Added Value of Vaisala AQT530 Sensors as a Part of a Sensor Network for Comprehensive Air Quality Monitoring

Abstract

Poor air quality influences the quality of life in the urban environment. The regulatory observation stations provide the backbone for the city administration to monitor urban air quality. Recently a suite of cost-effective air quality sensors has emerged to provide novel insights into the spatio-temporal variability of aerosol particles and trace gases. Particularly in low concentrations these sensors might suffer from issues related e.g., to high detection limits, concentration drifts and interdependency between the observed trace gases and environmental parameters. In this study we characterize the optical particle detector used in AQT530 (Vaisala Ltd.) air quality sensor in the laboratory. We perform a measurement campaign with a network of AQT530 sensors in Helsinki, Finland in 2020–2021 and present a long-term performance evaluation of five sensors for particulate (PM10, PM2.5) and gaseous (NO2, NO, CO, O3) components during a half-year co-location study with reference instruments at an urban traffic site. Furthermore, short-term (3–5 weeks) co-location tests were performed for 25 sensors to provide sensor-specific correction equations for the fine-tuning of selected pollutants in the sensor network. We showcase the added value of the verified network of 25 sensor units to address the spatial variability of trace gases and aerosol mass concentrations in an urban environment. The analysis assesses road and harbor traffic monitoring, local construction dust monitoring, aerosol concentrations from fireworks, impact of sub-urban small scale wood combustion and detection of long-range transport episodes on a city scale. Our analysis illustrates that the calibrated network of Vaisala AQT530 air quality sensors provide new insights into the spatio-temporal variability of air pollution within the city. This information is beneficial to, for example, optimization of road dust and construction dust emission control as well as provides data to tackle air quality problems arising from traffic exhaust and localized wood combustion emissions in the residential areas.

Low‐cost air quality monitoring networks for long‐term field campaigns: A review

“…Several interesting findings were achieved within the reviewed papers, demonstrating the potentiality of LC networks to greatly expand the air quality monitoring capability. LC networks allowed, for example, investigating ship emissions in harbour areas (Jayaratne et al, 2020; Merico et al, 2019), identifying restaurants as an important local contributor to PM 2.5 concentrations (Eilenberg et al, 2020; Kosmopoulos et al, 2022), finding that local sources are responsible for only a fraction (30%) of the total PM 2.5 in the urban core while the rest is transported from other areas (Kosmopoulos et al, 2022), identifying the best hours to practice physical activities in the open air (Nieckarz & Zoladz, 2020), improving air pollution monitoring during special events (Chao et al, 2021; Kuhn et al, 2021), and evaluating the impact on air quality of the Covid‐19 pandemic (Chadwick et al, 2021; Davidović et al, 2021; Mohd Nadzir et al, 2021; Mousavi & Wu, 2021), forest fires (Stavroulas et al, 2020), fireworks (Petäjä et al, 2021), a stone quarry (Molho et al, 2019) and a volcano (Whitty et al, 2020).…”

City Wide Participatory Sensing of Air Quality

“…An HOPE sensor PM 2.5 compared well with SMEAR III readings (not shown) but sensor NO 2 and O 3 were almost as twice the corresponding SMEAR III measurements. The personal exposure profile captured three elevated peaks during New Year's Eve fireworks celebrations which occurred throughout Helsinki (Petäjä et al, 2021). Not only did PM 2.5 peak late in the evening when the participant went for a walk, the was a general indoor air increase of PM 2.5 starting from 17:00 onward showing the effects of ambient air pollution inside the residence.…”

“…Finnish Meteorological Institute upgraded their city-wide ENFUSER Air Quality Land Use Regression service (Nurminen et al, 2020). Vaisala extended the fixed air quality network (Petäjä et al, 2021). UseLess provided digital voting app for city interventions.…”

“…(1994), IHR (in m 3 /hr) are 1.38 and 1.2 for male and female, respectively. Second, we make an assumption for the geometric mean diameter of ambient urban size distribution in Helsinki based on the size distribution data reported by Petäjä et al (2021). DF for PM 2.5 in this paper can then be assumed to have a range of 0.2-0.5 μg m −3 , according to the size-dependent regional deposition factor curves by ICRP model (e.g., Hussein et al (2013)).…”

Opinion: Insights into updating Ambient Air Quality Directive (2008/50EC)

“…1, the idea of a Supersite station is to support and complement existing regulatory monitoring and to provide novel insights into air quality (e.g. Kulmala et al, 2021). The instrumentation could cover measurements for the additional parameters described previously as well as for the more advanced parameters such as chemical composition of particles.…”