How is atmospheric aerosol linked to air pollution?
The haziness, known as smog, not only ruins a beautiful view but also seriously harms people breathing the air.
In the year of 2012, about 7 million deaths (almost double the population of Alberta!) worldwide were attributed to air pollution.
– World Health Organization Report (2014) –
The haziness is largely attributable to atmospheric aerosol which scatters light and reduces the visibility. Under the context of air quality, atmospheric aerosol is more frequently referred to as PM2.5, representing particulate matter with diameters ≤ 5 μm.
So how does aerosol, or PM2.5, harm our health?
Source: Garieiro and Garieiro, (2013) Vehicle Emissions – What will Change with Use of Biofuel?
As a general rule, the larger the particles, the more easily they will be trapped by the filtration system of our body. The small particles, however, can successfully escape from the filtration and reach deep inside our body. For example, the diagram above shows that PM2.5 is small enough to reach all the way to our alveoli. No wonder it is used as an indicator for air quality.
The scary part is that aerosol can carry harmful chemical substances within itself. As aerosol is penetrating deeply into out body, so are the harmful chemicals carried by aerosol.
What kind of chemicals are damaging our health? And how?
Actually, this is still poorly understood and also is an active research area which the Zhao Research Group will be working on. In particular, we are targeting the following areas:
- Aerosol-bound organic peroxides which are known to cause oxidative stress to the human body.
- Emission from solid fuel combustion(e.g., coal, firewood, crop residues and animal dungs).
- Emissions from cooking activities.