Aerosol Science - Science topic
An aerosol is a suspension of fine solid particles or liquid droplets in a gas. Examples include clouds, and air pollution such as smog and smoke. Aerosols have many technological applications including aerosol sprays; dispersal of pesticides; medical treatment of respiratory illnesses and in combustion technology. Aerosol science covers a wide range of topics, such as generation and removal of aerosols, technological application and their impacts on the environment and people.
Questions related to Aerosol Science
In dumping operation of hot wet materials, for example, there is emission of particulate matter together with water vapor, which difficult the measurement of opacity. Is there any way to solve this problem, or other techniques to quantify the PM?
It is said that due to high surface reflectance(bright surface) of snow covered region, estimation of AOD using spectral channels of sensors onboard satellites like MODIS, SUOMI-NPP and Sentinel-3, is limited. I am studying snow melt in Himalayan region where Aerosol Optical depth is crucial for correct estimation of Radiation processes. Are there any methods (or) alternative satellite sensors (or) indirect methods to capture the spatio-temporal variability of AOD over Himalayan snow covered regions?
I'm a PhD student from Germany and I'm working on the toxicity of wildfire particles. We used "Rupprecht & Patashnick" polypropylene filters for our experiment with a ChemVol sampler. They were bought in about 2007 from Thermo Fisher. But they don't sell them anymore. Now we are looking for a similar filter, ideally with a diameter of 150 mm. Our filters are made of 5 layers. The 2 outer layers are coarser than the inner 3. It is at least 2 mm thick and 23x23 cm large.
Do you have any advice on where I could get such a filter?
Please find attached a picture of a particle loaded filter and blank filters.
This was written on the sticker of the filterbag: 759-007955-0010 UM EA V-2 TOP Filter PKG., ULTRAFINE, 10 PER CHEMVOL 01/09/07
Thank you very much!
I am trying to compare the performance of several aerosols measurement techniques including the optical particles counter principles and photometer. The GRIMM records concentration in counts/liter whereas APS in dN/dlogDp, how do I normalize the GRIMM's reading?
I tried to estimate the correlation coefficient of AOD with water precipitation, and AOD with visibility for a short period of time. I found that for a long term data set, researchers have also measured good correlation at polluted cities. I am curious why it gives less correlation value, if we perform our study for a few months data?
1. Which software is comparatively easier to learn in order to analyze the available satellite data for air pollutants such as tropospheric ozone, PM10, NO2 etc.
2. Please recommend a guide to follow as well, if possible.
3. Approximately, how much time will it take to analyze data spanning 6 months?
Does the shape of aerosol affect its activation ability? how to affect?
If there were two particles with same stokes equivalent size, same chemical composition, same mix stated, but only a difference in the shape of particle, whether they have the same critical supersaturation, I wonder?
It would be pretty great if you can share some relevant references.
I need asymmetry factor and single scattering albedo in 385nm. I checked AERONET website but it had these parameters for only 4 specific wavelength. How can I derive them in any wavelength?
i want to import black carbon particles ( micro and nano different size) in cyclone (two phase) dpm fluent.
first question: i should use dpm model or vof?
second question: at entrance cyclone, particle injection type which one is selection for this work?(surface,group,...)
third question: how i make best meshing without icem?
fourth: how is define different size particle in fluent (all size covered)?
I've curious if there is anybody who is familiar with techniques that can image aerosols "real-time" at a nanometer scale. With some preliminary literature review, I see that digital holography has been tested with aerosols, but it seems like it is more applicable for coarse mode particles (diameter > 2.5 um). In the world of aerosol science, TEM is the standard for analyzing morphology of fine particles, but I was wondering if there are any newer technologies that could be incorporated into in-line measurements with something like a single particle soot photometer (SP2). Maybe it's a crazy idea but I'm curious!
I need ftp real time link to download cloud amount and Aerosol optical depth from MODIS. can anyone provide me this?. Instead of ordering data and analyzing data manually is not possible.
Thanks & Regards,
I used WRFChem V3.5.1 to simulate aerosols and gas concentration over China during Nov,2015, and I found that at some grid the simulated SO2 and NO2 concentrations were negative, how can I deal this ?
