USW researcher working on developing fast-working cannabis breathalyser

A University of South Wales (USW) academic is leading a research project which brings a marijuana breathalyser a significant step closer to real-world use.

Having carried out previous research, Dr Emanuele Alves - Senior Lecturer in Pharmacology and Toxicology ay USW and the project’s Principal Investigator - is leading a programme focused on developing a rapid, portable device capable of detecting, within minutes from a breath sample, the primary psychoactive compound in cannabis, known as THC. 

The work addresses a growing international challenge - how to reliably identify drug-impaired driving as cannabis use becomes more widespread.

The research builds on proof-of-concept studies which demonstrated how 3D‑printed test cartridges, combined with colour‑reactive chemical dyes, can detect cannabinoids in breath.

Using specialised cartridges embedded with so‑called ‘Fast Blue’ dyes, research showed that key cannabis compounds - Delta‑9 THC, CBD and CBN - can be identified through distinct colour changes.

Crucially, the work highlights the importance of distinguishing between psychoactive THC and non‑intoxicating compounds such as CBD. This difference is essential for reducing false positives and ensuring any future roadside test is scientifically robust and legally defensible.

“Our aim is to develop a tool that is fast, reliable and practical for real‑world use,” Dr Alves said.

“If drivers understand that marijuana impairment can be detected quickly and accurately, that alone could help deter drug‑impaired driving and improve road safety.”

The study, which builds on work Dr Alves carried out prior to joining USW, demonstrated early evidence that colour analysis could separate THC‑related compounds from CBD, supporting the feasibility of a low‑cost, portable breathalyser suitable for roadside testing. The findings are a strong foundation for future development, rather than a finished commercial product.

“While further validation and real‑world testing are needed, the results mark an important milestone in the evolution of drug‑detection technology, reflecting its potential value to policing, road safety, and public health.” Dr Alves said.