The ‘ins and outs’ of air quality monitoring
The National Institute for Health and Care Excellence (NICE) recently issued draft guidance on ‘Air pollution - outdoor air quality and health.’ In the following article Jim Mills, Managing Director of Air Monitors Ltd, explains why there will need to be more funding for monitoring if the mitigation measures mentioned in the guidance are to be implemented effectively. Jim also highlights the close relationship between outdoor air quality and the (often ignored) problems with indoor air quality.
The NICE guidelines are being developed for Local Authority staff working in: transport, planning, air quality management and public health. The guidance is also relevant for staff in healthcare, employers, education professionals and the general public.
Covering road-traffic-related air pollution and its links to ill health, the guidelines aim to improve air quality and so prevent a range of health conditions and deaths. Unfortunately, on the day that the draft guideline was published, most of the national media focused on one relatively minor recommendation relating to speed bumps. ‘Where physical measures are needed to reduce speed, such as humps and bumps, ensure they are designed to minimise sharp decelerations and consequent accelerations.’ Measures to encourage ‘smooth driving’ are outlined; however, the guidelines also address a wide range of other issues, which, in combination, would help tackle urban air pollution.
Public sector transport services should implement measures to reduce emissions, but this is an area that could involve the greatest financial cost.
Many local authorities would doubtless comment that they are already implementing many of the guideline recommendations, but refer to budgetary constraints on issues that involve upfront costs. This issue was raised on BBC Radio 4 when the issue was discussed on 1st December.
The NICE guidelines recommend the inclusion of air quality issues in new developments to ensure that facilities such as schools, nurseries and retirement homes are located in areas where pollution levels will be low. LAs are also urged to consider ways to mitigate road-traffic-related air pollution and consider using the Community Infrastructure Levy for air quality monitoring. There are also calls for information on air quality to be made more readily available.
LAs are also being urged to consider introducing clean air zones including progressive targets to reduce pollutant levels below the EU limits, and where traffic congestion contributes to poor air quality, consideration should be given to a congestion charging zone. The guidelines also highlight the importance of monitoring to measure the effects of these initiatives.
As part of the consultation process, NICE is looking for evidence of successful measures and specifically rules out “studies which rely exclusively on modelling.”
In summary, all of the initiatives referred to in the NICE report necessitate monitoring in order to be able to measure their effectiveness. However, most LAs do not currently possess the monitoring capability to do so. This is because localised monitoring would be necessary before and after the implementation of any initiative. Such monitoring would need to be continuous, accurate and web-enabled so that air pollution can be monitored in real-time. AQMesh is therefore the ideal solution; small, lightweight, quick and easy to install, these air quality monitors are able to monitor all the main pollutants, including particulates, simultaneously, delivering accurate data wirelessly via the internet.
Whilst AQMesh ‘pods’ are very significantly lower in cost both to buy and to run than traditional reference stations, they still represent a ‘new’ cost. However any additional costs are trivial in comparison with the costs associated with the adverse health effects caused by poor air quality, as evidenced in the recent report from the Royal College of Physicians.
Inside Out or Outside In?
The effects of air pollution are finally becoming better known, but almost all of the publicity focuses on outdoor air pollution. In contrast, indoor air quality is rarely in the media, except following occasional cases of Carbon Monoxide poisoning or when ‘worker lethargy’ or ‘sick building syndrome’ are addressed. However, it is important to understand the relationship between outdoor air quality and indoor air quality. Air Monitors is currently involved in a number of projects in which air quality monitoring is being undertaken both outside and inside large buildings, and the results have been extremely interesting.
Poorly ventilated offices tend to suffer from increased Carbon Dioxide as the working day progresses, leading to worker lethargy. In many cases HVAC systems bring in ‘fresh’ air to address this issue, but if that fresh air is in a town or city, it is likely to be polluted – possibly from particulates if it is not sufficiently filtered and most likely from Nitrogen Dioxide. Ventilating with outdoor air from street level is most likely to bring air pollution into the office, so many inlets are located at roof level. However, data from recent studies indicate that the height of the best air quality can vary according to the weather conditions, so it is necessary to utilise a ‘smart’ system that monitors air quality at different levels outside the building, whilst also monitoring at a variety of locations inside the building. Real-time data from a smart monitoring network then informs the HVAC control system, which should have the ability to draw air from different inlets if available and to decide on ventilation rates depending on the prevailing air quality at the inlets. This allows the optimisation of the internal CO2, temperature and humidity whilst minimising the amount of external pollutants brought into the indoor space. In circumstances where the outside air may be too polluted to be used to ventilate, it can be pre-cleaned by scrubbing the pollutant gases in the air handling system before being introduced inside the building.
The implementation of smart monitoring and control systems for buildings is now possible thanks to advances in communications and monitoring technology. AQMesh pods can be quickly and easily installed at various heights outside buildings and further units can be deployed internally; all feeding near-live data to a central control system.
Another example of indoor air quality monitoring instrumentation developing from outdoor technology is the ‘Fidas Frog,’ a new fine dust aerosol spectrometer developed by the German company Palas. The Frog is an indoor, wireless, battery-powered version of the hugely popular, TÜV and MCERTS certified Fidas 200. Both instruments provide simultaneous determination of PM fractions, particle number and particle size distribution, including the particle size ranges PM1, PM2.5, PM4, PM10 and TSP.
Evidence of outdoor air pollution contaminating indoor air can be obtained with the latest Black Carbon monitors that can distinguish between the different optical signatures of combustion sources such as diesel, biomass, and tobacco. The new microAeth® MA200 for example, is a compact, real-time, wearable (400g) Black Carbon monitor with built-in pump, flow control, data storage, and battery with onboard GPS and satellite time synchronisation. Samples are collected on an internal filter tape and wireless communications are provided for network or smartphone app integration and connection to other wireless sensors. The MA200 is able to monitor continuously for 2-3 weeks. Alternatively, with a greater battery capacity, the MA300 is able to provide 3-12 months of continuous measurements.
In summary, a complete picture of indoor air quality can be delivered by a combination of AQMesh for gases, the Palas Frog for particulates and the microAeth instruments for Black Carbon. All of these instruments are compact, battery-powered, and operate wirelessly, but most importantly, they provide both air quality data AND information on the likely source of any contamination, so that the indoor effects of outdoor pollution can be attributed correctly.