Air pollution can have serious health impact. In this blog i will explain, how to measure Dust Levels and why this is important. Due to the size of the topic I will split it into 3 parts:
What is Air Quality?
Air Quality is an abstract term and usually comprises measuring several indicators:
- Dust Levels – measured in µg/m3, for differently sized particles (See below)
- Volatile Organic Compound Gases (VOCs) – Formaldehide, Benzene, Acetone, etc – measured in ppm (parts per million)
- CO2 – measured in ppm
This blog series will cover the first topic, namely – Dust Levels.
Why Measure Dust Levels?
Compared to measuring CO2, where we can say that levels below 1000 ppm are fine, sadly for Dust this is not the case. World Health Organization advises that in fact there are no safe levels, and even at dust concentrations around 10 µg/m3, increased mortality is reported.
In one of it’s latest updates on the topic from 2013, the WHO states that:
Thresholds: For short-term exposure studies, there is substantial evidence on associations observed down to very low levels of PM2.5. The data clearly suggest the absence of a threshold below which no one would be affected. Likewise long-term studies give no evidence of a threshold. Some recent studies have reported effects on mortality at concentrations below an annual average of 10 µg/m3.
Now about PMxx and “µg/m3” – Dust particles are classified according to their size in microns. Wikipedia has this nice chart
Most available Dust Meters measure the PM2.5 and PM10 sized particles in the air in µg/m3. This comprises the set of Mold, House dust, Ash and others. Particles smaller than PM10 usually you can’t see in the air. So the dust you see from your furniture, pillows and so on is larger and not so problematic. I can’t frame it better than Wikipedia:
The size of the particle is a main determinant of where in the respiratory tract the particle will come to rest when inhaled. Larger particles are generally filtered in the nose and throat via cilia and mucus, but particulate matter smaller than about 10 micrometers, can settle in the bronchi and lungs and cause health problems.
Because of their small size, particles on the order of 10 micrometers or less (PM10) can penetrate the deepest part of the lungs such as the bronchioles or alveoli.
Similarly, so called fine PM, (often referred to as PM2.5), tend to penetrate into the gas exchange regions of the lung (alveolus), and very small particles (< 100 nanometers) may pass through the lungs to affect other organs
There are lot’s of reports from various countries, where increased rate of cardiovascular and respiratory deceases are monitored that correlate with the increased exposure to Dust particles and mostly PM2.5
Unfortunately measuring particles smaller than 100 nm is a complex and expensive task. There are also almost no reports for them. So for now this is a gray zone where we cannot get insight.
Increased Dust Levels are often result of various factors
- Weather – Unfavorable weather conditions (pressure/wind), causing generated dust not to be carried away
- Location – Cities in open plains or close to the sea would seldom experience increased Dust levels due to the air circulation. In contrast cities in valleys are prone to high dust levels at times
- Heating type – Wood and Coal-based heating tends to produce lots of Dust, which is currently the main pollutant. Especially in small cities where there is no traffic, you can still measure dust levels above 500 ug/m3, at times when it is cold outside and people heat their homes (evenings and mornings)
- Traffic – While it is hard to measure and seldom reported – dust produced from traffic and especially Diesel Particle Filters is also an important contaminant
The article in Wikipedia about Health Effects of Particulate Matter is a great source for detailed information.
Another interesting read with lot’s of references to WHO data and statistics is this one: Indoor PM2.5 Under 10: A Noble Goal. It describes how a guy in Beijing (with pollution levels above 300 µg/m3, tries to isolate his home and filter out dust.
Increased Air Pollution from dust can really affect your health. Knowing this and keeping it in mind can help you, because you can take action. There is an increasing number of gadgets that can report it (also online reports for some locations). And also the market for Air Purifiers is blooming. In the following parts i will show you solutions for measuring Dust levels for 20-60 eur and some DIY and commercial Air purifiers – for 20 – 400 eur.