Ambient Air, Environment & Energy

AIRBORNE DAMAGE: THE AROMATIC RED FLAG

The word ‘aroma’ draws out images of sweet smelling scents that attract us.

Flowers, food, perfumes…name them…produce aromas that we simply find captivating and irresistible.

But so does burning of fossil fuels such as diesel and wood.

POLYCYCLIC AROMATICS

Polycyclic aromatics are a special group of chemical compounds produced by incomplete combustion of organic matter such as fuel or wood.

As they’re released into the air, their particulates deposit onto the soil, crops or water.

But nowhere do polycyclic aromatics have a bigger significance than when harbored in the ambient air we breathe.

DIESEL EXHAUST

Picture a crowd of urbanites at a bus stage…

Imagine the ‘vrooming’,the hustle and bustle that goes with vehicles moving in and out of the station…

Picture many of them being ‘washed’ with a concoction that is diesel exhaust while trying to clear the air to catch a glimpse of the other side…

Black soot is everywhere…

The air is thickened not only with particulates but is also laced with a distinctive aroma…

Yes…aroma…

An aroma that is a composition of a mixture of gases…

Sulfur dioxides, nitrous oxides, ammonia, sulfides, carbon monoxide etc…

But within that smelly concoction are polycyclic aromatics.

CARCINOGENS

Polycyclic aromatics are compounds related to benzene known to cause respiratory problems if inhaled continuously over the long haul.

But of greater importance is one going by the name benzo (a) pyrene (BaP).

BaP is categorized by the IARC as a first class human carcinogen not only associated with lung cancer (through the air) but also colorectal cancer (through food).

But the presence of air pollutants such as BaP in diesel exhaust is dependent on other important factors.

ENGINE COMBUSTION EFFICIENCY

A 100% efficient engine is expected to burn all fuel producing only carbon dioxide and water.

But this efficiency is determined by several factors such as the quality of fuel and vehicle manufacture year.

KENYAN CONTEXT

Now picture the passengers we alluded to at the start.

Some of the public transport vehicles we use in Kenya are old, beat up and burn fuel very inefficiently.

But besides that, some of the fuel used is adulterated or from suspect sources.

Infact, some public service operators deliberately choose such fuel because of convenience and low cost.

With that being said, one can only imagine the kind of ambient air the common commuter is exposed to…

Air laced with all sorts of by-products of inefficient combustion of diesel.

This happens on a daily basis with many being exposed even for years without their knowledge.

Perhaps it pays to look afresh into air quality in our cities…

Perhaps county government environmental health departments need to tax old and inefficient vehicles running on our roads…

Perhaps there’s need to do continuous ambient air monitoring in our cities…where are the tinkerers, the innovators who can design air quality instruments which give us real time readouts?

Perhaps, it’s time innovators devise ways of protecting generations especially those living next to highways…

Perhaps it’s time to think critically about household air filters or face masks for those adversely exposed…

IN CONCLUSION

We can choose what to eat…

We can choose what to drink…

But we can’t choose what to breathe.

Let’s guard the quality of our air.