--- title: "SCAQMD Rule 1180 Fenceline Notification Thresholds | Aethair" description: "SCAQMD Rule 1180 fenceline notification thresholds for SO₂, H₂S, benzene, formaldehyde, PM, and more, with averaging periods and a recommended setup." url: https://aethair.io/standards/scaqmd_1180/ --- 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. [Schedule a call](https://calendly.com/d/ctdd-mkr-v9v/aethair-demo-website) [Configure SCAQMD 1180 Monitoring](https://aethair.io/build/?params=so2,h2s,btex,ch2o,nh3,hf,voc,pm2_5,pm10\&setting=outdoor) At a glance **South Coast Air Quality Management District** Ambient air: refinery fenceline notification (South Coast AQMD, California) 9 parameters · 9 limit values [Sulfur Dioxide (SO₂)](https://aethair.io/parameters/so2/) [Hydrogen Sulfide (H₂S)](https://aethair.io/parameters/h2s/) [BTEX / speciated VOC](https://aethair.io/parameters/btex/) [Formaldehyde (CH₂O)](https://aethair.io/parameters/ch2o/) [Ammonia (NH₃)](https://aethair.io/parameters/nh3/) [Hydrogen Fluoride (HF)](https://aethair.io/parameters/hf/) [VOC (Total)](https://aethair.io/parameters/voc/) [PM2.5](https://aethair.io/parameters/pm2_5/) [PM10](https://aethair.io/parameters/pm10/) 2 devices measure them all - **Aethair PRO** Aethair VOC (ppm PID) · Aethair H₂S · Custom MultiSense - **Thiamis** Defiant Technologies Specialty Air Analyzers · RAE Gas Detectors [Official text from South Coast Air Quality Management District](https://www.aqmd.gov/docs/default-source/rule-book/reg-xi/r1180.pdf) 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. [**Sulfur Dioxide (SO₂)** Gases & VOCs](https://aethair.io/parameters/so2/) **75 ppb** *1-hour, notification threshold* [**Hydrogen Sulfide (H₂S)** Gases & VOCs](https://aethair.io/parameters/h2s/) **30 ppb** *1-hour, notification threshold* [**BTEX / speciated VOC** Gases & VOCs](https://aethair.io/parameters/btex/) **8 ppb** *1-hour, notification threshold* benzene; toluene 1,300 ppb and xylenes 5,000 ppb [**Formaldehyde (CH₂O)** Gases & VOCs](https://aethair.io/parameters/ch2o/) **44 ppb** *1-hour, notification threshold* [**Ammonia (NH₃)** Gases & VOCs](https://aethair.io/parameters/nh3/) **4507 ppb** *1-hour, notification threshold* [**Hydrogen Fluoride (HF)** Gases & VOCs](https://aethair.io/parameters/hf/) **289 ppb** *1-hour, notification threshold* [**VOC (Total)** Gases & VOCs](https://aethair.io/parameters/voc/) **730 ppb** *1-hour, information-based threshold* total VOCs as non-methane hydrocarbons [**PM2.5** Particulate Matter](https://aethair.io/parameters/pm2_5/) **35 µg/m³** *24-hour, notification threshold* [**PM10** Particulate Matter](https://aethair.io/parameters/pm10/) **50 µg/m³** *24-hour, notification threshold* 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. [Customize this configuration](https://aethair.io/build/?params=so2,h2s,btex,ch2o,nh3,hf,voc,pm2_5,pm10\&setting=outdoor) ### Who measures each parameter | Parameter | Aethair PRO | Aethair IAQ | External | | - | - | - | - | | [Sulfur Dioxide (SO₂)](https://aethair.io/parameters/so2/) | MultiSense, SO₂ cartridges | — | [1 instrument](https://aethair.io/parameters/so2/) via Thiamis | | [Hydrogen Sulfide (H₂S)](https://aethair.io/parameters/h2s/) | H₂S cartridge | — | [4 instruments](https://aethair.io/parameters/h2s/) via Thiamis | | [BTEX / speciated VOC](https://aethair.io/parameters/btex/) | — | — | [1 instrument](https://aethair.io/parameters/btex/) via Thiamis | | [Formaldehyde (CH₂O)](https://aethair.io/parameters/ch2o/) | MultiSense cartridge | Built in | — | | [Ammonia (NH₃)](https://aethair.io/parameters/nh3/) | — | — | [1 instrument](https://aethair.io/parameters/nh3/) via Thiamis | | [Hydrogen Fluoride (HF)](https://aethair.io/parameters/hf/) | HF cartridge | — | — | | [VOC (Total)](https://aethair.io/parameters/voc/) | VOC (ppm PID), VOC (ppb PID) +2 cartridges | Built in | [2 instruments](https://aethair.io/parameters/voc/) via Thiamis | | [PM2.5](https://aethair.io/parameters/pm2_5/) | Built in | Built in | [3 instruments](https://aethair.io/parameters/pm2_5/) via Thiamis | | [PM10](https://aethair.io/parameters/pm10/) | Built in | Built in | [3 instruments](https://aethair.io/parameters/pm10/) 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 [**Aethair PRO** Built in + Aethair VOC (ppm PID), Aethair H₂S, Custom MultiSense (SO₂, CH₂O, HF) 7 of 9: SO₂, H₂S, CH₂O, HF, VOC, PM2.5, PM10](https://aethair.io/products/pro/) Covers part of it (combine on one Thiamis) [**RAE** Gas Detectors 4 of 9: H₂S, NH₃, SO₂, VOC](https://aethair.io/sensors/rae-gas-detectors/) [**TSI DustTrak** Particulate & Dust Monitors 2 of 9: PM10, PM2.5](https://aethair.io/sensors/tsi-particulate-dust-monitors/) [**Met One E-BAM** Particulate & Dust Monitors 2 of 9: PM10, PM2.5](https://aethair.io/sensors/met-one-particulate-dust-monitors/) [**Trolex** Particulate & Dust Monitors 2 of 9: PM10, PM2.5](https://aethair.io/sensors/trolex-particulate-dust-monitors/) [**Defiant Technologies FROG** Specialty Air Analyzers 1 of 9: BTEX / speciated VOC](https://aethair.io/sensors/defiant-technologies-specialty-air-analyzers/) [**TSI GM460** Gas Detectors 1 of 9: H₂S](https://aethair.io/sensors/tsi-gas-detectors/) [**RKI Instruments GX6000** Gas Detectors 1 of 9: H₂S](https://aethair.io/sensors/rki-instruments-gas-detectors/) [**AMETEK Brookfield Jerome** Specialty Air Analyzers 1 of 9: H₂S](https://aethair.io/sensors/ametek-brookfield-specialty-air-analyzers/) [**Particles Plus** Particulate & Dust Monitors 1 of 9: VOC](https://aethair.io/sensors/particles-plus-particulate-dust-monitors/) Solutions ## Solutions Judged Against SCAQMD 1180 ### [Oil & Gas / Petrochemical](https://aethair.io/solutions/oil-gas/) Fence-line VOC, H₂S, and methane leak detection [All solutions](https://aethair.io/solutions/) Article Library ## Articles on SCAQMD 1180 ### [Industrial Perimeter Air Quality Monitoring: Action Levels](https://aethair.io/resources/perimeter-air-quality-monitoring-guide/) 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](https://aethair.io/resources/choosing-aethair-monitoring-device/) Compare Aethair PRO, IAQ, and Thiamis to match the right device to your site, from commercial interiors to industrial and fenceline monitoring. [All articles](https://aethair.io/resources/) 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.