Olf-Actions International

08/08/2026

𝑶𝒅𝒐𝒓 𝑰𝒔 𝑵𝒐𝒕 𝑺𝒐𝒍𝒗𝒆𝒅 𝒃𝒚 𝑬𝒒𝒖𝒊𝒑𝒎𝒆𝒏𝒕. 𝑰𝒕 𝑰𝒔 𝑺𝒐𝒍𝒗𝒆𝒅 𝒃𝒚 𝑺𝒆𝒒𝒖𝒆𝒏𝒄𝒆.

Every plant manager facing odor complaints has been offered the same thing: a scrubber quote, a misting contract, a chemical program or worst, a false neutralizing agent. Most have bought at least one. Many are still receiving complaints.

Here is why. Treatment sold before diagnosis is treatment sized for a source that may not be your dominant emitter. We see it constantly: six figures spent on the stack that smells worst to a human standing beside it, while the actual driver of neighborhood impact was a roof exhaust nobody sampled.

Odor problems are solved by sequence: audit, sampling, analysis, impact modeling, engineering | then, if conflict has already erupted, committees, litigation science, and legal support. One method, borrowed from medicine, refined over 33 years and 5,000+ projects across three continents.

We are publishing the full sequence today, ten slides, in order. Read them and you will understand what no vendor will explain:
1 | why your operators' knowledge is the true starting point of every study
2 | why a sample that misrepresents its source will betray you years later
3 | why sources must be ranked by emission rate, not by how bad they smell
4 | why a dispersion map is the only honest answer to a neighbor's complaint
5 | why treatment must be sized after the diagnosis, never sold before it
6 | why a community that understands your data stops fighting your permit
7 | why an audit costs a fraction of what a class action discovers
8 | why science and law must be spoken by the same team, fluently.

We sell no equipment. Seventy treatment processes commissioned worldwide, none of them ours to sell, all of them sized from measured data. More than Ten million people have recovered their olfactory quality of life through this method.

This series teaches you each step, in order, so you understand exactly what your facility needs | and what it can finally stop fearing.

Yann H. Contratto P.E., M.E. 🇺🇸🇨🇦 | Expert Witness 🇺🇸
Founder & CEO | 𝑶𝒍𝒇-𝑨𝒄𝒕𝒊𝒐𝒏𝒔 𝑰𝒏𝒕𝒆𝒓𝒏𝒂𝒕𝒊𝒐𝒏𝒂𝒍 𝑰𝒏𝒄. | © 2026
| 𝑳𝑬𝑮𝑨𝑳 | 𝑻𝑬𝑪𝑯𝑵𝑰𝑪𝑨𝑳 | 𝑺𝑪𝑰𝑬𝑵𝑻𝑰𝑭𝑰𝑪 | 𝑬𝑵𝑮𝑰𝑵𝑬𝑬𝑹𝑰𝑵𝑮 | 𝑶𝑫𝑶𝑹 𝑬𝑿𝑷𝑬𝑹𝑻𝑺 |
| www.Olf-Actions.com/legal | [email protected] | +1 514 758 3974 |

08/03/2026

| PRELIMINARY ODOR AUDIT |
𝑬𝑽𝑬𝑹𝒀 𝑶𝑫𝑶𝑹 𝑳𝑨𝑾𝑺𝑼𝑰𝑻 𝑩𝑬𝑮𝑨𝑵 𝑨𝑺 𝑨 𝑾𝑨𝑹𝑵𝑰𝑵𝑮 𝑵𝑶𝑩𝑶𝑫𝒀 𝑴𝑬𝑨𝑺𝑼𝑹𝑬𝑫
Odor files rarely explode overnight. They accumulate: a handful of complaints, a first inspection, a petition, then a filing. At every one of those stages the problem was still yours to solve, quietly and at a fraction of the eventual cost. What was missing was measurement early enough to act on. A Preliminary Odor Audit maps your emission sources, ranks them by real impact and identifies which units drive the complaints, before a regulator or a plaintiffs' firm does it for you.

Across 33 years and close to 5,000 assessed sites, my team and I have seen the same pattern on every continent: the operators who called early kept control of their file, their budget and their relationship with their neighbors. The audit is deliberately scoped and fast, so the decision to act comes with numbers attached.

