Ambient Air Quality

Ambient Air Monitoring System


Monitoring ambient air quality is crucial for assessing the level of pollutants in the air and safeguarding public health. An efficient Ambient Air Quality Monitoring System provides real-time data on various air pollutants, helping authorities make informed decisions to mitigate pollution and protect the environment.

Why Choose PT Ecological Services?

PT Ecological Services offers a comprehensive Ambient Air Quality Monitoring System designed to meet the specific needs of environmental monitoring. With over 15 years of experience in environmental management, our team ensures that our monitoring systems deliver accurate and reliable data. We prioritize customer satisfaction, compliance with regulations, and environmental responsibility in all our solutions.

Compact Air Monitoring Device:

A device with brilliant sense of measuring the precise individual Climate affecting parameter. The product being conceptualized with the qualities of a swift intelligent technology with maximum precision and compactness along with easiest ever user interface access, collect, process and evaluate data for the world of analytics.


Automatically analyses time and location-based trend pollution patterns. Blazing speed processors re-define “Real time” monitoring services for true live data collection. Ultra-safe Operating Software developed for accessing data at blazing speed also protects the host devices and the central data storage system from malicious threats Readily interactive with all IOS and Android devices.

Various Applications:

  • Environmental monitoring in commercial communities and smart cities
  • Park / forest environmental monitoring of natural habitats
  • Real time monitoring in Industrial areas
  • Pollution control in traffic environment, roadways and tunnel pollution monitoring
  • Area wise determination of Air quality index and environmental impact assessment
  • Deriving heat maps for future trend of climate fitness.

Key Features

  1. Real-time Monitoring: Our Surface Water Online Monitoring System offers continuous real-time monitoring of water quality parameters such as pH, dissolved oxygen, turbidity, and conductivity, providing immediate insights into the health of surface water bodies.
  2. Remote Access: The system supports remote access capabilities, allowing users to monitor water quality data from any location with internet connectivity. This enables quick response to changes in water quality and facilitates efficient management of water resources.
  3. Data Logging: Comprehensive data logging features enable the storage and analysis of historical water quality data, facilitating trend analysis and long-term monitoring of surface water bodies.
  4. Customizable Alarms: Users can set customizable alarms to alert them to sudden changes or exceedances in water quality parameters, ensuring prompt action to address potential pollution events.
  5. Integration with GIS: The system integrates seamlessly with Geographic Information Systems (GIS), allowing users to visualize water quality data spatially and identify hotspots of pollution for targeted mitigation efforts.
Remote access to system and data Feature available
Interface RS485/RS232 port, Network port
Transmission network Optional 3G/4G/VPN/WIFI
Shelter material GI, Aluminium or stainless steel box optional
Scaffold material Q235
Scaffold height Standard height is 4.5m, Flange connection(1m fixed underground, 2*1.5m+1*0.5m)
Lightning arrester Length 1m, Q235 Galvanized material
Working environment Temperature: -30~+50℃, Humidity: 10%RH~90%RH, Pressure: 65~108Kpa
Shelter Protection grade IP65
Power supply DC12V, AC220V

The AP-370 series is a HORIBA’s measuring unit of Continuous Ambient Air Quality Monitoring System (CAAQMS). Continuous Ambient Air quality monitoring system are custom designed best to meet each application unique demands. This system is meant for measuring the concentration of air pollutants at various times instance of the day. The Concentration of air pollutants (such as S02, NOX, CO, O3, THC, etc). These stations monitor air pollution and send the data to remote server for archiving data and analysis. Mobile CAAQMS can be published via the internet to easy public access to raise awareness on current air pollution levels.

Automatic calibration
Auto-range function
Selective data output
Storing data in memory
Network communication (option)
Memory card for data management (option)
Readout view, concentration and mass
Easy-to-read, 320×240 LCD display with touch panel screen.
Minimal influence from interference components and ambient temperature.
Input/output via RS-232C port (option)
At last- a small, compact system

Conventional technology uses an optical chopper to obtain modulation signals. Instead, the APMA-370 uses solenoid valve cross flow modulation. Fixed amounts of the sample gas and the reference gas are injected alternately into the measurement cell. With the cross flow-modulation method, if the same gas is used for both the sample gas and the reference gas (e.g., zero gas could be used for both), no modulation signal will be generated. This has the great advantage that, in principle, when analyzing minute amounts of gas there is no generation of zero-drift. An additional advantage is that the elimination of rotary sectors precludes the need for optical adjustment. These features assure greatly improved stability over long periods of measurement. A further improvement is that in the front chamber of the detector, the measurable components, including interference components, are detected; in the rear chamber, only interference components are detected. By means of subtraction processing, the actual signal obtained is one that has very little interference.

