World Environment Day 2019 – Why is ambient air monitoring important?

In last week’s blog we touched on current approaches to managing air pollution, including implementing national objectives and accompanying air quality management strategies to meet them. This week’s blog will focus on ambient air quality monitoring, why it’s important and how you can find out if your business is required to monitor its air emissions.

What is ambient air quality?

Ambient air quality is a term used to refer to the quality of the outdoor air in our surroundings. As discussed in our first blog of this series, air pollution comes from a variety of sources including industry, vehicle emissions, household and agriculture. The resulting emissions from these sources are then dispersed by and mix with the surrounding air, forming part of the ambient air we breathe.

Ambient air monitoring

Once an air pollutant is released from an exhaust or stack it can be difficult to ascertain how the pollutant will be dispersed and behave in the atmosphere. Certain pollutants have been proven to react with existing gases to form more damaging secondary pollutants. Weather patterns also have an influence on these reactions, for example nitrogen oxides (NOx) can form Ozone (O₃) through a photo-chemical reaction which occurs in the presence of strong sunlight, causing ground level smog. Furthermore, air movements determine how these pollutants a dispersed both locally and across the continents.

In order to better understand the impacts and behaviour of these pollutants, continuous ambient air monitoring systems (CAMS) have been developed. This technology allows us to collect real-time, continuous data on the concentrations of pollutants present in the ambient air. Reasons to collect such data include to:

• assess the extent of pollution;
• provide air pollution data to the general public in a timely manner;
• support implementation of air quality goals or standards;
• evaluate the effectiveness of emissions control strategies;
• provide information on air quality trends;
• provide data for the evaluation of air quality models; and
• support research (e.g., long-term studies of the health effects of air pollution).

In order to monitor progress with the UK Clean Air Strategy, ambient air monitoring stations have been installed across the UK by DEFRA and form the UK air quality monitoring network known as AURN (Automatic Urban and Rural Network). The collected data depicts how air pollution is distributed across the UK and highlights areas exceeding legal limit values for pollutants covered by the legislation. You can explore the AURN interactive map.

Ambient air monitoring requirements

If your proposed development will cause the release of air pollutants covered by the legislation, you could be required, by either the Environment Agency or your local authority, to determine the impacts it will have on the local air quality. This will include an assessment of the current background levels compared with the predicted increase in emissions and resulting impact on nearby receptors. You may also be required to carry out continuous ambient air monitoring as a requirement of an environmental permit to conduct your business operations.

The monitoring of common ambient pollutants is well established, with a range of sophisticated instrumental methods in order to meet the monitoring requirements of a wide range of pollutants.