Emerging technologies, emerging markets – fostering the innovation potential of research infrastructures

1 Introduction

Societies are facing a number of environmental grand challenges (ENVRIplus WP 12) interlinking the four domains covered by ENVRIplus. The data provided by RIs through environmental observation is crucial in tackling these challenges. The present research supports this environmental monitoring role by facilitating the supply of novel measurement techniques, able to reinforce the role and impact of RIs.

1.1 Grand challenges

Climate change is a global issue caused by anthropogenic emissions of climate forcers, especially long lived greenhouse gases (GHG). Climate positive feedbacks take place in remote, vulnerable regional ecosystems (e.g. permafrost, Kuhry et al. 2013) mediated by GHGs are a major threat to be investigated and monitored over the long term. Air quality is another biggest issue. Human death associated to air pollution remain at significantly high levels. Ubiquitous aerosols result in complex effects on climate and in adverse health impacts. Further increase of temperatures cause the threat that Amazonian or Siberian forests become more vulnerable to fires. Changes in the environment include changes in the biosphere and, thus, the agriculture and food production (Parry et al. 2004). Due to droughts, most of the farmlands may turn into deserts, this would in turn challenge food security. Contrary to general belief, the agricultural activities will not be expanded to the northern regions in these conditions, because they will be limited with the poor land quality. Meat production, considered as one of the main sources of GHG, does not help to stabilize the situation, as it takes many plant-based nutrients to produce animal-based food. Monitoring environmental parameters of the oceans is another task of great importance. Ocean systems stay in close relation to the other domains and are heavily influenced by any changes of environmental parameters. Thus, rise of the average temperatures will shift the habitual areas of numerous fish species and may influence the procreation of others. Large concentrations of CO2 in the atmosphere above sea waters will decrease the solubility of oxygen in the water preventing sea animals from breathing. At the same time, dissolved CO2 can cause acidification of the water, preventing corals and other sea inhabitants from binding carbon and building shell structures.

1.2 Position of this work in the current landscape

Monitoring environmental parameters and climate change is a complex task which answers grand challenges. It is of crucial importance (Bell and Joseph 2018) for all countries and societies. Development of technologies for such monitoring is in huge demand and driven by numerous factors (fig.1). Among them are demand for the high quality of measurements and development of new types of measurements, reduction of measurements costs, necessity to control the pollution and avoiding the legislative responsibility for the contamination of the environment. Besides, there is a large societal demand based on the ongoing decrease of air, soil and water quality. Environmental monitoring is a complicated activity, because technical requirements for the innovative measurement platforms, systems and sensors can vary significantly across regions and domains. Such variations certainly create unwanted difficulties for the technology producers, especially small and medium enterprises (SMEs), due to their generally limited resources. European businesses are limited in their development in this field due to the inability to overcome the technological differences, to overview the possible paths for development of corresponding markets and to establish the contacts in-between research communities, technology producers and other supporting businesses. This deliverable of ENVRIplus project serves to overpass mentioned difficulties of environmental measurements in Europe. It is aimed to help SMEs, scientific communities and other interested partners to establish fruitful, beneficial collaborations and to understand the possible vectors of development of European environmental measurements and monitoring.

FIGURE1FACTORSINFLUENCINGTHEDEVELOPMENTOFTECHNOLOGY

1.3 Approach of this work: methodology

The aim of ENVRIplus Deliverable 1.1 was to analyze and identify useful technologies (sensors and platform-related) for environmental observations and services with high potential of turning into profitable businesses with the help of Research infrastructures (RIs). The task also aimed to explore the challenges and barriers (technical and market) and initial initiatives in the area. The resulting Deliverable 1.1 shall act as a guideline for the SMEs, inspiring future development and production decisions, as well as for the EU and national decision makers and funding organizations, highlighting specific emerging areas.

The work on Deliverable 1.1 has started from the “white board” exercise in Prague (2015), where participants (all experts from RIs) have first time identified the measurement variables, critical for RIs, corresponding sensors, capable of measuring this variables and SMEs which could produce such sensors. This work has continued at ENVRI weeks until 2017, when the face-to-face meeting between RIs and SMEs was organized in Grenoble in the frame of the 1st EU Environmental Research Infrastructures–Industry Joint Innovation Partnering Forum. The participants (SMEs and RIs members) shared their vision on development of environmental sensors and data communication systems and defined their possible applications.

The deliverable itself has been outlined at a meeting of Theme, work package and task leaders (Ifremer and CEA), in Brest (October 2017), where they discussed the possible structure of the deliverable and its content, main measurement parameters to focus upon and the best ways to show inter-connections between RIs.