Yann H. Contratto, P.E., M.E. | Expert Witness 🇺🇸
Founder & CEO | 𝑶𝒍𝒇-𝑨𝒄𝒕𝒊𝒐𝒏𝒔 𝑰𝒏𝒕𝒆𝒓𝒏𝒂𝒕𝒊𝒐𝒏𝒂𝒍 𝑰𝒏𝒄. | © 2026
| 𝑳𝑬𝑮𝑨𝑳 | 𝑻𝑬𝑪𝑯𝑵𝑰𝑪𝑨𝑳 | 𝑺𝑪𝑰𝑬𝑵𝑻𝑰𝑭𝑰𝑪 | 𝑬𝑵𝑮𝑰𝑵𝑬𝑬𝑹𝑰𝑵𝑮 | 𝑶𝑫𝑶𝑹 𝑬𝑿𝑷𝑬𝑹𝑻𝑺 |
| www.Olf-Actions.com/legal | [email protected] | +1 514 758 3974 |

07/29/2026

𝑶𝑫𝑶𝑹 𝑰𝑺 𝑵𝑶𝑾 𝑻𝑯𝑬 #𝟏 𝑬𝑵𝑽𝑰𝑹𝑶𝑵𝑴𝑬𝑵𝑻𝑨𝑳 𝑪𝑶𝑴𝑷𝑳𝑨𝑰𝑵𝑻 𝑰𝑵 𝑵𝑶𝑹𝑻𝑯 𝑨𝑴𝑬𝑹𝑰𝑪𝑨

Odor has quietly become the leading environmental complaint in North America, and it is now the fastest path from a quiet neighbor to a class action. Olf-Actions International exists for one reason, to resolve that risk at its source. We are the independent LEGAL, TECHNICAL, SCIENTIFIC and ENGINEERING team built entirely around odor, combining EN13725 olfactometry, AERMOD dispersion modeling and courtroom grade documentation into a single defensible strategy. Most of our clients never reach a courtroom, because we reach the problem first. For the rare case that escalates, our record speaks plainly, 19 class actions and 19 won. Whatever study you already have in motion, we strengthen it as an independent layer rather than replacing it.

Yann H. Contratto, P.E., M.E. | Expert Witness 🇺🇸
Founder & CEO | 𝑶𝒍𝒇-𝑨𝒄𝒕𝒊𝒐𝒏𝒔 𝑰𝒏𝒕𝒆𝒓𝒏𝒂𝒕𝒊𝒐𝒏𝒂𝒍 𝑰𝒏𝒄. | © 2006
| 𝑳𝑬𝑮𝑨𝑳 | 𝑻𝑬𝑪𝑯𝑵𝑰𝑪𝑨𝑳 | 𝑺𝑪𝑰𝑬𝑵𝑻𝑰𝑭𝑰𝑪 | 𝑬𝑵𝑮𝑰𝑵𝑬𝑬𝑹𝑰𝑵𝑮 | 𝑶𝑫𝑶𝑹 𝑬𝑿𝑷𝑬𝑹𝑻𝑺 | | www.Olf-Actions.com/legal | [email protected] | +1 514 758 3974 |

07/28/2026

PREVENT IT. OR WIN IT.

07/23/2026

𝙊̲𝙇̲𝙁̲ ̲𝘼̲𝘾̲𝙏̲𝙄̲𝙊̲𝙉̲𝙎̲ ̲𝙄̲𝙉̲𝙏̲𝙀̲𝙍̲𝙉̲𝘼̲𝙏̲𝙄̲𝙊̲𝙉̲𝘼̲𝙇̲ ̲|̲ ̲𝙒̲𝙃̲𝙀̲𝙉̲ ̲𝘼̲ ̲𝙈̲𝙐̲𝙉̲𝙄̲𝘾̲𝙄̲𝙋̲𝘼̲𝙇̲ ̲𝙋̲𝙇̲𝘼̲𝙉̲𝙏̲ ̲𝘽̲𝙀̲𝘾̲𝙊̲𝙈̲𝙀̲𝙎̲ ̲𝘼̲ ̲𝙋̲𝙐̲𝘽̲𝙇̲𝙄̲𝘾̲ ̲𝙊̲𝘿̲𝙊̲𝙍̲ ̲𝘾̲𝘼̲𝙎̲𝙀̲

Recurring odor complaints at a treatment plant rarely stay technical. They become public hearings, regulatory files and class actions. Our team resolves them at every level: EN13725 olfactometry, AERMOD modeling, source ranking, engineering that performs, and a legal defense that holds. One firm, the full chain.



Yann H. Contratto, P.E., M.E. | Expert Witness 🇺🇸
Founder & CEO | Olf-Actions International Inc.
LEGAL | TECHNICAL | SCIENTIFIC | ENGINEERING | ODOR EXPERTS
COMRS | www.Olf-Actions.com/comrs | [email protected] | +1 514 758 3974

07/21/2026

07/21/2026

𝙁𝘼𝘾𝙄𝙉𝙂 𝘼𝙉 𝙊𝘿𝙊𝙍-𝙍𝙀𝙇𝘼𝙏𝙀𝘿 𝘾𝙇𝘼𝙎𝙎 𝘼𝘾𝙏𝙄𝙊𝙉?
𝙊𝘿𝙊𝙍 𝘾𝙇𝘼𝙎𝙎 𝘼𝘾𝙏𝙄𝙊𝙉𝙎 𝘼𝙍𝙀 𝙎𝙐𝙍𝙂𝙄𝙉𝙂

Since 2020, odor-related class actions have accelerated from 300% a year to more than 700% in the first half of 2026 alone. When complaints turn to litigation, the operator carries the exposure. Our team stands with the companies and municipalities facing it, through ISOMP®: certified olfactometry, dispersion modeling, source ranking, and engineering guidance. No hype. No masking. Rigor that holds up before regulators and courts.

