Air pollution has been a rising concern due to rapid urbanization, increasing population, industrialization. The World Health Organization (WHO) report states that 90% of the people around the world breathe polluted air. To curb air pollution proper planning and mitigation strategies are required. Ambient air quality monitoring is the first most important step in mitigation. It helps in knowing and understanding the existing condition of the ambient air. Based on the results of the ambient air monitoring further mitigative and preventive solutions are proposed. Ambient air monitoring can be carried out using manual stations or automatic stations. Traditional manual stations go through a tedious process of manual sampling, chemical analysis, etc. It also generates erroneous data and fails to give continuous results. The detailed advantages and drawbacks of this ambient air quality monitoring devices are discussed in this paper. Robust ambient air monitoring is required to plan and execute the mitigation strategies. The first generation ambient air quality monitoring station fails in providing a representative air quality for a given region. Ambient air quality monitoring systems have evolved with time to overcome the drawbacks of its predecessor. The second and third generation stations are viz. Continuous Ambient Air Monitoring Stations (CAAQMS) and Low-cost sensor-based stations. The new generation monitoring systems ensure better spatiotemporal resolution and provide real-time data. Each monitoring system has its own advantages and disadvantages. Due to cheaper capital cost and high functionality, users are more inclined towards low-cost sensors. This paper explains the evolution of ambient air quality monitoring stations with time and technology. It covers the working principle, advantages, disadvantages, cost and comparison of the new generation monitoring stations. It further covers the future of the ambient air quality monitoring devices based on the work and research carried out by different government and research institutions around the world.

1. EVOLUTION OF AMBIENT AIR-QUALITY
MONITORING SYSTEMS
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2. Evolution of ambient air quality monitoring systemsINTRODUCTION
With increasing population, urbanization, and industrialization, air pollution is emerging as a significant
problem. According to WHO, 90% of the world population breathe polluted air. A study published in The Lancet
Journal of Planetary Health states that poor air quality is also the cause of around 1.24 million premature deaths
in India.
Air Quality Index (AQI) is a great way of representing and understanding overall pollution scenario. However, to
calculate AQI, it is necessary to measure the concentration of various air pollutants such as, PM2.5, PM10, CO,
NO2, SO2, O3, NH3, etc. Air quality monitoring is also important to understand the spatio-temporal variation of
various pollutants.
“You cannot manage, what
you cannot measure.
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3. There are many different approaches and
methods available to measure the pollutant
concentration in the ambient air.
Monitoring methods are chosen based on the
frequency, purpose, objective, and budget of
the monitoring program.
The three generations of air quality monitoring
systems showcase the technological
developments that have taken place over the
years.
Frequency Purpose
Evolution of ambient air quality monitoring systemsTHE EVOLUTION
Objective Budget
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4. HIGH VOLUME AIR SAMPLER (HVS)
High Volume Air Samplers (HVS) are traditional
manually operated units that are used to collect air-
pollutants like dust particles and gases by maintaining
constant air-flow from the instruments, usually for 24
hours.
The samples taken from this approach are grab
samples, and they are taken at fixed intervals.
Samples needs to be transported to a well-maintained
laboratory to carry-out analysis on samples to get
results.
Evolution of ambient air quality monitoring systemsFIRST GENERATION
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5. Timeline from collecting samples to
getting results.
TIME
CONSUMING
MONEY INTENSIVE
HIGH CHANCES OF ERROR
Evolution of ambient air quality monitoring systemsFIRST GENERATION
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6. CONTINUOUS AMBIENT AIR QUALITY MONITORING SYSTEM (CAAQMS)
CAAQMS consist of various sophisticated automatic
analyzers that measure the concentration of target
pollutants. These analyzers work on the principles such as
Ultraviolet Fluorescence, Non-dispersive infrared
spectroscopy, Gas Chromatography based continuous
analyzers, etc.
All such analyzers are placed in a fixed station, which is
usually the size of a kiosk lab.
They provide real-time to near-real-time air quality
results.
Evolution of ambient air quality monitoring systemsSECOND GENERATION
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7. Timeline from collecting samples to
getting results.
QUICK RESULTS
Real-time to near-real-time
HIGH DATA QUALITY
High accuracy, high precision
WIDE RANGE OF POLLUTANT
MEASUREMENT
VERY HIGH COST
High CAPEX, high OPEX
HIGH SPACE REQUIREMENT
Usual dimensions (4.2 x 3.5 x 2 m)
Evolution of ambient air quality monitoring systemsSECOND GENERATION
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8. SENSOR-BASED MONITORS / LOW-COST MONITORS
Sensor-based air quality monitors are the latest advancement
in the line of ambient air quality monitoring devices.
They measures a wide range of particulate and gaseous air
pollutants based on the proven working principles such as
light scattering, electrochemical sensors, photoionization
detection (PID), nondispersive infrared (NDIR), etc.
Due to very low capital cost compared to instruments of the
previous two generations, limited manpower associated with
its operation, and subsequent negligible operational cost,
they are also referred to as low-cost monitoring sensors. Low-
cost sensors consume less power and have capabilities to
work on battery backup & solar power.
Evolution of ambient air quality monitoring systemsTHIRD GENERATION
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9. Evolution of ambient air quality monitoring systemsCOMPARISON
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10. Oizom has a wide range of sensor-based air quality monitoring systems for all kinds of applications which
provides real-time air quality monitoring data along with meteorological parameters. Deep machine
learning algorithms of Oizom ensure high data quality which gives more than 90% accurate data when
calibrated against the standard reference system.
OIZOM’S OFFERING
POLLUDRONE ™
Ambient Air Pollution
Monitoring System
ODOSENSE ™
Ambient Odour
Analyzer
DUSTROID ™
Ambient Dust
Monitor
WEATHERCOM ™
Automatic Weather Station
Evolution of ambient air quality monitoring systems

11. Oizom not only provides air quality monitoring but also offers comprehensive and scalable analytics. The data
sent by OIZOM’s sensors over the cloud is made actionable by performing advanced analytics. The data can be
published on various mediums like Web App, Mobile App, Display units, and can be further used in dispersion
modelling, emission inventory, and health exposure studies.
Evolution of ambient air quality monitoring systemsOIZOM’S OFFERING
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