What is Nox?
Nitrogen oxides (NOx) are a group of highly reactive gases, primarily nitric oxide (NO) and nitrogen dioxide (NO₂), which are classified as harmful air pollutants. NOx emissions are a major contributor to poor air quality, environmental damage, and adverse human health effects.
Understanding how NOx is formed, how it is regulated, and the most effective NOx reduction technologies is essential for businesses operating combustion-based processes.
What Causes NOx Formation?
NOx can be produced naturally through high‑temperature events such as:
- Thunderstorms (via lightning)
- Forest and wildfires
- Microbial activity in agricultural fertilisation
However, the vast majority of NOx emissions come from man‑made industrial activities, particularly those involving the combustion of fossil fuels.
Key sources of industrial NOx emissions include:
- Vehicle engines and transportation fuels
- Power generation facilities
- Industrial boilers and plant combustion systems
- Waste, biomass, and coal‑fired processes
Whenever combustion occurs at high temperatures, nitrogen and oxygen in the air react to form NOx gases.
Why Controlling NOx Emissions Is Critical
When released into the atmosphere, NOx gases react with moisture, ammonia, and other airborne compounds to form nitric acid vapour. This reaction contributes to:
- Acid rain
- Smog formation
- Environmental degradation
- Climate change acceleration
From a health perspective, exposure to elevated NOx levels can:
- Irritate the lungs and airways
- Exacerbate asthma and respiratory conditions
- Cause long‑term, irreversible lung damage with prolonged exposure
The World Health Organisation (WHO) reports that:
- 99% of the global population breathes air that exceeds WHO air quality limits
- 7 million premature deaths worldwide each year are linked to air pollution
These findings underline the urgent need for cleaner industrial processes, improved emissions control, and effective NOx reduction strategies.
NOx Emissions Regulations in the UK
In the UK, companies that generate NOx emissions are legally responsible for ensuring they remain within permitted limits.
Key regulatory frameworks include:
- Environmental Permitting Regulations (2010)
- Medium Combustion Plant Directive (MCPD) (being implemented into UK law)
These regulations require:
- Regular accredited emissions monitoring
- Measurement of NOx and other pollutants such as VOC emissions
- Verification against Emission Limit Values (ELVs)
Compliance not only avoids enforcement action but also supports sustainability goals and corporate environmental responsibility.
Proven and Emerging NOx Reduction Technologies
Traditional NOx Abatement Solutions
Historically, industries such as power generation and energy‑from‑waste plants have relied on:
- Selective Catalytic Reduction (SCR)
- Selective Non‑Catalytic Reduction (SNCR)
Both systems use ammonia to convert NOx into nitrogen and water. SCR utilises a catalytic bed to accelerate the reaction.
However, these technologies can be limited by:
- Strict temperature requirements
- Poor mixing and residence time
- High operational and maintenance costs
- Reduced real‑world performance
Advanced NOx Control: Ozone Oxidation & Scrubbing Systems
Emerging NOx oxidation technologies offer a highly effective alternative.
These systems work by:
- Injecting ozone gas directly into the flue (including dirty flue gas environments)
- Oxidising NOx into nitrogen pentoxide (N₂O₅), which is water‑soluble
- Removing the N₂O₅ using an aqueous scrubbing system
This combined approach delivers:
- SCR‑level NOx reduction performance
- Fewer temperature and mixing constraints
- Applicability across a wider range of combustion processes
- Improved reliability in real‑world conditions
Partner with Experts in NOx Reduction
For organisations seeking effective NOx reduction, regulatory compliance support, or advanced emissions control solutions, expert guidance is essential.
Specialised Ozone Solutions provides proven technologies and specialist support to help businesses:
- Reduce NOx emissions
- Meet environmental regulations
- Protect employee health
- Improve environmental performance
Contact the SOS team today to discuss how we can support your NOx emissions reduction strategy.
