In my opinion trends (in measurements/environmental modelling) will be created by smaller particles (black carbon or ultrafine) due to health effects, also I think the same about NMVOCs (non-methane volatile organic compounds). NMVOCs are still increasing.

In my view in particulates matter u measure OC, EC and VOCs , its source profile modelling and personal exposure study.

Thanks Damian.

I think ultrafine particles are already known for long time as pollutants which cause damage to health (not an emerging pollutant)

Now what about NMVOCs,  do you know which one are increasing the most  and would deserve better monitoring and that we define standards ?

Alain

Although they have been around for a long time, Perfluorinated organics are really starting make news in Australia. The fact that they are mobile and persistent means that they are now being found virtually everywhere you look (not just old fire fighting sites/airports)....the challenge now is to create a regulatory and management framework to deal with the fall out.

Engineered nanomaterials and nanoparticles pose specific challenges and possible risks to the environemntal health and safety, due to the great diversity of nanomaterials manufactured in industrial settings and used in general life environments. Despite some recent research efforts, nanotechnology progresses are growing faster than the scientific knowledge about the health and safety aspects of nanomaterials. There are still knowledge gaps regarding the impacts of nanomaterials on human health and environment pollution. Thus, it is important that priorities in risk assessment and risk management processes are given, in particular to the large part of nanomaterials for which there is missing, incomplete or uncertain information regarding their potential hazards.

Particulate matter, especially nanoparticles (< 100 nm diameter).

Particulates, especially smog. In Africa, this pollutant is being released day in day out in uncontrollable quantities. I just cited Africa as an example. In the Western countries, its an entirely different headache altogether.

Nanometals and Microplastics are ones of the emerging pollutants of concern that we need to monitor  nowadays.

I would say US EPA has already marked the most important pollutants i.r. the criteria air pollutants

1. Ground level ozone

2.Particulate matter

3. CO

4.Lead

5.SO2

6. NO2

Having said this, we can not forget the precursors for example VOCs.

Monitoring air pollution - or at least working in agencies that do it - for some 20 years it is not that we are introducing new pollutants per se but that our understanding of what we are already producing increases. In mid-1990s, in the UK at least, the bigger worry was PM10 but we're now more worried about PM2.5 with negative health outcomes associated. That's evolving too with a move to worry, as others have noted, about PM1 or ultrafine particulates. Whilst PM is reducing overall, it is the PM10 fraction that is reducing at a higher rate in the UK than the PM2.5 according to the UK's Office of National Statistics at the nation level. I do wonder aloud if the PM1 fraction is also slow to reduce...?

Considering our grouping of PM by its aerodynamic diameter, I am concerned that we are not fully aware of the chemical species constituting 'PM' and how individual components act individually and in combination on human health. This needs more work and so will increase our knowledge of 'emerging' pollutants.

Of particular concern to me is the potential threat of nanoparticules, from whatever source, free in the environment. I echo the concerns of colleagues above.

I would say it depends on the area you are interested in monitoring and the types of emission sources in that area. What are the main industries? What types of fuels are predominantly used? If you are talking about an area dominated by wood cooking and heating, without industry, the pollutants to be monitored would differ from an area that mostly uses natural gas, or one that has chemical plant or refinery for example. As mentioned above, nmVOC are a big one, but if you are trying to decide which to measure, you have to look at the sources. In area of upstream oil and gas acrolein and formaldehyde may be important. With the rise of ethanol in fuel formaldehyde is also of concern, as is acetaldehyde, in areas with lots of traffic-based pollutants. 

Thank you Andrea and all others for pointing out about nanomaterials as emerging pollution but I am interested specifically in air pollution. So what will be the specific impact of nanomaterials on air pollution ? Any references is welcome.

Thanks in advance

I think it is more "nanoparticles", so ultrafine particles that can even be of natural origin, that folks are speaking of. There are potential man-made "nano-materials" in the atmosphere, but they are controversial and related to weather modification. Other sources could be soil-borne dust, etc.