All of use in central and northern Europe are suffering from the latest Icelandic insult: rather than settling their debts after their banks collapsed, they’ve sent us bits of less-than-prime Icelandic real estate. You can see some in this view from our flat yesterday:
Under the microscope the dust looks like this:
Source: Volcanic ash scraped from my car (Set) by Interactives. Can you spot the pollen grain?
The upshot of this is much coughing and eye-rubbing around here. But I’ve been rather sanguine about it (or is that the sisu?), because it has been a regular spring event for me.
During the Helsinki winters, it snows (more or less, now), so the council sends out its workmen to spread gravel over the snow, so pedestrians don’t slip and fall. Come the spring, the snow melts and the partially ground gravel and other dusty accumulations are left on the pavements (along with other, more malodorous deposits left by the local canine population). So the council sends out its workers to clean up the grit they had put down a few weeks earlier. this takes a few weeks (there are a lot of roads in Helsinki), during which time the weather conspires against us all by refusing to rain.
Now, this would might us some magnificent sunsets, but in most of Helsinki the trees are in the way.
Not a common site in Helsinki. Especially as it’s a photo of northern Frankfurt
The effect of this is that the concentration of dust particles in the atmosphere rises.
The dangerous ones are called PM10, or particulates (PM10 means that they are less than 10μm in diameter). They can get into the lungs and cause health problems. Perhaps not surprisingly, this has been studied in Helsinki. Eschewing obscurity, Antti Pönkä et al. called their study “Mortality and Air Pollution in Helsinki”. They took data on daily mortality and related it to concentrations of several air pollutants. They found overall effects of particulates, ozone, and nitrogen dioxide on mortality. In particular, there was a 3.5% increase in total mortality and 4.1% increase in cardiovascular mortality for an increase in PM10 of 10 µg/m3: this would equate to an increase of about 9% and 10% for each tick-mark in the figure above.
They also looked at the spring effects:
Every April, there is a significant increase in particulate concentrations in Helsinki. When the snow and ice melt, there is nothing that prevents the dust, which originates from the spreading sand, from causing slipperiness, or prevents erosion on street surfaces caused by studded tires. … In April, the mean daily number of all-cause deaths was 13.8; during the remaining months, it was 13.7. The corresponding numbers of mean daily deaths from respiratory diseases were 1.35 and 1.08, respectively. With respect to respiratory diseases, the relative risk of death related to PM10 was 3.1% (95% CI = 0.4, 6.0; PE= 0.0031; SE = 0.0014; p = .014) higher in April than during other months among persons under the age of 65 y; among the older persons, the corresponding percentage was 9.2% (95% CI = 1.6, 17.4; PE = 0.0088; SE = 0.0037; p = .009). The relative risk of all-cause and cardiovascular mortality, relative to PM10 in April, did not differ statistically significantly from the risk during the other months.
So an effect of the spring dust could be seen on respiratory illnesses. The lack of difference in total mortality is presumably because there are a lot of other things affecting mortality.
One wonders, then, what will be the effect of the Eyjafjallajökull volcano on human health. There certainly isn’t a panic about it, and the advice seems to be to be cautious if you have respiratory problems. According to the WHO, there hasn’t been any increase in pollution (that was up to Friday evening), but my lungs are telling me a different story. Of course, it might be that the concentration of particulates is relatively low, and I’m being affected by larger dust particles. And it will be interesting to see how this develops: as long as most of the ash stays high enough to only disrupt air traffic, I guess we’ll be safe and we can still enjoy the sunsets.
Pönkä A, Savela M, & Virtanen M (1998). Mortality and air pollution in Helsinki. Archives of environmental health, 53 (4), 281-6 PMID: 9709992