I am trying to dimension an activated charcoal adsorber to remove ambient VOCs before the air enters a system where I will collect plant volatiles. Can anyone provide information on the required contact time of air and activated charcoal? How much activated charcoal do I need per volume of air?
I am working on a bioaerosol detection project with WIBS-4, also I want to exam the aerosol using fluorescence microscope. I will use an 8 stage andersen impactor to collect the aerosol, but I'm having problem with how to put the samples I collected under microscope. Most other projects I read about were using greased cover glass slide with a single stage impactor to collect the samples used for fluorescence microscope. Can I use glass fiber filter or quartz fiber filter (both are designed for andersen impactor) under microscope? Or do I need to transfer the aerosol sample from the filter to a glass slide, if I have to do the transfer, what's the general procedure for that? Thanks a lot for reading this!
Sea salt aerosol, which originally comes from sea spray, is one of the most widely distributed natural aerosols. Sea salt aerosols are characterized as non-light-absorbing, highly hygroscopic, and having coarse particle size. Some sea salt dominated aerosols could have a single scattering albedo as large as ~0.97. Due to the hygroscopy, a sea salt particle can serve as a very efficient cloud condensation nuclei (CCN), altering cloud reflectivity, lifetime, and precipitation process. According to the IPCC report, the total sea salt flux from ocean to atmosphere is ~3300 Tg/yr (Source: Wikipedia).
In my opinion, the UV-carbon is always greater than BC (880nm), as the manual say, "If sampling a ‘normal’ aerosol, this ‘UV’ result will be closely equal to the ‘BC’ result. If sampling an aerosol that has a strong “blue” component (e.g. fresh diesel exhaust or tobacco smoke), then this ‘UV’ result will be substantially larger than the ‘BC’ result.".
But recently I read one paper titled "Absorption and scattering properties of organic carbon versus sulfate dominant aerosols at Gosan climate observatory in Northeast Asia" pubulished on ACP, the author seperated the data into two groups (370nm and 880 nm), based on the observed maxima daily-averaged value in 370nm and 880nm. That is, the author observed a greater value in 880nm than that in 370nm, which really confused me. I have read the paper several times, and I think I didn't misinterpret what the author's expressing.
how to conduct source apportionment studies for bioaerosols in ambient air? Which models / strategic study should be utilized to conduct the study? can anybody suggest some papers/ articles on the same?
I am curious whether it is possible or not to identify the SOA formation form the time series size distribution data from the chamber experiment.
When we use AMS or ACSM, the term 'non-refractory' is assigned to species that evaporate rapidly at 600 °C under vacuum conditions (e.g. organic matter, NH4NO3 and (NH4)2SO4. And regarding refractory aerosol components, which is not high enough to efficiently vaporize at 600 °C, usually include sea salt, many mineral oxides, elemental carbon (soot) and metals.
I want know what refractory organic aerosol is? Does it even exist? I think so, but could you give an example of their chemical composition?
I'm planning to collect aerosol samples on polycarbonate filters in an adverse environment. High mountain with high humidity and very low temperatures. The collection system will be composed of inlet tube (taking the sample from outside the building), in-line filter holder (located inside a heated building) and air pump. I'm concerned that the high humidity and the difference between inside and outside temperatures can ruin my samples. Is it a good idea to heat the inlet with a heater tape? Any suggestion? I'm not interested in volatile compounds and the filters are to be analyzed by scanning electron microscopy.
Cosmic rays have a slight interaction with clouds. How much significant is that interaction? Can that interaction change the energy budget of Earth and the dynamical processes which interact with the vapor content?
When a nuclear pollution happen, it means that we have air pollution whose form can be considered as nuclear aerosols. Therefore, I want to calculate and work on this topic but I need some optical properties about the particles that consist such nuclear aerosols.
