Polluting the Internet

A continent on fire

Will Morgan December 4, 2013

While preparing my poster for the upcoming AGU Fall Meeting, I downloaded some data on fire activity in South America for background on why we are interested in biomass burning in the region. I wanted to quickly check I had the data in the correct format, so I just plotted the coordinates of the fire counts without an outline of South America.

I was surprised to see that the fire locations for August-October 2012 did a great job of outlining South America on their own!

Map of fire locations during August-October 2012 in South America from MODIS data from the Terra and Aqua satellites provided by NASA’s Earth Observing System Data and Information System (EOSDIS).

The data is from the MODIS instrument on NASA’s Terra and Aqua satellites. The data reports fire locations based on measuring the emission of infrared radiation by the land surface from space (like the infrared cameras on your favourite police chase tv show). Any 1km pixel with a fire detected within it is then included in the data – there could be more than one fire within the pixel but the instrument can’t distinguish these. You can find out more information about the technique here.

The widespread nature of the burning across South America is striking. Huge areas of the continent have fires detected within them. This is an annual endeavour with many of the fires started by people for land use change and agriculture. The main “season” runs from August to October, with the peak usually in September. These fires have been occurring for several decades now and they have transformed vast swathes of South America.

The burning produces large amounts of smoke, which can build up and pollute our atmosphere. This has important consequences for regional and global climate, air quality and also ecosystem development. I’m part of a project called SAMBBA, which as well as being a great acronym, is attempting to address some of the aspects of biomass burning that we don’t understand (which is a long list). I’ve written about the project and my part in it here and here previously.

As the map above illustrates, it is quite a big deal in the region. Stay tuned for future updates on the project.

Spoiling the view

Will Morgan November 21, 2013

Probably the most obvious manifestation of air pollution comes when looking out of the window and scanning the horizon – does the landscape go on for miles or is the view reduced? The build-up of air pollution can often dramatically reduce visibility via a shroud of haze.

On a recent trip to the Turkish Mediterranean coast near Antalya, the impact of air pollution on visibility was abundantly apparent. Below are two photographs I took of the view.

View of the Beydağları Mountains in Antalya Province, Turkey. The top image is from the morning of 11th November 2013, while the bottom image is at sunset on the 12th November 2013. Photographs by Will Morgan (me).

The photographs look out to the west from the hotel I was staying in. In the top picture, there is little to see aside from a few tall buildings just observable beyond the trees in the foreground. In the bottom image though, the Beydağları Mountains can be seen, although the view is still hazy. The mountains were approximately 20 miles (32 km) away, so to not be able to see the mountains at all in the top picture requires a large amount of haze. During the ten day trip, views like the top image were far more common.

Antalya province is surrounded by the Taurus Mountains, with the Mediterranean sea to the south, so it forms a bowl-like basin where air pollution can build. It is also very sunny, which gives atmospheric chemistry an extra kick to form air pollution. This cocktail is similar to other pollution hotspots such as Mexico City and Los Angeles.

The other key feature is that temperature inversions are common in Antalya. Typically, the temperature cools in the lowest part of the atmosphere with height but these inversions see a reversal of this trend within the first few hundred metres, which prevents air rising and mixing efficiently. You end up with a basin with a lid on it, so when pollutants are emitted into this, they find it difficult to disperse. This is like mixing a squash or cordial with water and only filling the glass half way with water – the amount of cordial (pollutant emissions) remains fixed but the reduced water level (temperature inversion) sees the concentration rise. Below is a video of a demonstration of temperature inversions, which actually refers to air pollution in Denver.

Click here to display content from YouTube.
Learn more in YouTube’s privacy policy.

Always display content from YouTube

The apparent major source of air pollution in Antalya is the burning of low-quality coal and domestic wood burning, which is particularly prevalent during the winter. I also noticed small fires from agricultural and trash burning during my stay. Summer temperatures typically exceed 30°C, so air conditioning is common rather than central heating systems. Evening and overnight temperatures during the winter drop below 10°C, so some form of heating is required.

The impact of air pollution on visibility is clear in the region and the health implications are also known, with Doctors warning about the risk from air pollution. Just this week, there were news reports warning that Antalya would experience poor air quality this winter.