Yann H. Contratto, P.E., M.E. Expert Witness 🇺🇸,
Founder & CEO, Olf-Actions International
© Olf-Actions International Inc. 2026
| LEGAL | TECHNICAL | SCIENTIFIC | ENGINEERING | ODOR EXPERTS |
| www.Olf-Actions.com/legal | [email protected] | +1 514 758 3974 |

𝘽𝙐𝙄𝙇𝘿 𝘼 𝘿𝙀𝙁𝙀𝙉𝙎𝙄𝘽𝙇𝙀 𝙇𝙄𝙏𝙄𝙂𝘼𝙏𝙄𝙊𝙉-𝙍𝙀𝘼𝘿𝙔 𝘾𝘼𝙎𝙀

07/18/2026

They say a scent can awaken a memory more surely than any photograph. That is the whole idea behind Proust's madeleine, and it is the thread I followed to write my last nose-letter.

In Search of Lost Scent.
I share my olfactometric memories: from my beginnings in Europe in the early 1990s, to the nozzle of a fighter jet and the cleanrooms of a computing giant, all the way to today's American courtrooms. A story of family, of masters, and of transmission.
No, it is not about anosmia, only about everything a scent can hold of memory.
I would be truly happy to have you read it, and to hear your thoughts. 👇

There is, in the world of odors and olfaction, a story that few people know and that I hold dear enough to share. It is the story of a still young science, and of a large family to which I humbly believe I belong.

07/16/2026

AERMOD 26135 is out — here's what it actually changes for your odor dispersion studies.

This week, the US EPA released the AERMOD Modeling System v26135 (AERMOD + AERMET, along with AERSURFACE, AERMINUTE and AERPLOT), replacing the regulatory version 24142. I went through the transmittal memo so my network doesn't have to. Here's the bottom line for those of us running odor dispersion work.

The physics didn't change. No revision to plume dispersion, meander, turbulence or boundary-layer parameterization. For a given meteorology and source configuration, your odor concentrations — and your peak-to-mean adjustments — come out essentially unchanged.

Most of the fixes don't touch odor. The bulk target NOₓ→NO₂ chemistry (Tier 3 OLM/GRSM) and output handling — nothing that affects an inert odor tracer.
Three items do matter, though. AERMET now reads the new GHCNh surface-met format as ISHD is retired — a change to your data supply chain. Several AERMET corrections affect edge-case met processing (humidity, missing wind direction) — precisely the low-wind, stable conditions where odor peaks live. And AERSURFACE adds per-sector HIGHZ0/LOWZ0 flexibility, which shifts surface roughness, and therefore dispersion.

My advice: adopt 26135 for every new study, permit and litigation file. In expert-witness work especially, running the current EPA-promulgated version isn't a preference — it's a defensibility argument no opposing counsel can challenge. But never switch versions mid-study: keep consistency, and document it.
Odor is inert. Credibility isn't — it's built version by version, decision by decision.

© Olf-Actions International 2026

07/15/2026

🎬 "A very particular set of skills." — the courtroom edition.
Years ago, in a U.S. courtroom, during a major odor class action, the judge stopped me with a simple question: did resolving an odor case really require chemical engineering, mathematics, fluid dynamics, meteorology and law — all at once? To confirm, I answered with the line I've always loved: "I bring a very particular set of skills…"

The judge smiled. Then fought back a laugh. I kept going — French pride fully engaged — convinced my delivery had won the room. My attorney leaned in and whispered: "Yann… that's the exact line Liam Neeson says in Taken*, right before he promises to hunt someone down."* A Frenchman, in English, quoting Bryan Mills word-for-word — and the only person who didn't get the reference was me. Truly lost in translation 😅 (at least I didn't finish with a karaoke, Bill Murray would've been proud).

Here's the thing, though: the judge's question was the right one. Solving an odor conflict genuinely demands all of it — EN13725 olfactometry, AERMOD atmospheric dispersion modeling, process and odor-control engineering, regulatory drafting, and expert testimony that holds up under cross-examination. 130 cases, 19 class actions, all won.

So yes, I may occasionally get the cultural references lost in translation. But the science, the engineering and the law? Those translate perfectly — in any language, in any courtroom.
(And "a very particular set of skills" is now officially retired from my testimony 😄.)