Further on, the structure of current deliverable was proposed and discussed at the ENVRIplus meeting in Malaga, Spain, during November 2017. Participants from various RIs agreed on “domain” structure of the document, meaning that the important environmental parameters and technologies for their measurements were sorted by four domains (Atmosphere, Biosphere, Hydrosphere and Solid Earth). In addition, participants decided to add the “market” section to the document, where economy-related questions could have been discussed, such as RIs being innovative partners and contributors to the new technologies, promotion of businesses and market demands. This chapter was meant to provide the relation to the ENVRIplus WP18, “Liaison to users: industry, innovation economics” and identify existing and new user communities interested in application of novel environmental technologies. The timelines for the deliverable preparation and submission were discussed too.

After ENVRIplus meeting in Malaga, the task leader, CEA, presented its vision of the document by practical example, referring to the emerging technologies, relevant for measurements of GHG. This section was chosen by CEA as participant to ENVRIplus on behalf of ICOS. With this piece of work, authors have approached numerous instrumentation experts to know their opinion about existing and emerging technologies for environmental measurements with high potential. Among these experts were the specialists from atmospheric (ICOS, IAGOS, SIOS, ACTRIS) marine (EURO-ARGO, JERICO), ecosystem / biosphere (ANAEE) and solid earth (EPOS) domains. Participants were offered to follow the structure of the document proposed by the task leader and to write similarly about the technologies of interest for their RIs. Besides that, the discussions have touched the important points of availability of new platforms for sensors installations, power supplies for the sensors and international market development of environmental monitoring instrumentation.

During the ENVRIplus meeting in Zandvoort, Netherlands during May 2018, the task leader presented the resulting work to the participants and requested final comments. After the deliverable was commented upon, the document had been modified accordingly and submitted to the internal and external reviewers prior to the submission to the ENVRIplus head office.

1.4 Structure of this document

The document aims at easing the reader’s walk through the presented information.

Chapter one, introduction, shows the background and explains the necessity of this document. It describes grand environmental challenges and consequent necessity in advanced environmental measurements and technologies. It positions the work in the current landscape, explains methodology of work and structure of the document.

Chapter two deals with the technologies for atmospheric measurements, such as measurements of GHG and Aerosols parameters. This chapter analyses the strengths and weaknesses of the technologies, and identifies main providers. Described technologies represent those that are mostly valued by scientists and that are the most wanted or expected to become available on the market in the nearest future. Similar structure is accepted for the chapters three, four and five, corresponding to the measurements of land biosphere, marine, and solid earth parameters.

Each of the chapters two-five is complemented with the section of market overview, where authors talk about main market trends influencing the development of corresponding sensors and main driving forces for such development.

Chapter six describes the on-going development of the new platforms for environmental measurements. Among those are unmanned autonomous vehicles for atmospheric, biosphere and marine measurements as well as wireless sensor networks.

Chapter seven is specifically dedicated to the issue of energy supply, which is a critical issue for the measurements performed in the remote, hard-accessible areas. It describes various means of energy supply, such as solar panels, wind and water turbines, fuel cells and others.

Chapter eight discusses the place of research infrastructures on the technological market. This chapter demonstrates the connections of research infrastructures with the other market players, such as individual researchers, SMEs, large companies and grant holders. It addresses traditional and innovative business models and societies interested in development of new sensors.

Chapter nine gives an overview to the meeting of ENVRIplus participants with the industrial producers of environmental sensors in Grenoble (18-19 May 2017) in order to underline the strong dedication of environmental RIs to the establishment of strong relations with the market players.

Finally, chapter ten provides the final conclusions. It summarizes the trends of technology and market developments, the possible applications of sensor technologies.

It also refers to the Annex 1 table, where authors show the possibilities of cross-utilisation of sensors by various research infrastructures, thus underlining similarities of RIs in the field of technologies.

2 Measurement of atmospheric parameters

2.1 Measurements of Greenhouse gases (GHG)

2.1.1 Why measuring GHG is important

Climate change is mainly caused by accumulation of large excesses of greenhouse gases (GHG) in the atmosphere, mainly CO2 and CH4, but also N2O, SF6 and some others(Table 1).Thus,GHG measurements are needed to understand the drivers of climate change and to help mitigating adverse climate change.

TABLE 1 EXAMPLES OF GREENHOUSE GASES AND THEIR ANTHROPOGENIC SOURCES

Thus, along with the development of societal need for climate action, scientific communities and industrial companies need to take significant efforts to ensure proper measurements and quantifications of GHG fluxes. Current environmental legislation in most-economically developed countries prescribe large emitters to submit an annual emissions report. The data about the emissions can be collected following two main paths. The companies may (1) estimate the emissions based on inventories (typically exemplified by UNFCC reporting and constitutes the basis of INDC in the frame of the Paris agreement), or (2) perform GHG concentration monitoring by means of instruments or sensors combined with inverse modelling to retrieve GHG fluxes (now admitted in the discussion as per UNFCCC methodology. Inventory approaches are widely used nowadays, because they are relatively cheap and do not require complicated installations or service. On the other hand, direct measurements of produced GHG concentration by means of special sensors are highly precise but the finally retrieved GHG fluxes values may have a high uncertainty due to inverse modelling. Assuming that environmental regulations in the EU and worldwide are getting stricter, one can see the instrumental measurements of GHG as the target that GHG producers shall aim. In truth, producers of GHG shall be genuinely interested in accurate measurements of GHG, because it will help them to cope with the strict environmental legislation in the future,reduceoperatingcosts,fuelconsumptionandwasteproduction,etc.