The cross flow modulation type, infrared-absorption technology eliminates the need for adjusting optical alignment.
The APMA-370 uses an AS type (anti shock) interference-compensating detector, and a purified reference gas. The reference gas is generated by purging the sample through an oxidation process, where an oxidizing catalyst burns the CO to CO2. These features eliminate interference from other elements, resulting in highly accurate measurements.
The APMA-370 does not use such components as reflecting mirrors, that attract foreign matter. This means the optical bench stays clean assuring you of stable results over long periods of time.
Principle Cross flow modulation, non-dispersive infrared (NDIR) absorption technology
Application CO in ambient air
Range Standard ranges: 0-10/20/50/100 ppm; 0-5/10/20/50 ppm; auto range ~ manual range selectable; can be operated by remote switching. Optional (measurable) ranges: 4 ranges selectable from 0-100 ppm, within 10 times range ratio; auto range ~ manual range selectable; can be operated by remote switching.
Lower detectable limit:- 0.02 ppm (3 sigma)

The UV fluorescence method operates on the principle that when the SO2 molecules contained in the sample gas are excited by ultraviolet radiation they emit a characteristic fluorescence in the range of 220-420 nm. This fluorescence is measured and the SO2 concentration is obtained from changes in the intensity of the fluorescence. The reactive mechanism is (1) SO2+hν1→SO2* (2) SO2*→SO2+hν2 (3) SO2*→SO+(O) (4) SO2*+M→SO2+M Here, (1) shows the excited state of the SO2 molecules that have absorbed the amount of energy hν1 by ultraviolet radiation. (2) shows the amount of energy, hν2 emitted by the excited molecules as they return to the ground state. (3) shows the decomposition by the light emitted from the excited molecules. (4) shows the quenching, i.e., the energy lost by the excited molecules colliding with other molecules. The APSA-370 uses an Xe lamp as the light source, and the fluorescent chamber design minimizes scattered light. The optical system has been carefully designed with low background light, making it possible to take measurements with a highly stable zero point. In addition, a reference detector monitors any fluctuation in the intensity of the light source. This allows the unit to calibrate itself automatically for sensitivity, resulting in greater span stability.

The APSA-370 uses an innovative detector and a new optical system for low background, high sensitivity (0.05 ppm F.S.), and greatly improved stability.
The fluorescent chamber design gives measurements with minimum influence from moisture
The unit has built-in aromatic hydrocarbon cutter with a selective transmission membrane. This reduces the influence of interference components. Coupled with Horiba’s unique flow-path, it also makes it possible to extend the working life of the cutter and to take measurements effects of sample flow variations.
In comparison with the FPD method, the APSA-370 design is (1) highly selective for SO2, (2) requires no supplemental gas, and (3) gives linear output.
Compensation for the lamp’s luminous energy decline guarantees prolonged calibration stability
The sample inlet has a built-in PTFE filter
Principle UV fluorescence (UVF)
Application SO2 in ambient air
Range Standard ranges: 0-0.05/0.1/0.2/0.5 ppm; auto range ~ manual range selectable; can be operated by remote switching.Optional (measurable) ranges: 4 ranges selectable from 0-10 ppm, within 10 times range ratio; auto range ~ manual range selectable; can be operated by remote switching.
Lower detectable limit:- 0.5 ppb (3 sigma)

Cross flow modulation type, reduced pressure chemiluminescence (CLD). The chemiluminescence method uses the reaction of NO with O3 NO+O3→NO2*+O2 NO2+NO2+hν A portion of the NO2 generated as the result of this reaction becomes NO2*. As these excited molecules return to the ground state, chemiluminescence is generated in the range of 600 nm to 3,000 nm. The light intensity is in proportion to the concentration of NO molecules and by measuring it we obtain the NO concentration of the sample. A DE oxidation converter changes the NO2 to NO, which is measured. In other words, the NO2 concentration can be obtained by the difference between (1) the NOx concentration measured when the sample gas is directed through a converter and (2) the NO concentration measured when the gas is not run through the converter.

The APNA-370 uses a combination of the dual cross flow modulation type chemiluminescence principle and the referential calculation method. This gives it the advantages of the single-detector method plus the ability to do continuous measurements of NOx, NO, and NO2. The design gives great stability and extremely high sensitivity (0.1 ppm F.S.)
Standard equipment includes a drier unit with an automatic recycle function to provide dry ambient air as the ozone source. This makes long-term continuous measurements possible.
The detector uses a silicon photodiode sensor to reduce size and prolong working life.
All the necessary features are built right into a single rack-sized unit, including a reference-gas generator, an ozone-source drier unit, an ozone decomposer, and a sampling pump. No supplemental gas is required.
Principle Cross flow modulation type, reduced pressure chemiluminescence (CLD)
Application NO2, NO and NOx in ambient air
Range Standard ranges: 0-0.1/0.2/0.5/1.0 ppm; auto range ~ manual range selectable; can be operated by remote switching. Optional (measurable) ranges: 4 ranges selectable from 0-10 ppm, within 10 times range ratio; auto range ~ manual range selectable; can be operated by remote switching.
Lower detectable limit:- 0.5 ppb (3 sigma)

Flame ionization detection method (FID) with selective-combustion. The flame ionization detection method (FID) ― used in combination with the selective-combustion system ― utilizes the ionization that occurs as the result of the high-temperature energy from combustion at the tip of the burner jet when organic carbon compounds are introduced into the hydrogen flame. The hydrogen flame is located between two electrodes. When an electrical voltage is applied across these electrodes a minute ion current proportional to the hydrocarbon concentration is produced. This current is monitored by a low leakage amplifier, giving a voltage readout for THC. To measure CH4 the sample gas is passed through the selective catalytic combustion unit (the NMHC cutter), which oxidizes NMHC without oxidizing CH4. This is shown as A below. B represents the THC concentration measured without passing the gas through the NMHC cutter. Thus B- A will give the concentration of NMHC. The final concentration value is calculated using a relative-sensitivity correction coefficient, k, as shown below.

