Monitoring Dust and Indoor Air Quality

Here are my thoughts regarding ‘Dust and Indoor Air Quality’. I saw a paper many years ago about indoor air quality. It divided up the reasons for complaints, i.e. temperature/humidity 25%, CO2 25%, air velocity 10%. At the time these were the only parameters being measured or capable of measurement and they were conveniently classified in this paper. The paper also suggested that identifying indoor air quality issues was near impossible. Despite measurements and confirmation air quality is OK, people still often complain. Before working for Shawcity I worked at the Churchill Hospital and I was responsible for the heating on the wards. At the time I wasn't familiar with CO2, VOCs and dust etc. I regularly received complaints from Nursing staff that wards were too hot. I would check out the temperature and identify temperatures of 20-21 deg C! More significant was the fact that at these temperatures several patients were too cold".

Dust and Indoor Air Quality

Identifying the causes of poor indoor air quality is challenging. This is due to the need to monitor for several parameters:

 Temperature & Humidity
CO2 Levels
Air Velocity
Presence of VOCs
Dust Levels

Monitoring the levels of CO2

Levels of Carbon Dioxide  CO2 are always a useful and reliable indicator of poor indoor air quality.Typically, levels of CO2will indicate 500-600ppm to confirm a well ventilated and low occupancy work space.

During periods of cold weather and in areas where air conditioning does not exist, levels of CO2 are frequently high. This situation is often due to high occupancy levels with CO2 levels exceeding 1000ppm. However, if the office density is very high, during meetings for example, CO2 levels can climb to 2,000ppm+. Reducing levels usually demands increasing ventilation by opening windows. Reducing CO2 this way is likely to result in further complaints because of the cold.

One possible solution is an air conditioning system offering adequate ventilation with acceptable temperature control. However, what is acceptable to many workers is unacceptable to others. Complaints regarding excessive air movement are not uncommon. Measurement of air velocity is another parameter  that needs to be considered when measuring air quality in the workplace.

Monitoring and measuring the presence of VOCs

It is important to identify the presence of volatile organic compounds (VOCs) as these are frequently  found in many work spaces such as: 

Trichloroethylene is used in Dry Cleaning facilities 
Toluene, formaldehyde and other toxic VOCs are found in Hairdressing Salons and Beauty Parlours
Cleaning and degreasing fluids, printing inks and other VOCs will be found in many offices
Specialist work facilities (Sterilised Area) often have toxic gases such as carbon monoxide (CO), ammonia (NH3) , Ozone (O3)

These toxic gases must be considered and measured to identify the risk of poor indoor air quality and to prevent the potential long term effects of your health.

Measuring Dust Levels
Exposure to Dust in the workplace

All exposure limits are based on personal exposure. At this time there are NO limits for background or static samples. However, to identify dust contamination, static samples provide valuable information to get an idea of general levels of contamination. Dust is split into three size ranges, which have different effects on the respiratory system of a human being. The smaller the particle the deeper into the lungs it can penetrate and most likely settle onto the lining and cause respiratory illness.

Historically respirable dust (PM2.5) has demanded the most attention but in the last few years, particles of larger sizes (PM4 & 10) have been investigated for their effect on the upper respiratory tract (throat, nose and mouth). Inhalable dust includes  particle sizes up to 100 microns. Respirable dust includes  particle sizes up to 10 microns.

Dust Sampling

Measurement of dust levels is very important. Traditionally dust samples have been taken to identify inhalable and respirable dust.

Dust sampling is capturing the contaminant from a known volume of air and measuring the result as a concentration. A pump draws the air through a filter medium, normally a paper filter for dust. The volume of air is measured against the amount of contaminant captured. This gives the concentration, which is expressed as milligrams per cubic metre (mg/m3). Dust is a solid particulate capable of temporary suspension in air.

Personal dust sampling continues to be popular for many organisations trying to identify indoor air quality; real time dust indication is now an accepted technique for static dust sampling. Using a light scattering Photometer allows for dust levels to be continuously monitored and identifies periods when dust levels are exceptionally high. 

Solution for monitoring indoor air quality

The EVM 7 is the perfect solution for indoor air quality monitoring. Continuously measuring up to 7 different parameters:

Carbon Dioxide (CO2)
Volatile Organic Compounds (VOC’s)
Toxic Gas (H2S/CO)
Air Velocity

Dust measurement is available in real time with the ability to configure the detector to identify total, inhalable  or respirable dust  using a dial in impactor. Dust samples can also be simultaneously collected onto a cassette for laboratory testing.

Contact us if you would like to discuss the functionalities of the EVM7

Filter Results

News & Events News Events

Register for a Shawcity account

  • Manage your quotations and track order progress
  • Store your contact and delivery information for easy check-out
  • Use the ‘Add to favourites’ feature to make reordering simple.