2.1.2 Existing common techniques

2.1.2.1 Overview

There is a number of techniques dedicated to the measurements of GHG concentrations in the atmosphere as well as to measurements of various gaz phase components. Among the mostusedtechniquesare:

• Optical techniques for concentration measurements: Fourier transform infrared spec- troscopy, UV-DOAS, IR camera, solar occultation flux. Laser measurements based tech- niques:tunablediodelaser,cavityringdownspectroscopy,LIDAR(DIAL)
• Non-opticaltechniquesforconcentrationmeasurements:gaschromatography,massspec- trometry,photo-acousticalmeasurements,electro-chemicalmeasurements
• Experimental approaches of analysis: radial plume mapping, tracer correlation,back- groundLagrangianstochastic,

2.1.2.2 FourierTransformInfraredSpectroscopy(FTIR)

FTIR is a broadband optical spectroscopy method, capable of performing real time monitoring of GHG (Schütze et al. 2013; Hase et al. 2015) and volatile organic substances in the air (Christian et al. 2004). FTIR uses characteristic spectral features of individual compounds for the detection and, thus, can detect numerous substances even in highly polluted zones. It can detect and identify the vibrational frequencies of all molecules, capable of absorption of IR energy (Bacsik et al. 2007). FTIR systems are normally represented with two types of systems, namely extractive cell and open-path. For extractive FTIR measurements, the beam is passed through the cell, located in the instrument and containing gas sample of interest. Sample cell path lengths can range from 10 cm to 150 m folded-path cells.

Open path FTIR spectrometers are not equipped with an internal measurement cell. Indeed, the measurement is done along an external optical path. Thus, the path length pay vary from several meters to several hundred meters. Open path FTIR devices are represented by monostatic or bistatic configurations. In monostatic configuration, emitter of light and its detector are located in one compartment, while external light reflectors are used to reverse the light beam from the lights source to the detector. This configuration is beneficial, since both emitter and receiver of light can be connected to the same power source. In bistatic configuration, light emitter and light detector are in different locations. The typical bistatic configuration uses the sun as the light source (e.g. FTIR spectrometer used in the TCCON project) and by measuring thus the direct solar spectra, measures the mean concentration of GHG and other compounds in the total atmospheric column.

TABLE2STRENGTHSANDLIMITATIONSOFFTIR

TABLE3PRODUCERSOFDEVICESFORFTIR

2.1.2.3 Ultraviolet Differential Optical Absorption Spectroscopy (UV-DOAS)

The UV-DOAS is an optical remote sensing technology (Leytem et al. 2009), determining concentrations of gaseous species of interest through measuring the absorption of UV light by chemical compounds in the gas phase and calculating their concentration through Beer- Lambert law (Volkamera et al. 1998). Open path UV-DOAS instrument can be deployed in several modes, namely monostatic, bistatic and passive (EPA Handbook: Optical Remote Sensing for Measurement and Monitoring of Emissions flux, 2011). Constructions of monostatic and bistatic configurations is similar to those of FTIR, described above. Passive configuration uses the ambient light to measure the concentrations of pollutants and does not require a transmitter in its construction. Such configuration is especially suitable for the installation on the balloon stations to measure the concentrations of the pollutants in the atmosphere.

TABLE4STRENGTHSANDLIMITATIONOFUV-DOAS

TABLE5PRODUCERSOFDEVICESFORUV-DOAS

2.1.2.4 Tunable Diode Laser Absorption Spectroscopy (TDLAS)

TDLAS is a family of techniques based on the generation of light beam, characterized with the narrow wavelength and small cross-section area (Laser) (Pattey et al. 2006). This Laser beam is passed through the sample of gas, and detectors determine gas concentration by measuring the amount of absorbed light (Lackner 2007). Measured absorption spectra is matched with the ambient conditions, such as temperature and pressure and, at known effective path length, is used to determine the concentration of the gas. Developed over 30 years ago, near- infrared NIR-TDLAS is a technology with the high technology readiness level, commercially successful at multiple markets. During last years the TDLAS technology was improving, mainly due to the development of new laser sources, such as semiconductor quantum cascade lasers (QCLs) and inter-band cascade lasers (ICLs) (Sonnenfroh et al. 2004, Frish, 2014). These are midinfrared laser sources (Mid-IR) suitable for measurements in the molecular fingerprint spectral region, where absorption line strengths are much stronger than in the NIR region. Because of that, MWIR can be used for detection of complex molecules, difficult to detect with NIR TDLAS. The further efforts are taken to reduce MWIR sensor noise and energy consumption by use of uncooled pulsed or low-power laser sources and small area uncooled detectors. Further reduction of MWIR laser cost by high-volume production, will make MWIR TDLAS sensors commercially attractive and widely used.

