Smoke — be it from tobacco, haze, fires, charcoal or wood stoves, or barbecues — has been linked to a plethora of health problems.

But do we know how smoke harms the body? Let's begin by going back to the basics: what is smoke?

Smoke is the concentrated aerosol of airborne particulates, vapours, and gases that are the by-products of combustion or burning.

In an occupational setting, surgeons, firefighters, vehicle-related workers and chefs are among those most commonly exposed to smoke in the workplaces — surgical; fire, wildfire or bushes; exhaust and biomass. 

Wildfires do not only affect the weather and climate but they also releases a large amount of carbon dioxide, carbon monoxide and fine particulate matter into the atmosphere.

This smoke has microscopic particles that can penetrate deep into the lungs, causing health effects from irritated sinuses to lung diseases. The ultrafine particles, which are naked to the human eye, can travel deep into the respiratory tract.

For that reason, smoke from wildfire can cause a broad range of effects on respiratory health and exacerbate medical conditions, including asthma and heart diseases.

Another smoke that we tend to ignore comes from biomass.

Almost half the world's population relies on biomass fuels as they serve as the primary energy source for cooking, heating, and lighting.

The process of preparing wood-fired or smoked pizza, barbecues, and food grilled using biomass fuels are among daily activities that expose people to smoke.

Thus, it is important to note that this form of energy usage is associated with high levels of indoor air pollution.

One of the major pollutants from burning these biomasses is particle pollution, known as soot.

This happens to be the most dangerous, causing strokes and even death when lodged deep in the lungs.

Besides, the smoke released from biomasses usually impacts cardiovascular and respiratory diseases leading to pneumonia, tuberculosis, and chronic obstructive pulmonary disease.

To the majority of those who are not exposed to smoke in occupational setting, exposure to tobacco smoke would be the primary concern.

What makes tobacco smoke harmful is that 60 per cent of the particles inhaled in mainstream smoke are deposited in the lungs, whereas ultrafine particles (

In addition, the gases released from burning tobacco — such as carbon monoxide, hydrogen cyanide and nitrogen oxide — can diffuse into the bloodstream via the alveoli.

One of the most common chemical compounds found in tobacco smoke is polycyclic aromatic hydrocarbons (PAHs), which have been identified as carcinogenic (cancer-causing).

Sidestream smoke, released from smouldering cigarettes between puffs, carries a high concentration of PAHs as well as other chemical constituents compared with mainstream smoke inhaled from the cigarette butt end.

Mainstream smoke— which contains higher levels of toxins, such as cyanides, phenols and organic acids — when exhaled form environmental tobacco smoke alongside sidestream smoke that passive smokers are exposed to.

The combination of particle deposition and inhalation of harmful gases contributes to the damage caused by smoke to the lungs, as well as the full human body via the circulatory system.

These harmful constituents lead to lung cancer, heart disease and stroke.

Contrary to popular belief, nicotine is not the primary source of smoking-related diseases but the smoke generated due to the burning of tobacco.

So what can we do to protect ourselves from smoke? If possible, we should try to eliminate combustion activities entirely using any other alternative processes.

If it is not practical, we can reduce it by improving or modifying the process.

We can also limit our exposure to smoke, such as investing in an air filtration system or having a supply of dust masks (N95).

These can help reduce the exposure of the harmful particulate matter in our surroundings.

On the other hand, smokers are highly encouraged to quit their smoking habit if they are able to.

If they are unable to, they can opt for other alternatives, such as nicotine gum, patch or even switching to smoke-free tobacco alternatives as the first step towards smoking cessation.

The reasoning behind the alternatives is the much better option compared with continuous harm to the person and those around.

The writer is associate professor and occupational safety and health expert, Universiti Putra Malaysia

https://www.nst.com.my/opinion/columnists/2022/05/797643/many-kinds-smoke-and-their-danger-us