Tackling the challenge is not easy though, especially given that the geographical and meteorological conditions in the region can’t be controlled. Antalya illustrates the interplay between these natural factors and our own role in pollutant emissions, which presents particular difficulties when trying to improve air quality. This interplay is prevalent across the globe.

Do you think that’s air you’re breathing?

Will Morgan November 1, 2013

Air pollution has been a major issue in our atmosphere since the Industrial Revolution, with the smoke emanating from the many factories leading to smog settling over our cities and countryside.

The author Johanna Schonpenhauer remarked in 1830 that Manchester was:

Dark and smoky from the coal vapours, it resembles a huge forge or workshop.

As industrialisation and motor vehicles spread across the globe, so did the issue of air pollution. Recently, Sydney has been blanketed by dense smoke from bush fires, while a city in Northern China suffered with air pollution levels that were 40 times the safe limit recommended by the World Health Organisation. These are very visible examples of air pollution but often the problem is what we don’t see. Even relatively low levels of air pollution can be harmful to our health, especially if we are exposed for long periods.

Industrial Landscape 1955 by L.S. Lowry (1887-1976). The image depicts a typical industrial scene inspired by the smoke and factories of Great Manchester.
Source: Tate.

Breathing in the fumes from cars, factories and anything else that involves burning fuel can have serious short and long-term implications for our health. Air pollution has been linked to both causing and aggravating heart and lung diseases, which are the leading causes of death worldwide. The World Health Organisation recently declared that air pollution is a leading environmental cause of cancer deaths. During and after major air pollution events, the number of people suffering heart attacks and respiratory problems is known to increase.

The most dangerous type of air pollution is from tiny particles that are suspended in the air, known as aerosols or particulate matter. Outdoor air pollution is estimated to have contributed to around 3.2 million deaths in 2010, which represents 3.1% of all deaths globally. A recent report by the European Environment Agency concluded that around 90% of people living in European cities are exposed to levels of air pollution that are damaging to our health. Closer to (my) home, it is estimated that nearly 29,000 deaths each year in the UK occur due to particulate matter pollution. As well as outdoors, we are also exposed to air pollution indoors; at the global level, about 3.5 million deaths in 2010 were attributed to indoor air pollution. This represents 4.3% of all deaths and ranks third behind high blood pressure (7%) and tobacco smoking including second-hand smoke (6.3%).

Click here to display content from YouTube.
Learn more in YouTube’s privacy policy.

Always display content from YouTube

As the above video from NASA demonstrates, air pollution by aerosols is a global issue.

Air pollution is also known to worsen existing health problems. For example, it exacerbates symptoms of Chronic Obstructive Pulmonary Disease (COPD), which is an incredibly unpleasant respiratory condition where the airways in the lung become progressively degraded over time and there is no known cure. The predominant cause of COPD is tobacco smoking, as well as occupational exposures during activities such as coal mining. Exposure to air pollution further decreases the quality of life for COPD sufferers. Studies indicate that air pollution outdoors, is likely a minor cause of COPD but indoor air pollution using biomass fuels or coal for heating and cooking may be a major cause of COPD in the developing world.

About 50% of deaths from COPD in developing countries are attributable to biomass smoke, of which about 75% are of women.

For non-smokers, indoor air pollution may be the biggest risk factor for COPD globally. Burning of biomass fuel can generate aerosol particulate pollution concentrations that are 2-20 times greater than safety standards specified by the World Health Organisation over a 24 hour period, with shorter term concentrations that are 200 times greater. Remember that this is likely to be fairly routine exposure over prolonged periods (years-to-decades). As someone who studies outdoor air pollution, I can tell you that that is a heck of a lot of aerosol!

Controlling emissions

While the establishment of Clean Air Acts in countries such as the UK and USA in response to heavy urban smog episodes led to major improvements in the levels of air pollution in the atmosphere, there are ongoing issues in these countries still. Air pollution may not be as visible in such countries but it is not an obstacle that has been overcome. The situation is likely to get worse in rapidly developing countries in Asia, South America and Africa. Problems with indoor air pollution are particularly pronounced in these countries also.

Air pollution, both indoors and outdoors, is a major global issue which presents a challenging conundrum for both scientists and policy makers.

