Air Quality Monitoring Methods
Air serves as a major transporter of pollutants and diseases. To determine the quality of air, technicians must first collect particles from the air. Several methods seek to efficiently collect these particles. Scientists must then rely on a variety of devices, ranging from microscopes to chemical catalysts, to identify the contents of the air.
Other People Are Reading
-
Gravimetric Instruments
-
Gravimetric instruments, also known as filter-based instruments, collect particles so that they can be sent to a laboratory for analysis. The laboratory can determine the mass of each kind of particle in the air. This type of analysis requires a lot of labor, since the matter must be shipped to the lab and technicians must spend time analyzing the lab results. Also, these methods take weeks or months to yield results. Particulate matter collection takes 24 hours. There must be consistent airflow through the filters.
Optical Monitoring Devices
-
Optical air quality monitoring devices look at aspects of the atmosphere that are light-absorbing or light-scattering. These instruments cost less money, provide readings instantaneously and consume very little power. They can also be moved anywhere. However, they are less accurate than the filter-based monitoring systems. Based on the consistent effects of particulate matter in the air on light, the monitoring devices can detect changes in the air quality. Then, technicians can bring in filter-based monitoring devices to get a more accurate assessment of the air quality.
-
Specific Sensors
-
When technicians are looking for specific kinds of pollutants, they can use sensors designed specifically to detect and send notifications when air pollution abatement systems fail to remove pollutants from the air, such as with filters designed to remove exhaust released through smokestacks.
Weather Monitoring
-
Weather can have negative effects on air quality. For example, a smokestack releases plumes that the wind can blow towards populated areas, reducing the air quality in those areas. Weather instruments can detect wind direction, wind speed, air temperature, solar radiation, barometric pressure and relative humidity.
Petri Dishes
-
One passive way to detect bacteria in the air is to open up petri dishes and expose them to the air. Then, scientists can incubate the petri dish and count the amount of bacteria that they find in the air. If each petri dish is exposed and incubated using the same time frames, scientists can gauge how many bacterial pollutants float in the air.
Impingers
-
Impingers force air into a liquid medium very quickly. Particles get suspended in the liquid, and technicians can study the suspended particles. When searching for microbial agents, technicians incubate the liquid to encourage growth. This method can sometimes damage some particles, making the results less accurate.
Impaction Systems
-
Particles hit solid surfaces while moving through a tube at a high velocity. Some of the particles fall, landing on a collection plate that technicians can then analyze. To detect microbial agents, technicians incubate the collection plate. These impaction systems take longer to get results than the impingers.
-
References
- Photo Credit Jupiterimages/Photos.com/Getty Images
