Pollution by Numbers: A Look at the Figures Behind our Air Quality

In my opening post (see 17th August 2018), I introduced the topic of air pollution and why it’s causing us so many problems. I now want to introduce you to the causes of air pollution, and what we can do to try to prevent it. 

As I mentioned, PM2.5/10, NOX and SOX are some of the most prevalent air pollutants in our atmosphere, and they are emitted from a variety of sources. Unsurprisingly, industry and traffic are a significant source of these pollutants, as large amounts of fossil fuels are burnt in these practices. 

Deep breath for incoming data. 

First off is the number of kilotonnes emitted of each pollutant: 

Below are average annual emissions of NOx, SOx, PM10 and PM2.5, in the United Kingdom, by sector:

As we can see, industry contributed the most to PM2.5 and PM10 emissions in 2016, whilst energy and road transport did so for SOx and NOx emissions respectively. 

Trying to make industry ‘cleaner’ is not an easy task, especially at an individual level. We can make more informed choices about the companies we buy from e.g. sourcing products from companies that have made a commitment to reducing their environmental impacts, and lobbying companies that haven’t. There is a definite trend in companies improving their environmental credentials, such as by investing in carbon offsetting schemes and using recycled materials. Manufacturers also invest heavily in pollution reduction technologies, for example in sulphur dioxide scrubbers that remove SO2 from emitted gases.  

Happily, the transport sector is somewhere we can make a real difference. There are roughly 31 million cars on the roads in the UK today, with about 12.5 million of these being diesel. The cleanest diesel vehicles emit around 500 mg/km. Widely lauded as a 'cleaner' fuel 20-30 years ago due to lower CO2 emissions as compared to equivalent petrol vehicles, diesel has recently come under closer scrutiny by the scientific community and governments alike for other emissions, particularly for nitrogen oxides. Switching to electric vehicles, using public transport and engaging in active commuting methods, such as running or cycling will make a significant difference in overall transport emissions. 

I hope you can appreciate that air pollution is a multi-faceted issue, with many sources. But, creative actions can be taken to try to prevent it, or at least mitigate some of the worst effects. 

As always, I hoped you enjoyed reading this post. Please let me know what you think by dropping a comment below, or by liking the article.

Stay tuned! 

N.B. Emissions data aggregated from the National Atmospheric Emissions Inventory  | Traffic data aggregated from the United Kingdom Department for Transport 

The Air we Breathe

If you’ve read my bio section, been to my Instagram account, or ever spoken to me in real life, you’ll know that my current research focusses on air quality.

Why is this important? 

We breathe when we sleep, we breathe when we wake up, we breathe when we work. We breathe every minute of every day. It’s estimated that we take in roughly 7-8 litres of air per minute, or 11,000 litres per day. That’s a lot of air. 

For something we are exposed to so much, we give very little consideration to what we are actually breathing in. Thankfully, this is something that is changing. For the last few decades, scientists have been busily researching what is being emitted by our vehicles and our industries. In the face of a major public health crisis, governments internationally have begun taking note of our air quality and are slowly, but steadily, taking action. 

Unsurprisingly, some of the world’s most polluted countries are classified as developing, due to poor energy infrastructure, polluting industries and a lack of robust policy frameworks controlling pollution. Measuring particulate matter concentrations is a well-used parameter with which to evaluate air quality. Particulate matter is a type of microscopic pollutant that constitutes a large part of emitted pollutants. They are measured in two diameters, PM2.5 and PM10, denoted in microns. As the particles are so small, they can easily get into the human body, causing cardiovascular, neurological and pulmonary issues. 

The Institute for Health Metrics and Evaluation based at the University of Washington estimate that 5.5 million people die worldwide, each year, from causes directly associated with poor air quality. PM2.5 concentrations in cities such as Beijing and New Delhi can be recorded at 300 µg/m3. This is almost ten times higher than the European standard maximum limit of 25 µg/cm3.

Evidently, this is a huge problem in our developing countries, but it is also becoming a significant issue in developed countries too. London is often regarded as one of the most polluted cities in Europe. PM2.5.concentrations average greater than 18 µg/cm3 in central London, gradually decreasing to lower levels in more suburban areas. Air quality is also measured against other metrics, such as nitrogen dioxide (NO2), sulphur oxides (SOX) and ozone (O3). 

Air pollution is a huge research area and is much bigger than what I can type in a single blog post, so I hope you’ve found this brief overview useful/informative/worrying/all of the above, and I’ll outline some causes and solutions in my next post!

Feel free to drop a comment below and let me know what you think!