Dr. Jordan White Talks Particulate Matter and His Experience with Pollution Exposure

Air Pollution Exposure & Human Health

Exposure to air pollution is largely inevitable, I have found from personal monitoring over the past 3 years. From a walk around the neighbourhood, to being downwind of central heating exhausts, to wood-burning and diesel smoke presented unavoidably close. These facts are common for so many people living in the UK and beyond, both urban and rural. Particulate matter is understood to reduce life expectancy by 6 months on average, and most of the short-term acute exposures that contribute to the cumulative burden go unnoticed or forgotten.

Fine particulate matter (PM2.5) has a complex impact on human health. Once inhaled, these elements and compounds may pass through in to the blood stream, scarring blood vessels. Others may become lodged in the deepest parts of the lungs.

It’s critical for the protection of human health that we keep watch on air pollution. It’s a global issue that is as much a social and economic challenge as it is an environmental one. The composition of the air is becoming more complex as our adopted technologies evolve and change. The green revolution does not ensure good air quality.

Low Effort Ways to Improve Air Quality

Air pollution is a societal issue, which harms our surrounding environment. Air pollution is fundamentally a human choice and acceptance that a partaking activity leads to the emission of a compound in to the atmosphere. This may appear a gross over-simplification, but we can all reduce our emissions, be that directly or indirectly.

Monitoring Air Quality with a Zephyr®

Working at EarthSense, I have access to the Zephyr® air pollution monitor, that I use for my work for controlled tests, as well as personal exposure monitoring. I’ve long held the belief that air pollution monitoring networks are insufficient to adequately represent one’s personal exposure. There are certain scenarios that play out, such as smoke from woodburning entering my home, that makes it clear air pollution can be so incredibly localised. I’ve collected primary air pollution data over the past four years (not consistently nor continuously, unfortunately) by carrying Zephyr® air pollution monitors on my back. I’ve also helped others to collect their own measurements, including corporates, local councils, schools, academics, and passionate individuals.

My work commute is a 6-mile cycle journey, a transect through Leicester. I cycle through three parks and I’m otherwise cycling on the road. I see tens of bikes, and hundreds of vehicles. Roads can be treacherous places when exposed to rain, spray, and exhaust fumes; but on a sunny day it’s a delight - it’s a great workout, and there’s a sense of accomplishment. With a Zephyr® air pollution monitor attached to my backpack, I collect information on the air quality (including particulate matter) and my location. The air quality can be poor at all of the expected locations – busy roads, junctions, behind buses and trucks. But how poor? And why should this matter to you?

Findings & Why it Matters

Measured PM2.5 exposure during cycling commute

To the left is an example of the measured particulate matter pollution on my cycle commute to work, and I expect this is an underestimate of reality*. My exposure peaks whilst stopping at busy intersections, the air smells bad, as the hum of vehicles is constant. Note it’s not all bad, cycling through parks is repeatedly shown to be the best way to avoid air pollution in cities. Sometimes it can be as simple as avoiding emission hotspots to reduce exposure. Notice the spatial trends rather than the absolute concentration values, consider the relative risk and exposure on this south to north transect through an urban area.

What you’re seeing below is the average PM2.5 in my vicinity on several journeys on foot, bike, and car over the past 12 months. There’s nothing particularly unique about these journeys, aside from the air pollution monitor sampling the air around me. What do you see? Pollution loading is highly variable both in space and time in the city I live in, and doesn’t always follow your intuition. Leicester is a typical example of a medium-sized city with common urban challenges including overuse of private vehicles, urban sprawl, congested trunk roads at various times of the day, domestic woodburning, the list goes on. On a single journey to the West Midlands wind speeds were high, reducing PM concentrations. On a journey to East Anglia, settled conditions prevailed and some farms were spreading slurry.

Average PM2.5 levels over previous 12 months

Individual actions can reduce emissions and improve our shared environment. Small improvements in air quality can have a big impact. The harms of air pollution are real -between 28,000 – 38,000 deaths each year attributed to long term exposure (https://www.gov.uk/government/news/public-health-england-publishes-air-pollution-evidence-review) in the UK.

* Whilst in motion, the Zephyr® is likely to be less effective at sampling PM