TABLE6STRENGTHSANDLIMITATIONOFTDLAS

TABLE7PRODUCERSOFDEVICESFORTDLAS

2.1.2.5 Non Dispersive Infra-Red sensor (NDIR)

NDIR is a technique that has a long track record in this community. In NDIR, an infrared lamp shines the light through a tube filled with sample of air. Gas molecules in the experimental tube absorb the light of the wavelength matching with the size of gas molecules according to Beer-Lambert Law. The detector measures the attenuation of the wavelengths in order to determine the gas concentration. The detector is equipped with the optical filter that removes all light wavelengths, except the wavelengths that are absorbed by the gas of interest (Hummelga et al. 2015).

TABLE8STRENGTHANDLIMITATIONSOFNDIR

TABLE9COMPANIESPRODUCINGNDIR

2.1.2.6 Cavity ring down spectroscopy (CRDS)

CRDS is a technique that is a part of TDLAS family. Contrary to traditional adsorption techniques measuring the absolute change in light intensity after passing the light beam through the certain volume of sample, CRDS technique is based on the measurements of light intensity decay rate, exiting from a high-finesse optical cavity (Berden et al. 2010). By using cavity resonance to reach the light intensity threshold before switching the laser off and measuring the time of light decay. CRDS technique are less sensitive to variations in laser source intensity. In addition, CRDS techniques reveal excellent sensitivity since the reflectivity of the closed optical cavity yields much longer effective sample path length (up to several km). TABLE 10 STRENGTHS AND LIMITATION OF CRDS

TABLE 11 PRODUCERS OF DEVICES FOR CRDS

2.1.2.7 Light Detection and Ranging/Discovery and Launch (LIDAR/DIAL)

LIDAR is the method of remote atmospheric sensing based on the measuring the distance to the target by illuminating the target with the pulsing laser light and measuring the reflected light impulses. LIDAR does not require the establishment of line of sight or installation of retro- reflectors. DIAL is a special application of LIDAR, proposed to locate and measure the concentrations of pollutants in the atmosphere (Browell et al. 1998). The device sends the pulsing laser beam, alternating between two wavelengths, to the region of interest in the atmosphere. Upon reaching the region of measurements, the light of one wavelength is adsorbed by the compound of interest or scattered at reduced intensity, while the light of another wavelength is scattered elastically. This scattered light is collected by receiving optics, analysed and used to determine the concentration and location of the pollutant. The light of the wavelength, scattered at reduced intensity, is used to determine the concentration of substance of interest, while the light scattered elastically is used to measure background light scattering. Location of pollutant can be measured based on the delay of backscattered light to the detector. Raman LIDAR technique is seen as potentially interesting for CO2 measurements. A prototype has been developed in China and is capable to measure CO2 atmospheric concentrations, with night-time measurement limitations (Zhao et al. 2008).

TABLE 12 STRENGTHS AND LIMITATIONS OF LIDAR/DIAL

TABLE13PRODUCERSOFDEVICESFORLIDAR

2.1.3 Emerging techniques for GHG measurements

2.1.3.1 Overview

Development of technologies for GHG measurements is a constant process ongoing in several directions. Significant efforts are dedicated to the development of technologies based on the new physical principles and improving the existing technologies, making them more suitable for the analysis of GHG. Large work is made to improve the detection limits and limits of quantification of existing techniques, making them capable of in-situ and real-time analysis of GHG, working in environmental “dirty” conditions and at wide range of environmental conditions. Below we provide a short summary of techniques, which, we believe, deserve special attention, as well as those that have a large potential for further improvements and developmentsforthepurposeofGHGmeasurements.

2.1.3.2 Laser Dispersion Spectroscopy (LDS)

Traditional spectroscopy techniques detect light intensity to determine the concentration of gas. In contrast, LDS (Daghestani et al 2014) uses the phase of light for these purposes. This makes the LDS technique highly insensitive to the intensity fluctuations. Thus, LDS technique can perform precise real time measurements of trace gas molecules in “dirty” environments, where intensity fluctuations may result from soot, fog or other interceptors of the optical path. LDS technique can detect the contaminants in broad range (ppb to percentage level), since the dispersion approach shows linear response over a broad concentration range.