I am trying to estimate the residence time of dust aerosol over the MENA region. I have tried to compute it using the equation T=fct(radius, normalized_radius,Twet). But, Twet varies with the meteorology (3*1e5, 6.91*1e5). From literature, residence time of dust is : 1) varying between ~2 and 8 days, 2) varying between ~2.4 and 12.9 days, 3) global mean is ~2.7 days, 3) average of ~4days, …
Anyone can suggest more precise season specific residence time for the MENA region.
You help is greatly appreciated.
what is a good method to estimate cloud base height using a ceilometer ? any body knows if application of FFT is better after calcluation of CBH from signal on the estimated CBH or is better to do on the ceilometer signal ? any idea about wavelet method on the cloud base heigh?
Most meteorological models that simulate rain do not take a particulate emission inventory as input, as do chemistry-coupled meteorological models. Is there an improvement of rain prediction in the latter case? If meteorological models do not work with particle emissions injected into the atmosphere, do they assume some particles in atmosphere to predict rain?
there are different method to estimate cloud base height , with putting threshold on backscatter signal of ceilometer or estimated visibility using the ceilometer data , now what is the best way to calculate cloud base height from point of view of a pilot. , the extinction coefficient can give vsibility and it is a straight forward method , how one can calculate extinction coefficient accurately , other than klett method ,i need less assumption.
I am using TSI 3076 constant output atomizer to generate particles as given in the manual using NaCl salt conc. about 0.15 g/Lt in clean water. as per the manual peak should show up around 60-70 nm. but i am getting much bigger particles say 0.3 micronmeter. silical gel is dried enough. please suggest what could be the possible reasons.
Posafai et al (2004), argued that to their knowledge, individual-particle studies of coal and oil burning emissions and of urban aerosols do not indicate the presence of tar balls. In my research I have identified spherical organic particles that have similar characteristics to tar balls in smoke emissions from domestic fixed-bed coal combustion.
I need the aerosol particle size from MISR Level 3 data for the North-East India (NEI) (22-30˚N, 88-98˚E) region. From the Monthly global data how can we choose the aerosol small mode particle size for my required region i.e., NEI. Can anyone provide me the methods of analyzing Level 3 MISR data for aerosol small mode particle size. Here I am attaching one of Level 3 aerosol data obtained from MISR.
I can obtain the MODIS derived aerosol small mode fraction from giovanni. But I have no idea how to obtain the aerosol particle size from MISR sensor of Terra satellite. I can not found the latitude and longitude of my required locations. Can anyone provide me a better idea to obtain the particle size from MISR data. I will be grateful to you if you provide me some idea of analyzing the MISR Level 3 data.
According to Müller, D., et al. "Aerosol‐type‐dependent lidar ratios observed with Raman lidar." Journal of Geophysical Research: Atmospheres (1984–2012) 112.D16 (2007). Basically Lidar ratio of 20-30 sr are categorized as marine aerosol, 30-40 sr are for polluted marine aerosol, 40-60 sr are for urban aerosol, 50-80 sr are for wood (biomass) burning aerosol. But how about Lidar ratio smaller than 20 sr and greater than 80 sr? Are there any aerosol types corresponding to these Lidar ratio?
Few studies consider the increased ventilation rate associated with active travel modes. Ventilation rates are important because it affects the amount of inhaled pollutants. There is some research for cyclists but Dirk’s et al (2012) study suggests we lack research on pedestrians:
Does someone has recent research that does provide insight into pedestrian’s ventilation rate?
I need to convert the estimated vertical sandblasting flux (in microgram/m2/s) in to the surface dust concentrations (in microgram/m3). Can anybody help me please..
i want to calculate single fibre filtration efficiency of nanofibers can any one let me know that µ - air dynamic viscisity in kg/m.s @ 25˚c, T- absolute temperature in kelvin @ 25˚c, λ-mean free path of air molecule in meter have standard value or it get varies depends on the particle size. if it has std value please provide me the values with reference article.
I am struggling to calculate the specie specific uncertainty for Polycyclic Aromatic Hydrocarbons in Positive Matrix Factorization version 5. I was reading the guide however, could not understand how to calculate uncertainty. Below is the paragraph given in PMF guide.
