• Campbell Associates


Bus stops can be considered a potential hot spot for air pollution due to their proximity to the roads. Passengers waiting at bus stop can be at a higher risk of being exposed to greater amounts of vehicle-based pollution. Air quality monitoring at sites such as bus stops is essential for calculating the amount of pollution that waiting passengers and pedestrians using the pavement are exposed to.

New bus stop shelters are often mains powered in order to provide lighting and electronic advertising/information panels. As a result, they can also be used to power newly implemented air quality sensors which can then ascertain the levels of pollution that users of specific bus stops are being exposed to.

One of Campbell Associates customers, DustScanAQ, were recently asked by Lancaster University to monitor air quality at a bus stop located in an underpass on their campus. The particular bus stop in question is a cause of concern for University administrators due to its location within a tunnel which offers little air dispersion and no mechanical ventilation. As a result this area can yield potentially high concentrations of air pollution from the more than 300 idling buses and unrestricted private vehicles that stop there on a daily basis.

DustScanAQ deployed one of our Aeroqual AQY Micro Air Quality Stations at this bus stop between June to November 2019. In doing so their intention was to ascertain just how high the levels of air pollution at this bus stop were so that a low emission zone in the underpass could then be implemented if necessary.

The evaluation period from June to September showed high peaks of NO2 within the tunnel. After further discussions with the University, mitigation measures were implemented in September, which included widening the footpath, upgrading over 30% of the bus fleet to Euro VI engines and introducing a one-way system for buses only. The mitigation measures were implemented prior to the final two months of monitoring period and resulted in a great reduction of the NO2 hourly mean as well as a great reduction in PM10 and PM2.5. The chart below shows the comparison of the NO2 data before and after the implementation of the mitigation measures.

DustScanAQ now plans to monitor air pollution at the bus stop for a further six months starting from the beginning of 2020 to ensure that the recorded lower levels of air pollution remain this way. The team at Campbell Associates are eagerly awaiting the results of the next survey and are optimistic that the mitigation measures implemented there will help to successfully maintain the previously improved levels of air quality. Our thanks to Satty Jandu and DustScanAQ for carrying out this survey and sharing the results with us