CH4 Concentration A

NMHC Concentration k (B – A)

THC Concentration A + k (B – A)

The APHA-370 uses a combination of the flame ionization detection method and selective-combustion.
This gives it the advantage of the single-detector method plus the ability to perform continuous measurements, free of zero-drift, for THC, NMHC, and CH4. The design gives great stability and high sensitivity (0-5 ppm F.S.)
The APHA-370 has a relative-sensitivity correction function for CH4 and NMHC.
All the necessary features are built right into a single rack-sized instrument, including a catalytic unit for selective combustion (i.e., an NMHC cutter); a catalytic unit for generating reference gas and auxiliary combustion air (standard); and a sampling pump. The only supplemental gas required is H2.
Principle Flame ionization detection (FID) with selective combustion
Application THC, NMHC, and CH4 in ambient air
Range Standard ranges: 0-5/10/20/50 ppmC; auto range ~ manual range selectable; can be operated by remote switching. Optional (measurable) ranges: 4 ranges selectable from 0-100 ppmC, within 10 times range ratio; auto range ~ manual range selectable; can be operated by remote switching.
Lower detectable limit:- 0.022 ppm (3 sigma)

Cross flow modulation type, Non dispersive ultra-violet absorption method (NDUV) The ultra-violet absorption method works on the principle that ozone absorbs ultra-violet rays in the area of 254 nm. Measurements are taken from continuous, alternate injections of the sample gas and the reference gas into the measurement cell, controlled by a long-life solenoid valve. The cross flow modulation method is characteristically zero drift free. A comparative calculation circuit automatically compensates for all fluctuations in the mercury vapour light source and in the detector. This means that, in principle, the APOA-370 makes it possible to carry out zero-span drift free, continuous measurements. In addition, HORIBA’S unique deozonizer for the comparison gas line is unaffected by interference elements or moisture retention, prolonged, stable measurement is possible.

The APOA-370 uses the cross flow modulation type, ultra-violet absorption method in conjunction with the comparative calculation method.
This permits continuous measurement with great stability and high sensitivity (0.1 ppm F.S.)
Horiba’s innovative heated deozonizer provides reference gas by decomposing the O3 found in the sample gas. This has the advantages of (1) reducing the influence from interference, (2) making the monitor insensitive to great changes in moisture content, and (3) prolonging the working life of the monitor.
All gas connections are either PTFE or glass.
Principle Cross flow modulation type, Ultra-violet-absorption method (NDUV)
Application O3 in ambient air
Range Standard ranges: 0-0.1/0.2/0.5/1.0 ppm; auto range ~ manual range selectable; can be operated by remote switching. Optional (measurable) ranges: 4 ranges selectable from 0-10 ppm, within 10 times range ratio; auto range ~ manual range selectable; can be operated by remote switching.
Lower detectable limit:- 0.5 ppb (3 sigma)


CAQMS play a crucial role in assessing air quality, identifying sources of pollution, and protecting public health and the environment. By providing timely and accurate data, CAQMS enable informed decision-making for pollution control measures and regulatory compliance.

CAQMS consists of sensors, analyzers, and data acquisition systems deployed at strategic locations to continuously sample and measure air pollutants. The collected data is transmitted to a central database for analysis, interpretation, and dissemination to relevant stakeholders.

Some key benefits of CAQMS include:

– Early detection of air pollution events
– Assessing the effectiveness of pollution control measures
– Supporting public health initiatives by providing information on air quality trends
– Facilitating compliance with air quality regulations
– Enhancing public awareness and engagement on environmental issues

Yes, CAQMS can be tailored to monitor specific pollutants or parameters based on the requirements of the monitoring site or regulatory mandates. Customization may involve selecting appropriate sensors, analyzers, and sampling methodologies.

Regulatory requirements for CAQMS vary by jurisdiction and may include standards for monitoring methods, data quality assurance, reporting frequency, and permissible pollutant levels. Adherence to these regulations is essential for environmental compliance.

CAQMS undergo rigorous calibration, validation, and quality assurance procedures to ensure the accuracy and reliability of air quality measurements. Regular maintenance and performance audits further enhance the reliability of the system.

Yes, CAQMS data can be integrated with other environmental monitoring systems, such as weather monitoring stations, water quality monitoring networks, and ecological monitoring programs. Integration enables a comprehensive understanding of environmental conditions and interactions.

Selecting the right CAQMS involves assessing factors such as monitoring objectives, site characteristics, regulatory requirements, budget constraints, and vendor expertise. It’s essential to choose a system that meets the specific needs and challenges of the monitoring site effectively.