—————————————————————————————————————————————————-

A condensed version of this post featured on the Manchester Science Festival blog.

Cooking up some aerosol

Will Morgan October 25, 2013

Ever wondered how many aerosol particles are emitted by microwaving popcorn? Or how polluted a football match is? I’m going to assume your answer is no but it turns out that science has the answer anyway!

Outdoor air pollution is a significant concern but air pollution indoors and in other enclosed spaces is of comparable importance. A US study estimated that around half of our exposure to aerosol particles occurs indoors. Breathing in aerosol particles is known to cause both long and short term implications for our health. Globally, it is estimated that outdoor air pollution accounts for 2.7-3.5 million deaths every year, while indoor air pollution from burning fuels for heating households ranges from 2.6-4.4 million.

Pass the popcorn

As well as household heating, another source of exposure to aerosol particles indoors is from cooking. Just this week, a paper was published on aerosol particle emissions from microwaving popcorn. One of the main findings of the study was that:

The emitted PM concentrations varied significantly with flavour.

Where PM stands for Particulate Matter, which is another term used for aerosol particles. Butter flavoured popcorn (both Movie-theatre-style and standard) was the worst offender, while fat-free popcorn was the lowest (a win-win health benefit for the fat-free version). The study also found that replacing the standard (greasy) packaging with a brown paper bag, often led to dramatic decreases in the amount of aerosol particles produced. One way of reducing the amount of aerosol particles produced could be to change the packaging.

Source: Wikimedia Commons.

While the general premise of the study sounds somewhat whimsical, there is a serious side to the issue. One of the motivations for the study was that the chemicals released by microwave cooking may have led to former popcorn factory workers suffering from lung disease. The study did conclude that microwaving a single bag would not represent a serious health concern, especially when compared to other household sources. However, the risk would be elevated for people working in manufacturing the popcorn or involved with selling it e.g. in a cinema.

Who ate all the frankfurters?

It isn’t just cooking in the home that can lead to exposure to aerosol particles – sporting events are also an issue. Two recent studies investigated air pollution at a football match in Germany between FSV Mainz 05 and VFL Wolfsburg played at the Coface Arena, which is a 34,034 capacity stadium (the official attendance was 31,069). Measurements inside of the stadium showed very clear signals due to the football match, with aerosol concentrations increasing on average by 5 times the normal levels.

The study identified aerosols related to cooking within the stadium, with the build-up to the match seeing a steady increase up to kick-off. The largest peak in cooking aerosol occurred just before kick-off. Two more peaks were also seen at half-time and full-time.

Source: Wikimedia Commons.

As well as aerosols relating to cooking, the study also showed that cigarette smoke was the major contributor to aerosol concentrations within the stadium. Smoking is permitted within football stadiums in Germany, although there are ongoing discussions regarding banning it. The results of the study suggest that this would be a good idea in terms of local air quality within the stadium, especially considering the well-known risks from inhaling cigarette smoke. The level of cigarette smoke aerosol was much more consistent throughout the match compared with the cooking aerosols. The largest peak was actually at half-time – the German fans in this instance preferring a cigarette to food.

Again, the study sounds somewhat whimsical and I’ve been to conferences where the work is presented and people are quite keen to check out something a little different from the usual conference fare but again there is a more serious aspect to the research. The measured concentrations within the stadium often exceeded targets set by the European Union and World Health Organisation that are designed to limit health effects. This presents an issue for public safety and it is worth bearing in mind that the Coface Arena is relatively small compared to many stadiums.

An aerosol cookbook

The studies above highlight just a few instances where cooking can produce significant quantities of aerosol particles, which can harm our health given prolonged exposure. Exposure to aerosol particles from cooking is often increased by the enclosed space that it occurs in. When we are outside, the atmosphere is quite efficient at dispersing and reducing the amount of pollution in our vicinity – this isn’t so easy in an enclosed kitchen (or football stadium).

Aerosols from cooking sources are not always confined to enclosed spaces, as they have been detected in sizeable amounts in outdoor experiments in several locations such as London, Barcelona and Beijing. Compared to other sources of aerosols such as traffic emissions, cooking aerosols may seem like small-fry, but we are all exposed to these types of particles on a regular basis. Nourishing our understanding of these aerosol particles will help to limit our exposure to them.