Viridian Air conducts air quality impact assessments of a wide range of developments from small residential schemes in or near Air Quality Management Areas, to major mixed-use schemes. The assessments can be standalone reports or form part of an Environmental Impact Assessment. Air Quality Impact and Residential Suitability assessments are essential to demonstrate that proposed developments meet the National Air Quality Objectives.

We follow the Defra Technical Guidance in carrying out air quality assessments. This includes establishing the baseline air quality using the air quality monitoring data from local authority’s precision and diffusion tube networks, and Defra’s background air quality maps (for current and future years). Relevant local and national planning and air quality policies are taken into consideration in developing the scope and methodology of the assessment.

Detailed AQA including Dispersion Modelling

Detailed air quality dispersion modelling, if required, is carried out to model traffic and dispersion of emissions for the base year, the business-as-usual (without the scheme) future year (when the development is expected to be in the operations phase) and the future year with the scheme. This is to check if the predicted air quality concentrations meet the National Air Quality Objectives and Air Quality Neutrality Assessment. In London, an AQA must demonstrate air quality neutrality and residential suitability in case of residential developments.

Mitigation Plan
A sound mitigation plan is developed (for both Basic and Detailed AQA) in consultation with the client for control of construction dust and to minimise exposure of sensitive receptors to air pollution concentrations. This is essential to meet the National Ambient Air Quality Objectives and to minimise health and ecological risks to sensitive receptors.

We conduct air quality dust risk assessment (AQDRA) during demolition, construction and trackout phases of the development. Dust risk assessments are based on the IAQM’s Guidance on the “Assessment of Mineral Dust Impacts for Planning”. Dust assessments are generally risk based, taking into account the magnitude of emissions, sensitivity of the area to health and ecological risk. GIS maps showing all ecological and human sensitive receptors within buffers of 20m, 50m, 100m, 200m, 350m and 500m are prepared to determine the sensitivity of receptors to health and nuisance risk.

We develop emission management or mitigation plan for control of dust emissions during demolition, construction and trackout phases to minimise health and ecological risks depending on the dust risk assessment.

We develop operation stage emission mitigation plan to minimise exposure of sensitive receptors to air pollution concentrations due to the development under consideration. A sound emission mitigation plan is even more important if the development is near or within an Air Quality Management Area (AQMA). We work with the client and follow the IAQM/local authority guidelines to develop an effective mitigation plan.

We investigate the air quality neutrality of the development in terms of the building (mainly energy) emissions as well as the transport emissions (due to the new trips generated by the development).

We specialise in workplace air quality monitoring to comply with the Health and Safety Executive (HSE)  regulations. Have your employees complained of poor air quality, dusty environment or feeling drowsy or tired? If yes, you need workplace air quality monitoring to check the level of ventilation (carbon dioxide build-up), levels of dust (PM10 or PM2.5), or volatile organic compounds (VOCs). We will check the levels against the HSE Workplace Exposure Limits (WELs), and if required, propose appropriate mitigation measures.

We conduct monitoring of cleanrooms or clean zones in industries such as pharmaceuticals, medical devices, healthcare, aerospace, life sciences, and microelectronics. This could be either for the ISO 14644 compliance or for maintaining consistent, high quality environmental conditions required for specialised production processes.

We can help developing your monitoring plan for cleanrooms. This could vary from visits to the site on a regular or on an ad hoc basis. The monitoring plan will define what parameters need to be monitored as well as the number of measurement devices and their bespoke location within the cleanroom together with the alert and action levels required. The implementation of continuous monitoring will help to achieve the ISO 14644-1:2015 classification
of air cleanliness by particle concentration. 

We can assist you with the Simple Calculation of Atmospheric Impact Limits (SCAIL) assessment for determining the impacts from agricultural and combustion sources. SCAIL assessment is mainly used to assess the impacts on semi-natural sources like SSSIs (Sites of Special Scientific Interest) and SACs (Special Areas of Conservation). SCAIL Agriculture and SCAIL Combustion tools provide an estimate of the amount of acidity, nitrogen or sulphur deposited to a habitat or sensitive ecosystem.

SCAIL assessments are useful for initial screening of sources for IED (Industrial Emissions Directive) applications or appropriate assessments under the Habitats Directive.