TABLE14STRENGTHSANDLIMITATIONSOFLDS

TABLE15PRODUCERSOFDEVICESFORLDS

2.1.3.3 Laser Photoacoustic Spectroscopy (LPAS)

Photoacoustic Spectroscopy is a technique, based on the measurements of the acoustic effects, emerging during absorption of light by the analysed matter (gas). Upon radiation of gas by light, the temperature of gas increases, leading to a periodic expansion and contraction of gas volume, synchronous with the modulation frequency of radiation. This generates a pressure wave (sound) that can be detected by the microphone (Dumitras et al. 2007). Intensity of generated sound is proportional to the light intensity, and that is why laser light sources are widely applied in this technique. Even though the technique was applied for atmospheric measurements more than 30 years ago (Meyer, Sigrist 1990), the technology is significantly advancing due to the development of new laser sources (Gondal et al. 2012; Wang and Wang 2016) and other parts of experimental set-ups, such as resonators (Tavakoli et al. 2010).

TABLE16STRENGTHSANDLIMITATIONSOFLPAS

TABLE 17 PRODUCERS OF DEVICES FOR LPAS

2.1.4 Development of GHG sensors market

2.1.4.1 Overview

There is crucial need in the development of technologies and sensors to monitor GHG emissions in the Earth’s atmosphere and especially to monitor industrial GHG fluxes in Europe and worldwide. To fulfil this need, a number of RIs such as ICOS or IAGOS, were established to provide the access to the GHG measurement facilities to all interested communities. Besides that, a large number of companies are providing services and dealing with production of sensors and technologies for GHG measurements. It is expected that co-emergence of denser networks and national/international legal frameworks will expand market opportunities in this field. Below we describe the main international events and legislation acts that will strongly influence the development of GHG sensor market. We also provide an estimateoftheGHGsensorsmarket,thenumbersbeingfoundintheopensources.

2.1.4.2 Developmentofnormativedocumentsrelatedtoclimatechange

1. The well-known Kyotoprotocol, adopted on 11 December 1997 and entered in force on 16 February 2005 set the internationally binding GHG emission reduction targets.
2. In 2007 - 2009, important international conferences in Bali(2007) and in Copenhagen(2009) gave a strong value to the independent information that allows monitoring and verification of GHG emissions with the purpose of their reduction in the future. As a result, at Copenhagen conference (2009), national emission reduction targets were agreed upon by the economically developed countries.
3. In 2010, at climate change conference in Cancun, Mexico, developed countries agreed to strengthen the GHG emissions reporting frequency and to develop low-carbon national plans and strategies. Developing countries were also encouraged to develop such plans and strategies.
4. In 2010 in France, the project of decree for GHG emissionreporting provided a national legal framework to monitor the emissions from large communities and industrial settings. This opened the market for simple and relatively cheap sensors for GHG detection around industrial sites and landfills.
5. In 2012 in Doha Kyoto protocol was extended until 2020.
6. In 2016, Paris agreement on climate change was developed, announcing one of the main aims to make finance flow consistent towards lowering greenhouse gas emissions and climate-resilient development. Later in 2016, both USA and China joined Paris agreement for climate change, the declaration was meant to push other countries to formally join the agreement. As of October 2017, 195 UNFCCC members have signed the Parisagreement and 169 have become part of it.
7. In November 2017 UN FCCC subsidiary body for scientific and technological advice noted the increasing capability to systematically monitor GHG concentrations and emissions,through in situ as well as satellite observations and its relevance in support of the Paris Agreement.

Despite the difficulties that world countries face in negotiations of international agreements for GHG flux reductions, there is a clear progress in development of legislative documents covering this issue. Thus, all EU countries are required to monitor their emissions under the EU’s greenhouse gas monitoring mechanism, which sets the EU’s own internal reporting rules based on international agreements. The reporting covers the emissions of seven GHG from land use, forestry, industrial and energy processes, etc., projections, policies and measures to cut GHG emissions, national measures to adapt to climate change, low carbon strategies, financial and technical support for developing countries as well as national governments’ use of revenues from the accounting of allowances in the EU emissions trading systems. In future, EU plans to cut emissions by 40% by 2030 on 1990 level while the US plans the cut of 28% by 2025 compared to 2205. Other large countries are expected to join these plans too. Up-rising concern of society about the atmosphere pollution will increase the amount of private sector and R&D projects dedicated to the measurements of GHG gases in the atmosphere. In summary, the combination of private national and international requests will broaden the technological market of sensors for GHG monitoring.

