Invisible threats: understanding PM2.5 and PM10 in your indoor air

What is an airborne partiuclate?

An airborne particulate, also known as particulate matter (PM), is a microscopic solid or liquid particle that remains suspended in the air. These particles are incredibly diverse in size, shape, and chemical composition, originating from both natural sources like dust and pollen, and human activities such as combustion and industrial processes. Categorized by their aerodynamic diameter, particularly as PM10 (coarse particles) and PM2.5 (fine particles), these tiny airborne components can persist in the atmosphere for varying durations depending on their size, and their presence is a key factor in air quality assessments due to their potential impacts on human health and the environment.

What is the legislation for England?

The HSE have set exposure standards to comply with the requirements of The Control of Substances Hazardous to Health (COSHH) Regulations. These are described in the HSE document EH40, which is updated annually. Currently, these are:

• 10,000 ug/m3 (8 hour time weighted average) for total inhalable dust.
• 4,000 ug/m3 (8 hour time weighted average) for respirable dust.

Total inhalable dust is defined as the fraction of airborne dust which enters the nose and mouth during breathing and is therefore available for deposition in the respiratory tract. Respirable dust approximates to the proportion which penetrates to the alveoli within the lung.

European emissions standards have highlighted a yearly average of 40 μg/m³ and 25 μg/m³ for PM10 and PM2.5 respectively. The ‘WHO’ standards outline a guideline of 20 μg/m³ and 10 μg/m³ for PM10 and PM2.5 respectively.

Can they be monitored?

Yes! Absolutely. Our monitors provide reliable, high-quality data on particulate concentrations, enabling local authorities, construction sites, and environmental consultants to effectively assess air quality, identify pollution sources, and demonstrate compliance with the stringent standards set to protect public health across the United Kingdom.