Table 1.
Advantages and disadvantages of bioaerosol sampling techniques.
| Bioaerosol sampling techniques | Advantages of the technique | Disadvantages of the technique |
|---|---|---|
| Impaction | Widely used due to economic feasibility Direct collection of microorganisms on to growth medium reduces the post sampling process required Multiple samples can be processed without sterilizing the sampler in between the sampling Inhalable fractions of bioaerosols are sampled by several commercially available impaction samplers |
Restricted only to culture based enumeration method When sampled in highly contaminated site culture plates gets overloaded making enumeration difficult due to overlap of colonies Sampling efficiencies can also be effected by wind speed during sampling |
| Impingement | Technique widely used hence considerable amount of data on collection and efficiencies are available Use of liquid collection medium instead of solid reduced the problem of overloading as well as loss due to physical stress on microorganisms No restriction on the type of enumeration technique used subsequently |
Post collection processes required for quantification Sterilization of sampler required between consequent sampling Due to evaporation of liquid medium problem of loss may be encountered Sampling efficiencies can also be effected by wind speed during sampling Liquid sampling is not compatible with size fractionation |
| Filtration | Simple and economically feasible No restriction on the type of enumeration technique used subsequently Includes the potential for size fractionation |
Post collection processes required for quantification Filters are prone to overloading when sampled in highly contaminated environment Low recovery efficiency due to desiccation of microbes on filters Sampling efficiency effected by wind |
| Gravity | Easily available and economically feasible In same time many samples can be taken from different places without disturbing airflow Comparable and reliable results Reproduce real conditions |
Not always accepted by official guidelines Greatly relies on air currents Bias towards larger particles Weakly correlated with counts of other quantitative methods Weakly correlated with defined volume of surrounding air Sampling time is very high compared to other techniques |
| Electrostatic precipitation | Due to reduced stress on microorganisms while collection recovery efficiency is good Highly feasible for low power monitoring of bioaerosols |
Viability of bacteria is found to be effected by electric charge Limited study done on this technique till date |
| Cyclone | Good collection efficiency because of reduced particle bounce and loss through re-entrainment Sterilization process easy |
Due to evaporation of liquid medium problem of loss may be encountered |
| Thermal precipitator | Good collection efficiency for smaller sized particles and helps in determining size distribution of the particles. Air flows freely through the sampler, thereby pressure drop is small and vacuum source is not needed. |
Collection rate very low. Collection area small. High temperature affects the viability of the microorganisms collected. |
| Condensation technique | Major processing time period is very less Ultrafine bioaerosol particles can also be sampled and detected easily. Viability of the microorganisms maintained throughout. |
Complex system requiring expertise to handle. |