2.1.4.3 Market overview by the leading players

In 2010, Chemical and Engineering news (Reisch 2010) asked the representatives of largest producers of GHG sensors about their vision of the market in the future and its size. The representatives of Fischer Scientific estimated the global market as 700 million USD; the estimate included the monitors of acid rain precursors and other pollutants such as lead, ozone and GHG. They said that the sales of GHG monitors could increase greatly if they were added to the governmental networks of ambient air quality monitoring stations. They added that measurements of GHG had only a small share of the market, but they expected the increase in the sales due to the changing legislations around the world. Li-COR Biosciences confirmed that they expected the tangential expansion of industrial markets. The company was strongly counting on their governmental and scientific customers, planning to sell several thousand high precision GHG monitors per year. Representatives of Shimadzu Scientific instruments agreed that academic customers were their main customers, but they also started the work to adapt their products for the industrial applications. Oppositely, Agilent technologies reported that their key customers were industrial players. They have developed their gas chromatograph for easy GHG analysis. Some other companies focused on the infrared absorption GHG measurements. For example, representatives of Picarro said that they were experiencing strong growth, selling their cavity-ring-down technologies to 47 countries around the world. Another instrument maker Los Gatos sold several hundred instruments to measure the CO2 and methane emissions. Los Gatos owns its own CRDS technology. They worked with several large partners like General Electric to deploy their instruments at several industrial facilities. Additional contender, Tiger Optics, claimed to sell over 800 instruments for monitoring industrial gas quality.

2.2 Measurement of atmospheric aerosols

2.2.1 Why measurement of atmospheric aerosols is important

Aerosols are represented by small particles suspended in the atmosphere. If these particles are large and their concentration is sufficiently high we can notice their presence as they scatter light, reduce visibility and cause the redden sunrises and sunsets. There are three known types of aerosols. The first is the volcanic aerosol, which forms after major volcanic eruptions. This type of aerosol is formed by Sulphur dioxide gas, converted to droplets of sulphuric acid in the stratosphere sometime after eruption. Once formed, these aerosols can remain in the atmosphere for about two years. Second type of aerosols is desert dust. Particles of these aerosols are composed of minerals and thus readily absorb and scatter sun radiation. They can be transported over large distances and are believed to be responsible for the formation of storm clouds. Finally, human made sulphate-based aerosols come in the form of smoke originating from burning fossil fuels. The concentration of these aerosols is highest in the northern hemisphere, where the industrial activity is the highest.

It is well known that global climate change is highly dependent on the complex interactions between solar radiation and atmospheric particles, however the magnitude of this interaction as well as its effects are poorly understood. For example, scientists still argue whether aerosols are promoting mostly global warming or global cooling<refhttps://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WGIAR5_SPM_brochure_en.pdf</ref>.Numerous models were developed for better understanding of interactions of aerosol particles with solar and terrestrial radiation, formation of droplets and ice crystals initiated by interactions of aerosol particles with atmospheric gaseous H2O. Many of models and simulations contradict each other, because the parameters of aerosols and their particles are presented in- correctly. This wrong understanding of aerosol properties is a direct consequence of lack of direct measurements and detailed characterization of all aerosol properties. Instrumentation for measurements of aerosol properties can be divided accordingly to the specific characteristics of aerosols they are designed to measure.

• Total number and mass concentration of particles
• Optical properties of aerosol
• Chemical compositeon of the particles
• Size distribution of particles

2.2.2Aerosol common measurement techniques

2.2.2.1 Aerosol number concentrations

2.2.2.1.1 Condensation particle counters (CPC)

Condensation particle counters are normally used to measure the total particle concentrations in aerosol (Kesten et al. 1991). In the continuous flow diffusion CPC, ambient aerosol enters in the device chamber through the inlet and is exposed to a supersaturated vapour of a working fluid. This exposure results in the rapid growth of particles, which after that are exposed to the light of laser. Scattered light of laser is detected by photodiode and the individual particles are counted. Based on the amount of calculated particles and known flow of gas through the system, one can calculate the total number concentration in the aerosol.

TABLE 18 STRENGTHS AND LIMITATION OF CPC

TABLE 19 COMPANIES PRODUCING CPC

2.2.2.1.2 Passive Cavity Aerosol Spectroscopy Probe (PCASP)

PCASP is one of the few techniques dedicated to the measurements of particle number concentrations as a function of size in situ, while being mounted on the exterior of the aircraft (Jonsson et al. 1995). The instrument measures the intensity of light scattered from the individual particles within the aerosol, which pass through a focused laser beam. PCASP collect side scattered light, the collected light being proportional to the to the particle size. Particle number concentration is derived from measured particle size, knowing the particle refractive index, shape and wavelength of the incident light.

TABLE20STRENGTHSANDLIMITATIONSOFPCASP

TABLE21PRODUCERSOFDEVICESFORPCASP

2.2.2.2 Aerosol optical properties

2.2.2.2.1 Photoacoustic Absorption Spectroscopy (PAS)/Photoacoustic Extinctiometer (PAX)

Photoacoustic absorption spectroscopy is the technique that determines the absorption coefficient, through the measurement of sound, produced on radiation of aerosol particles by laser light (Lack et al. 2006). Part of incoming laser intensity is scattered or transmitted, while the remaining fraction is absorbed by either by light absorbing particles or surrounding gas, Absorbed radiation generated particle heating and increase in pressure, detected by sensitive microphone. Photoacoustic spectrometers have fast response time and are well fitted for airborne applications. A similar technique is used by photoacoustic extinctiometers to measure also scattering coefficient.