"The equation-based uncertainty file provides species-specific parameters that EPA PMF 5.0 uses to calculate uncertainties for each sample. This file should have one delimited row of species, with species names (Table). The next row should be species-specific method detection limit (MDL) followed by the row of uncertainty (species-specific). Zeroes and negatives are not permitted for either the detection limit or the percent uncertainty. If the concentration is less than or equal to the MDL provided, the uncertainty (Unc) is calculated using a fixed fraction of the MDL "
Unc. Aluminium Ammonium Arsenic Barium
2 0.00419 0.0125 0.00098 0.0068
10 10 10 10 10
In above mentioned Table decimal values are MDL value of given species but I don't know that what is "10" and "2", if 10 is uncertainty then how can we calculate it?
Secondly I have 52 weeks samples (1 sample per week and 17 studied species). My question is whether I have to calculate Uncertainty of all species for all sample or I can use only one uncertainty values for all samples.
I am planning to apply suitable spatial-temporal model in gaseous concentrations (NO, NO2, NOx, and CO) measured at 30 monitoring station in Brisbane, Australia. Among them, 25 stations are short term monitoring data, approximately 2 weeks per site and rest of them are EPA monitoring data.
I am using R statistical software and trying to find out any suitable why to find out proper spatial-temporal model.
Previously, I tried R-INLA which did not work well for my purpose.
If you have any suggestion regarding this issue, it would be great help for me.
Has anyone measured or parameterized the atmospheric analogue of well known Mueller matrix for ocean water (Voss and Fry 1984)? I need it for polarization sensitive radiative transfer simulation. I think that the polarization effects of light scattering in the atmosphere, caused mainly by Rayleigh scattering, should be weakened by aerosols, dust and water droplets. But is there any known parameterization (e.g. for optical thickness as a parameter) that results in angular distribution of Mueller matrix?
Has there been any research on the effects of inhalation exposure to Nitrocellulose lacquer and related solvents in Humans? Particularly helpful would be cases involving exposure in woodworking industries (musical instruments, furniture, etc.).
Are there currently any safety standards regarding the use of aerosolized nitrocellulose lacquer in regards to exhausting out the solvent fumes?
I want to atmospherically correct Landsat 8 images with GrassGIS using Aerosol Optical Depth, obtained from MODIS-Data.
My question is about Channel 1 of Landsat 8 supposed to visualise coastal aerosols. I cannot find any evidence that such valuable information, as coastal aerosols ( anyway, such wavelength range), is included in analysis in available soft.
I'm very interested, how it can be used and by what soft? Can it really provide better results?
Designed for research and control aerodisperse contaminants (aerosols) in air or other gases, for the occasional periodic sampling.
AFA filters are made of various modifications with respect to the method of analysis
Air showers (a.k.a. air tunnels, air curtains, air booths) are used in "clean room" design to control the particulate (dust) introduction into the clean room operations. In addition, air showers have been employed to reduce lead contamination of garments at other facilities such as secondary lead smelters and indoor firing ranges. I am looking for any studies/research into their effectiveness or design evaluation. Please advise. Thank you.
What is the mechanism associated for these variation? How does this effect vary for different aerosol type, surface types? Do we have any complete study which explains the mechanism associated in different regions of solar and thermal band?
I have ionic data for aerosol, trace gases and surface snow. The chemical species under study include : NO2, NO3-, SO2, SO42-, Cl. I would like to study the inter-conversion of these precursor species within the air snow boundary layer. How the meterological parameters effect their conversion reactions. Can anyone suggest a simple box model for this study?
I want to analyze inorganic ions in aerosol samples, where the sample size and concentrations both are very small. Please suggest any suitable method for ion analysis other than IC.
I started using the multistage impactor MOUDI and I wonder about the best ideas for the interpretation of the results considering wall losses. Any suggestion or shared protocol is welcome.
For the extraction of organic compounds associated with airborne particulate matter, we used different organic solvents as Benzene, toluene, hexane, dichloro methane etc. Which solvent is suited best for the exaction of organic components associated with particulate matter ?
