Effects of Air Pollution on Materials and Cultural Heritage: ICP Materials Celebrates 25 Years of Research

Figure 6

Annual average HNO₃ concentration at ICP Materials test sites for the three one-year campaigns 2002-2003, 2005-2006, and 2008-2009. The grey squares have been excluded when calculating the linear regression lines 𝑦=0.80𝑥+0.05 (2005-2006 versus 2002-2003), 𝑦=0.80𝑥−0.03 (2008-2009 versus 2005-2006), 𝑦=0.64𝑥+0.02 (2008-2009 versus 2002-2003).

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