TABLE22STRENGTHSANDLIMITATIONSOFPAS/PAX

TABLE 23 PRODUCERS OF DEVICES FOR PAS

2.2.2.2.2 Absorption photometers/aethalometer

Absorption photometers (or aethalometers) are devices that determine the light absorption coefficient of aerosols through the measurement of transmissivity of a filter that is gradually loaded with particles (Arnot et al. 2005). They usually employ light sources at several wavelengths from the UV to near IR. Most of the available commercial instruments use systems for automatic change of the filter when transmissivity is below a critical level, while some of them measure also the backscattered light in order to compensate the final measurement for this effect. Some instruments provide directly the value of the equivalent black carbon (in gram per cubic meter) that would produce this absorption, through the assumption of a specific absorption coefficient per unit mass.

TABLE24STRENGTHSANDLIMITATIONSOFABSORPTIONPHOTOMETERS/AETHALOMETERS

TABLE 25 COMPANIES PRODUCING ABSORPTION PHOTOMETERS/AETHALOMETERS

2.2.2.2.3 Nephelometers

Nephelometers are instrument devoted to the measurement of the scattering coefficient of the aerosol particles (Heintzenberg and Charlson 1996). They usually work following the so- called inverse method, that is, they measure the light scattered the particles in a specific direction and that was emitted by a (hemi)-spherical source. It is inverse in the sense that the scattering coefficient refers to the light scattered in any direction and coming from a very narrow one. They can operate at one or more wavelengths, from UV to near IR. They need periodic calibration with standard gas, such as CO2.

TABLE26STRENGTHSANDLIMITATIONSOFNEPHELOMETERS

TABLE 27 COMPANIES PRODUCING NEPHELOMETERS

2.2.2.2.4 LIDARs

Atmospheric LIDAR is a class of instruments that uses laser light to study atmospheric properties from the ground up to the top of the atmosphere (Kavaya and Menzies 1985). Such instruments have been used to study, among other, atmospheric gases, aerosols, clouds, and temperature. The transmission unit consists of a laser source, followed by a series of mirrors, and a beam expander, which sends the collimated light beam vertically up to the open atmosphere. Part of the transmitted radiation is scattered by atmospheric components (i.e., gases, molecules, aerosols, clouds) backward to the LIDAR, where a telescope collects it. The backscattered light is driven to an optical analyser where the optical signal is first spectrally separated, amplified and transformed to an electrical signal. Finally, the signal is digitized and stored in a computer unit. While knowing the aerosol properties (forward problem) and predicting the LIDAR signal is a straightforward calculation, the inverse process is mathematically ill-posed (i.e., non-unique and incomplete solution space), showing a strong sensitivity on input uncertainties.

TABLE 28 STRENGTHS AND LIMITATIONS OF LIDARS

TABLE 29 COMPANIES PRODUCING LIDARS

2.2.2.3 Aerosol chemical properties

2.2.2.3.1 Time of Flight Aerosol Mass Spectrometer (TOF-AMS)

TOF-AMS is used to study the chemical and physical nature of aerosol particles online and is constructed as a combination of AMS vacuum system, particle focusing, sizing and evaporation/ionization components with a compact orthogonal acceleration reflection time-of-flight spectrometer (De Carlo et al. 2006). Aerosol particles in the size range of 0.04 to 1.0 micrometres are sampled into a high vacuum system where they are focused into a narrow beam. This beam is then directed via ionization quadrupole mass spectrometry. Particle aerodynamic diameter is determined from particle time of flight (velocity) measurements using a beam chopping technique.

TABLE30STRENGTHSANDLIMITATIONSOFTOF-AMS

TABLE 31 PRODUCERS OF DEVICES FOR TOF-AMS

2.2.2.4 Aerosol size distribution

2.2.2.4.1 Optical Particle Counters (OPC)

A high intensity light source is used to illuminate the particle as it passes through the detection chamber. The particle passes through the light source (typically a laser or halogen light) and the redirected light is detected by a photodetector. The amplitude of the light scattered is measured and the particle is counted and tabulated into standardized counting bins, after assumption of the refractive index of the particles (Snider and Petters 2008)

TABLE 32 STRENGTHS AND LIMITATIONS OF OPTICAL PARTICLE COUNTERS

TABLE 33 COMPANIES PRODUCING OPTICAL PARTICLE COUNTERS

2.2.2.4.2 Differential Mobility Particle Sizer (DMPS)

Differential mobility particle sizing is an alternative to the optical sizing technique for measurement of submicron aerosol size distributions (Wiedensohler et al. 2012). Differential mobility techniques are able to measure much smaller particles, down to 2.5nm and are not sensitive to differences in refractive index, but are not able to achieve the same temporal resolution as optical instruments, and are also sensitive to variations in particle shape. The Differential Mobility Particle Sizer (DMPS) couples a differential mobility analyser, which classifies charged particles according to their mobility in an electric field, and a condensation particle counter (CPC) to count particles of a specific mobility. Other instruments using variations on this technique include the SMPS and HTDMA.

