Category: Science

I received a notification for the EU Commission that they are preparing a public consultation relating to the EU air quality directives.  I decided to follow some of the links provided, and respond to the consultation, and I was really stunned by a lot of what I found.  These directives are a perfect example of science gone wrong.

I think like nearly everyone else on the planet, I like my clean air.  Remember the war on drugs?  At the time, if you were against the war on drugs, that meant you were FOR drugs, right?  This is a little bit of the same scenario.  If you are against bad science and poorly crafted directives, you must be FOR dirty air, right?

These air quality directives originate from the 1970s, and have been influenced by various international agreements and periodic reviews, but not a lot of science.  The way they function now is the EU requests a list of standards from the WHO, who in turn respond with a list of various pollutants and their corresponding limits.  These limits come with very little justification, and the WHO themselves have no meaningful transparency.  These limits come more or less directly from what has been used in the US over the last half century or so.

The EU then convenes a number of ‘expert panels’, which try to apply some science and justification to these limits, but in reality have no choice but to accept them.

Is it no surprise that these directives then in turn support very specific technologies and industries?

PM2.5

This is the so-called ‘fine’ particulate matter, very small nano-particles 2.5nm in size.  These are not to be confused with ‘coarse’ particles, PM10, 10nm in size.  These particles are all so small they can’t be seen with the human eye, and have proved very difficult to detect and measure.  In fact, we have only been aware of their existence for about 20 years, and only had good methods for measuring them for about 5 years.

There is good science to suggest these are very dangerous, and there is considered to be no safe limit of exposure.  They can cause a variety of health and environmental problems.

There are a lot of sources of these particles, including for example rubber tires driven on asphalt, and almost all sources of combustion.  In fact there are so many sources of these particles, they now realize they are present in combination with almost all other air pollutants.  This also draws into question almost every scientific study on air pollution done before 2013, since they didn’t know these particles existed and couldn’t measure them, they weren’t taken into account.  This had the effect of making all other air pollutants seem more serious than they really were.

About the only place you won’t find large numbers of these particles is the exhaust of diesel engines, because the technology of filtering these particles is considered very good, and modern cars are fitted with these filters.

Alphabet Soup with Nitrogen

Nitrogen is a very mobile element.  What I mean by that is there are a number of compounds containing nitrogen in the environment, these interact with one another, and move around.  For example, in terms of air quality, nitrogen oxide (NO) is often identified as a culprit.  In more general term, NOx is often used, because in fact NO, NO2 and NO3 are all common components of air pollution.  Often associated with this type of pollution is ozone (O3), because rather than forming NO4, you usually end up with NO + O3.

Nitrogen is part of ammonia (NH3), which is naturally occurring.   Animal and human manures are high in nitrogen.  Agricultural fertilizers are high in nitrogen.  The nutrient solutions used by industrial mega-greenhouse operations are a major source of nitrogen based air pollution here in the Netherlands.  All of these sources of nitrogen play a role in nitrogen based air pollution.  In fact, only about 15% of airborne nitrogen comes from vehicle exhaust.

Poor air quality in cities is often associated with nitrogen, because you have for example sewage treatment as a major source, as well as sometimes nearby agriculture, together with vehicle exhaust.  Plants and other vegetation which might potentially remove some of the nitrogen from the air, are often in short supply in cities.

What are the consequences of this type of pollution?  Nitrogen has definitively been identified as a trigger for childhood asthma, but the mechanism for this is poorly understood.  All other studies that have previously identified nitrogen as a danger to human health have been discredited, due to not taking into account PM2.5 (see above).  There are many scientists who do not believe nitrogen is a threat to human health.

In case you might be tempted to think I hate children, let me assure you I care about childhood asthma.  I think this link could shed light on the consequences for others as well, and I hope there is more research on this.  I do think more research is warranted before we commit so many resources to nitrogen based urban air pollution.  I also think research has to consider all sources of nitrogen air pollution, and not just diesel engines.

Effects on Plants

This being a blog primarily about agriculture issues, I have to say something about their conclusions about the effect of nitrogen based air pollution on plants.  I must admit, I laughed really hard when I read this.

This is from the position paper on NO2, dated 1999, on the EU Commission website:

2.3  Effects on vegetation by nitrogen oxides

Nitrogen oxides are absorbed by vegetation in the same way as CO2 through stomata. Nitrogen oxides are dissolved in the stomata cavity water and form nitrite and nitrate, which in turn are reduced to NH3 and eventually incorporated into organic compounds. (e. g. Wellburn, A.R., Wilson, J., Aldrige, P.H. 1980). If too much NO2 is absorbed over time, acute damage may occur in form of necrosis. Biological membranes (e. g. Mudd et al. 1984) and chloroplasts (Wellburn et al. 1972, Lopata & Ulrich, 1975) are assumed to be damaged. Acute effects occur at very high concentrations, which are seldom observed in ambient air, except near very large point sources (Stonybrook Lab., 1994). There is a range of long term exposure effects (Guderian and Tingey, 1987). Up to a certain level, no effects are observed. Above this, NO2 may stimulate growth. However, higher doses will decrease growth in relation to controls.  There is at present a dispute over which nitrogen oxides are the most toxic. Further knowledge is necessary to assess the situation.

This paper then went on to say this science justifies the safe levels of exposure for plants as established by the WHO.

If you’re a gardener, you’ll almost certainly recognize the mechanism of foliar feeding, and here it is in case you need a cited source to it.  I have posted about this before.

So basically, nitrogen fertilizes your plants.  Too much fertilizer kills your plants.  Furthermore, the science of the effects of air pollution on plants stops at the leaves of the plants.  The amount of fertilizer the plants may receive from other sources, for example what is applied by a farmer, is beyond the remit of this paper.

Other Consequences of NOx

Some of the papers on the EU Commission website mention other considerations.  For example, nitric acid is a compound that might be produced, and this in turn can be a threat to historical monuments in the form of acid rain.  I have to admit, this is beyond the scope of what I’ve already researched.

I also want to emphasize that I do recognize nitrogen as a serious environmental pollution, but I don’t think anything can be accomplished by looking at air quality out of context.  All sources of nitrogen have to be considered together, and effects on all parts of the environment have to be considered.

General Thoughts

Since we are in the process of reducing greenhouse gas emissions, and phasing out fossil fuels, you have to wonder why the EU Commission is suddenly paying so much attention to air quality.  It seems the situation will be very different in 10 or 20 years time, and fossil fuel emissions will certainly decrease on their own.

In addition, as we consider ways to remove CO2 and other greenhouse gases from the atmosphere, agriculture will be key to these efforts.  It’s not likely the world will be able to remove and sequester CO2, without regenerative agriculture.  The consequence of regenerative agriculture is a buildup of nutrient rich topsoil, which is composed of nitrogen (N) and carbon (C).  We will sequester both greenhouse gases and air pollution at the same time in this way.

When as a gardener you make compost, you’re participating in this system of regenerative agriculture.  You mix the browns with the greens…