I want to use a TSI CPC 3025A for some particle measurements. The butanol was removed and the CPC dried for transportation. Now I want to restart the CPC again. Until now the instrument is running for about 3 h but the "liquid level" LED is still off.
Does anyone of you has some experience on how long it usually takes until the LED should turn on? Or what I can do to check if anything is wrong?
What is the IPCC estimate of radiative effect of natural aerosols? I have found their estimate for anthropogenic, but not for natural aerosols.
Aerosol composition measurement date files were downloaded from ARM (Atmospheric Radiation Measurement) website. The files, named as "sgpaerosolbe1turnC1.s1.YYYYMMDD.000000.custom.cdf", contain SSA in red, green and blue wavelength, by which how can I extract aerosol composition, including mineral dust, sea salt, haze, smoke etc?
I’d really appreciate your reply, if possible, you're welcomed to contact me via my email email@example.com.
Thanks a lot!
Aerosol extinction coefficients are usually assumed to decrease exponentially with height, the assumption is approximately appropriate on conditions of long-term averaging but remain skeptical for a specific case. My question is how to judge by other atmospheric elements whether the aerosol extinction profile approximates an exponential distribution of not?
Thanks a lot for your reply!
I am getting decrease of absorption enhancement during aging of biomass burning aerosol. Nothing help on looking size distribution data. Can anyone explain to me why such happening?
US-EPA AP-42 guidance on emission factor uses the concept of wind "fastest-mile" for the estimation of fugitive dust from wind erosion of storage piles.
The definition of "fastest-mile" given in the guidebook is "the wind speed corresponding to the whole mile of wind movement that has passed by the 1 mile contact anemometer in the least amount of time".
I cannot understand what this quantity represents and how it is measured with an anamometer.
Moreover I would like to know if there is a way to convert measured average or maximum hourly wind speed to the fastest-mile needed for estimating the emission.
Although I have been able to get most of the information related to Landsat 8 and its bands from landsat.usgs.gov website, still, I haven’t been able to explore the complete potential of its bands, especially the new Band 1 (Coastal/Aerosol Band : 433-453 nm) and its application in coastal and near shore processes research. I tried searching for previous research articles in using coastal band but I was not quite satisfied with the search results.
There are several supersaturation levels starting from .2 up to 2% in a CCN counter. Which supersaturation level should I choose during an experiment? Is there any review or paper regarding this topic?
For example, AOD reading from x - y represent minor aerosol contained in the atmosphere, AOD reading higher than z means the air is polluted etc...
I'm looking for a method to produce organic aerosol particles in the submicrometer range with a known shell/core morphology. Ideally, core and shell should consist of chemically similar organic compounds with a low vapor pressure and a high viscosity. Are there any methods which do not require more than one SMPS?
If SSA at 1020nm value is much less than other wavelengths, i.e. 400, 500, 680, 870, derived through radiance inversion technique; this variation is observed throughout the year, only the value changes slightly. In other words from 400nm to 870nm there is a modest increase in tendency in SSA values thereafter it reduces sharply in 1020nm wavelength. Please also provide some relevant reference if available.
Health risks caused by short term exposure to ultrafine particles generated by residential wood combustion: A case study of Temuco, Chile http://www.sciencedirect.com/science/article/pii/S0160412014000221
What's the relationship between Volume relative concentration (%) and Particle number relative concentration of the three Basic aerosol constituent (Dust-Like,Water-Soluble,Soot) in the aerosol models, such as Continental, which the Volume relative concentration (%) and Particle number relative concentration is 70, 29, 1 and 2.26278*10-6 , 9.37437*10-1 , 6.25607*10-2 respectively. Or how can I get the Particle number relative concentration when giving the Volume relative concentration (%) of different Basic aerosol constituent?
Maybe someone knows the formula which links dilution ratio and dew point? The calculations of dew point are needed with specific dilution ratio to prevent particulate sample, collected by the DGI, from the vapor condensation. The flue gas temperature is 150 degrees of C.
I want to compare concentrations of aerosol constituents across various data resolutions. Is it better to upscale or downscale the resolution to match that of a reference sensor before comparison?