Regional and hemispheric air quality and its impact on the environment

The research in our group is focused on regional to hemispheric scales, but at the same time also approaching higher resolution (towards the urban background scale). The work includes application and development of a number of themes, ranging from development of emergency preparedness applications and daily air quality forecasts, to assessments of past, present and future air quality and environmental impacts. We focus mainly on surface ozone, particulate matter and deposition of nitrogen and sulfur.

Scheme showing the different research themes related to regional and hemispheric air quality and its environmental effects
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Particulate matter smaller than 10 mm (PM10) causes negative impacts on health and affects the climate since it is a short lived climate pollutant (SLCP). Background concentrations of PM are significant in many regions, including Sweden. We develop and use the MATCH model to describe the background PM concentration and its constituents in Europe and other parts of the world. The work is, for example, used in health impact assessments and the impacts of future scenarios. PM10 and PM2.5 are also daily forecasted by operational MATCH versions maintained by us. Volcanic or radiative particles emitted in volcanic eruptions and nuclear accidents are handled in our systems for emergency preparedness. Projects include for example MACC, ACCEPTED, SCAC.


Surface ozone causes negative impacts on the environment and has adverse effects on human health, and affects the climate since it is a short lived climate pollutant (SLCP). The background level of surface ozone is high in many parts of the world. We develop and use the MATCH model to describe the surface ozone concentration and its impacts on climate, human health and the environment. Further we investigate the impact of future climate and air pollution emission scenarios on the surface ozone concentration, and mapping of the past and present situation. Surface ozone is also daily forecasted by operational MATCH versions maintained by us. Projects include REANALYSIS, IMPACT2C, ACCEPTED, SCAC.


Atmospheric deposition of sulfur and nitrogen causes acidification of ecosystems, whereas deposition of base cat ions can act to neutralize the acidifying compounds. Nitrogen deposition also causes eutrophication of ecosystems, e.g. marine/estuary, forests and meadows. We develop and use the MATCH model to describe the deposition of nitrogen, sulfur and base cat ions and its impacts on the environment. For example we map the past and present situation, and investigate the impact of future scenarios on the deposition. Projects include ECLAIRE, CLEO.

Short-lived climate pollutants (SLCP)

Some air pollutants also impact the climate. These pollutants are called short-lived climate pollutants (SLCP) and include surface ozone and particles. We develop and use the MATCH model to describe the tropospheric concentration of these pollutants. Projects include SCAC.

Emergency preparedness

Volcanic eruptions may case large disruptions in air traffic as well as cause impacts on health and the environment. Nuclear accidents can cause emissions of radioactive nuclides into the air and consequently deposition to the ground, causing long term population dose effects. Governmental agencies may need our support in war situations or acts of terrorism for guidance of hazardous species spreading with the wind. We develop and maintain operational systems based on the MATCH model for the national and international emergency preparedness in cooperation with Nordic and international parties, together with or in support of Swedish governmental agencies. Projects include vulkan, biosmitta, MSB.

Air quality forecasts

Sensitive persons, e.g. children and elderly people, benefit from forecasts of air quality. On days with high levels of air pollution they may choose to avoid exposure by staying indoors or staying away for hot spots of air pollutants. We develop operational forecasting systems for air quality. The development includes data assimilation of air chemistry measurements. Species in special focus are PM2.5, black carbon, NO2 and surface ozone. Two operational forecasting systems are currently operational, the daily forecast of surface ozone on the SMHI web page, and the daily forecast of PM10, PM2.5, SO2, NO2 and surface ozone on the MACC web page. The latter includes an ensemble of models covering Europe, utilizing measurement data through data assimilation. Projects include MACC.

Mapping of the past and present state

Mapping of the past and present air pollution levels is important for the knowledge on the state of the environment. It is also important for the follow up on the effects of legislation enforcement on air quality, to investigate whether emission decrease cause decreasing levels in air pollution. The assessment of the contribution of specific emitters can help with choices in the political process. We develop and use the MATCH model for mapping of the present and past concentration of surface ozone and PM, and deposition of sulfur, nitrogen and base cat ions. Projects include CLEO, ECLAIRE, SCAC, REANALYSIS, the Swedish environmental monitoring.

Future scenarios

Emissions of species causing air pollution may change into the future due to changes in legislation, due to changes in population and activities, and due to climate change impacting natural emissions. This will cause changes to the concentration of surface ozone, PM and deposition of sulfur, nitrogen and base cat ions. Climate change may also have a (small) impact on air pollution levels. We develop and use the MATCH model to investigate the impact of changes in emissions and climate on future air quality. Projects include CLEO, ECLAIRE, IMPACT2C, ACCEPTED.

Environmental impacts

Human activities cause irreversible and reversible impacts on natural ecosystems, crops are reduced both in amount and quality, and forest production is affected. By describing the past, present and future air pollution concentration and deposition we contribute to the knowledge on these impacts. Projects include ECLAIRE, CLEO. 

Focus areas

Many areas in the world are impacted by deteriorated air quality. Many of our studies are focused on Europe and Sweden, where the emissions are fairly well known (with some exceptions). We also model surface ozone, particles and deposition in other parts of the world, e.g. South Africa, India, south-east Asia and Chile. Projects include Sida funded bilateral work.