TABLE 34 STRENGTHS AND LIMITATIONS OF DIFFERENTIAL MOBILITY PARTICLE SIZER

TABLE 35 PRODUCERS OF DEVICES FOR DMPS

2.2.2.4.3 Aerodynamic Particle Sizer

The aerodynamic particle sizer uses the principle of inertia to size particles (Wang and John 1987). In this instrument the particle and sheath flow are constricted through a nozzle, accelerating the airflow. Particles within the airflow are also accelerated, but by different amounts depending on particle surface area and mass, thus particles exiting the jet have a velocity related to their aerodynamic diameter. Aerodynamic diameter is defined assuming spherical particles and unity density. The APS measures particle velocity by passing the particles through two laser beams separated by about 200 microns. A particle passing through both beams produces two pulses of scattered light, the time delay between the pulses being related to the velocity and hence aerodynamic diameter of the particle.

TABLE 36 STRENGTHS AND LIMITATIONS OF AERODYNAMIC PARTICLE SIZER

TABLE 37 COMPANIES PRODUCING AERODYNAMIC PARTICLE SIZER

2.2.3 Emerging technologies for aerosol properties measurements

2.2.3.1 New approach for ice nucleation detection

Budke at al 2008 described a novel device for ice nucleation measurements based on the following principles. Turbulent mixing of cold dry air with warm humid air is performed in the Fast Ice Nucleus Chamber. Resulting ice particles with the size over 4 μm formed during 10 s of experimental time are separated from the droplets based on their individual circular depolarization properties and counted by an optical detector. Biological fraction is measured by special fluorescence channel.

TABLE 38 STRENGTHS AND LIMITATIONS OF ICE NUCLEATION DETECTION

2.2.3.2 Measurements of particle morphology

Aerosol Particle Spectrometer with Depolarization (APSD) measures light scattered at two angles from individual particles and the extent at which these particles rotate the incident plane of polarization when they pass through a focused laser beam. The amount of scattered light is used to determine the particle size using Mie theory, while the direction of scattered light is used to determine the deviation of particles shape from sphere.

TABLE 39 STRENGTHS AND LIMITATIONS OF APSD

2.2.4 Development of market of aerosols measurements

Aerosols impair visibility, affect ecosystem processes and can deposit onto surfaces, damaging materials. They also make an impact on climate change: most particles are reflective and lead to net cooling, while some, especially black carbon particles, absorb energy and promote global warming. Breathing particulate matter/ aerosols can cause coughing, difficulties in breathing, irregular heartbeat, nonfatal heart attacks, aggravated asthma, and decreased lung functioning and general irritation of airways. It can be a reason of premature death of people with heart or lung disease, as well as general decrease of life quality of exposed population.

This is causing increased demand for the medical services and care, meaning additional healthcare expenses for the governments and local authorities. 

Keeping in mind the above mentioned problems, local and state authorities would be the first in the list of parties, interested in monitoring and preventing air pollution with aerosols, both those, appearing due to the natural reasons, for example sandstorms, or forest fires and due the anthropogenic activity. State authorities would also be interested in development the legislation that would oblige large industrial and energy providers to monitor their fluxes of aerosols and analyse their composition. Thus, we believe that the main markets for the aerosol measurement devices will be:

• The countries of Middle East and North Africa (due to the large desert areas and exposure to sand storms)
• Developing countries, producing electricity mostly by burning of fossil fuels (mainly coal)
• Countries, which are in the state of rapid development of infrastructure.

Increased concern of people about their health will increase the amount of private and state- funded research projects, dedicated to the investigations of aerosols, especially in the urban areas. Thus, we also expect universities and private companies to become strong consumers of sensors for aerosol measurement.

Measurement responses of modern devices for aerosol measurements depend largely on aerosol properties including particle shape, composition and density. These parameters may vary significantly depending on the type of aerosol, often remain unknown and bring significant uncertainties to the measurements. Thus, we think that more effort needs to be taken to improve measurement accuracies for realistic atmospheric samples. The measurement of organic species in atmospheric particles requires additional development. Atmospheric aerosols normally include dozens of organic compounds, and only a small fraction (∼10%) of these can be detected and identified by modern analytical methodologies. Total particulate organic carbon mass concentration measurements is another challenge due to the difficulties in determination of evaporative losses during sampling, adsorption of gas- phase organic compounds onto sampling substrates and the unknown relations between carbon mass and mass of the particulate organics. The development of improved methodologies for such measurements should be a high priority for the future. The new models of mass spectrometers capable of measuring the composition of individual particles have recently been developed. These instruments have to be improved to provide quantitative information on species mass concentrations, and more work is needed to perform routine interpretation of large datasets generated during field sampling.