---
title: "EPA Method 327: Ethylene Oxide Canister Sampling | Aethair"
description: "EPA Method 327, promulgated with the 2024 HON update in Appendix A to 40 CFR Part 63, measures ethylene oxide and vinyl chloride at a facility fenceline…"
url: https://aethair.io/standards/epa_method_327/
---

Measurement method · US EPA

# EPA Method 327: canister sampling of ethylene oxide and vinyl chloride

EPA Method 327, promulgated with the 2024 HON update in Appendix A to 40 CFR Part 63, measures **ethylene oxide and vinyl chloride** at a facility fenceline by collecting whole-air samples in **canisters** and analyzing them in a laboratory. Under the HON, each sample runs **24 hours** and samples are collected **every five calendar days**, at eight canister locations around the monitoring perimeter.

[Schedule a call](https://calendly.com/d/ctdd-mkr-v9v/aethair-demo-website) [All standards](https://aethair.io/standards/)

At a glance

**US EPA** Measurement method

0 parameters

[Official text from US EPA](https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-63/appendix-Appendix%20A%20to%20Part%2063)

Who uses it

## Who Uses It

Chemical plants subject to the 2024 HON fenceline requirement ([40 CFR 63.184](https://aethair.io/standards/epa_hon_fenceline/)) that emit ethylene oxide or vinyl chloride. Their action levels are 0.2 µg/m³ for ethylene oxide and 3 µg/m³ for vinyl chloride, as an annual average Δc. The other HON compounds are sampled with passive tubes under EPA Methods 325A and 325B.

Monitoring

## How It Relates to Continuous Monitoring

None of the instruments we offer measure ethylene oxide or vinyl chloride, so Method 327 sampling relies on laboratory analysis. Continuous boundary monitoring of the other gases and of wind still supports a facility's program, for example in tracing when and from where releases occurred.

Solutions

## Solutions That Rely on EPA Method 327

### [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 EPA Method 327

### [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.

[All articles](https://aethair.io/resources/)

Questions

## EPA Method 327 FAQ

What does EPA Method 327 measure?

Ethylene oxide and vinyl chloride in whole-air canister samples, analyzed in a laboratory.

How often are Method 327 samples collected under the HON?

Each sample runs 24 hours, collected every five calendar days at eight canister locations around the perimeter.

What are the HON action levels for the Method 327 compounds?

0.2 µg/m³ for ethylene oxide and 3 µg/m³ for vinyl chloride, compared with the annual average Δc.