials, and hot-swappable gas sensor cartridges and a differential-pressure option add more.
Built-inPM10PM2.5Gas 1
Aethair VOC (ppm PID)
VOC (Total)A 10.6 eV photoionization detector (PID) ionizes volatile organic compounds for direct ppm readings across a…
Also fits: Aethair VOC (ppb PID), Aethair MultiGas+, Aethair VOC (ppb PID, wide range)
Gas 2
Aethair H₂S
Hydrogen Sulfide (H₂S)Filtered four-electrode electrochemical sensing resolves H₂S to parts per billion, for wastewater, odor, oil…
MultiSense
Custom MultiSense built to order
Sulfur Dioxide (SO₂)Formaldehyde (CH₂O)Hydrogen Fluoride (HF)Built to order for the MultiSense socket with the Aethair SO₂ cartridge's sensor (0-100 ppm, 5 ppb resolution), the Aethair MultiSense cartridge's sensor (0-10 ppm, 10 ppb resolution), and the Aethair HF cartridge's sensor (0-10 ppm, 0.05 ppm resolution).
Expansion
Free: differential pressure
Also measures 11 more
Dew PointHeat IndexRelative HumidityIlluminance / LightParticle Count (by size)PM1Total PM / Mass Conc.Barometric PressureEquivalent Continuous Level (Leq)Sound Pressure Level (SPL)Air Temperature -
Thiamis connects 2 instruments
A gateway that connects the third-party instruments you choose to the Aethair Platform.
-
Defiant Technologies Specialty Air Analyzers
BTEX / speciated VOCDefiant Technologies FROG portable gas chromatograph (GC-PID).
-
Also measures 8 more
Methane (CH₄)Chlorine (Cl₂)Carbon Monoxide (CO)Carbon Dioxide (CO₂)Combustible (LEL)Nitric Oxide (NO)Nitrogen Dioxide (NO₂)Oxygen (O₂) -
Who measures each parameter
| Parameter | Aethair PRO |  Aethair IAQ | External |
|---|---|---|---|
| Sulfur Dioxide (SO₂) | MultiSense, SO₂ cartridges | — | 1 instrument via Thiamis |
| Hydrogen Sulfide (H₂S) | H₂S cartridge | — | 4 instruments via Thiamis |
| BTEX / speciated VOC | — | — | 1 instrument via Thiamis |
| Formaldehyde (CH₂O) | MultiSense cartridge | Built in | — |
| Ammonia (NH₃) | — | — | 1 instrument via Thiamis |
| Hydrogen Fluoride (HF) | HF cartridge | — | — |
| VOC (Total) | VOC (ppm PID), VOC (ppb PID) +2 cartridges | Built in | 2 instruments via Thiamis |
| PM2.5 | Built in | Built in | 3 instruments via Thiamis |
| PM10 | Built in | Built in | 3 instruments via Thiamis |
Devices
Devices That Cover SCAQMD 1180
How much of this standard one Aethair monitor covers, followed by the third-party instruments in the sensor catalog that measure its parameters. Each connects to Environet through a Thiamis gateway, which adds whatever the monitor leaves out.
Aethair monitors
Covers part of it (combine on one Thiamis)
RAE Gas Detectors4 of 9: H₂S, NH₃, SO₂, VOC
TSI DustTrak Particulate & Dust Monitors2 of 9: PM10, PM2.5
Met One E-BAM Particulate & Dust Monitors2 of 9: PM10, PM2.5
Trolex Particulate & Dust Monitors2 of 9: PM10, PM2.5Defiant Technologies FROG Specialty Air Analyzers1 of 9: BTEX / speciated VOC
TSI GM460 Gas Detectors1 of 9: H₂S
RKI Instruments GX6000 Gas Detectors1 of 9: H₂S
AMETEK Brookfield Jerome Specialty Air Analyzers1 of 9: H₂S
Particles Plus Particulate & Dust Monitors1 of 9: VOCSolutions
Solutions Judged Against SCAQMD 1180
Oil & Gas / Petrochemical
Fence-line VOC, H₂S, and methane leak detection
Article Library
Articles on SCAQMD 1180
Industrial Perimeter Air Quality Monitoring: Action Levels
What industrial perimeter monitoring requires at fenceline and construction sites: DER-10 CAMP action levels, EPA fenceline rules, and continuous records.
How to Choose an Air Quality Monitor: PRO, IAQ, or Thiamis
Compare Aethair PRO, IAQ, and Thiamis to match the right device to your site, from commercial interiors to industrial and fenceline monitoring.
Questions
SCAQMD 1180 FAQ
What are the Rule 1180 notification thresholds?
Among others: SO₂ 75 ppb, H₂S 30 ppb, benzene 8 ppb, formaldehyde 44 ppb, ammonia 4,507 ppb, and hydrogen fluoride 289 ppb as 1-hour averages; PM2.5 35 µg/m³ and PM10 50 µg/m³ as 24-hour averages; and 730 ppb for total VOCs as an information-based threshold.
What happens when a Rule 1180 threshold is exceeded?
The facility's web-based notification program automatically notifies the public, giving the pollutant, the concentration measured, and the threshold, and sends follow-up notifications while the exceedance continues.
Which facilities fall under Rule 1180?
Petroleum refineries and specified related facilities in the South Coast Air Quality Management District, each under an approved Fenceline Air Monitoring Plan.
Monitor Against SCAQMD 1180
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