Summary
This is an air-quality study, not a disinfection study. Hypochlorous acid appears here as a chemical deodorant — sprayed into a broiler house’s exhaust air to oxidise ammonia and knock down dust before either leaves the site. No organism was tested and no antimicrobial claim is made. It is included because the economics are unusual and because it is one of the few peer-reviewed accounts of HOCl used at this scale in livestock ventilation.
Why ammonia is the problem
Ammonia is the most problematic component of environmental pollution in poultry production. The paper takes 25 ppm as the level above which bird productivity suffers — reduced weight gain, impaired feed conversion, carcass condemnation, and damage to the mucous membranes of the respiratory tract, which raises susceptibility to respiratory infection. The authors cite Chinese statistics putting roughly 56% of farming-related environmental complaints down to air pollution, 62.5% of those concerning odour, with farm closures for rectification a common outcome. The existing answers are either cheap and ineffective — a deodorant screen sited badly enough to impede ventilation, which can itself harm the flock — or effective and expensive: the biological deodorisation tower the authors use as a comparator costs over $390,000 to build.
How it was done
| Setting | A commercial broiler house in Yunfu, Guangdong, China — 68 × 12 × 3.0 m, three rows of cages, six fans each moving 44,000 cubic metres an hour under longitudinal negative pressure |
|---|---|
| The system | An ammonia removal blocking system: a 12.0 × 3.5 × 3.0 m frame carrying a twelve-needle nylon netting layer aligned with the airflow, with a spray system of three pipes of twelve nozzles each, a 750 W high-pressure pump and a one cubic metre tank |
| Candidates compared | Hypochlorous acid at 80 ppm, chlorine dioxide at 70 ppm, and other candidate deodorants |
| Method | Three stages: computational fluid dynamics modelling of the house’s airflow to find the best screen position, then an airtight environmental simulation chamber to rank the deodorants, then field validation in the working broiler house |
| Placement | The simulation indicated 3.5 m from the fan outlet — close enough to capture the plume, far enough not to restrict ventilation. Simulated wind speeds matched measured values within acceptable error. |
Result
- Hypochlorous acid at 80 ppm and chlorine dioxide at 70 ppm were both cost-effective and achieved high ammonia removal in the simulation chamber.
- In field validation, 80 ppm hypochlorous acid in the blocking system removed 82% of the ammonia and 77% of the dust from the exhaust air.
- Cost: about $1,900 to install and $590 a year to run.
What this establishes, and what it does not
- Nothing here is a microbiological result. No pathogen was tested, no reduction in any organism was measured, and the paper makes no antimicrobial claim. Do not cite it as one.
- It is one house, one climate, one geometry. The 3.5 m placement is specific to that building. The transferable part is the method — model the airflow before siting the screen, rather than placing it by habit — not the number.
- The economics are the headline. A four-figure capital cost where the conventional engineered answer is six figures is what makes this worth filing, particularly for operations that have dismissed exhaust treatment as unaffordable.
- Not a product claim. EcoloxTech generators are regulated by the EPA as devices and carry no efficacy claims of any kind. This is cited as published research by an unrelated group.
What it means in practice
Hypochlorous acid is used here as a deodorant rather than a disinfectant, oxidising ammonia in broiler house exhaust air. The result is an air-quality and odour-complaint answer at a four-figure capital cost, where the conventional biological tower is six figures. No organism was tested, so nothing in this study supports an antimicrobial claim.
Conditions tested
| Parameter | Value |
|---|---|
| Concentration | 80 ppm hypochlorous acid, sprayed into the exhaust air stream |
| Contact time | Continuous, in a spray barrier 3.5 m from the fan outlet |
| Measured result | 82% ammonia removal and 77% dust removal in field validation, at about $1,900 to install and $590 a year to run |
| Relevant sectors | Agriculture & Livestock, Livestock, Poultry & Eggs |
| Publication | Poultry Science, 2025 |
| Authors | Jingjing Luo, Jinsheng Rong, Shizhen Zhou, Haoliang Wang, Miao Li, Xiliang Yan, Yingbao Wu, Yan Wang (South China Agricultural University) |
Reading this responsibly
Published figures are obtained under controlled conditions, usually on clean surfaces or in defined matrices. Organic load, surface condition, temperature and application coverage all affect real-world performance. Use these numbers to design a protocol, then validate it on your own site with environmental swabbing.
Applying it
Concentrations in this range are within the adjustable output of every EcoloxTech commercial system, so implementing this protocol is a settings question rather than a procurement one. Where the claim needs to sit on a registered label, see HOCl-AS200, EPA Reg. No. 101112-1.