title: Black carbon trends in southwestern Iberia in the context of the financial and economic crisis. The role of bioenergy.
abstract: Since black carbon concentrations are useful to reveal changes in anthropogenic activities, measurements taken from 2007 to 2015 in a Portuguese city are used to assess to which extent the ambient air was impacted by the economic crisis. The average black carbon concentrations are representative of an urban area of small size (1.3 ± 1.3 μg m-3). The highest concentrations are observed in the heating season, being biomass combustion one of the causes for the high values. The daily cycle of black carbon concentrations presents both morning and evening peaks, mainly due to road traffic and, in the heating season, to domestic heating as well. The yearly averaged black carbon mass concentrations decreased 33 % from 2007 to 2015, possibly due to a combination of the economic recession and environmental legislation. The reduction in road traffic led to a decrease in the daily morning peak from 2007 to 2015. This reduction was not followed by a decrease in the evening peak, explained by an increase in biomass burning. Biomass is the cheapest heating fuel in Portugal, and its consumption increased in the aftermath of the economic crisis. The use of bioenergy is an alternative to fossil fuels and presents many advantages. However, energy policies should discourage inefficient biomass burning and promote better ways of exploiting the available energy resources and emission air pollution mitigation strategies.
authors.affiliation: Departamento de Física, Escola de Ciências e Tecnologia, Universidade de Évora, Rua Romão Ramalho 59, Évora, Portugal. imbm@uevora.pt.|LAETA, IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001, Lisbon, Portugal. imbm@uevora.pt.
authors.forename: Isabel
authors.identifier: http://orcid.org/0000-0002-9764-6830
authors.initials: I
authors.lastname: Malico
authors.affiliation: Departamento de Física, Instituto de Ciências da Terra, Instituto de Investigação e Formação Avançada, Universidade de Évora, Rua Romão Ramalho 59, Évora, Portugal.
authors.forename: Sérgio Nepomuceno
authors.initials: SN
authors.lastname: Pereira
authors.affiliation: Departamento de Física, Instituto de Ciências da Terra, Escola de Ciências e Tecnologia, Universidade de Évora, Rua Romão Ramalho 59, Évora, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Costa
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis; D002947:Cities; D057172:Economic Recession; D004784:Environmental Monitoring; D052638:Particulate Matter / Q000032:analysis*; D011174:Portugal; D012621:Seasons; D053260:Soot / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D053260:Soot
keywords: Air quality; Bioenergy; Biomass burning; Black carbon; Economic crisis; Urban environment